well, the batteries now supplied by Minelab are NiMh (Nickel Metal Hydride) and NOT nicads. Different batteries entirely. Supposedly NiMh batteries DO NOT develop Memory issues as outlined in your post. Old habits die hard though, and I like to let the batteries run down all the way before I charge them by leaving by leaving the threshold on the Excaliber until it quits. Funny thing about NiMh, I was reading another post and this may not only be not needed with NiMh batteries BUT if you run them down with a little lamp like we used to do with the old Nicad batteries to wipe out any memory, the batteries can SWITCH POLARITY and fry when you try to charge them!!! I am obviously NOT a battery expert so I don't know about that one. I do know that NiMh batteries DO NOT tend to develope memory issues and DO NOT need to be cycled down to zero charge like the old nicads, and if the other post about a polarity shift is correct, something we all did for years to PROTECT our Nicads can actually be HARMFULL to these new NiMh batteries
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Rechargeable batteries for Excalibur
- Thread starter crs
- Start date
Art (NWOH)
New member
Excal, right??
You don't have ni-mh unless the rechargeable pack has been modified.
Ni-mh won't run long in alkaline packs. Insufficient voltage.
100 ma sounds wrong for an Xcal. Would be right for Elite and GT packs, but they have the higher capacity ni-mh (1000 mah) as opposed to the 750 mah ni-cds for the older Sovs and Xcals. They use 60 ma chargers.
If you run a timed full charge on the 750 mah ni-cd with a 100 ma charger, you will be cooking it. You would have to reduce charge time to about 2/3 of what is recommended in the book (60/100x12 to 14hrs).
Don't try to recharge the alkaline pack loaded with ni-mh batteries.
HH
You don't have ni-mh unless the rechargeable pack has been modified.
Ni-mh won't run long in alkaline packs. Insufficient voltage.
100 ma sounds wrong for an Xcal. Would be right for Elite and GT packs, but they have the higher capacity ni-mh (1000 mah) as opposed to the 750 mah ni-cds for the older Sovs and Xcals. They use 60 ma chargers.
If you run a timed full charge on the 750 mah ni-cd with a 100 ma charger, you will be cooking it. You would have to reduce charge time to about 2/3 of what is recommended in the book (60/100x12 to 14hrs).
Don't try to recharge the alkaline pack loaded with ni-mh batteries.
HH
Art (NWOH)
New member
Someone recently checked with Minelab, and was told that Xcals still have ni-cds. So if you don't know for sure, then treat them as you would with ni-cds.
As far as running the pack down too low, or completely dead........this will cause reverse charge and damage to ni-mh and ni-cd alike.
I have also seen conflicting advice on the forums, and in the instruction books of ni-cd powered tools and such concerning charging and storage. I know for a fact that some of this stuff will do in your batteries..........
For example.....
Run the batt flat before recharge.
Store the batt fully discharged.
Reasons NOT to do this stuff........
Running a pack flat reverse charges some of the cells.
I have stored packs long enough that they fully discharged by themself. They were completely ruined. Seems the integrity of a battery falls apart if there is no charge remaining to keep it stable.
HH
As far as running the pack down too low, or completely dead........this will cause reverse charge and damage to ni-mh and ni-cd alike.
I have also seen conflicting advice on the forums, and in the instruction books of ni-cd powered tools and such concerning charging and storage. I know for a fact that some of this stuff will do in your batteries..........
For example.....
Run the batt flat before recharge.
Store the batt fully discharged.
Reasons NOT to do this stuff........
Running a pack flat reverse charges some of the cells.
I have stored packs long enough that they fully discharged by themself. They were completely ruined. Seems the integrity of a battery falls apart if there is no charge remaining to keep it stable.
HH
Art (NWOH)
New member
Since we are talking about a "smart" charger....
It's for lead batteries. There is a small problem here.....
I would guess that it periodically samples the battery voltage to see if it is up to the full charge level, and kicks in if voltage is too low. Now.....
Different kinds of batteries have different voltage at full charge. In this case we say that anything "close" to 12 volts is a 12 volt battery. However full charge on batteries constructed of different materials do not produce the same exact voltages.
You can check this out with a volt meter.......
Measure the voltage of your alkaline pack with alkalines in it. Then put lithium cells in it and repeat. Then measure your ni-mh pack. Measure a ni-cd pack if you have one. Then measure your car or lawnmower battery (lead). You will see that a 12 volt battery is not really 12 volts.
So back to the subject of the "smart" charger in question.......
If I am correct it is intended to work with lead batteries, and therefore decides if the LEAD battery is up to full charge or not. Apparently, the charger is not cooking the detector batteries so it must be terminating the charge before it gets to an overcharge condition. This by itself should not cause a problem.
However.....
Since the charger is made for lead batteries , it may be shutting down before the detector batteries reach full charge (different construction, right?). In effect, a "short" charge. If so, then just how much too short? Enough to reduce operating time to a significant degree?
