This is a good topic to be pinned, especially for those starting out in looking after their batteries properly rather than the way we've been doing up till now:blush: also very handy to have info at hand without having to dig through the whole forum as it gets demoted by new topics
Find's Treasure Forums
Welcome to Find's Treasure Forums, Guests!
You are viewing this forums as a guest which limits you to read only status.
Only registered members may post stories, questions, classifieds, reply to other posts, contact other members using built in messaging and use many other features found on these forums.
Why not register and join us today? It's free! (We don't share your email addresses with anyone.) We keep email addresses of our users to protect them and others from bad people posting things they shouldn't.
Click here to register!
Need Support Help?
Cannot log in?, click here to have new password emailed to you
Excal Charger.
- Thread starter excalme
- Start date
Critterhunter
New member
Yea, I'd like to see certain always asked topics on the Sovereign put into a sticky in the forum so it's always at the top. They do that a lot in other forums. Heck, they even have a nice sticky in either the Explorer or Etrac forum with various field reports on all the coils available for those machines. That sort of thing is nice to always have handy for both newbies and seasoned users. Who's the moderator in this forum, anyway?
Critterhunter
New member
Wow, I really need to start reading over my messages before posting. Meant to say when you see NO improvement in the capacity after say the 4th or 5th cycle then that's a sure sign that that's as good as it's going to get in terms of exercising the pack. Once the capacity put back into the pack after draining/charging (at the same amp rate mind you, charging at a different rate than the last time might alter the numbers) isn't improving anymore for say a few cycles in a row (like #4 and #5) then you can assume the pack's capacity is as big as it's going to get.
Critterhunter
New member
Thanks, that makes one guy who found it useful. 
Make sure you follow all the links to the various other threads in this forum that we've sprinkled various other battery/charger info into. Read all that and if you survive it then you'll be a armed with just about everything you'll need to know on the topic.
Make sure you follow all the links to the various other threads in this forum that we've sprinkled various other battery/charger info into. Read all that and if you survive it then you'll be a armed with just about everything you'll need to know on the topic.Critterhunter
New member
This link might be of interest. Just trying to keep all these threads attached for future reference by people. I cover some good lipo brand names sold by Hobby King, where the Accucel 6 charger is sold...
http://www.findmall.com/read.php?21,1164138
http://www.findmall.com/read.php?21,1164138
Critterhunter
New member
Kered posted his lipo battery mod for the XS in the mods forum. Figured it deserved notice here since this seems to be the "once stop" battery/charger resource thread. Great job on that mod, by the way!
http://www.findmall.com/read.php?22,1230451
http://www.findmall.com/read.php?22,1230451
Critterhunter
New member
Back in the day when lipos were first getting popular among the RC crowd most lipo chargers didn't have balancing functions, and many lipos didn't even have a balancing plug for that matter. Anyway, my first charger was/is a Celectra which didn't have balancing ability. When flying a plane if the ESC is programmed properly it should cut off the motor at about 9V for a lipo to indicate the battery LVC has been hit. If you reset the throttle you can still power up the motor again for seconds at a time to get yourself in the proper position for landing if need be. However, when drawing a 3 cell lipo anywhere near it's 9V (3V per cell) maximum drainage (to avoid battery damage) cell balance becomes critical. If one cell is 3.2V, one is 2.8V, and the third is at 3.0V then obviously the ESC thinks all is well because the total is still 9V, but you run the risk of damaging any cell below 3V. Also, when charging a lipo each cell should never excede 4.2V (12.60V total for a 3 cell series pack). A charger unable to monitor each cell separately could then do the reverse, charging one to say 4.5V and another to only 3.9V, while the third might be at the proper 4.2V. Again, bad news.
Along comes a company selling a little balancing card called the "Blinky" for about $25. Now any lipo with a Molex balancing plug could be balanced before, during, and after charging. Even though my other two lipo chargers now have balancing functions like the Accucel 6, I still use the card for the first charger. Also, it's still handy to fine tune the cell balance after charging on a balance charger. Once they are taken off the charger the cells can settle a bit and get slightly out of balance. By throwing them on the Blinkey after charging and letting it "tune" the pack for say 30 minutes I can be assured that it's as good as it's going to get. The card balances the cells by draining any cells higher in voltage than the lowest one down to that level. It indicates this by blinking one or two lights on for a 3 cell as it drains that one or two down to the lowest cell voltage of the three. It's kind'a neat to see it work with randomly flashing lights here and there. Another handy feature of this card is that it will quickly check the voltage of all the cells the instant it is plugged in. If they don't all 3 light up for a few seconds on initial connection to it then one of the cells is out of voltage parameters for the lipo. I like this feature because I can check a pack after use for a safe voltage level (that it's not drained down too far) without having to break out my multimeter and check each cell individually. Of course a good charger like the Accucel 6 will show you cell voltage but this is something I can carry in my pocket when say retreiving a plane from the field. If the Blinky tells me it's status isn't good then I'll quickly rush the pack to a charger. The longer a cell sits below it's 3V mininum the more prone it will be to risking damage.
Here's some info on the Blinky. Not at all required if you had the Accucel 6 but a neat little "toy" to use here and there. Besides, it looks cool...
http://www.espritmodel.com/index.asp?PageAction=VIEWPROD&ProdID=4388
Along comes a company selling a little balancing card called the "Blinky" for about $25. Now any lipo with a Molex balancing plug could be balanced before, during, and after charging. Even though my other two lipo chargers now have balancing functions like the Accucel 6, I still use the card for the first charger. Also, it's still handy to fine tune the cell balance after charging on a balance charger. Once they are taken off the charger the cells can settle a bit and get slightly out of balance. By throwing them on the Blinkey after charging and letting it "tune" the pack for say 30 minutes I can be assured that it's as good as it's going to get. The card balances the cells by draining any cells higher in voltage than the lowest one down to that level. It indicates this by blinking one or two lights on for a 3 cell as it drains that one or two down to the lowest cell voltage of the three. It's kind'a neat to see it work with randomly flashing lights here and there. Another handy feature of this card is that it will quickly check the voltage of all the cells the instant it is plugged in. If they don't all 3 light up for a few seconds on initial connection to it then one of the cells is out of voltage parameters for the lipo. I like this feature because I can check a pack after use for a safe voltage level (that it's not drained down too far) without having to break out my multimeter and check each cell individually. Of course a good charger like the Accucel 6 will show you cell voltage but this is something I can carry in my pocket when say retreiving a plane from the field. If the Blinky tells me it's status isn't good then I'll quickly rush the pack to a charger. The longer a cell sits below it's 3V mininum the more prone it will be to risking damage.
