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Budget DIY Replacement NiMh Excalibur battery pack
- Thread starter WaderMike
- Start date
deepdiger60
New member
That is a great job 
and does not look to complicated , have you used it yet to see how long the charge last before you need to juice up again ? , i see no reason why that could not be done for the Sovereign i opened a weak pack i have it wont hold a charge very long i replaced it with a new one wow !! $$ it has to be cheaper the way your doing it . I took a photo of the GT rechargeable battery pack ,Also you can see the wax they use is brown at the point where it covers that small circuit board that is where all GT rechargeable pack gets very warm when recharging i think that is what weakens that plastic tab most people have break off, what do you think ? . Good job Jim
and does not look to complicated , have you used it yet to see how long the charge last before you need to juice up again ? , i see no reason why that could not be done for the Sovereign i opened a weak pack i have it wont hold a charge very long i replaced it with a new one wow !! $$ it has to be cheaper the way your doing it . I took a photo of the GT rechargeable battery pack ,Also you can see the wax they use is brown at the point where it covers that small circuit board that is where all GT rechargeable pack gets very warm when recharging i think that is what weakens that plastic tab most people have break off, what do you think ? . Good job JimI cant see why you couldnt do the same with that pack, looks straight forward enough, is that some sort of circuit/thermal cut out thingy below the middle of the pack??
Suppose it doesnt matter really as you would just wire the new cells up to it the same
Not having a Sovereign, I cant check to see??
There are threads on replacing the standard battery with Lithium ones but if your just going to replace the standard NiMHs, its got to work out cheaper, and you can still use the stock charger
good luck..& HH
Suppose it doesnt matter really as you would just wire the new cells up to it the same
Not having a Sovereign, I cant check to see??
There are threads on replacing the standard battery with Lithium ones but if your just going to replace the standard NiMHs, its got to work out cheaper, and you can still use the stock charger
good luck..& HH
Critterhunter
New member
Great job of a DIY project.
You're right about being careful not to short those cells. I was mucking with some Sub-C nicad cells I was soldering up, not thinking they had a charge from the factory, and man those flat metal battery soldered connectors will get red hot in a split second. Gave myself some nasty burns when I wasn't paying attention to that. Not much risk of blowing a nimh or nicad up with a dead short, UNLESS it's let to run wild for more than a few seconds or so.
Never short a lipo though, as they can go nuclear from that, as can most batteries, especially ones lithium based. If changing connectors on those cut one wire at a time to prevent a dead short with the cutters, solder and heat shrink it to the next connector, and only then cut the other one from the old connector to transfer to the new one. No need to change plugs on lipos anyway, as most plug types are standard. Usually tiny JST plugs (JXT?) for smaller lipos or low current draws (such as in the case of a metal detector), or Deans Ultras for higher power demands ability.
I would only worry about charging the cells in the POD if you use a higher amp rate. A safe rate in the POD might be about 100 to 300ma. Any higher and collective heat that can't escape the POD might shorten their life as heat is very bad for batteries, but the only problem with continued removal/installation is you risk a water leak unless the POD seal is kept attended to with proper lubricant and is kept clean.
Not sure if the vents on nicads/nimhs are used for the normal charging process. Been years since I read up on it but if I remember right they only vent if charged too fast and as a safety valve to release pressure of built of gasses from too fast of charging, but once done the pack won't have much life left after that (again, memory serving), so gas build up shouldn't be an issue unless you are blasting the pack at say 2 or 3 times C.
You need to read up on the specs of those cells and see what the max fast charge rate they are designed to handle, but even with nimhs or nicads designed for excessively high charge rates I still won't push past 1C (1 hour charge roughly for a completely dead pack, which in this case would be 1.5 amps). Still, I rarely push nimhs or nicads that fast. Only rarely when in a hurry.
Most I'll do is a usual about 1/4th to 1/3rd C charge rate, which in this case would be 350ma charge rate roughly for 1/4th C or say about 500ma for roughly a 1/3rd rate. That should be more than healthy for the cells while not risking heat build up being sealed in the POD, but feel the POD halfway and then near end of charge, and if it's more than just very mildly luke warm I wouldn't charge that fast anymore, or put the POD on an ice pack while charging.
The stock Excalibur packs have a thermal overload switch in them where if the heat builds up it opens, and it's a quick and dirty way to turn the charge on and off since the wall "charger" is just a transformer with no shut off circuit. Stupid, as those thermal switches have a very limited lifespan usually.
Or, you could drill a hole in the pod and thread it to seal it with a allen wrench bolt when in the water, and remove it while charging if you are worried about heat or gasses too I guess, but as said I don't think venting should happen unless the pack is at critical mass for too fast of a charge rate.
Do NOT trust the AUTO charge functions on the Accucel. It's an excellent charger with extra value at only $20, and so is very big in RC, being able to charge numerous cell types, with fine adjustment of charge rates and such, and save settings for future different packs you charge, but the AUTO function where it picks the charge rate and M/V threshold setting to determine shutoff is flaky. No need to use it anyway so long as you know what you are doing.
For nimhs I set the m/v setting at 5 for nimhs and 12 for nicads. If it is terminating too early I'll raise it to 7 and 14 respectfully. Some packs require higher or lower settings sometimes if they are difficult, but always better to undershoot it so the charger doesn't see the final dip during charging of the voltage and might then overcharge it.
As for the capacity and timer safety settings, I turn those off as well, because based on charge rate the pack might take longer to charge then expected due to it's state of being drained, and also a good healthy nimh, nicad, or lipo will often hold as much as say 300ma or more capacity than the label says. If you set the capacity to turn off the charger then you might be cheating yourself out of run time, but be darn sure you've got the m/v setting right so it sees the end of charge. I always put my charger/battery in the middle of a cement floor when I can't keep a constant eye on it, or I charge where I'm in the room to monitor it while doing other things. Feel the pack often. Hot means too fast of a charge rate or it missed termination due to an error in the m/v setting and is over charging it.
This charger doesn't need the cell count set for nimhs or nicads. Only lipos. It will automatically figure out how many cells are in the pack and charge accordingly to the right peak voltage target. That's why you only need to set the m/v threshold for one cell and it'll do the math for the others. The m/v setting is the dip in voltage when fully peaked that it expects to see. Set to low it will false terminate due to the little dips and rises while charging. Nimhs drop lower at the final peak than nicads, thus why the m/v setting is higher for nicads, and also why a nimh should never be used on a nicad charger. Using a nicad on a nimh charger presents less risk, but more than likely it will false terminate due to the larger valleys (dips) in voltage while charging.
That charger has features not seen on chargers costing well over $100 with it's computer screen and numerous settings. There are huge threads on the web exploring it's functions and giving tips on it, but watch what you read and confirm things because some people have ideas that are just dead wrong in others opinions.
Using dielectric grease on the battery ends after soldering isn't really needed. Mainly that's used for batteries not soldered together so they don't build up oxide to prevent current flow. That's the reason why cells are soldered together, to prevent that. I have loose nimh cells in plane transmitters that I just installed in an AA holder that I use a thin film of dielectric great on because I never remove them and just charge in their holder. Removing/installing cells to charge lessons the need for the oxide preventor, since the act of removing/installing them keeps the ends clean somewhat.
The cost of lipos these days from some sources is cheaper than nimhs or nicads. The 3 cell series 750ma Rhino pack I use in my GT's alkaline holder via a tiny plug I soldered in only cost me around $7, so I bought an extra as a backup. I can still move the little plug out of the way and use 8AAs in there again but never have. 1 hour charge times or less without pushing the lipo, smaller and lighter than 8AAs, doesn't self discharge on the shelf, etc.
If using nimhs or nicads I'd shoot for low self discharge ones they have these days so they don't drain dead waiting for the next hunt, as that will greatly shorten run times. Do your research though as some don't live up to their claims of being LSD cells.
Ran my 3 cell lipo in my GT the other day for over 9 hours. Never hit low battery alarm. Based on the 705ma that was put back in when I charged it, I bet I could have got another 4 hours or so maybe out of it, as the Rhino holds more capacity than the label says. Plus, lipos hold their voltage very high until near drained to dead (9V for a 3 cell pack is considered drained and should never be drained past that), so even with a lower capacity a lipo pack it might very well run longer than a somewhat higher capacity nimh pack used. The Sovereign/Excaliburs low battery alarm hits around 10V, so it's perfect to prevent over draining a 3 cell lipo past 9V which could ruin it.
Kered has crammed a 1450ma 3 cell lipo for like $12 into his GT alkaline holder and into his XS2a or such Sovereign for extremely long run times, and there are bigger capacity packs that will fit as well, as lipos offer more capacity in less pack size than pretty much any other battery on the market, and at a much lighter weight usually.
I already had the Acucel 6 charger for my RC electric planes and other projects, and I already had hacked a computer power supply as my 12VDC source to power it, but even buying all these things outright is dirt cheap. About $20 for the Accucel 6, another $10 for a DC power supply (or run it off a car battery), and another about $14 for my two lipo packs I use in my GT, which I then built a stick plane to take advantage of those cells for flying, as all my other planes I build I design for using a 2250ma 3 cell lipo pack which is a good bit bigger.
You're right about being careful not to short those cells. I was mucking with some Sub-C nicad cells I was soldering up, not thinking they had a charge from the factory, and man those flat metal battery soldered connectors will get red hot in a split second. Gave myself some nasty burns when I wasn't paying attention to that. Not much risk of blowing a nimh or nicad up with a dead short, UNLESS it's let to run wild for more than a few seconds or so.
Never short a lipo though, as they can go nuclear from that, as can most batteries, especially ones lithium based. If changing connectors on those cut one wire at a time to prevent a dead short with the cutters, solder and heat shrink it to the next connector, and only then cut the other one from the old connector to transfer to the new one. No need to change plugs on lipos anyway, as most plug types are standard. Usually tiny JST plugs (JXT?) for smaller lipos or low current draws (such as in the case of a metal detector), or Deans Ultras for higher power demands ability.
I would only worry about charging the cells in the POD if you use a higher amp rate. A safe rate in the POD might be about 100 to 300ma. Any higher and collective heat that can't escape the POD might shorten their life as heat is very bad for batteries, but the only problem with continued removal/installation is you risk a water leak unless the POD seal is kept attended to with proper lubricant and is kept clean.
Not sure if the vents on nicads/nimhs are used for the normal charging process. Been years since I read up on it but if I remember right they only vent if charged too fast and as a safety valve to release pressure of built of gasses from too fast of charging, but once done the pack won't have much life left after that (again, memory serving), so gas build up shouldn't be an issue unless you are blasting the pack at say 2 or 3 times C.
You need to read up on the specs of those cells and see what the max fast charge rate they are designed to handle, but even with nimhs or nicads designed for excessively high charge rates I still won't push past 1C (1 hour charge roughly for a completely dead pack, which in this case would be 1.5 amps). Still, I rarely push nimhs or nicads that fast. Only rarely when in a hurry.
Most I'll do is a usual about 1/4th to 1/3rd C charge rate, which in this case would be 350ma charge rate roughly for 1/4th C or say about 500ma for roughly a 1/3rd rate. That should be more than healthy for the cells while not risking heat build up being sealed in the POD, but feel the POD halfway and then near end of charge, and if it's more than just very mildly luke warm I wouldn't charge that fast anymore, or put the POD on an ice pack while charging.
The stock Excalibur packs have a thermal overload switch in them where if the heat builds up it opens, and it's a quick and dirty way to turn the charge on and off since the wall "charger" is just a transformer with no shut off circuit. Stupid, as those thermal switches have a very limited lifespan usually.
Or, you could drill a hole in the pod and thread it to seal it with a allen wrench bolt when in the water, and remove it while charging if you are worried about heat or gasses too I guess, but as said I don't think venting should happen unless the pack is at critical mass for too fast of a charge rate.
Do NOT trust the AUTO charge functions on the Accucel. It's an excellent charger with extra value at only $20, and so is very big in RC, being able to charge numerous cell types, with fine adjustment of charge rates and such, and save settings for future different packs you charge, but the AUTO function where it picks the charge rate and M/V threshold setting to determine shutoff is flaky. No need to use it anyway so long as you know what you are doing.
