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Thread: Priming new-old-stock NiCD batteries for use

  1. #1
    Flashaholic*
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    Default Priming new-old-stock NiCD batteries for use

    I recently purchased a couple of new-old-stock NiCD battery stick packs. Accessing the cells individually is difficult but possible if required (security bit screw, I have the tool). They are 17 years old - manufacturing date is stamped into the casing. Both packs contain 2 cells and measured 2V out of the packaging. They come with trickle chargers that are designed for a 12 hour charge.

    Am I correct in assuming that if I charge them fully with the included trickle charger and then gently cycle them 5-10 times, they should prime nicely and work acceptably given their age?

    Are there any precautions I can take to increase the chance of a successful recovery?

    I am aware of the method usually used to remove voltage depression (bring them to ~0.5V per cell slowly using a very light load). Do I need to do this or should it be OK to just use them?

    For those of you curious, they are from the Game boy Pocket "battery charger set" only sold in Japan as far as I know, model MGB-002 (battery stick) and MGB-003 (wall wart charger). I purchased them because they cost almost nothing brand new and I have previously read that NOS NiCD batteries tend to recover well for light load applications - and they cost <$5 per set.

    I own a lab bench power supply I can use for manual priming if required.

    Any advice appreciated! I have old eneloops from 2005-2006 that I have kept in good condition, but those see use. This will be the first time I attempt to prime old NiCD cells.

  2. #2

    Default Re: Priming new-old-stock NiCD batteries for use

    I found some 18 to 20 year old aaa nicad( sanyo made) that were esentially 0 volts. Some charge discharge cycles brought them up to somwhere near thier normal capacity of only 250mah, but thats good enough for some short duration high drain non vital devices. Yours at 1v should be cycled probably 3 times full charge, full discharge to 1 volt, then a fourth time to deep discharge, less than 1v under light load but not for too long as you dont want a weak cell to go into reverse voltage. Moniter after that to see if they suffer very much voltage depression under load, nicads should have very little.

    Nicads do very well stored at dead to nearly dead for long periods of time if not at a high temperature.

  3. #3
    Enlightened
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    Default Re: Priming new-old-stock NiCD batteries for use

    If you have the proper bit I would open them up first tocheck for any sign of leaks. NiCds are incredibly durable as far as the amount of deep cycling is concerned. Itís almost always leaks that do them in first.


  4. #4
    Flashaholic*
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    Default Re: Priming new-old-stock NiCD batteries for use

    Thanks for your advice fmc1 and herektir. I'll open them up and check for noticeable leaks (if they are shrink wrapped into a stick I can make a small incision to look at the middle of the pack too) and cycle them gently to begin with. I thought gentle cycling might be a good idea, nice to hear that it probably will work. The GB Pocket itself should be a good test load for initial cycling, and I'll use a dummy load for the deep discharge.

  5. #5
    Flashaholic*
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    Default Re: Priming new-old-stock NiCD batteries for use

    Lots of info about charging NiCd at this site:

    http://www.electrodynam.com/rc/totm/totm1100.shtml

  6. #6
    Flashaholic*
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    Default Re: Priming new-old-stock NiCD batteries for use

    Thanks SubLGT for the link. I need to read up more about NiCD, the chemistry I never really had to deal with

    I'm happy to say that slowly cycling them so far is working. They have been through 1 cycle and held the rated capacity according to the manufacturer (based on the time it can power a game boy). I'll do a few more cycles followed by a deep discharge cycle. I couldn't see any corrosion which is surprising given the age!

  7. #7
    Flashaholic*
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    Default Re: Priming new-old-stock NiCD batteries for use

    Thank you everyone for your advice.
    Just popping in to update this old thread with the outcome for anyone else who buys these. TL;DR: New-old-stock official battery sticks for the GB Pocket/GB Color/GB Light (works with all 3) are probably OK as both of mine are now performing properly. They are so cheap that you can get them and swap the cells for modern NiMH cells if you wish.

    Both battery sticks are performing much better than expected. I applied the following procedure to prime them for use:
    1. Check voltage out of the box - mine were ~2.0V for both so 1.0V per cell. If severely discharged, more care is probably necessary
    2. Check for leaks internally - they can be opened reasonably easily with a gamebit screwdriver
    3. Charge for 12 hours using the supplied trickle charger (nameplate rating: 3.1V DC, 100mA - the charger internally is a very basic linear PSU with backfeed protection diode and resistor)
    4. Inspect for leaking cells
    5. Discharge using a Gameboy system until it powers off - first discharge yielded ~80% expected capacity based on the instructions supplied
    6. Inspect for leaking cells again
    7. Repeat the charge/discharge 4 more times and then check for leaks once finished. If no leaks are seen at this point they are probably OK.

    Optional steps:
    Discharge the pack down to ~1.2V (0.6V per cell) using a light constant current load (I used 50mA). You will need to use another device to do this as the Gameboy will cut out before that voltage is reached. It's probably not a good idea to go below that to avoid cell reversal, just in case one cell is weaker.
    Check for excessive self discharge: Make a note of how long they last 24h after a charge. Fully charge the pack, wait for 2 weeks and check again.

    After priming them they both hold 100% of the expected capacity according to the manual and have fair self discharge behavior for the chemistry! I don't own a device that can measure the capacity accurately, I am just going by the expected runtimes given.

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