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The NiMH chargers that I've seen have a negative delta-V detection and a timer shutoff. I've had problems charging the Eneloops when used on devices that drain

The NiMH chargers that I've seen have a negative delta-V detection and a timer shutoff. I've had problems charging the Eneloops when used on devices that drain the battery too much. When they are inserted into the charger, the voltage seems to rise too quickly and and somehow confuses the charger so that it stops charging early. In those situations, I've resorted to charging those batteries twice. First time, charge for 5-10 minutes to raise their voltage. Then remove and reinsert the batteries to charge a second time using a more normal voltage curve. Maybe it's a quirk of my charger. I didn't know about lithium AA/AAA rechargeable batteries. Interesting. I see that most are rated at 1200-1500mAh (AA) and 400-500mAh (AAA). These are only a little over 1/2 the capacity of the NiMH that I normally use. I guess the charging circuitry takes up room in the battery.

leggomylibro 7y ago
Got any charger recommendations? :) And yeah, the lithium AA/AAAs were news to me too. I learned about them when I got a headlamp that could either take 3 AAA batteries or a same-sized lithium battery with +/- contacts in the right places. I think the single-cell ones include a buck converter along with the charging circuit, which probably cuts down on the space they can devote to the battery itself.
- bxparks 7y ago
  Yup, it's old but I use this Titanium Smart Fast 8 Bay AA/AAA charger (https://www.amazon.com/gp/product/B0035HCTLS https://www.amazon.com/gp/product/B0035HCTLS). The manual states that it has negative delta-V and timer shutoff. One of the Amazon reviewers mentions a problem with deeply discharged batteries, similar to what I've seen where I need to charge the battery twice. By the way, this situation happens mostly on my motion-activated staircase LED lights which take 4 x AA. That thing is amazing because it works until 3 x AA are essentially dead and only 1 x AA is giving out power. For most of my other devices, the device stops working before the battery voltage becomes that low.

leggomylibro 7y ago

Got any charger recommendations? :) And yeah, the lithium AA/AAAs were news to me too. I learned about them when I got a headlamp that could either take 3 AAA batteries or a same-sized lithium battery with +/- contacts in the right places. I think the single-cell ones include a buck converter along with the charging circuit, which probably cuts down on the space they can devote to the battery itself.

bxparks 7y ago
Yup, it's old but I use this Titanium Smart Fast 8 Bay AA/AAA charger (https://www.amazon.com/gp/product/B0035HCTLS https://www.amazon.com/gp/product/B0035HCTLS). The manual states that it has negative delta-V and timer shutoff. One of the Amazon reviewers mentions a problem with deeply discharged batteries, similar to what I've seen where I need to charge the battery twice. By the way, this situation happens mostly on my motion-activated staircase LED lights which take 4 x AA. That thing is amazing because it works until 3 x AA are essentially dead and only 1 x AA is giving out power. For most of my other devices, the device stops working before the battery voltage becomes that low.