Here's some info on the Blinky. Not at all required if you had the Accucel 6 but a neat little "toy" to use here and there. Besides, it looks cool...
http://www.espritmodel.com/index.asp?PageAction=VIEWPROD&ProdID=4388
Critterhunter
New member
Kered, haven't heard you say anything yet on how you are liking the lipo install on your Sovereign. Have you been out using it yet and do you notice any difference in weight while swinging it than using the stock rechargable pack? It should be much lighter but being up under the arm you might not feel much difference. I know I do with my lipos, but that's on a light GT build where any drop in weight can be felt more easily probably.
Done 16+ hours and then checked the voltage, still at 11.4v, and working fine, i know they hold thier charge then drop off fast when close to flat so i charged it again and it took 737ma to full again(only half discharged as its a 1450mah), thats about 46ma per hour(thats less than my test).
I chest mount so i haven't noticed any weight difference but i'm sure there is, if i remember on i'll weigh the box with the different batteries to see the difference and let you know. been full of busy with car but its now sorted(fingers crossed) The main reason for the mod was economical rather than weight(i swing the etrac for 8 hours with the SEF 15x12) $7.60 compared to $50 for double the duration was well worth it.
I chest mount so i haven't noticed any weight difference but i'm sure there is, if i remember on i'll weigh the box with the different batteries to see the difference and let you know. been full of busy with car but its now sorted(fingers crossed) The main reason for the mod was economical rather than weight(i swing the etrac for 8 hours with the SEF 15x12) $7.60 compared to $50 for double the duration was well worth it.
Sorry, I don't intend to hijack this thread. It just looks like the obvious place to ask this question. This thread has become sort of like a battery forum...
I'll use this scenario to demonstrate what I am asking about.
I have a Kaito KA-1103 portable radio. It came with 1300MAH rechargables. When I use the rechargables and they get low the radio just turns off. I've noticed with other radios that have used alkalines that when the alkalines get low the radio does not turn off, the sound just becomes distorted.. especially if I turn it up louder. (I have not tried alkalines in the Kaito but I have some in it now to see what will happen when they get low... i'm tired of being in the middle of something and having the radio just turn itself off).
Why is this?? and is it the same with detectors?
BTW, if you like general coverage radios this Kaito is awesome. It is on par with the Sony ICF-2010 I used to use but cannot get fixed... better than the Hallicrafters SX-43 I grew up with.
Julien
I'll use this scenario to demonstrate what I am asking about.
I have a Kaito KA-1103 portable radio. It came with 1300MAH rechargables. When I use the rechargables and they get low the radio just turns off. I've noticed with other radios that have used alkalines that when the alkalines get low the radio does not turn off, the sound just becomes distorted.. especially if I turn it up louder. (I have not tried alkalines in the Kaito but I have some in it now to see what will happen when they get low... i'm tired of being in the middle of something and having the radio just turn itself off).
Why is this?? and is it the same with detectors?
BTW, if you like general coverage radios this Kaito is awesome. It is on par with the Sony ICF-2010 I used to use but cannot get fixed... better than the Hallicrafters SX-43 I grew up with.
Julien
Good radios and other equipment mostly have a voltage regulator similar to detectors, when the battery voltage gets to a preset low limit the voltage regulator can no longer produce the required voltage to run the appliance and they cut off so as to protect the circuits, circuits can be damaged by too low or too high voltage. Cheaper apparatus just goes on and on till the batteries are flat.
In a radio the speaker is probably the bit that consumes the most, turning it up draws extra current and hence the distortion etc. if you plugged in headphones it would probably run much longer without distortion as headphones use much less current, the same happens in detectors, they run longer on headphones than on the speaker.
Simply put in laymans terms the way i understand things is Voltage regulators have 2 main functions
1, produce a constant stable voltage to critical circuits enhancing component life
2, Amplify the length of time a circuit can be run from a given power source.
Example
take a circuit disigned to run at 10v, inbuilt into compnants of the circuit is a tolerence, it may run from 12v to 8v
ideally a 10v power supply is needed but if you use this voltage from the start the circuit would stop working at 8v so batteries wouldn't last very long
using 12v without voltage regulation the circuit will run but is at the maximum tolerence when the batteries are new and converts the extra voltage to heat(normally) , eventually you get to 10 v and the appliance runs normal, as the battery further discharges below 10v the tolerence is again exercised and the circuit struggles to work, eventually it can't and stops, this constant use of the high and low tolerence limits causes failure in components.
the same circuit with a voltage regulator draws a constant 10v from the 12v batteries,so the batteries discharge at a lesser rate(than if direct), once the 10v is reached all is still ok, below 10v the regulator draws a bit more current to convert to a stable 10v and the batteries will discharge slightly faster, untill the minimum 8v is reached, once the regulator can no longer produce the minimum voltage it cuts off.
from this you can see that the circuit would probably run for longer and also the component tolerences are not being exercised to the full hence longer component life.
this is my understanding of the benefits of voltage regulators, i'm not an electronics buff so don't quote me on the above
In a radio the speaker is probably the bit that consumes the most, turning it up draws extra current and hence the distortion etc. if you plugged in headphones it would probably run much longer without distortion as headphones use much less current, the same happens in detectors, they run longer on headphones than on the speaker.
Simply put in laymans terms the way i understand things is Voltage regulators have 2 main functions
1, produce a constant stable voltage to critical circuits enhancing component life
2, Amplify the length of time a circuit can be run from a given power source.
Example
take a circuit disigned to run at 10v, inbuilt into compnants of the circuit is a tolerence, it may run from 12v to 8v
ideally a 10v power supply is needed but if you use this voltage from the start the circuit would stop working at 8v so batteries wouldn't last very long
using 12v without voltage regulation the circuit will run but is at the maximum tolerence when the batteries are new and converts the extra voltage to heat(normally) , eventually you get to 10 v and the appliance runs normal, as the battery further discharges below 10v the tolerence is again exercised and the circuit struggles to work, eventually it can't and stops, this constant use of the high and low tolerence limits causes failure in components.
the same circuit with a voltage regulator draws a constant 10v from the 12v batteries,so the batteries discharge at a lesser rate(than if direct), once the 10v is reached all is still ok, below 10v the regulator draws a bit more current to convert to a stable 10v and the batteries will discharge slightly faster, untill the minimum 8v is reached, once the regulator can no longer produce the minimum voltage it cuts off.
from this you can see that the circuit would probably run for longer and also the component tolerences are not being exercised to the full hence longer component life.
this is my understanding of the benefits of voltage regulators, i'm not an electronics buff so don't quote me on the above
Critterhunter
New member
Kered, cool! That run time jives with what I figured my new (still on back order) 750MA 3 cell packs (I bought two) will give me in run time. I wanted to be able to do at least two full day (7 or 8 hours) hunts without needing to recharge. I haven't measured the amp draw on my GT but based on what I guessed the amp draw was on how long it runs roughly on a 450ma lipo pack I figured I'd be well into the 17 or 18 hours or more with a 750ma pack. On the GT due to the dimensions of lipos this is the biggest pack I can fit without building my own with the cells configured differently. Still, one of these 750ma packs will only use up about half the battery holder's space so I could probably parallel the two and put my run time at around 40 hours if I wanted to. I could do that with my 450 and 500ma packs but 17 or 18 hours matches the stock rechargable pack and will give me more than enough run time with a 750ma one. I'm just sick of having to re-charge or swap packs with every 7 or 8 hour hunt.