For nimhs I set the m/v setting at 5 for nimhs and 12 for nicads. If it is terminating too early I'll raise it to 7 and 14 respectfully. Some packs require higher or lower settings sometimes if they are difficult, but always better to undershoot it so the charger doesn't see the final dip during charging of the voltage and might then overcharge it.
As for the capacity and timer safety settings, I turn those off as well, because based on charge rate the pack might take longer to charge then expected due to it's state of being drained, and also a good healthy nimh, nicad, or lipo will often hold as much as say 300ma or more capacity than the label says. If you set the capacity to turn off the charger then you might be cheating yourself out of run time, but be darn sure you've got the m/v setting right so it sees the end of charge. I always put my charger/battery in the middle of a cement floor when I can't keep a constant eye on it, or I charge where I'm in the room to monitor it while doing other things. Feel the pack often. Hot means too fast of a charge rate or it missed termination due to an error in the m/v setting and is over charging it.
This charger doesn't need the cell count set for nimhs or nicads. Only lipos. It will automatically figure out how many cells are in the pack and charge accordingly to the right peak voltage target. That's why you only need to set the m/v threshold for one cell and it'll do the math for the others. The m/v setting is the dip in voltage when fully peaked that it expects to see. Set to low it will false terminate due to the little dips and rises while charging. Nimhs drop lower at the final peak than nicads, thus why the m/v setting is higher for nicads, and also why a nimh should never be used on a nicad charger. Using a nicad on a nimh charger presents less risk, but more than likely it will false terminate due to the larger valleys (dips) in voltage while charging.
That charger has features not seen on chargers costing well over $100 with it's computer screen and numerous settings. There are huge threads on the web exploring it's functions and giving tips on it, but watch what you read and confirm things because some people have ideas that are just dead wrong in others opinions.
Using dielectric grease on the battery ends after soldering isn't really needed. Mainly that's used for batteries not soldered together so they don't build up oxide to prevent current flow. That's the reason why cells are soldered together, to prevent that. I have loose nimh cells in plane transmitters that I just installed in an AA holder that I use a thin film of dielectric great on because I never remove them and just charge in their holder. Removing/installing cells to charge lessons the need for the oxide preventor, since the act of removing/installing them keeps the ends clean somewhat.
The cost of lipos these days from some sources is cheaper than nimhs or nicads. The 3 cell series 750ma Rhino pack I use in my GT's alkaline holder via a tiny plug I soldered in only cost me around $7, so I bought an extra as a backup. I can still move the little plug out of the way and use 8AAs in there again but never have. 1 hour charge times or less without pushing the lipo, smaller and lighter than 8AAs, doesn't self discharge on the shelf, etc.
If using nimhs or nicads I'd shoot for low self discharge ones they have these days so they don't drain dead waiting for the next hunt, as that will greatly shorten run times. Do your research though as some don't live up to their claims of being LSD cells.
Ran my 3 cell lipo in my GT the other day for over 9 hours. Never hit low battery alarm. Based on the 705ma that was put back in when I charged it, I bet I could have got another 4 hours or so maybe out of it, as the Rhino holds more capacity than the label says. Plus, lipos hold their voltage very high until near drained to dead (9V for a 3 cell pack is considered drained and should never be drained past that), so even with a lower capacity a lipo pack it might very well run longer than a somewhat higher capacity nimh pack used. The Sovereign/Excaliburs low battery alarm hits around 10V, so it's perfect to prevent over draining a 3 cell lipo past 9V which could ruin it.
Kered has crammed a 1450ma 3 cell lipo for like $12 into his GT alkaline holder and into his XS2a or such Sovereign for extremely long run times, and there are bigger capacity packs that will fit as well, as lipos offer more capacity in less pack size than pretty much any other battery on the market, and at a much lighter weight usually.
I already had the Acucel 6 charger for my RC electric planes and other projects, and I already had hacked a computer power supply as my 12VDC source to power it, but even buying all these things outright is dirt cheap. About $20 for the Accucel 6, another $10 for a DC power supply (or run it off a car battery), and another about $14 for my two lipo packs I use in my GT, which I then built a stick plane to take advantage of those cells for flying, as all my other planes I build I design for using a 2250ma 3 cell lipo pack which is a good bit bigger.
Critterhunter
New member
I never looked close at the little charge circuit in the GT/Elite rechargeable packs. I suspect it has both a thermal cutoff switch, a diode to prevent reverse polarity, and also a tiny charge circuit, as I have heard some say the little green light on the pack either dims or goes out when the pack is charged. The wall transformer is just that, with no brains, and just puts out a steady very low trickle rate of current.
On older Sovereigns and I think the Excalibur they lack any charge termination circuit at all and just feature perhaps a thermal overload switch, because when you trickle charge there isn't really much need (to manufacturers that is) to terminate the charge when peaked. For nicads I always heard this was fine, but for nimhs I always heard continuing to trickle charge after the pack has peaked will shorten it's life.
Either way, unless you let the nimh sit for hours on the wall transformer probably not much harm done. I just hate using those dumb wall transformers that come with detectors and cordless drills just to be cheap, and the fact that they are using a trickle charge so they don't need to provide a shut off circuit means ultra slow charge times of say 10 hours or more on a dead pack, well beyond a slow rate needed to insure long term pack health.
If I had an Excalibur I'd be throwing a 3 cell lipo in it for various reasons, so long as it's small enough to fit, or one of the 3 cells could be moved in the pack as well to fit a bigger one in it. There are horror stories of lithium based cells (lipos, lithium ion, etc) exploding or venting when they are exposed to water. The truth is that if there is a puncture in the pack that allows that you'd know it long before that, because even moisture in the air can ignite it.
The bigger worry would be the pack getting wet in say salt water and creating a dead short between the batter terminals. But at least back when I read up on proper lipo disposal, you were to drain it all the way dead via a light bulb or such and then throw it into a bucket of salt water so the salt would complete the circuit and continue to drain the pack to completely dead (takes days).
