Batteries fit in there pretty snugly. In test use for a 4-D LED outside light they seem to work OK.
Questions:
I’m not accustomed to using NiMh in parallel. Series, sure. Do they ‘self balance’ like lithium in parallel?
Is there the problem of ‘weakest link’ going dead, and getting reverse current through the weakest cell, or would it be 3AA-battery in this case? The individual AA cells are parallel, but the application is series; sort of a working 3P4S.
Can the batteries be charged safely in the adapter like a regular D-cell? Is that safe? Got an old, but good Maha 808 that has had lots of use charging old NiMh D cells. Those are getting pretty ancient and not sure I want to buy more.
Or, do AA need to come out for individual charging? Sure, can be done but 12 batteries in a snug adapter is a bit of a nuisance vs just putting them in a charger.
The converter you are using simply allows you to use AA batteries in lieu of D batteries. The only thing you lose by doing this is capacity. The battery circuit if you will stays the same.
Generally speaking, the batteries you use should be all the same brand, the same capacity, the same age, and they should all be charged at the same time.
you never charge nimh in parallel with smart chargers, it confuses them, delta V are not likely to be the same even in same cells from same batch. dumb timed chargers are ok, did it myself. just triple the time. tripling current is tricky, cells have different IR, and most of the current will go thru a cell with lowest IR possibly damaging it, so do not exceed charging current more than 1 cell can take. but the best thing to charge separately or in series, xs1p
Good info, makes sense. Didn’t think about the ramifications of different IR for charging. Thanks.
Addendum; I do have a couple old dumb chargers with very low output. Guess I have to decide which is more annoying, taking all the AA out to charge, or waiting for HOURS for the cassettes to charge intact.
Lithium-certainly
NiMh-? Seems like it should do so but I don’t know for sure. I’ve used a charged cell to ‘jump’ a dead one, so definitely some current flowing. OTOH, a dead cell will go from 0v > like 1.23v in seconds that way, and something about the damage/resistance from being 0v makes it show up as having a much higher voltage than it’s ‘peers’ when being then charged on a smart charger. It’s also far more likely to terminate prematurely. So….something is going on there.
They do tend to ‘settle out/normalize’ after a proper cycle.
They will level out in parallel, they have no choice.
There will be current from the fullest cell(s) to the least full cell(s).
NiMH charges even with minute currents, like in those cheapo garden lights, even in winter.
If you had D cells in the light one of them could be subpar too.
Just use AA NiMH of the same age and quality and it’ll be fine.
When in doubt, test the AA’s individually.
I wouldn’t worry about it if all works as intended.