A bit more on regulators- Linear regulators can not increase the voltage. They only can bring it down to a desired voltage level. They do this by wasting the excess voltage as heat on their heat sink. Switching regulators can (I think, been a while since I read up on them) both increase and decrease voltage. To increase it they trade amp ability of the battery for voltage increase. In either case they are much more efficient than linear regulators in that they don't waste excess energy as heat, but rather control the voltage output by "pulsing" the output on and off. This is called Pulse Width Modulation. Light dimmers on walls do the same thing, as do brushless speed controls for RC motors. They'll switch the output voltage on and off at faster or slower rates in order to increase or decreased the voltage "seen" by the device being controlled. Switching regulators are much more noisy than linear and for that reason they usually require extra chokes/capacitors/or other components to cancel out any noise generated.
A bit more on regulators- Linear regulators can not increase the voltage. They only can bring it down to a desired voltage level. They do this by wasting the excess voltage as heat on their heat sink. Switching regulators can (I think, been a while since I read up on them) both increase and decrease voltage. To increase it they trade amp ability of the battery for voltage increase. In either case they are much more efficient than linear regulators in that they don't waste excess energy as heat, but rather control the voltage output by "pulsing" the output on and off. This is called Pulse Width Modulation. Light dimmers on walls do the same thing, as do brushless speed controls for RC motors. They'll switch the output voltage on and off at faster or slower rates in order to increase or decreased the voltage "seen" by the device being controlled. Switching regulators are much more noisy than linear and for that reason they usually require extra chokes/capacitors/or other components to cancel out any noise generated.
Critterhunter
New member
Got my higher capacity lipos in the mail the other day. Should be able to go two or three 8 hour hunts without needing to re-charge, and still way lighter than AAs or the stock rechargable pack.
Critterhunter
New member
Another PM question that I thought would be useful here...
(QUOTE)
Critter,
Check out these batteries and tell me your thoughts ....BTW ...I finally got my order thru to Hobby King after contacting customer service later in the day .....Thanks
(END QUOTE)
http://www.thomasdistributing.com/shop/powergenix-2500-mwhrs-aa-nickel-zinc-rechargeable-batteriesbrfour-pack-p-1905.html?SP_id=&osCsid=a98rm8a91donrsllit8gi3gna7
It's been about 5 years since I investigated similar batteries that claim to use a unique chemistry and so provide 1.5V or higher voltage compared to the "official" 1.2V per cell of nicads or nimhs (I find this to be not true...a good quality nimh or nicad with high capacity will often charge to a much higher voltage than this.). At the time when I was checking these "other" types of rechargeables out similar to what you linked to I found that they didn't have nearly the cycle life of a nimh or nicad, meaning that they could only be charged and drained a substantially less amount of times than nimhs/nicads. Not sure if that's improved over the last five years but I would think that if that has been corrected you would be seeing these cells for sale more than your average nimh/nicad packs.
Remember that increased voltage does NOTHING for a detector's performance these days. They have voltage regulators in them that will only allow a certain amount of voltage to reach the detector's circuit. For instance, the machine may require say 9V to run on in a steady state but it's battery pack might be 8 AAs (12V). The regulator takes that 12V and drops it down to what the machine requires to run steadily on. Otherwise the performance or stability of the machine would be constantly fluctuating as the voltage level of the battery dropped while draining.
Some people also confuse the capacity (commonly stated in milliamps) of the battery and think that this allows you to supply more amperage to the detector. What you have to understand is that any device only draws exactly what it needs in amps, regardless of battery capacity. If for instance the device draws half an amp to power it's self increasing the size (or capacity) of the battery does nothing to change that. I've compared it this way before but I like the old saying....It doesn't matter if the battery is the size of a pack of smokes or the size of a house, the device will only draw the amount of amps it needs to run it's self and nothing will change that.
The only thing that must be paid strict attention to is the voltage parameters of the device you plan to power. If it wants a 12V battery then you risk damaging the unit if you try to supply it with more than that. Linear regulators shunt off the extra voltage a battery is providing by turning it into heat. If you supply a voltage too high then the regulator is either going to burn up or if you are lucky it will shut down on what's called an internal thermal overload. If that's the case then it will start working again once it cools down properly. As you can see, though, providing more voltage will do nothing for most devices and in particular modern metal detectors.
One other thing about battery capacity. It's capacity is directly related to run time. The other the milliamps the more run time you will get on the detector, NOT the more power the detector will have as so many commonly confuse things. It just means longer run times.
The only way capacity directly related to amp draw is in that it has some impact on how much current (amps) it can safely supply to a device. It may seem a little confusing but just follow me here as I try to explain it. It's rather simple to understand but I'm good at over complicating explanations...
Some batteries are rated by what is called a "C" rating. What this means is how much in the way of amps the battery can supply. If the device being powered by the battery wants to draw more amps than the battery can handle then the battery will get very hot, have a short life, or worse. Let's take a 2200ma lipo battery as an example. In this example the RC plane motor I'm powering with it wants to draw 40 amps. The lipo is rated at 10C. 10x2200ma=22 amps. As you can see the battery will be unable to hold up under that kind of amp draw. Bad things might happen or at the very least the battery will have a very short life. Now take another 2200ma lipo as another example. This one is rated at 20C. 20x2200ma=44 amps. This battery can handle the amp draw of that motor. However, most play it safe and easy on their batteries by never drawing more than 80% of the amp ability the have. This insures longer battery life. Lipos usually have two "C" ratings. One is continuous (meaning non-stop amp draw ability, in this case 20C for the above battery), the other is "burst C" rating.
Burst C means how much amp draw the battery can sustain for say 30 seconds at a time. A 20C battery might have a burst rating of 30C, so the above battery would then be able to handle 66 amps for thirty second durations. Any longer than that and you risk damaging the battery. Burst capability is useful in RC in that it allows you to say go to full throttle on a plane for 30 seconds at a time, throttling back some after that to give the battery time to rest and cool down.