[size=large]Disclaimer: Use my advice in this post, the prior one, and any others I've posted with extreme caution. Verify and confirm on your own, as there are many opinions out there on battery care. I just go by what I've read and experienced myself over the years, but am not saying I'm right. Risk to person, places, or property is a very real danger when messing with any battery type, even non-rechargeables or car batteries in an auto.[/size]
On older Sovereigns and I think the Excalibur they lack any charge termination circuit at all and just feature perhaps a thermal overload switch, because when you trickle charge there isn't really much need (to manufacturers that is) to terminate the charge when peaked. For nicads I always heard this was fine, but for nimhs I always heard continuing to trickle charge after the pack has peaked will shorten it's life.
Either way, unless you let the nimh sit for hours on the wall transformer probably not much harm done. I just hate using those dumb wall transformers that come with detectors and cordless drills just to be cheap, and the fact that they are using a trickle charge so they don't need to provide a shut off circuit means ultra slow charge times of say 10 hours or more on a dead pack, well beyond a slow rate needed to insure long term pack health.
If I had an Excalibur I'd be throwing a 3 cell lipo in it for various reasons, so long as it's small enough to fit, or one of the 3 cells could be moved in the pack as well to fit a bigger one in it. There are horror stories of lithium based cells (lipos, lithium ion, etc) exploding or venting when they are exposed to water. The truth is that if there is a puncture in the pack that allows that you'd know it long before that, because even moisture in the air can ignite it.
The bigger worry would be the pack getting wet in say salt water and creating a dead short between the batter terminals. But at least back when I read up on proper lipo disposal, you were to drain it all the way dead via a light bulb or such and then throw it into a bucket of salt water so the salt would complete the circuit and continue to drain the pack to completely dead (takes days).
[size=large]Disclaimer: Use my advice in this post, the prior one, and any others I've posted with extreme caution. Verify and confirm on your own, as there are many opinions out there on battery care. I just go by what I've read and experienced myself over the years, but am not saying I'm right. Risk to person, places, or property is a very real danger when messing with any battery type, even non-rechargeables or car batteries in an auto.[/size]
Wow Critterhunter, thank you for the very informative replies, I really appreciate them 
I read up on your posts in the sticky on batteries before starting any of this (and with setting up the Accucell, infact the purchase of that charger was mainly down to reading your posts, ...thank you sir ) and wouldnt have attempted any of it without having all that info to read at hand, plus advice on charge rates etc
Not sure I want to go the Lipo route at the moment, there are a couple of very small cracks in the screw thread part of both my pods (overtightening/impact shock??) and I wouldnt want to risk any potential leaks
youve given me loads to think about, your input is very much appeciated, cheers
Mike
GL & HH
I read up on your posts in the sticky on batteries before starting any of this (and with setting up the Accucell, infact the purchase of that charger was mainly down to reading your posts, ...thank you sir
) and wouldnt have attempted any of it without having all that info to read at hand, plus advice on charge rates etcNot sure I want to go the Lipo route at the moment, there are a couple of very small cracks in the screw thread part of both my pods (overtightening/impact shock??) and I wouldnt want to risk any potential leaks
youve given me loads to think about, your input is very much appeciated, cheers
Mike
GL & HH
Critterhunter
New member
My advice is either useful or hated, so guess it was a coin flip on that...
You might also want to search back about a month or two in this forum, as somebody was looking into using LifePo4 cells in their Sovereign, and they seemed perfect in many respects. Still in hard casing though so not as light as a lipo, but still lighter than a nimh or nicad being lithium based I guess. They are supposedly more able to stand up to accidental abuse without as much risk of things going nuclear, and also have a few other perks to them.
I forget off hand but I think the Accucel does Life cells, so I bet (need to research that) that charging mode is compatible with LifePo4 and maybe LifePo4 is just an advancement in chemistry for abuse/reliability reasons. Or, might be by setting the per cell voltage to one of the other lithium based cell types you can "fudge" a charge mode to charge them, but be very careful and know what you are doing.
You might also want to search back about a month or two in this forum, as somebody was looking into using LifePo4 cells in their Sovereign, and they seemed perfect in many respects. Still in hard casing though so not as light as a lipo, but still lighter than a nimh or nicad being lithium based I guess. They are supposedly more able to stand up to accidental abuse without as much risk of things going nuclear, and also have a few other perks to them.
I forget off hand but I think the Accucel does Life cells, so I bet (need to research that) that charging mode is compatible with LifePo4 and maybe LifePo4 is just an advancement in chemistry for abuse/reliability reasons. Or, might be by setting the per cell voltage to one of the other lithium based cell types you can "fudge" a charge mode to charge them, but be very careful and know what you are doing.
Cool!! Thanks for sharing. HH Ron
During this past winter I made up a Lipo pack too, but mine is bigger battery as it is the 2200 and used a old rechargeable pack I had around just to see how it will work. I got the battery for $7 and the charger for around $20 like you and a DC adapter for around $15. Being the battery is bigger I mounted it on the outside of the pack and fastened it with industeral velco and have the wire with the conector soldered to the termanals of the GT battery box. Now I can slide it open and disconect the plug and connect to my charger as it has the same adapter as the battery does. I just tried it indoors and it seems to work good and being I am probably going to hipmount in a camera bag I may make a extention cable so the battery can sit in one of the pouches it has. As of now it sits on the outside of the GT battery pack as it is too thick.
Critterhunter
New member
Rick, that's cool. You should get tons of run time with a lipo pack that size. I have a bunch of 2250ma 3 cell lipos I use for my electric RC plane builds to power them. I had thought about putting one on my GT but this particular brand/style of lipo is a bit thicker than the alkaline holder. I was thinking of mounting it via velcro on top of the GT right up along side the shaft mount to keep it somewhat protect, because lipos have soft foil shells and one puncture or slit in the woods by a branch or something would be a very bad situation. I have wrecked them so badly in planes though they they were squashed like a front end wreck on a car, and yet they never went nuclear (I isolated them for days and kept an eye on them) and still worked fine.
I could have bought a much higher lipo capacity to run in my GT's alkaline holder, but even though lipos are very light I was shooting for saving every gram of weight on my light weight land shaft build, so I opted for 750 packs- Two, one for a backup. Still, just the other day I hunted over 9 hours with the machine never turned off during breaks, and found the charger had put 705ma of capacity back into it, so it still had run time and probably more than expected, as these lipos, like nimhs or nicads, often hold more capacity than their label says if they are in good health.