Since our rechargeables have a different operating curve than a lead battery, we could be coming up a little short here. Not to mention what this could do to a ni-cd.
Not going to buy one to run some tests on to see what it's going to do. Will stick with what I have.
HH
It's for lead batteries. There is a small problem here.....
I would guess that it periodically samples the battery voltage to see if it is up to the full charge level, and kicks in if voltage is too low. Now.....
Different kinds of batteries have different voltage at full charge. In this case we say that anything "close" to 12 volts is a 12 volt battery. However full charge on batteries constructed of different materials do not produce the same exact voltages.
You can check this out with a volt meter.......
Measure the voltage of your alkaline pack with alkalines in it. Then put lithium cells in it and repeat. Then measure your ni-mh pack. Measure a ni-cd pack if you have one. Then measure your car or lawnmower battery (lead). You will see that a 12 volt battery is not really 12 volts.
So back to the subject of the "smart" charger in question.......
If I am correct it is intended to work with lead batteries, and therefore decides if the LEAD battery is up to full charge or not. Apparently, the charger is not cooking the detector batteries so it must be terminating the charge before it gets to an overcharge condition. This by itself should not cause a problem.
However.....
Since the charger is made for lead batteries , it may be shutting down before the detector batteries reach full charge (different construction, right?). In effect, a "short" charge. If so, then just how much too short? Enough to reduce operating time to a significant degree?
Since our rechargeables have a different operating curve than a lead battery, we could be coming up a little short here. Not to mention what this could do to a ni-cd.
Not going to buy one to run some tests on to see what it's going to do. Will stick with what I have.
HH
Art (NWOH)
New member
Really, from what I have read.......
The ideal "trickle" to maintain a battery at full charge would be just enough current to offset the internal leakage of the battery that causes it to self drain over time. This would be a VERY low current......at least if the battery is good.
I don't want to open a whole new can of worms here, with this kind of stuff.......
How fast of a charge is too fast?
What defines "trickle charger"?
What trickle charging rate is safe after batteries get fully charged?
At what rate do batteries self drain?
How much can you abuse batteries before they go to crap?
How can I tell if the pack has a bad cell?
How long can I charge my batteries with my car battery charger on "boost" before they explode?
Nope......getting real burned out on the battery issue.
Your Sunray charger sounds something like a camcorder charger I have. You push refresh and it cycles the battery through a safe discharge then recharges. Very handy.
HH
The ideal "trickle" to maintain a battery at full charge would be just enough current to offset the internal leakage of the battery that causes it to self drain over time. This would be a VERY low current......at least if the battery is good.
I don't want to open a whole new can of worms here, with this kind of stuff.......
How fast of a charge is too fast?
What defines "trickle charger"?
What trickle charging rate is safe after batteries get fully charged?
At what rate do batteries self drain?
How much can you abuse batteries before they go to crap?
How can I tell if the pack has a bad cell?
How long can I charge my batteries with my car battery charger on "boost" before they explode?
Nope......getting real burned out on the battery issue.
Your Sunray charger sounds something like a camcorder charger I have. You push refresh and it cycles the battery through a safe discharge then recharges. Very handy.
HH
I am just going by what the ownwers manual says about battery type(Nimh VS NiCad) The Excaliber is a year old so would have whatever was new at that time.Manual does say they are NiMh though.WHATEVER! As long as I am detecting I don't care if they are Martian Anti Matter batteries!Always did like Alkaline batteries anyway, but my 1280-x would run so long on a fresh set I would forget when I put in Batteries, NOT SO with the Excaliber, bigtime battery hog.
Art (NWOH)
New member
They do suck some juice.
The packs in the Elite and GT really added some run time over the older ni-cds.
Been so long since I ran out a set of alkalines that I don't remember how long they last.
If you really do have a 100 ma charger, then they may well have switched batteries and charger to match the GT.
I have gotten to the point that I would have to see something for myself before I believe it anymore.
Have fun.
HH
The packs in the Elite and GT really added some run time over the older ni-cds.
Been so long since I ran out a set of alkalines that I don't remember how long they last.
If you really do have a 100 ma charger, then they may well have switched batteries and charger to match the GT.
I have gotten to the point that I would have to see something for myself before I believe it anymore.
Have fun.
HH
Of course,
The original charger is design for Ni Ca who needs a smaller current 60mA. Ni -Mh batteries can be charged with bigger current, for our type 100mA. Using the original charger will make no harm to the batteries. Only the time will be the regular time for the original batteries.
All the best,
Cristian
The original charger is design for Ni Ca who needs a smaller current 60mA. Ni -Mh batteries can be charged with bigger current, for our type 100mA. Using the original charger will make no harm to the batteries. Only the time will be the regular time for the original batteries.
All the best,
Cristian