In the non-RC world the same example might be used for your auto's battery. It might have what is called "Cranking Amps". That's how much current the battery can supply for short periods of time to run the starter to get the engine going. Once the starter is done doing it's job obviously it isn't running anymore, so the amp draw goes way down and the normal "continuous" amp draw of that battery is only being used to power the engine and other devices in the car. As a side note, once a car is started it mainly runs off the power from the alternator. It also re-charges the battery as it runs so it's ready to start the engine again next time. If the alternator stops working then the car draws it's power only from the battery. In that case if you see the "battery" light come on on your dash then if you're lucky you've got about 40 miles or so of run time to power the engine's ignition and other things until the battery drains to low. A sure sign of the alternator going bad while driving (besides the dash light) is things like the wipers will start slowing down and lights will dim. Find a gas station quick or you're going to be stranded.
One more thing about capacity to sum things up. You might have realized by the above examples of "C" ratings that besides it's amp draw rating the battery's ability to deliver amps is directly impacted by the capacity. As an example, a 10C battery at 1000ma can deliver 10 amps. Conversely, a 1000ma battery rated at 20C can deliver 20 amps. But, as said, that does not increase the performance of a device so long as it's needed amp draw is lower than the 10 amps of the first battery. If it drew 9 amps then I would say you are pushing it with a 10C 1000ma battery and being hard on it. Either buy another 1000ma battery rated at a higher C rating or buy another 10C battery to increase it's amp delivering ability that way. For example, a 10C 1500ma battery can deliver 15 amps and so would probably be a more wise option for that device which wants to draw 9 amps. The golden rule in RC is 80% of the continuous C rating, so if the battery can deliver 10 amps in total continuously I would use it to run anything that will draw more than 8 amps.
OK, yet again "one more thing" here while I'm at it...The voltage input of many DC devices is fairly diverse, even in things that don't have regulators. Your typical device X (use your imagination) that runs on batteries might call for say a 9V battery. In reality, though, it might very well be able to run on anything from 6 to 15 volts and still work fine. Lower voltage isn't going to break it (it just won't work), but something too high can very well burn the regulator up (if it has one) or the circuit inside it's self.
As a final bit of info on regulators most are linear and because they turn the extra voltage into heat they are not very efficient. Switching regulators pulse the voltage output to the device to control the voltage output and so are much more efficient in that they don't waste energy by burning off excess voltage as heat. Switching regulators are more expensive though, but more importantly they are very noisy. Often a circuit will require extra parts to take the noise out of the voltage output from it. I'm not sure but I would suspect on a delicate device like a metal detector and IC chips the regulator probably is linear to both keep the price down and also to prevent introducing circuit noise into the detector. While little switching regulators like this are very expensive, they are still more pricey than linears, and you would also have to add a fair amount of noise cancelling electronics to the detector to keep the noise from doing things like locking up IC chips. I'm not sure which they use. I never paid that much attention to it when I've had one part. Typical linears will have a large metal heat sink on top of them to bleed off the heat. They look like a somewhat larger flat black transistor in certain respects. From memory I think switching regulators this small look more like a transformer along with having a few extra parts, but it's been a while since I've looked at one of those.
I used this example before but it's interesting- Switching regulators I think work somewhat like the dimmer on your house lights. Use turn the dial and what they do is increase (to brighten) or decrease (to dim) the switching on/of (called pulse width modulation) of the voltage going to the light. This constant "on/off" of the voltage output generates a lot of circuit noise.
OK, now I'm really done with today's class. I just thought this info would be useful to others in detector land. It's kind of frustrating to keep hearing people say that better batteries gave their detectors higher performance. Total bunk!
I also can't tell you how many times I've heard people say rechargeables won't work in a device, or won't provide as long of run time. That may have been true twenty years ago with low capacity rechargeables but isn't the case for the most part these days with the advent of high capacity cells. Even if they only had 1.2V per cell (though I find nimhs to generally charge higher than this), a high capacity nimh cell will hold it's voltage higher for longer than a normal shelf battery. What that means that is even if the store battery starts out with a higher voltage it will soon drain down and drop more in source voltage than a good nimh or nicad. Along with the other info above on regulators and such, that also means there should be no issues and also that you usually get 2 or 3 times longer run times from a good high capacity nimh or nicad (2500ma or higher) than your average non-rechargeable store battery. In my digital camera my 2500ma nimhs run it much longer than any "brand name" non-rechargeable battery.
Rechargeables have come a long way but myths seem to die hard due to the bad experience people had with them years ago. A rechargeable flash light that would only stay lit for 5 minutes back in the day, etc. If you're now a little more impressed with today's nimhs and nicads then wait until you see a lipo in action. Much less weight, longer run times, higher amp delivering ability, faster charge times (about 1 hour). They've got it all and when these electric cars start using the current variations of lipo chemistry (the safer ones like A123 cells) as the price comes down you'll see the weight of the car decrease while the mileage roughly triples. A123 cells are already finding their way into certain power hand tools for the amount of power (high voltage and amps) they can deliver along with less weight. Lipos also hold their voltage high to the very end of the drain cycle, resulting in more available power to the power tool (or future electric car), where as the conventional nimhs or nicads they currently use might prevent you from driving at the highest speed possible after the battery nears the end of it's drain cycle.
Whew! That was a long one even for me...
(QUOTE)
Critter,
Check out these batteries and tell me your thoughts ....BTW ...I finally got my order thru to Hobby King after contacting customer service later in the day .....Thanks
(END QUOTE)
http://www.thomasdistributing.com/shop/powergenix-2500-mwhrs-aa-nickel-zinc-rechargeable-batteriesbrfour-pack-p-1905.html?SP_id=&osCsid=a98rm8a91donrsllit8gi3gna7
It's been about 5 years since I investigated similar batteries that claim to use a unique chemistry and so provide 1.5V or higher voltage compared to the "official" 1.2V per cell of nicads or nimhs (I find this to be not true...a good quality nimh or nicad with high capacity will often charge to a much higher voltage than this.). At the time when I was checking these "other" types of rechargeables out similar to what you linked to I found that they didn't have nearly the cycle life of a nimh or nicad, meaning that they could only be charged and drained a substantially less amount of times than nimhs/nicads. Not sure if that's improved over the last five years but I would think that if that has been corrected you would be seeing these cells for sale more than your average nimh/nicad packs.
Remember that increased voltage does NOTHING for a detector's performance these days. They have voltage regulators in them that will only allow a certain amount of voltage to reach the detector's circuit. For instance, the machine may require say 9V to run on in a steady state but it's battery pack might be 8 AAs (12V). The regulator takes that 12V and drops it down to what the machine requires to run steadily on. Otherwise the performance or stability of the machine would be constantly fluctuating as the voltage level of the battery dropped while draining.
