Power Supply

[Oldrottenhead]

memory?

[drutgat]

memory?

Oh....I've forgotten what I was going to say     
Seriously, Nicads and NiMH's have memory of sorts, although it is much more critical with Nicads.

What this means is that it is very important with Nicads to charge them for the exact time specified, because if you over or under charge them, you permanently reduce their capacity. It is also crucial with Nicads to run them down totally before recharging them, for this same reason.

There is also a memory effect with NimH's, but it's not as crucial as with Nicads, although good practice (fully discharging a battery before recharging) will ensure the longest life of a battery.

Lithium Ion batteries are almost devoid of this memory effect.

One common example of a context in which it is possible to notice the memory effect is with cordless (chordless?  ) 'phones. I don't know about the U.K. any more (haven't lived there in years), but in N. America, most cordless 'phones have NiMH batteries. If one replaces the 'phone on the cradle after every use, rather than leaving it off the cradle until the battery runs down, one will find that the battery needs to be charged more often, and that its overall 'life' is shorter than if it had been treated as described above.

[hardlock]

Couple notes on batteries.  Don't get suckered into cheap, no-name, high capacity NiMHs on Ebay.  Half are miss-labeled, some won't hold a charge, others only get a few cycles and just not worth the few bucks you "save".  My biggest grip is that NiMHs have no shelf life when pre-charged and when needed have run themselves down.....

I do electric RC stuff and have thought about using LiPolys wired to fit the adaptor plug.  That way when they run down the AAs would kick in(?).  Lipos can sit forever and not loss their charge as well as being flat to lay against the back of the unit without a big space disadvantage.  Any thoughts?