Rechargable Batteries

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allstarnz

1711 posts

Uber Geek

Trusted

#15313 15-Aug-2007 15:03

I have a small amount of Ni-Mh rechargeable batteries, which I leave charged to pop into whatever device happens to go flat.

However recently I have noticed the 'charged' batteries are flat. I think possibly the charger might be bung, but I suspect not.

Do NiMh batteries retain their charge properly out of a device? Is it better practice to leave them uncharged, then charge them on demand? I don't really like doing this, as they take ages to charge.

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Bung

4547 posts

Uber Geek

#82511 15-Aug-2007 15:15

Ni-MH do go off if you leave them. I suspect that the older they are the quicker they decline. I don't trust mine unless they've been charged within days of use. The newer hybrid type like Sanyo Eneloop are much better at retaining charge and are sold ready to use straight away.

Mattnzl

261 posts

Ultimate Geek

#82548 15-Aug-2007 19:28

I've found the recent higher capacity nimh AA's (2500mah +) seem to self discharge a lot quicker than my older ~1600-2000mah ones.
The worst culprits are my Sanyo 2500's which I got for the digicam which self discharge in about 3-4 weeks, yet older Nexcell ones in the kids toys last for up to 3 months - even with a bit of use. Might swap them around and see if it still happens~!

Eneloop ones do look good, but not as much capacity (only 2000mah I think).

Bung

4547 posts

Uber Geek

#82551 15-Aug-2007 19:56

Eneloop and similar types may only be 2000-2100mAH but I don't think all of the higher rated cells actually meet their claimed capacity. The Eneloop type also have a slightly higher voltage which helps with things like Canon cameras which have low voltage detectors that can be a bit touchy and shut down early.

Mattnzl

261 posts

Ultimate Geek

#82569 16-Aug-2007 07:21

Cheers Bung, might give them a go then as I do have a Canon.

sneeble

29 posts

Geek

#82695 17-Aug-2007 11:06

I use varta 15 minute rechargeables. Basically with high discharge flashes, canon camera and nikon cameras with slave flashes these batteries are still going strong after 3 years hammering. One thing that made me choose these was the 12v charge adapter. I spend a lot of time travelling and being able to charge at 12v or 240 is invaluable.