Some people also confuse the capacity (commonly stated in milliamps) of the battery and think that this allows you to supply more amperage to the detector. What you have to understand is that any device only draws exactly what it needs in amps, regardless of battery capacity. If for instance the device draws half an amp to power it's self increasing the size (or capacity) of the battery does nothing to change that. I've compared it this way before but I like the old saying....It doesn't matter if the battery is the size of a pack of smokes or the size of a house, the device will only draw the amount of amps it needs to run it's self and nothing will change that.
The only thing that must be paid strict attention to is the voltage parameters of the device you plan to power. If it wants a 12V battery then you risk damaging the unit if you try to supply it with more than that. Linear regulators shunt off the extra voltage a battery is providing by turning it into heat. If you supply a voltage too high then the regulator is either going to burn up or if you are lucky it will shut down on what's called an internal thermal overload. If that's the case then it will start working again once it cools down properly. As you can see, though, providing more voltage will do nothing for most devices and in particular modern metal detectors.
One other thing about battery capacity. It's capacity is directly related to run time. The other the milliamps the more run time you will get on the detector, NOT the more power the detector will have as so many commonly confuse things. It just means longer run times.
The only way capacity directly related to amp draw is in that it has some impact on how much current (amps) it can safely supply to a device. It may seem a little confusing but just follow me here as I try to explain it. It's rather simple to understand but I'm good at over complicating explanations...
Some batteries are rated by what is called a "C" rating. What this means is how much in the way of amps the battery can supply. If the device being powered by the battery wants to draw more amps than the battery can handle then the battery will get very hot, have a short life, or worse. Let's take a 2200ma lipo battery as an example. In this example the RC plane motor I'm powering with it wants to draw 40 amps. The lipo is rated at 10C. 10x2200ma=22 amps. As you can see the battery will be unable to hold up under that kind of amp draw. Bad things might happen or at the very least the battery will have a very short life. Now take another 2200ma lipo as another example. This one is rated at 20C. 20x2200ma=44 amps. This battery can handle the amp draw of that motor. However, most play it safe and easy on their batteries by never drawing more than 80% of the amp ability the have. This insures longer battery life. Lipos usually have two "C" ratings. One is continuous (meaning non-stop amp draw ability, in this case 20C for the above battery), the other is "burst C" rating.
Burst C means how much amp draw the battery can sustain for say 30 seconds at a time. A 20C battery might have a burst rating of 30C, so the above battery would then be able to handle 66 amps for thirty second durations. Any longer than that and you risk damaging the battery. Burst capability is useful in RC in that it allows you to say go to full throttle on a plane for 30 seconds at a time, throttling back some after that to give the battery time to rest and cool down.
In the non-RC world the same example might be used for your auto's battery. It might have what is called "Cranking Amps". That's how much current the battery can supply for short periods of time to run the starter to get the engine going. Once the starter is done doing it's job obviously it isn't running anymore, so the amp draw goes way down and the normal "continuous" amp draw of that battery is only being used to power the engine and other devices in the car. As a side note, once a car is started it mainly runs off the power from the alternator. It also re-charges the battery as it runs so it's ready to start the engine again next time. If the alternator stops working then the car draws it's power only from the battery. In that case if you see the "battery" light come on on your dash then if you're lucky you've got about 40 miles or so of run time to power the engine's ignition and other things until the battery drains to low. A sure sign of the alternator going bad while driving (besides the dash light) is things like the wipers will start slowing down and lights will dim. Find a gas station quick or you're going to be stranded.
One more thing about capacity to sum things up. You might have realized by the above examples of "C" ratings that besides it's amp draw rating the battery's ability to deliver amps is directly impacted by the capacity. As an example, a 10C battery at 1000ma can deliver 10 amps. Conversely, a 1000ma battery rated at 20C can deliver 20 amps. But, as said, that does not increase the performance of a device so long as it's needed amp draw is lower than the 10 amps of the first battery. If it drew 9 amps then I would say you are pushing it with a 10C 1000ma battery and being hard on it. Either buy another 1000ma battery rated at a higher C rating or buy another 10C battery to increase it's amp delivering ability that way. For example, a 10C 1500ma battery can deliver 15 amps and so would probably be a more wise option for that device which wants to draw 9 amps. The golden rule in RC is 80% of the continuous C rating, so if the battery can deliver 10 amps in total continuously I would use it to run anything that will draw more than 8 amps.
OK, yet again "one more thing" here while I'm at it...The voltage input of many DC devices is fairly diverse, even in things that don't have regulators. Your typical device X (use your imagination) that runs on batteries might call for say a 9V battery. In reality, though, it might very well be able to run on anything from 6 to 15 volts and still work fine. Lower voltage isn't going to break it (it just won't work), but something too high can very well burn the regulator up (if it has one) or the circuit inside it's self.
As a final bit of info on regulators most are linear and because they turn the extra voltage into heat they are not very efficient. Switching regulators pulse the voltage output to the device to control the voltage output and so are much more efficient in that they don't waste energy by burning off excess voltage as heat. Switching regulators are more expensive though, but more importantly they are very noisy. Often a circuit will require extra parts to take the noise out of the voltage output from it. I'm not sure but I would suspect on a delicate device like a metal detector and IC chips the regulator probably is linear to both keep the price down and also to prevent introducing circuit noise into the detector. While little switching regulators like this are very expensive, they are still more pricey than linears, and you would also have to add a fair amount of noise cancelling electronics to the detector to keep the noise from doing things like locking up IC chips. I'm not sure which they use. I never paid that much attention to it when I've had one part. Typical linears will have a large metal heat sink on top of them to bleed off the heat. They look like a somewhat larger flat black transistor in certain respects. From memory I think switching regulators this small look more like a transformer along with having a few extra parts, but it's been a while since I've looked at one of those.
I used this example before but it's interesting- Switching regulators I think work somewhat like the dimmer on your house lights. Use turn the dial and what they do is increase (to brighten) or decrease (to dim) the switching on/of (called pulse width modulation) of the voltage going to the light. This constant "on/off" of the voltage output generates a lot of circuit noise.
OK, now I'm really done with today's class. I just thought this info would be useful to others in detector land. It's kind of frustrating to keep hearing people say that better batteries gave their detectors higher performance. Total bunk!
