Wikipedia:Reference desk/Archives/Science/2022 September 25

= September 25 =

Old AA/AAA battery chargers
I have a few AA/AAA NiMH chargers from one or two decades ago. They were rarely used. Should I use them when my current supply of alkalines run out, or should I buy new chargers? Thank you. Imagine Reason (talk) 21:55, 25 September 2022 (UTC)
 * I'm still using mine. I don't think that they have changed the specs, so any battery sold today that can be recharged should be rechargeable on an older model charger. It just may take longer. Abductive  (reasoning) 06:01, 26 September 2022 (UTC)
 * My C/D/AA/PP3 charger from 30 years ago still works fine. Martin of Sheffield (talk)
 * It depends more in the specific charger than the age. If your old charger is one of those dumb chargers that charges batteries for 18 hours or something then shuts off, then I'd recommend a new charger. If it's a decent smart charger which has some method of trying to detect when the battery is charged (preferably more than simply by voltage) then it's probably fine. This is especially the case for low self-discharge NiMH batteries which is what you really want to use in nearly all cases. Note that it's better to charge NiMH batteries slowly, while the 18 hours is unnecessary, I'd also avoid any charger that charges a mostly discharged cell in 1 hour or something. The Maha Powerex MH-C401FS is one decent smart charger that I think may be 2 decades old or close to it. (It has a switch for slwo and fast charging.) But even Sanyo Eneloop chargers may be over a decade old by now I think. Nil Einne (talk) 07:08, 3 October 2022 (UTC)
 * Duracell Rechargeable Accu: "Charge only Duracell NiMH rechargeable..."; a more generic 9V charger, "Only for 6F22 battery". Both with red/green LEDs. Imagine Reason (talk) 22:38, 3 October 2022 (UTC)