AA Battery Charger

[ryanwc]

I have two battery chargers, one from roughly 2002, and one from about 2009. Both worked, but I haven't used them in recent years. Tried this week, and both have failed. I'm wondering why.

The older charger is a Radio Shack "Universal NICD / NiMH" charger. Universal because it has slots for 4 different size batteries. At the time, I had an outdoor recreation business that was required to use a cash register, but the location had no electricity, so everyday, I'd take the batteries home and recharge them. Never had a problem with it, but eventually installed solar there and hadn't used it in a while.

I bought NiMH AA rechargeable batteries last week, and have tried charging them with it several times to no avail.

Is there some change in the battery manufacturing that requires a different current or resistance today, that makes this not work? Or has something gone decayed in the 16 years since last use? Normally, I'd think a simple wired electrical item should last that long.

The 2009 charger is an Envirocharger, and reads "only use 365 everyday value alkaline batteries." I did try charging the NiMH using that, though it obviously isn't recommended. I only succeeded in generating heat.

Any recommendations? It feels a little ridiculous that I'm trying to reduce waste, but have primarily succeeded in buying batteries and chargers that will need to be thrown away.

 

[Showkey]

Pure Energy Envirocharger for AA and AAA Rechargeable Alkaline Batteries
Charges any combination of 1 to 4 AA or AAA Rechargeable Alkaline batteries

Given the above description the charger is only going to work alkaline batteries.

I would not use any of these products charging any batteries unsupervised.

Can’t imagine alkaline recharging as any merit or value compared to NiMH ( which is also outdated) compared to Lithium in today’s world.

 

[BillK]

My NIMH charger is at least 10-12 years old and still works fine with new batteries. I suspect your old charger decided it had lived long enough.

 

[maswov]

If you haven't used it in a long time there might be some corrosion on the contacts. Use an INK eraser to clean the contacts and wipe it down with isopropyl alcohol.

 

[HenryAZ]

I have the Powerex MH-C9000 (which has been replaced by the MH-C9000PRO, at about the same price. It features battery analyzing. You can use this condition your battery the first time around (takes a long time), and it shows you the actual mAh the cell is capable of, so you can pair them up based on similar mAh capability. I found in a batch of 16 Eneloop Pro AA batteries a range of mAh from 24xx to 26xx mAh. It is not cheap, by comparison with other chargers, but also does things other charges cannot. I believe it is worth the money I paid for it.

 

[CoogarXR]

Does the radio shack unit have a Ni-Mh/NiCd switch? I know many of them did. Maybe it's on the NiCd instead of Ni-Mh?

 

[ryanwc]

Thanks, folks. I seem to have made the Radio Shack charger work. The batteries are now in our programmable thermostat and it's working.

I suspect maswov's answer may have been correct. The Radio Shack charger does not have a switch to toggle between NiCd and NiMh. Even the first couple times, the sequence of charger lights suggested it was working properly. But when I would transfer the batteries to the thermostat, it would read low.

I did move the charger from the basement to the first floor, mostly for supervision, but who knows whether there's some mild difference with the basement outlet that prevents full charging. (I have an inverter power supply I plug into my truck's cigarette lighter to run my laptop, and when the truck is not actually running, the inverter runs, but doesn't have sufficient power to supply the laptop, so I know such things can happen.)

But I doubt that's it. My sense is that there may have been some mild corrosion or maybe just an oily or dusty coating that had built up over 15 years, and that pushing the batteries in and back out a few times eventually scrubbed it away, creating a better connection, sufficient to more fully charging the batteries.

 

[ryanwc]

Another thing, that Henry's answer calls to mind. For the previous two, failed efforts, I had set the RS to drain the batteries fully, then recharge them. This time, I just put them in and didn't try to condition them first. I vaguely remember reading about some batteries that need a cycle of "fully charge", then let sit and charge a bit more. I wonder if that's relevant here.

The next question for me is whether they'll last, or just go Low in a few days. Since it's hard to believe that the few minutes of the most recent cycle added all that much power compared to the initial cycle.

 

[Lassen Forge]

NiCad and NiMH take different charging regimens... your charger is probably looking at the batteries, and either getting an internal short shutdown or not even recognizing the NiMH batteries as something that CAN be charged. You're lucky it took some charge, but yeah, that's why there's a switch on the switchable ones...