I also can't tell you how many times I've heard people say rechargeables won't work in a device, or won't provide as long of run time. That may have been true twenty years ago with low capacity rechargeables but isn't the case for the most part these days with the advent of high capacity cells. Even if they only had 1.2V per cell (though I find nimhs to generally charge higher than this), a high capacity nimh cell will hold it's voltage higher for longer than a normal shelf battery. What that means that is even if the store battery starts out with a higher voltage it will soon drain down and drop more in source voltage than a good nimh or nicad. Along with the other info above on regulators and such, that also means there should be no issues and also that you usually get 2 or 3 times longer run times from a good high capacity nimh or nicad (2500ma or higher) than your average non-rechargeable store battery. In my digital camera my 2500ma nimhs run it much longer than any "brand name" non-rechargeable battery.
Rechargeables have come a long way but myths seem to die hard due to the bad experience people had with them years ago. A rechargeable flash light that would only stay lit for 5 minutes back in the day, etc. If you're now a little more impressed with today's nimhs and nicads then wait until you see a lipo in action. Much less weight, longer run times, higher amp delivering ability, faster charge times (about 1 hour). They've got it all and when these electric cars start using the current variations of lipo chemistry (the safer ones like A123 cells) as the price comes down you'll see the weight of the car decrease while the mileage roughly triples. A123 cells are already finding their way into certain power hand tools for the amount of power (high voltage and amps) they can deliver along with less weight. Lipos also hold their voltage high to the very end of the drain cycle, resulting in more available power to the power tool (or future electric car), where as the conventional nimhs or nicads they currently use might prevent you from driving at the highest speed possible after the battery nears the end of it's drain cycle.
Whew! That was a long one even for me...
Critterhunter
New member
OK, I lied
Critterhunter
New member
For my next never ending lecture 
...I have some solar yard lights from Harbor Tool & Freight that came with junk nicad batteries. Hey, what do you want for $8 or whatever for 4 lights. Actually the lights work pretty good, it's just that the nicads they came with (one single AA nicad per light) didn't have the capacity they should have. They are rated at 600ma. A while back I cycled these like 5 times (drain dead/re-charge) to try to exercises some life back into them. That helped for a while, but they still didn't hold the kind of capacity they should. Often in the last hour of darkness before daylight only one or two of them would still be lit.
So, I finally got around to picking up some good replacement cells for these things. Up at Harbor Tool & Freight I found 700ma AA nicads, a four pack for like $3 on sale. Can't beat that price. They have Nimh AAs at like 2200 or 2500ma for like $5 for a 4 pack. Not too bad. Notice that in general (but not a hard rule) nimhs normally have a higher capacity than the older nicad technology. That's not always the case, though, as I've seen some nicads cells with some rather high capacity. So long as the capacity is the same there isn't really much difference these days in nimhs or nicads. Nicads in general can withstand higher amp draws and faster charge rates better. They also tend to hold their charge on the shelf longer. Nimhs tend to be lighter and with higher capacity. They also aren't as prone to memory problems like nicads, but nicads are better in that respect these days. So long as you drain dead and re-charge them here and there (like 2 or 3 times a year) they shouldn't suffer that, and it's still a good idea to exercise nimhs in the same fashion as well. It will increase their capacity.
Anyway, since these solar lights use Nicads I needed to replace them with nicads. Any time you have a device with a "charge" circuit in it that make darn sure you replace the batteries with the same type. They can be higher capacity (longer run time), but it's never a good idea to put a nimh in something that calls for nicads or vise versa. The batteries they came with were only 600ma (and didn't even really hold that...junk). By using a 700ma nicad in these lights I'll increase their run time. Chances are now that I won't wake up in the morning only to find one light if any still burning. Not only that, but I look at the extra capacity of these cells as reserve power for those dark and gloomy days when there isn't much light and as a result the batteries don't get as much charge put back into them before night fall. On a typical rainy day all four of the lights would be dead within about 3 to 4 hours after dark. Now it will have extra reserve capacity from sunny days that it can burn through on those dark days. Kind'a like saving money for a rainy day.
These lights weren't really meant for replacing the batteries in. Heck, they are so cheap why would anybody want to do that? Still, with a few screws removed here and there I had them apart. Rather than being soldered in place (to prevent oxide build up causing a short or bad connection), these cells just sit in a normal AA holder. That's not good in a device where the battery is never being removed. Normally removal/insertion action of changing batteries in a holder in a way cleans the battery holder contacts. When you talk about the very low amp draw these lights require it doesn't take much dirt or corrosion build up at all for power to no longer flow. For that reason I'll be coating the battery leads as well as the holder's contacts with a thin film of dielectric (probably spelled it wrong) grease. You can get little .99 cent packs of these at any auto parts store. They often call them spark plug boot grease and it's used to prevent oxide build on on the spark plug terminals, as well as keep the spark plug boots from sticking to them down the road. Smear a very thin/light coat of this stuff on things like detector battery plugs. I'll be doing this with these solar lights to prevent loss of current flow down the road.
So when you get a new nimh or nicad there's a way to condition it for longer life and run times, and that's the whole point to this message. It will not only provide them with a larger capacity but also prolong their life. It's good to do this with new batteries but also good to do with any nimh or nicad two or three times a year to keep them from developing memory problems and also to exercise the capacity of the cells to increase it.
With that it mind my next message (NEXT MESSAGE?
) will cover how I set up the Accucel 6 charger for these nicads. I'll cover proper MV setting, amp charge rates, as well as amp drain rates I used to cycle these cells 5 or 6 times. I stuck them in a 4AA holder, meaning all four cells are in series with each other in a holder from Radio Shack. Might as well cover the amp rates I used now...
.3 amps to charge them and .3 amps to drain them. This is roughly 1/3rd of 1C. A 1C charge rate would be 700ma and take about an hour to do. That's OK with nicads but I prefer slower charge rates for them and Nimhs, in particular when conditioning new cells for sure. You don't want to 1 hour blast charge these things right off the bat. Be easy on them and cycle them charged/drained dead about 5 times at an amp rate that will take like 2 to 3 hours. A better amp rate would be 1/10th C, or in other words on your stock GT rechargeable pack which is 1000ma that would be 100ma. 100ma X 10 Hours= 1000ma. However, obviously if I was to cycle these cells at that slow of a rate it's going to take a life time (10 hours to charge, 10 hours to drain X 5 Times) to do that. It's good to slow charge your cells whenever you can. The slower the better but anything beyond a 10 hour charge rate is pointless. That's as easy as it gets on a cell.
Still, roughly 1/3rd C is fairly easy. Two to three hours to charge, two to three hours to drain is being pretty nice and easy on these cells to condition them and get them into shape. Once done you can blast charge most nimhs or nicads (I wouldn't go above a 1C charge rate, meaning 1 hour for a completely dead pack to charge), but try to charge them as slow as possible when ever you can. No need to go past 1/10th C, or 10 hours on a completely dead pack, though. Typically I'll charge my stock Minelab rechargeable pack using this charger at say 1/4rd to around 2/3rds C. Meaning, since the pack is 1000ma I'd probably charge it at 250ma for a total of about 4 hours on a completely dead pack. Your stock wall "charger for that pack is I believe 50ma output, which means it takes that thing about 20 hours to charge a completely dead pack.
