small NIMH cells and self-discharge rates?

[Alex728]

A question about AA cells rather than big'uns for e-bikes...

I use 4 x 2300mAH ones for a digital camera, which I keep in my pannier bags when riding. I try and keep this charged at all times in case I see something interesting, but even with the camera switched off I have to charge the cells at least every week.

But when I used previously some 1500mAH cells they held their charge longer.

Do the higher capacity ones have faster a self-discharge rate?

 

[rog_london]

A question about AA cells rather than big'uns for e-bikes...

I use 4 x 2300mAH ones for a digital camera, which I keep in my pannier bags when riding. I try and keep this charged at all times in case I see something interesting, but even with the camera switched off I have to charge the cells at least every week.

But when I used previously some 1500mAH cells they held their charge longer.

Do the higher capacity ones have faster a self-discharge rate?

SOME digital cameras are very voltage sensitive, and really only completely happy with proper alkaline AA cells, even though they are supposed to work with NiMH cells.

What does tend to happen is, after a short while, those NiMH cells get a bit 'lazy' if not used much, which doesn't mean that they self discharge at a high rate, but that when you do use them their terminal voltage drops a bit too far for the camera. A digital camera often has quite high power demands, and they are usually OK on NiMH cells as long as those cells are in frequent use.

I have an Olympus camera which suffers from that problem. I've moved on to one that has an internal Li-Ion battery, and that works very much better.

There isn't a solution therefore if you have one of those. The problem is worse with the larger cells because in general the higher the capacity of the cell, the lower the short-term current delivering capacity will be, because you sacrifice electrode size and surface area for active content.

Rog.