Storing NiCad battery pack long term. More I read, more I'm confused

I have a Surefire 10X Dominator, and own two batteries for it. The battery it uses is a B20 NiCad. I would like to store one of these batteries away for long term storage, and use the other one for general usage. I want to try and preserve one of these batteries because they are long out of production, cannot be rebuilt, at least without some great technical know how, and once they are shot I'm going to be left with a $500 paperweight.

I'm reading around on the best way to store NiCad batteries and I'm seeing conflicting information, and now I'm confused as ever. Some are saying to completely discharge the battery for storage, some are saying don't do that, leave a little bit of charge, others saying that the battery will obtain a "memory effect", while others are saying that it's best just to use the battery.

Can someone please clear this up for me? I really want to do my best to preserve this battery as it's not replaceable.

Nicd and nimh have high self discharge. I think they will be completely dead in 6-12 months. I would do a trickle charge every few months. However, that said, you would be better using 2 packs and rotating them. I think BOTH packs would see longer life and overall better performance.

turbodog said:

Nicd and nimh have high self discharge. I think they will be completely dead in 6-12 months. I would do a trickle charge every few months. However, that said, you would be better using 2 packs and rotating them. I think BOTH packs would see longer life and overall better performance.

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Ni-cad has a memory effect though....trickle charges won't be good I would think.....

For my ni-cad battery packs I don't need for awhile, I drain them flat, then put a little bit of charge in them just to make sure none of the individual cells are left in a reverse-charged state. Essentially, they're stored empty. Ni-cad is very tough, and should last a long time. The killer is the "memory effect" you get from partial discharge-charge cycles, so just leave them flat and don't worry about it.

Hello DayofReckoning,

NASA did extended research into storing NiCd cells. Here is a synopsis of what they do. You can find further information by searching in the NASA site but it can be difficult to find sometimes.

I tend to store my packs mostly discharged. I am constantly surprised at how robust this chemistry is. However, the packs frequently take a few cycles to get back to normal performance.

Years ago I did a Surefire B90 NiCd to NiMh conversion. I think the thread was "Twice the run time and brighter" or something along those lines. If you can find someone that is capable of building battery packs you can probably work with them to convert your pack.

The biggest problem was matching the NiMh cells. I bought more cells than I needed, tested each one to match them, had the pack assembled, then tested again to make sure nothing was damaged during assembly.

I still use my 8NX. I have a couple of the original B90 NiCd battery packs that have reduced capacity but still work. I also have several of the NiMh conversion batteries that are working fine. I do a charge/discharge on the NiCd packs once a year and store them discharged on the shelf.

Tom

My friend received X10 today. The batteries are almost dead. What can replace them? I mean, what is the voltage of the original battery? Then we could make something based on lithium or select cadmium cells of the desired voltage and diameter

Nikel cells do not like being stored, they need to cycle to stay in shape, nicd are most robust, and will take long storage best, keep them charged, they do not like being topped off, discharge it before charging it again, i still have 10+ years old power tool batteries in good shape.

I don't really understand. I used to have an RC car back in the late 80's with Panasonic Ni-Cads that would run forever. I had a shaver with Ni-Cads that lasted WELL over 20 years. I've never had such luck with NIMH, they usually go dead within a few years to the point of unusable.

NiCds were very robust. Unfortunately, they had a high self-discharge rate. They survived quite well when left discharged for a long time.

Not so the NiMh. A few deep discharges and they're dead.

The best NiMh you can buy are eneloop or eneloop lite. But even with these, deep discharge should be avoided if possible.

Yea, and even though I liked the survive ability of Ni-Cads, they were also toxic to the environment. Which is a lot of the reason why NIMH was born. Plus they can sell you more batteries after the latest set you bought failed...

So kinda a horse a piece I guess. More green for the corps and more land fill filler vs. toxic to the environment.. pick your poison.

The traditional advice with NiCad cells was to store them completely discharged. In the early days, large (10s of Ah) cells would arrive from the manufacturer with a shorting strap across the terminals.

Obviously, you should never deep discharge a pack with multiple cells in series, since the weakest cell/s will effectively be reverse charged and thus damaged when you attempt this.

It's a real shame that NiCads are now almost impossible to buy.

As others have said: NiMh cells do not like being deep discharged and seem to "go off" with age, no matter how carefully you treat them. I have some 12 year old low self discharge NiMh cells that have been carefully managed and regularly conditioned using a Maha smart charger. All still have close to their original capacity when measured. The internal resistance has steadily risen over time though and they are no longer suitable for use in any high powered torches.

Yea, that's what happens with NIMH. The internal resistance goes bonkers over time and they crystalize and become unusable. Even if you take good care of them, they just don't last more than a few years normally.

desert.snake said:

My friend received X10 today. The batteries are almost dead. What can replace them? I mean, what is the voltage of the original battery? Then we could make something based on lithium or select cadmium cells of the desired voltage and diameter

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I don't know if you mean X10 or 10X Dominator, but I specified this pack as a replacement back in 2018 and all three that I built are still working fine (better runtime than factory spec on account of the higher capacity). https://www.batteryspace.com/custom-nimh-battery-7-2v-2700mah-sanyo-2xi3-a.aspx You will need basic hand tool/soldering skills + some patience to do the rebuild but the internals of the B20 battery handle are pretty self-explanatory once you pop out the spiral retainer ring and unscrew the charging lug bolts