I'm happy with 9+ hours anyway. By far I'll never hunt longer than that in one day, and if I'm camping I'll just bring the second pack, or the beauty of the Accucel is that it runs off a 12VDC power source, so like when we are flying RC planes you can just pop the hood and use alligator clips to hook it up to your car battery. So long as the car battery is good, we've charged 10 to 20 packs or so in a day's RC flight of planes and never had the battery get so low it wouldn't start the car or truck. Or, just start the engine once in a while to let it idle and charge the battery again.
The Accucel has a low battery (meaning power source) alarm you can set. Be careful how low that is set as some wall DC inverters might sag a bit under the load and sound off the low voltage alarm. I didn't have mine set high enough to indicate my car battery was getting low and one day I was charging RC packs all day while flying and never started the car. The car battery was old and weak, and sure enough after everybody left the flying field I went to start the car and it wouldn't crank.
So...Here's the thing...Most lipos meant for RC can hold up to some very high amp draws (roughly 40 to 60 amps with some of my 2250ma packs), so I used a lipo to assist my car battery in starting it. I only had small wire alligator clips to hook the lipo to the battery terminals, but I figured they would carry the current for that split second of starting the car when cranking it long enough to hold up to the current flow. Sure enough, car started, but the insulation on those thin alligator jumper wires I used was BAKED.
Since then I set the low source voltage alarm on the Accucel to 11.5V, in that should a car battery get that low in voltage it should still have enough power to crank the motor. When it drops down to say 10V or so that's when you might have issues, but I now drive another truck and with a good battery in it, so I don't much worry about it.
Rick, do you charge your lipo via the white balance port plug on it? Using the main power leads alone (without the balance plug) for hooking the battery up to a charger is a bad thing to charge from, as that won't keep the cells in balance. Used to be when lipos first came out they lacked a balance plug to access the cells in parallel to monitor and cut off voltage to each cell individually when they were fully charge, and that's why lipos got a bad rap at first because an overcharged cell could cause a fire. Virtually all lipos and lipo chargers these days use a balance charging plug on them, unless they are 1 cell packs which obviously don't need it. Some chargers only require the balance plug to be plugged in while charging, while the Accucel requires both it and the main power lead to be plugged into the charger as well.
On the Accucel, it always powers up to I think a lipo charge mode that is the old style non-balance port method. This mode will only require the main power lead of the battery but is a very bad idea due to not using the balance plug as well. You have to hit the plus key and move to the balance charging mode and ALWAYS use that mode for safety. Plug in both battery leads and charge it at no higher than the proper charging max rate that pack allows. I always do 1C, as it isn't harsh on lipos to charge them in an hour.
There is also a "fast" charge mode. It may sound like it ups the amp rate but all it does is cut out the very low trickle current near the end to top off the lipo. When I'm in a hurry I use that and it cuts about 20 minutes off the charge time sometimes, while not losing too much capacity put back in (probably in the 100 to 200ma range or so).
If storing a lipo for long periods (months), use the sleep mode to put it at the proper long term voltage for lipo storage and then throw it in a fire proof box in the refrigerator. I've got lipos that have been sleeping for a few years in there. I need to pull them out and check their sleep voltage status, as while lipos have almost zero self discharge and are ready for action months after charging, they do still drain but at a very slow crawl compared to nimhs/nicads.
The AA "ribs" inside the GT's alkaline holder I clipped down so my lipo wasn't riding on a pointy surface. I need to dremel those ribs all the way down to lesson the risk of a puncture further and make sure there is no sharp surfaces. Regular AAs will still fit fine, you just might have to put a piece of tape across them to hold them better in place where the ribs might have did that.
For the main power connector on the Accucel to it's power source, I always just use alligator clips so I can adapt it to a car battery, my hacked computer power supply, or other 12VDC sources fast. The hacked computer power supply I garbage picked I mounted voltage post on to clip the alligator clips to, and using alligator clips on a car battery is obvious that way.
Many guys in RC will have a wall inverter to power their chargers while charging packs inside the house, and instead of using a DC power plug for their charger(s) to plug into the 12V power source, they hook the power source up to two metal wires (coat hangers work well) that they mounted away from each other on a wood block much like two parallel monkey bars at a play ground. That way they can clip several chargers up to the power source fast via alligator clips. So long as the DC invertor can hold up to the current draw of several chargers at once it works fine so you can charge several packs at once with different chargers.
If anybody is considering using a lipo in their Sovereign, but you are worried about proper set up of a computerized charger, there are several cheap plug and play chargers out there for around $7. One I have as a backup to my Accucel or as a second (I use 3) lipo charger when rotating RC plane packs in the field, is the Hextroniks plug and charge simple charger. It's an excellent value and many use it. Not much you can do wrong with it. Simply set the charge current selector switch to 1C of the pack or anything lower than that, and then plug in the lipo via it's balance plug and that's it. The charger will turn 3 lights to red (for a 3 cell lipo's 3 cells), and as each cell is fully charged the lights will one at a time turn green. This charger is built like a tank out of aluminum (it has a blue and silver case) and has a big fan on it that comes out when charging to keep the charger cool.
Some lipos can hold up to higher than 1C max charge rates these days, but way I look at it who can't wait an hour for a dead pack to charge? Dead being a 3 cell has been drawn down to near 9V, as it should never be drawn down further than 3V per cell or it could hurt the pack. Besides, using the 1C math it's much easier to computer max charge rate. IE: 1 amp for a 1000ma lipo, .750 (that's point 750) amps for a 750ma pack, or say 2.2 amps for a 2200ma pack.
It doesn't hurt a lipo to charge at slower rates, but doing that offers no greater life span to them, unlike some nimhs or nicads where a 1C charge rate might lower their cycle life or capacity over time, unless they are meant for high charge rates of that or higher. Really most nimhs/nicads are just fine with 1C, provided the pack is not getting warm. Heat destroys batteries over time.
I always shoot for about 1/3rd to 1/2C max for nimhs, nicads, and only charge at up to 1C when in an absolute hurry, like say when my plane transmitter is getting low in power in the field. With that, I'll even charge the 2500ma nimh pack in (made one with Energizer 2500ma AA nimhs) at say 3 to 4 amps just to quickly get a full charge in it again, but I know that's abusing those Energizers, but don't care as I have boat loads of them laying around somebody gave me.