Many people charge a nimh or nicad at 1C, meaning 1 hour for a 1000ma dead pack. That is OK but most believe it will shorten it's life. Stick your hand on the pack at various times through that hour. Is it getting very warm? That's telling your that you are pushing it and shortening the life of the cells. On the other hand, even if you are easy on the cells it is healthy to blast charge a nimh or nicad 2 or 3 times a year. This will break down crystals causing resistance in the cells which lowers the voltage output or lessons the capacity of them. Some even like to blast them at a much higher rate. Say 3 amps on a 1000ma pack, or 3XC. While I might do this for about five minutes I don't trust that kind of amp rate for any length of time. That could very well cause a cell to explode on you, so be very careful if you are playing with those kinds of numbers. But, I do know guys who use Nicads in RC and they'll blast them all day long at like 15 minute charge times on a completely dead pack.
That's insane to me, but they want to get back up in the air as quick as possible. I'd at least wear protective eye ware and gloves when doing those kinds of charge rates. Keeping the packs cool with a fan or ice packs would also be a good idea. But the way I look at it why be in such a rush when you don't have to. Charge the pack as slow as you can whenever you can. If you have to be in the field in an hour then charge it at 1C, but keep it in a safe place while charging and check it for heat with your hand.
How many cycles does a new pack need? As a rule of thumb about 3 to 6 dead/charge cycles will get it in top shape. With a good charger your can monitor the amount of capacity put into and drained out of the cell. After about the 5th or 6th cycle if I no longer see the capacity increasing with each cycle then I'll stop there. Usually by then the pack is as good as it's going to get. Then 2 or 3 times a year at least cycle the pack dead and charge it like 3 times in a row to keep it in top form. If the pack seems bad or to have too little capacity you might try blast charging it to break down any crystals that have formed. Here and there it's healthy for a pack.
So my solar light cells have been cycling for a few days and they are on their last cycle (#6 I think). I recorded the charged and discharged millamps with each cycle to note the improvement of the capacity. Tomorrow I'll post those numbers for cycles 1 through 6 to show you how the cells improved. While I've already noted some fair improvement in capacity, I've noticed larger increases in higher capacity and namely better brand name cells than these cheap no-name Harbor Tool Nicads. Just the same they did show improvement, and it is above the 700ma rated capacity of the cells. That's how you know if the cells are in good shape. Anything near the listed capacity means they are doing OK, but if they show higher capacity than what the label says then you can be assured that they are in real good shape.
My M/V or "Threshold" setting for Nicads on this charger is 14m/v. if I were to charge these cells at a 10 hour charge rate I would lower that a bit to like maybe 12 m/v, just to be sure the charger notices when they are peaked. A lower charge rate doesn't show as pronounced of a drop in voltage when the cells peak than a higher one. A 1 hour amp rate would for sure use at least 14m/v. For Nimhs I mainly use 7 m/v regardless of how fast or slow I charge them. Same deal with nicads, you don't have to change the m/v based on amp charge rate. I just like to play it on the safe side some times and lower it a hair when doing real low charge rates, or raise it a few digits when doing real high ones to prevent a false peak where the charger thinks the pack is done charging. 12m/v is something some use on nicads all the time regardless of how fast or slow they are being charged.
This charger has a separate discharge and charge amp rate. I set them both to .3 amps for the first cycle and then raised it to .4 amps for the next four cycles. This charger also has a function that will automatically keep charging/discharging the cells for how ever many cycles you choose up to 5 total. After it's done it will display the discharged and charged capacity for each cycle so that you can record that for future reference. It helps to keep track of the life span of your cells. If 5 years from now they are still near the highest capacity you ever got into them then obviously they are still doing well.
Tomorrow I'll post the capacity numbers to show the improvement of these cells as they were cycled. Need a cigarette...
...I have some solar yard lights from Harbor Tool & Freight that came with junk nicad batteries. Hey, what do you want for $8 or whatever for 4 lights. Actually the lights work pretty good, it's just that the nicads they came with (one single AA nicad per light) didn't have the capacity they should have. They are rated at 600ma. A while back I cycled these like 5 times (drain dead/re-charge) to try to exercises some life back into them. That helped for a while, but they still didn't hold the kind of capacity they should. Often in the last hour of darkness before daylight only one or two of them would still be lit.So, I finally got around to picking up some good replacement cells for these things. Up at Harbor Tool & Freight I found 700ma AA nicads, a four pack for like $3 on sale. Can't beat that price. They have Nimh AAs at like 2200 or 2500ma for like $5 for a 4 pack. Not too bad. Notice that in general (but not a hard rule) nimhs normally have a higher capacity than the older nicad technology. That's not always the case, though, as I've seen some nicads cells with some rather high capacity. So long as the capacity is the same there isn't really much difference these days in nimhs or nicads. Nicads in general can withstand higher amp draws and faster charge rates better. They also tend to hold their charge on the shelf longer. Nimhs tend to be lighter and with higher capacity. They also aren't as prone to memory problems like nicads, but nicads are better in that respect these days. So long as you drain dead and re-charge them here and there (like 2 or 3 times a year) they shouldn't suffer that, and it's still a good idea to exercise nimhs in the same fashion as well. It will increase their capacity.
Anyway, since these solar lights use Nicads I needed to replace them with nicads. Any time you have a device with a "charge" circuit in it that make darn sure you replace the batteries with the same type. They can be higher capacity (longer run time), but it's never a good idea to put a nimh in something that calls for nicads or vise versa. The batteries they came with were only 600ma (and didn't even really hold that...junk). By using a 700ma nicad in these lights I'll increase their run time. Chances are now that I won't wake up in the morning only to find one light if any still burning. Not only that, but I look at the extra capacity of these cells as reserve power for those dark and gloomy days when there isn't much light and as a result the batteries don't get as much charge put back into them before night fall. On a typical rainy day all four of the lights would be dead within about 3 to 4 hours after dark. Now it will have extra reserve capacity from sunny days that it can burn through on those dark days. Kind'a like saving money for a rainy day.
