pb1592

I'm sure this has been asked before, there are even YouTube videos on the subject, but I'd like some specific clarification on the subject if possible.

1) When reviving a dead 7.2v nicd/nimh pack, I understand I need to manually connect it to another power source to give it a little charge so that a smart charger will detect it and charge it normally. When doing this I can simply connect another good battery to the dead one, (+ to -) for about a minute right?

2) I have several nicd/nimh packs that seem to only charge about 25% or so. They worked fine when last used before sitting in storage for a few years. I've heard of "shocking" the pack to dissolve crystal buildup in the cells that supposedly inhibit current flow. Without disassembling the individual cells, how exactly would I "shock/zap" a faulty pack back to life (what voltage, amperage, time)? Cycling these batteries at a low (< .5amp) trickle doesn't seem to help. With a 2-to-4 amp quick charge they begin to get warm as expected when the smart charger shuts off, but when I use them it seems like they only have about 25% of an expected full charge. Are these packs toasted?

Can the entire pack be shocked/zapped for this to be effective or would individual cells need to be done individually?

Truckracer

My Feedback: (19)

While you can revive NiCd packs to some degree and this might be OK for some types of equipment, I would never recommend that for RC equipment. I can guarantee the revived packs will never have anywhere near their full capacity. Better to just buy new and while you are at it, maybe it is time to update to a different battery chemistry. Most modern batteries offer far better lifespan than Nixx ever had and at a far lower cost per year of ownership / service life.

cyclops2

Remember You HAVE NO FAILSAFE of any servos when a cell OPENS UP. No power is available. Should act just like pulling the battery plug apart.

pb1592

Thanks for the responses. I usually use lipo for outdoor use but in the winter months when I mess around with RC's in the house I like to use nimh simply due to the fire risk of lipos. With nimh's i dont have to worry about removing and storing the batteries after every single use. I have several 7.2v nimh packs which are essentially brand new, never really used, just been in storage for a few years and now wont hold much of a charge. I thought there might be a way to restore them to full function but it seems like it's probably not worth the time and in the end won't work out too well.

cyclops2

If the model can carry a LIFEPO4 set of cells ? Do it. I have posted how safe they are. They can be fully charged up & not used for over 5 years. Still recharge to full power. NO FIRE hazard. For in house stuff.

HueyHauler

I use a 6-12v charger. Most go to 10amp charge. Jerry rig a connector for the battery to the clamps on the charger. Do this outside & wear safety glasses just in case something happens. Just connect the Negative, turn on the charger & quickly touch the Positive battery with the positive Charger. You'll see a spark, no worry, hopefully. I've done NiCd & NiMh batteries from Drills & RC's. A majority came back to life, some didn't. How long will they last ?? Don't know but it'll get you buy until you can get a new one !!