reconditioning *HIGH* cells on Maha Wizard One

I have several cells that do not charge and show up as HIGH. I know people can get around this by placing it on a dumb charger for a few minutes and then trying again on the C-9000 to trick it. Is there a way once it does recognize the cell to sort of recondition it so the C-9000 will recognize it everytime instead of the routing with the dumb charger first? I have not very old 900mAh NiMH Sanyo AAA cells doing this which is odd as they maybe have 30-50 cycles on them tops. No where near the 500-1000 cycles they are supposed to have.

Beacon of Light said:

I have several cells that do not charge and show up as HIGH. I know people can get around this by placing it on a dumb charger for a few minutes and then trying again on the C-9000 to trick it. Is there a way once it does recognize the cell to sort of recondition it so the C-9000 will recognize it everytime instead of the routing with the dumb charger first? I have not very old 900mAh NiMH Sanyo AAA cells doing this which is odd as they maybe have 30-50 cycles on them tops. No where near the 500-1000 cycles they are supposed to have.

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The only way to (possibly) recondition a cell like that is to run it through a break-in cycle. But if a cell is either dried out or too far degraded this will not help. AAA cells are very fragile and most brands and makes will fail prematurely. The most consistently reliable AAA cells I have come across are Eneloops. Second to Eneloops are some Kodak/GP Pre-Charged cells.

To persuade the C9000 to accept them on a break-in cycle, you might try completely discharging each cell individually down to a very low voltage by connecting a 1.5 V bulb across the terminals overnight. Then warm the cell up in your hand before putting it in the C9000. If it works, set the capacity to 800 mAh rather than 900 mAh to be on the safe side.

If it doesn't work, it is fair to say the cells are worn out and no longer good for demanding uses.

Forum went crazy. Duplicate post deleted.

would one of DatilLEDs battery drainers work for this purpose? They drain the cells down to .5 volts IIRC. I tried running the discharge cycle on my C9000 but the voltage was increasing as time went on. I thought the reading should decrease until it goes down to zero? Is this normal?

Beacon of Light said:

would one of DatilLEDs battery drainers work for this purpose? They drain the cells down to .5 volts IIRC. I tried running the discharge cycle on my C9000 but the voltage was increasing as time went on. I thought the reading should decrease until it goes down to zero? Is this normal?

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If the voltage starts increasing during a discharge this means the cell is "waking up" and is a good sign. You should certainly try running a discharge at 100 mA and letting it run to completion.

ok I will try that. What happens once it is completed as in fully discharged? Does it charge the cell? How far does it discharge the cell? What procedure after that step is complete? Break-In charge?

Beacon of Light said:

ok I will try that. What happens once it is completed as in fully discharged? Does it charge the cell? How far does it discharge the cell? What procedure after that step is complete? Break-In charge?

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Discharge on the C9000 takes the cell down to 0.9 V measured under load and then stops. It does nothing further until you intervene. After the discharge has completed you can try to put the cell on a break-in cycle with a setting of 800 mAh and see if the C9000 will accept it. If the cell is still not accepted you can try shorting the terminals of the discharged cell with a wire for a few hours, and try warming it up in your hand before trying again.

How do you normally charge and use these cells, out of interest?

Usually set the 700-900mAh AAA's on a 500-600mAh charge

I just discovered 6 of my AAA batteries killed by a GMRS radio systems trickle charger. 2 eneloop and 4 la crosse. Was going to just bin them, but after seeing this thread I suppose I will see what can be done. The Maha just says high for each of these cells and won't allow a recondition or discharge or any other function for that matter. A physical inspection of the La Crosse cells looks perfectly normal, but the Eneloops have a rust colored stain all around the anode. Is that a sign of venting, or....?

Resting voltage was at ~1.33V I am one Eneloop as we speak with a 3.3 ohm resistor. Voltage immediatley dropped to 1.0 volts or so and within 5 minutes was down to .83

I don't have much hope for any of these cells but I don't suppose I have much to lose.

If the cell has higher internal resistance, discharging on the C9000 won't be as effective, since it measures the voltage under load. This is a good thing for healthy cells, since it lets the charger know their relative state of charged capacity, but it doesn't let you sufficiently discharge these cells with higher internal resistance either.

Using something like a rheostat or potentiometer and monitoring the voltage to keep a constant 0.9V would probably work better, but be more tedious.

Maybe I'll make something to do this for me. Next project??? :naughty: