NiMH, how can I increase shelf life?

[Muse]

I thought one of the handsets of my cordless phone system had a battery problem, so I ordered a complete set of replacement battery packs. There are 3 packs each consisting of 3 NiMH AAAs, and the packs say 700mah, got them off eBay. Now I think the handset was maybe just not making good contact in the charger and AFAIK it's OK. The batteries already in the handsets may be better quality than the replacements I bought, which cost me $7.99.

I haven't charged the replacement packs, they are just as I received them, and the instructions that came with them say to charge them fully before use. Is there some way I can store these replacement packs so they won't deteriorate as fast as in a drawer? Can I for instance freeze or refrigerate them and extend the shelf life? Should I charge them before storage?

 

[eh4]

You could make up some more packs using AAA Eneloops instead. I'm sure there are how to's, kits and even folks that would build you some for a reasonable fee, it's mostly heat shrink wrap, a little wire and contact pads.
You'd be able to have the original packs as back ups, just charge them up before you know you're going to be using the radios.

 

[901-Memphis]

Low room temp low humidity recharge once a year

Drawer is fine avoid heat. You can vacuum pack and refrigerator them if you want but it's not necessary


You can leave them at their present charge.

 

[Nubo]

You might want to make sure the originals were not NiCD. I did this once with a cordless phone and it turned out I had replaced NiCD with NiMH. NiMH don't handle the kind of abuse in the application as well as NiCD (being run down to flat, etc...)

 

[oKtosiTe]

What Nubo said. NiCd cells survive more inconsistent charge cycles much better than NiMHs do, and can be stored without a charge for a long time without any adverse effects.

 

[Muse]

Low room temp low humidity recharge once a year

Drawer is fine avoid heat. You can vacuum pack and refrigerator them if you want but it's not necessary


You can leave them at their present charge.

This is confusing me. Firstly, the originals are also NiMH. Should I charge them before storing these replacements? I want to keep them in case the originals do die. I do have a vacuum sealer, although I've yet to use it!

 

[901-Memphis]

Depends on what charge they arrive at. If they are charged already you can leave them to store but if they are low charge i would charge before storing.

 

[Muse]

Depends on what charge they arrive at. If they are charged already you can leave them to store but if they are low charge i would charge before storing.

It isn't easily determined. Maybe I can but they are in sealed battery packs with a proprietary connector. Maybe I can get a reading off the connector with a multimeter. I could just put them in the units and charge and then remove and store, really not sure where I should store them, in the freezer, refrigerator or a cool drawer.