PS- Might add, that when charging nimhs or nicads, sometimes the faster the charge rate the higher you need to set the m/v threshold setting on a charger that allows you to do that, as the peaks and valleys in the charging process might be more pronounced. I always shoot for 5 m/v on a nimh and 12 m/v for a nicad. If the pack false terminates and I know it's not done charging, then I'll raise the # by 2 and try again.
I could have bought a much higher lipo capacity to run in my GT's alkaline holder, but even though lipos are very light I was shooting for saving every gram of weight on my light weight land shaft build, so I opted for 750 packs- Two, one for a backup. Still, just the other day I hunted over 9 hours with the machine never turned off during breaks, and found the charger had put 705ma of capacity back into it, so it still had run time and probably more than expected, as these lipos, like nimhs or nicads, often hold more capacity than their label says if they are in good health.
I'm happy with 9+ hours anyway. By far I'll never hunt longer than that in one day, and if I'm camping I'll just bring the second pack, or the beauty of the Accucel is that it runs off a 12VDC power source, so like when we are flying RC planes you can just pop the hood and use alligator clips to hook it up to your car battery. So long as the car battery is good, we've charged 10 to 20 packs or so in a day's RC flight of planes and never had the battery get so low it wouldn't start the car or truck. Or, just start the engine once in a while to let it idle and charge the battery again.
The Accucel has a low battery (meaning power source) alarm you can set. Be careful how low that is set as some wall DC inverters might sag a bit under the load and sound off the low voltage alarm. I didn't have mine set high enough to indicate my car battery was getting low and one day I was charging RC packs all day while flying and never started the car. The car battery was old and weak, and sure enough after everybody left the flying field I went to start the car and it wouldn't crank.
So...Here's the thing...Most lipos meant for RC can hold up to some very high amp draws (roughly 40 to 60 amps with some of my 2250ma packs), so I used a lipo to assist my car battery in starting it. I only had small wire alligator clips to hook the lipo to the battery terminals, but I figured they would carry the current for that split second of starting the car when cranking it long enough to hold up to the current flow. Sure enough, car started, but the insulation on those thin alligator jumper wires I used was BAKED.
Since then I set the low source voltage alarm on the Accucel to 11.5V, in that should a car battery get that low in voltage it should still have enough power to crank the motor. When it drops down to say 10V or so that's when you might have issues, but I now drive another truck and with a good battery in it, so I don't much worry about it.
Rick, do you charge your lipo via the white balance port plug on it? Using the main power leads alone (without the balance plug) for hooking the battery up to a charger is a bad thing to charge from, as that won't keep the cells in balance. Used to be when lipos first came out they lacked a balance plug to access the cells in parallel to monitor and cut off voltage to each cell individually when they were fully charge, and that's why lipos got a bad rap at first because an overcharged cell could cause a fire. Virtually all lipos and lipo chargers these days use a balance charging plug on them, unless they are 1 cell packs which obviously don't need it. Some chargers only require the balance plug to be plugged in while charging, while the Accucel requires both it and the main power lead to be plugged into the charger as well.
On the Accucel, it always powers up to I think a lipo charge mode that is the old style non-balance port method. This mode will only require the main power lead of the battery but is a very bad idea due to not using the balance plug as well. You have to hit the plus key and move to the balance charging mode and ALWAYS use that mode for safety. Plug in both battery leads and charge it at no higher than the proper charging max rate that pack allows. I always do 1C, as it isn't harsh on lipos to charge them in an hour.
There is also a "fast" charge mode. It may sound like it ups the amp rate but all it does is cut out the very low trickle current near the end to top off the lipo. When I'm in a hurry I use that and it cuts about 20 minutes off the charge time sometimes, while not losing too much capacity put back in (probably in the 100 to 200ma range or so).
If storing a lipo for long periods (months), use the sleep mode to put it at the proper long term voltage for lipo storage and then throw it in a fire proof box in the refrigerator. I've got lipos that have been sleeping for a few years in there. I need to pull them out and check their sleep voltage status, as while lipos have almost zero self discharge and are ready for action months after charging, they do still drain but at a very slow crawl compared to nimhs/nicads.
The AA "ribs" inside the GT's alkaline holder I clipped down so my lipo wasn't riding on a pointy surface. I need to dremel those ribs all the way down to lesson the risk of a puncture further and make sure there is no sharp surfaces. Regular AAs will still fit fine, you just might have to put a piece of tape across them to hold them better in place where the ribs might have did that.
For the main power connector on the Accucel to it's power source, I always just use alligator clips so I can adapt it to a car battery, my hacked computer power supply, or other 12VDC sources fast. The hacked computer power supply I garbage picked I mounted voltage post on to clip the alligator clips to, and using alligator clips on a car battery is obvious that way.
Many guys in RC will have a wall inverter to power their chargers while charging packs inside the house, and instead of using a DC power plug for their charger(s) to plug into the 12V power source, they hook the power source up to two metal wires (coat hangers work well) that they mounted away from each other on a wood block much like two parallel monkey bars at a play ground. That way they can clip several chargers up to the power source fast via alligator clips. So long as the DC invertor can hold up to the current draw of several chargers at once it works fine so you can charge several packs at once with different chargers.
If anybody is considering using a lipo in their Sovereign, but you are worried about proper set up of a computerized charger, there are several cheap plug and play chargers out there for around $7. One I have as a backup to my Accucel or as a second (I use 3) lipo charger when rotating RC plane packs in the field, is the Hextroniks plug and charge simple charger. It's an excellent value and many use it. Not much you can do wrong with it. Simply set the charge current selector switch to 1C of the pack or anything lower than that, and then plug in the lipo via it's balance plug and that's it. The charger will turn 3 lights to red (for a 3 cell lipo's 3 cells), and as each cell is fully charged the lights will one at a time turn green. This charger is built like a tank out of aluminum (it has a blue and silver case) and has a big fan on it that comes out when charging to keep the charger cool.