These lights weren't really meant for replacing the batteries in. Heck, they are so cheap why would anybody want to do that? Still, with a few screws removed here and there I had them apart. Rather than being soldered in place (to prevent oxide build up causing a short or bad connection), these cells just sit in a normal AA holder. That's not good in a device where the battery is never being removed. Normally removal/insertion action of changing batteries in a holder in a way cleans the battery holder contacts. When you talk about the very low amp draw these lights require it doesn't take much dirt or corrosion build up at all for power to no longer flow. For that reason I'll be coating the battery leads as well as the holder's contacts with a thin film of dielectric (probably spelled it wrong) grease. You can get little .99 cent packs of these at any auto parts store. They often call them spark plug boot grease and it's used to prevent oxide build on on the spark plug terminals, as well as keep the spark plug boots from sticking to them down the road. Smear a very thin/light coat of this stuff on things like detector battery plugs. I'll be doing this with these solar lights to prevent loss of current flow down the road.
So when you get a new nimh or nicad there's a way to condition it for longer life and run times, and that's the whole point to this message. It will not only provide them with a larger capacity but also prolong their life. It's good to do this with new batteries but also good to do with any nimh or nicad two or three times a year to keep them from developing memory problems and also to exercise the capacity of the cells to increase it.
With that it mind my next message (NEXT MESSAGE?
) will cover how I set up the Accucel 6 charger for these nicads. I'll cover proper MV setting, amp charge rates, as well as amp drain rates I used to cycle these cells 5 or 6 times. I stuck them in a 4AA holder, meaning all four cells are in series with each other in a holder from Radio Shack. Might as well cover the amp rates I used now....3 amps to charge them and .3 amps to drain them. This is roughly 1/3rd of 1C. A 1C charge rate would be 700ma and take about an hour to do. That's OK with nicads but I prefer slower charge rates for them and Nimhs, in particular when conditioning new cells for sure. You don't want to 1 hour blast charge these things right off the bat. Be easy on them and cycle them charged/drained dead about 5 times at an amp rate that will take like 2 to 3 hours. A better amp rate would be 1/10th C, or in other words on your stock GT rechargeable pack which is 1000ma that would be 100ma. 100ma X 10 Hours= 1000ma. However, obviously if I was to cycle these cells at that slow of a rate it's going to take a life time (10 hours to charge, 10 hours to drain X 5 Times) to do that. It's good to slow charge your cells whenever you can. The slower the better but anything beyond a 10 hour charge rate is pointless. That's as easy as it gets on a cell.
Still, roughly 1/3rd C is fairly easy. Two to three hours to charge, two to three hours to drain is being pretty nice and easy on these cells to condition them and get them into shape. Once done you can blast charge most nimhs or nicads (I wouldn't go above a 1C charge rate, meaning 1 hour for a completely dead pack to charge), but try to charge them as slow as possible when ever you can. No need to go past 1/10th C, or 10 hours on a completely dead pack, though. Typically I'll charge my stock Minelab rechargeable pack using this charger at say 1/4rd to around 2/3rds C. Meaning, since the pack is 1000ma I'd probably charge it at 250ma for a total of about 4 hours on a completely dead pack. Your stock wall "charger for that pack is I believe 50ma output, which means it takes that thing about 20 hours to charge a completely dead pack.
Many people charge a nimh or nicad at 1C, meaning 1 hour for a 1000ma dead pack. That is OK but most believe it will shorten it's life. Stick your hand on the pack at various times through that hour. Is it getting very warm? That's telling your that you are pushing it and shortening the life of the cells. On the other hand, even if you are easy on the cells it is healthy to blast charge a nimh or nicad 2 or 3 times a year. This will break down crystals causing resistance in the cells which lowers the voltage output or lessons the capacity of them. Some even like to blast them at a much higher rate. Say 3 amps on a 1000ma pack, or 3XC. While I might do this for about five minutes I don't trust that kind of amp rate for any length of time. That could very well cause a cell to explode on you, so be very careful if you are playing with those kinds of numbers. But, I do know guys who use Nicads in RC and they'll blast them all day long at like 15 minute charge times on a completely dead pack.
That's insane to me, but they want to get back up in the air as quick as possible. I'd at least wear protective eye ware and gloves when doing those kinds of charge rates. Keeping the packs cool with a fan or ice packs would also be a good idea. But the way I look at it why be in such a rush when you don't have to. Charge the pack as slow as you can whenever you can. If you have to be in the field in an hour then charge it at 1C, but keep it in a safe place while charging and check it for heat with your hand.
How many cycles does a new pack need? As a rule of thumb about 3 to 6 dead/charge cycles will get it in top shape. With a good charger your can monitor the amount of capacity put into and drained out of the cell. After about the 5th or 6th cycle if I no longer see the capacity increasing with each cycle then I'll stop there. Usually by then the pack is as good as it's going to get. Then 2 or 3 times a year at least cycle the pack dead and charge it like 3 times in a row to keep it in top form. If the pack seems bad or to have too little capacity you might try blast charging it to break down any crystals that have formed. Here and there it's healthy for a pack.
So my solar light cells have been cycling for a few days and they are on their last cycle (#6 I think). I recorded the charged and discharged millamps with each cycle to note the improvement of the capacity. Tomorrow I'll post those numbers for cycles 1 through 6 to show you how the cells improved. While I've already noted some fair improvement in capacity, I've noticed larger increases in higher capacity and namely better brand name cells than these cheap no-name Harbor Tool Nicads. Just the same they did show improvement, and it is above the 700ma rated capacity of the cells. That's how you know if the cells are in good shape. Anything near the listed capacity means they are doing OK, but if they show higher capacity than what the label says then you can be assured that they are in real good shape.
My M/V or "Threshold" setting for Nicads on this charger is 14m/v. if I were to charge these cells at a 10 hour charge rate I would lower that a bit to like maybe 12 m/v, just to be sure the charger notices when they are peaked. A lower charge rate doesn't show as pronounced of a drop in voltage when the cells peak than a higher one. A 1 hour amp rate would for sure use at least 14m/v. For Nimhs I mainly use 7 m/v regardless of how fast or slow I charge them. Same deal with nicads, you don't have to change the m/v based on amp charge rate. I just like to play it on the safe side some times and lower it a hair when doing real low charge rates, or raise it a few digits when doing real high ones to prevent a false peak where the charger thinks the pack is done charging. 12m/v is something some use on nicads all the time regardless of how fast or slow they are being charged.
This charger has a separate discharge and charge amp rate. I set them both to .3 amps for the first cycle and then raised it to .4 amps for the next four cycles. This charger also has a function that will automatically keep charging/discharging the cells for how ever many cycles you choose up to 5 total. After it's done it will display the discharged and charged capacity for each cycle so that you can record that for future reference. It helps to keep track of the life span of your cells. If 5 years from now they are still near the highest capacity you ever got into them then obviously they are still doing well.
Tomorrow I'll post the capacity numbers to show the improvement of these cells as they were cycled. Need a cigarette...