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I’m trying to resurrect this old NiCd pack. Cleaned it up and gave it a few charge-discharge cycles. I remember these matched cells going for $60-$80 back in the day. Seems like it tops out at 800mah and it should be 1400mah. Any suggestions on bringing it back?

Beyond anything drastic try doing a series of trickle charges and full discharges . If you see the capacity going up it may just need some action to come back.

I have tried ‘jumping’ unresponsive nimh packs with short high voltage charges with limited success.

That was the trick, shock the cell with 12v to try and break up crystallisation. Zapping the cell with reverse polarity also seems to ring a bell.

I also recall something about freezing the pack to help break up crystallization.

RC10th wrote: ↑Tue Aug 20, 2024 4:19 am That was the trick, shock the cell with 12v to try and break up crystallisation. Zapping the cell with reverse polarity also seems to ring a bell.

Be careful with revere polarity. I managed to reverse the polarity of a lead acid battery so now my kids power wheels goes in reverse when they floor it.

JosephS wrote: ↑Tue Aug 20, 2024 4:49 pm

RC10th wrote: ↑Tue Aug 20, 2024 4:19 am That was the trick, shock the cell with 12v to try and break up crystallisation. Zapping the cell with reverse polarity also seems to ring a bell.

Be careful with revere polarity. I managed to reverse the polarity of a lead acid battery so now my kids power wheels goes in reverse when they floor it.

I've heard that Power Wheels use 540 size motors. That thought makes me daydream about making a Power Wheels RC.

Frankentruck wrote: ↑Tue Aug 20, 2024 4:53 pm I've heard that Power Wheels use 540 size motors. That thought makes me daydream about making a Power Wheels RC.

They already make them. Kids can sit in them while someone else controls it.

Interesting.

I would have to do my own conversion. I should have kept my son's Jeep.

It's a 40 year old battery, using 50+ year old technology. Let it RIP. It is a very nice looking pack, and would go great in a shelfer. For a runner, maybe upgrade to 30+ year old NiMH technology.

What is that?

juicedcoupe wrote: ↑Tue Aug 20, 2024 5:22 pm

Frankentruck wrote: ↑Tue Aug 20, 2024 4:53 pm I've heard that Power Wheels use 540 size motors. That thought makes me daydream about making a Power Wheels RC.

They already make them. Kids can sit in them while someone else controls it.

I have one of those. Upgraded it to LiFe. Without a kid and no lead acid battery they are quicker then you would expect. Looks to be close to a 550 size. Didn't upgrade the motor out of fear or burning out the drive board.

Frankentruck wrote: ↑Tue Aug 20, 2024 6:01 pm What is that?
1000014000.png

Fuse? I remember they didn't always have the solder drop fuse.

morrisey0 wrote: ↑Tue Aug 20, 2024 5:45 pm It's a 40 year old battery, using 50+ year old technology. Let it RIP. It is a very nice looking pack, and would go great in a shelfer. For a runner, maybe upgrade to 30+ year old NiMH technology.

My sentiments exactly. From what I can see, it appears to be a fairly decent looking display battery.

Lizardking wrote: ↑Mon Aug 19, 2024 7:07 pm I’m trying to resurrect this old NiCd pack. Cleaned it up and gave it a few charge-discharge cycles. I remember these matched cells going for $60-$80 back in the day. Seems like it tops out at 800mah and it should be 1400mah. Any suggestions on bringing it back?

I tried to do this exact same thing and had little success. Best bet is to just get some nimh batteries and retire the old ones.

NiCd's generally aren't affected by being stored for long periods in a discharged state. Old race packs used to be stored with battery bugs attached to keep them fully discharged. The NiCd is far better than the NiMh for devices that rarely get used.

NiMh on the other hand would be ruined by sitting discharged for long periods. Also keep in mind that the high capacity NiMh cells also started getting physically larger so be careful if you do chose NiMh cells.

I would charge and discharge the pack a few times, it will likely false peak quite a few times, so if your charger has a peak detection lock out feature set it so the pack gets a decent charge, or temporarily lower the peak sensitivity. Keep an eye on cell temps while charging this way. Also warming the pack will help reduce false peaks and help the pack take a charge. After discharging put the battery on a equalizing tray to bring all the cells down to the same voltage before charging. You'll know the pack is taking a charge when it gets warm, if one cell is getting really hot and the others are cold/luke warm then you may have a problem.

Do this a few times and you should notice the pack performance increase.


From memory some of the fancy chargers from back in the day had a buzz mode which was hard on cells but was designed to break up crystallization within the cell and remove their memory. The theory of the 12v zap method from a car battery was to "blow" the crystals off the electrodes inside the battery. Many batteries can be saved but some cells cannot, they won't be as good as brand new but make good practice packs. If you have multiple packs you can swap dead cells out.