Some lipos can hold up to higher than 1C max charge rates these days, but way I look at it who can't wait an hour for a dead pack to charge? Dead being a 3 cell has been drawn down to near 9V, as it should never be drawn down further than 3V per cell or it could hurt the pack. Besides, using the 1C math it's much easier to computer max charge rate. IE: 1 amp for a 1000ma lipo, .750 (that's point 750) amps for a 750ma pack, or say 2.2 amps for a 2200ma pack.
It doesn't hurt a lipo to charge at slower rates, but doing that offers no greater life span to them, unlike some nimhs or nicads where a 1C charge rate might lower their cycle life or capacity over time, unless they are meant for high charge rates of that or higher. Really most nimhs/nicads are just fine with 1C, provided the pack is not getting warm. Heat destroys batteries over time.
I always shoot for about 1/3rd to 1/2C max for nimhs, nicads, and only charge at up to 1C when in an absolute hurry, like say when my plane transmitter is getting low in power in the field. With that, I'll even charge the 2500ma nimh pack in (made one with Energizer 2500ma AA nimhs) at say 3 to 4 amps just to quickly get a full charge in it again, but I know that's abusing those Energizers, but don't care as I have boat loads of them laying around somebody gave me.
PS- Might add, that when charging nimhs or nicads, sometimes the faster the charge rate the higher you need to set the m/v threshold setting on a charger that allows you to do that, as the peaks and valleys in the charging process might be more pronounced. I always shoot for 5 m/v on a nimh and 12 m/v for a nicad. If the pack false terminates and I know it's not done charging, then I'll raise the # by 2 and try again.
Yes I used the balance port too and had wondered what that extra wires were for on the pack, but when I read the manual on the charger I seen what it was for. I have 2 different Accucel charger and the first one can be used on different type of batteries, but it came with no owners manual. The second one I got was a new one from what i understand that was recommended when I ordered in the pack and seems much easier to use and and has different lights on when it does the balance on the pack so I can see when each cell is balanced out. I order in both the male and female connectors (don't know what style they are, but was the type the battery pack have on them) so I put one on the charger and going to try to fine the thinner ones that will fit in the GT pack or some of the older XS style battery box.
Just waiting for the snow to leave and the ground to thaw as I got the pack in and the 12X10 SEF coil on ready to go. We are in a winter storm watch until Monday morning with 3-14 inches of snow coming which is odd this time of the year up here in ND.
Rick
Just waiting for the snow to leave and the ground to thaw as I got the pack in and the 12X10 SEF coil on ready to go. We are in a winter storm watch until Monday morning with 3-14 inches of snow coming which is odd this time of the year up here in ND.
Rick
Critterhunter
New member
Rick, anxious to hear your thoughts on the 12x10 and also look forward to hearing more from Ron who thus far seems to be doing well with it. I can say I just did another 8 hour hunt today with the S-12 and it gave me extra motivation to fix the short on my 12x10's cable behind the plug so I can go back to it.
Sounds like the 2nd charger you got was the Hextronics? In a metal aluminum case with lights that turn green from red as each cell reaches it's target voltage and is done charging? I have that charger and it's a great simple plug and charge charger which only requires you to set the sliding amp charging rate switch to what you want. It's very popular as a durable 2nd or 3rd charger in the field, but in terms of versatility for various battery types besides just lipos, the Accucel is probably the most popular out there in RC circles. Fantastic value in a charger for about $20, with features not seen on chargers costing over $100.
The Accucel 6 has a manual online but doesn't come with it when shipped. That manual has a few errors in it due to it's English translation and such. The Accucel will show you the individual cell voltage as they charge in balance charging mode. Once the charge starts just hit the plus key and it'll toggle to another screen which shows the per cell voltages.
I prefer that display when charging just to monitor that the cells were relatively close to each other when the charge starts, and also that none are lagging behind as the charge proceeds to the end, which could indicate a cell is having issues and the pack might not have much life yet. Never seen that happen yet in a lipo, but just the same I like to keep tabs on such things.
If you hit the minus key while a pack is charging and continue to press it off and on, it will toggle through various settings that it's using to show for the pack. Off hand I don't remember if it shows anything with lipos, but I know with nimhs and nicads it'll toggle through what things are set for with them and such. With a lipo, after hitting the plus key to see the individual cell voltages as they charge, hit it again and you'll return to the original charging display which shows total pack voltage and the capacity thus far put back into the pack.
The sleep mode will charge or drain a pack to a targeted voltage for long term storage, and once done I'll throw any cells I don't plan to use for months into the refrigerator in a fire proof metal box painted inside to prevent shorts, and also rooms created for each pack via drywall (which is non-flammable) I cut up. That way if a lipo goes nuclear on me it won't take the others with it. The lid should have several small vent holes drilled into it like a speaker cover so should a pack vent or explode it won't blow the lid off, but the holes shouldn't be so big as to allow a flame to lick it's way up out of it onto something.
I take this precaution with all my batteries, nicads, nimhs, etc, and not just lipos. Better safe than sorry. Only lipo that stays out and about is the current one in my GT when it's being used, and about every 4 months I'll yoke out the other 750ma Rhino pack I use and use that for a while, putting the other back to bed in the box with a sleep charge. The sleep charge is to insure maximum capacity holding ability when a lipo comes back into use again, as it's been found a certain voltage is the best for that when not in use for months or even several years.
Although lipos have about a zero self discharge factor, I do have many 2250ma 3 cell packs I use in my RC electric planes that have been sleeping for about a year or two, which I really should take out and re-do the sleep charge thing with to make sure they are where they should be voltage wise. If over time a cell drops below 3V it could ruin the pack, but I have recovered lipos in planes that got stuck in trees for a few days and had drained past that a bit.
Most lipo chargers will refuse to charge a lipo that has a cell below 3V, not just for safety reasons but also because many lipo chargers require you to set the cell count of the pack (3 in this case), and then they read the pack voltage to make sure it matches what a 3 cell pack should be. That's so if you accidentally set the pack cell count to a 4 cell pack or something, the charger won't overcharge a 3 cell pack trying to reach a 4 cell pack's higher voltage. It's a dual safety feature. You set it, but then the charger confirms it.
