Question on charging disposable (primary) alkaline batteries

[SamTexas]

I have heard of claims that certain specially developed chargers can successfully charge primary alkaline AAA and AAs. If you have tried this, please share both your successes and failures along with the name of the associated chargers and batteries. Thanks.

 

[amberwolf]

Sorry I only have a negative result to offer:
Most times I've tried it have resulted in a lot of heat, a little bit of charge which self-discharges, and sometimes an exploded battery (even at low currents like <100mA). D-cells and C-cells didnt' heat up much but AA and AAA and 9V often did.

The only actual chargers I tried for this were no-name generic chargers meant for NiMH and NiCd, and that wasn't often. Usually just using a lab PSU.

I don't recommend trying to do it even with a "safe" charger unless you do it outside or in something relatively safe like an oven or other metal box that could contain the results, if bad.

 

[SamTexas]

Thanks AW. That's what I want to hear, both successes and failures.

Yes, a Nickel battery charger would not do it. It has to be done with pulses, thus a special charger. There are many out there that are supposed to be doing that, but I want to hear it from members who had actually tried them and what the results were.

 

[wesnewell]

I've been recharging alkaline cells for at least 30 years. All alkaline batteries are rechargeable and most non alkaline are too. Been using the same charger for those same 30 years. IIRC I got it radio shack. GN Deluxe Universal WY-108. It does AAA-D cells, 9V, and even button cells. Yes, you can recharge lithium button cells too. For alkaline it's best to not run them below 1.3V. I've recharged some many times over many years. But I've forgot a few in the charger and they would burst after a while. A real mess to clean up, but nothing else.. Not sure if the newer models do better monitoring voltage, but I'd think so. Mine will just keep pumping juice into them until they burst.Shouldn't charge them any higher than ~1.65V - 1.7V while charging. Higher than that risk rupture.

Search ebay for alkaline battery charger. FWIW, I've also charged alkaline batteries using a nicad/nimh charger that I ordered by mistake, but the one I have has to be done in pairs and I don't use it.

 

[dogman dan]

That sort of confirms what I thought. It can be done with the typical nicad/nimh charger. The main risk is bursting cells, so you'd not be doing it near people. Just another reason to have a charging space that's durable and fire resistant.

The question I've wondered about was how much capacity do you get on a recharge? It's not near original is it? Is it enough to be worthwhile? I've just been using either nimh or nicad for close to 30 years. Mostly to power work site radios, but also cameras and flashlights. A decent set of nimh c cells, when new, could last most of a work week in the radio if played not so loud. Even when 3-4 years old, theyd last 2 days. I've just found it convenient to just use the nimh for stuff like that.

 

[wesnewell]

Since they're cheap, I never did any real capacity test, but new batteries are usually around 1.60-1.63V. No problem charging them back to that voltage, so I'd guess you can get close to full capacity from them for a while as long as you don't take them under 1V dod. Once you take them too low, they won't charge back to full voltage most of the time. I also never kept track of the charge cycles, but I've used some 4 years past their expiration date. If they won't charge back to at least 1.5V I toss them.

 

[SamTexas]

Thanks wesnewell. I'll read your posts again more carefully and come back for more questions.

 

[amberwolf]

Once you take them too low, they won't charge back to full voltage most of the time.

That's probably a good part of my failure problem (aside from always using a constant current rather than pulses).

 

[alsmith]

Try 'alkaline battery charger' in the ebay search box.......

 

[SamTexas]

Try 'alkaline battery charger' in the ebay search box.......

I know there are dozen of them out there. Just like there are countless junky BMSs out there. I was looking for the ones that actually worked for someone.