I have a 4 handset cordless phone system (the house/grounds are pretty widespread). I had a couple that seemed to be dead, so I ordered a couple of new batteries (Ni-MH). I'm not even sure what that stands for.

Anyhow, before the batteries arrived, I discovered that the supposedly "dead" batteries had just been left off their charger stands. When charged overnight, they're back as good as new.

So - how do I store the new batteries until needed? In the old days we used to store batteries in the refrigerator, but I have no idea what's the right thing to do with these.

While we're at it, are different techniques needed for Li-ON or even NiCad batteries?

Ni-MH batteries have a memory issue -- if you don't fully discharge, full charge will diminish over time -- so might not be a bad idea to just swap out for the new batteries.

Don't keep them in fridge. Newer NiMH batteries has long shelf life. I think they lose like 1% per month. And if you try to use them 2 years later and you lost 25%.. you could just recharge them.

Here is pretty much more than you need to know about keeping these puppies healthy.

NiCad (Nickel cadmium)--I doubt you'll find them anymore. I haven't seen one in ages. The EPA doesn't like the cadmium part.

NiMH (Nickel Metal Hydride)--what you're dealing with. The charge that's in them now is no big deal. It's going to leak away over time, just charge them up when you actually use them. There is a tradeoff between charge loss and capacity, the batteries with the highest capacities will bleed their charge much faster than ones optimized for keeping their charge.

Li-Ion (Lithium ion)--these have a long shelf life but should not be allowed to sit around for ages. Charge them up periodically. The problem is that there is an electronics pack in with the battery that is powered from the battery. Many of these aren't designed to cope with the battery truly going dead and will be bricked if it happens. (Note that the battery shuts down with a certain amount of power left in it. Running the battery out doesn't kill the electronics.)