But when I've had a lipo get a cell or two below 3V and the charger refused to charge it, I give it a very slow (like say 50ma) charge on a nimh or nicad charger for a few minutes to gently bring the pack back up to proper miminal voltage and then throw back on a lipo charger to finish the job. This kind of thing might be risky though. Never read into it, but I've never had issues with doing that and returned a lipo back to service with no problems.
Again, this might be a safety risk. Not sure on that, but I know it's a common practice among guys who had a plane stuck in a tree for a few days. If the lipo is all the way dead, chances are even if it's brought back up to minimal voltage to throw on a lipo charger, it probably won't offer much performance after that.
Then again, chemistry's continue to be tweaked in lipos to both make them safer and also hold up to abuse. I can say the first lipos I bought a good 7+ years back didn't hold up to much abuse at all and would quickly fail to deliver the performance they had new, while the ones I've bought in about the last 5 years are much more robust to high amp draw applications without bloating or losing capacity.
PS- On these ultra small/light 750ma Rhino packs ($7 a piece) after a 9 hour hunt or so I'm not even hitting the low battery alarm. Last time I charged it after that it put 705ma back in, and since lipos, like nimhs or nicads, often hold more capacity than the label says, I'd suspect I can go at least 12 to 14 hours if not longer with one of these little packs. I was shooting for every ounce I could save on my light weight land rig, so I'm completely happy with the run time. I don't turn off my detector when taking breaks anymore, so the run time is completely on for the entire time. I'm doing that now so I don't have to reset the ground balance for PP mode after setting it via All Metal Tracking mode.
Sounds like the 2nd charger you got was the Hextronics? In a metal aluminum case with lights that turn green from red as each cell reaches it's target voltage and is done charging? I have that charger and it's a great simple plug and charge charger which only requires you to set the sliding amp charging rate switch to what you want. It's very popular as a durable 2nd or 3rd charger in the field, but in terms of versatility for various battery types besides just lipos, the Accucel is probably the most popular out there in RC circles. Fantastic value in a charger for about $20, with features not seen on chargers costing over $100.
The Accucel 6 has a manual online but doesn't come with it when shipped. That manual has a few errors in it due to it's English translation and such. The Accucel will show you the individual cell voltage as they charge in balance charging mode. Once the charge starts just hit the plus key and it'll toggle to another screen which shows the per cell voltages.
I prefer that display when charging just to monitor that the cells were relatively close to each other when the charge starts, and also that none are lagging behind as the charge proceeds to the end, which could indicate a cell is having issues and the pack might not have much life yet. Never seen that happen yet in a lipo, but just the same I like to keep tabs on such things.
If you hit the minus key while a pack is charging and continue to press it off and on, it will toggle through various settings that it's using to show for the pack. Off hand I don't remember if it shows anything with lipos, but I know with nimhs and nicads it'll toggle through what things are set for with them and such. With a lipo, after hitting the plus key to see the individual cell voltages as they charge, hit it again and you'll return to the original charging display which shows total pack voltage and the capacity thus far put back into the pack.
The sleep mode will charge or drain a pack to a targeted voltage for long term storage, and once done I'll throw any cells I don't plan to use for months into the refrigerator in a fire proof metal box painted inside to prevent shorts, and also rooms created for each pack via drywall (which is non-flammable) I cut up. That way if a lipo goes nuclear on me it won't take the others with it. The lid should have several small vent holes drilled into it like a speaker cover so should a pack vent or explode it won't blow the lid off, but the holes shouldn't be so big as to allow a flame to lick it's way up out of it onto something.
I take this precaution with all my batteries, nicads, nimhs, etc, and not just lipos. Better safe than sorry. Only lipo that stays out and about is the current one in my GT when it's being used, and about every 4 months I'll yoke out the other 750ma Rhino pack I use and use that for a while, putting the other back to bed in the box with a sleep charge. The sleep charge is to insure maximum capacity holding ability when a lipo comes back into use again, as it's been found a certain voltage is the best for that when not in use for months or even several years.
Although lipos have about a zero self discharge factor, I do have many 2250ma 3 cell packs I use in my RC electric planes that have been sleeping for about a year or two, which I really should take out and re-do the sleep charge thing with to make sure they are where they should be voltage wise. If over time a cell drops below 3V it could ruin the pack, but I have recovered lipos in planes that got stuck in trees for a few days and had drained past that a bit.
Most lipo chargers will refuse to charge a lipo that has a cell below 3V, not just for safety reasons but also because many lipo chargers require you to set the cell count of the pack (3 in this case), and then they read the pack voltage to make sure it matches what a 3 cell pack should be. That's so if you accidentally set the pack cell count to a 4 cell pack or something, the charger won't overcharge a 3 cell pack trying to reach a 4 cell pack's higher voltage. It's a dual safety feature. You set it, but then the charger confirms it.
But when I've had a lipo get a cell or two below 3V and the charger refused to charge it, I give it a very slow (like say 50ma) charge on a nimh or nicad charger for a few minutes to gently bring the pack back up to proper miminal voltage and then throw back on a lipo charger to finish the job. This kind of thing might be risky though. Never read into it, but I've never had issues with doing that and returned a lipo back to service with no problems.
Again, this might be a safety risk. Not sure on that, but I know it's a common practice among guys who had a plane stuck in a tree for a few days. If the lipo is all the way dead, chances are even if it's brought back up to minimal voltage to throw on a lipo charger, it probably won't offer much performance after that.
Then again, chemistry's continue to be tweaked in lipos to both make them safer and also hold up to abuse. I can say the first lipos I bought a good 7+ years back didn't hold up to much abuse at all and would quickly fail to deliver the performance they had new, while the ones I've bought in about the last 5 years are much more robust to high amp draw applications without bloating or losing capacity.
PS- On these ultra small/light 750ma Rhino packs ($7 a piece) after a 9 hour hunt or so I'm not even hitting the low battery alarm. Last time I charged it after that it put 705ma back in, and since lipos, like nimhs or nicads, often hold more capacity than the label says, I'd suspect I can go at least 12 to 14 hours if not longer with one of these little packs. I was shooting for every ounce I could save on my light weight land rig, so I'm completely happy with the run time. I don't turn off my detector when taking breaks anymore, so the run time is completely on for the entire time. I'm doing that now so I don't have to reset the ground balance for PP mode after setting it via All Metal Tracking mode.