Topping off almost full Eneloop batteries

[y_p_w]

The charger is different even though it's got the same model number. The back of my older one has the date code (YY-MM) heat stamped into the plastic. The newer one is printed in some sort of ink and a YYMMDD exact date. The older charger has "AA" in a box while the newer one has "AE". I haven't opened it up, but I did years ago for the older one and saw it had a charging circuit from Elan Microelectronics, which is no longer in that business. The newer one also has really bright green charging indicators, although they're still buried behind the plastic and it's still hard to tell which battery it represents until both are lit. The older one has a duller (not sure if it's just worn) green color and less brightness. Panasonic obviously found a different charging circuit supplier, although I'm thinking these are probably just commodity parts at this point.

The newest one lights up almost immediately if there's a battery detected. The older ones have this delay where they'll light up one at a time (about a half second apart) until all four positions light up. A light position will flash when there's a fault detected. That's unlike my other Sanyo or Eneloop branded chargers that flash when charging and stay solid when done.

And I have never had a single Sanyo/Panasonic/Fujitsu/whatever low self-discharge battery fail as long as it wasn't used in a device that charged in-situ (like a cordless phone). I don't use my Maha charger any more, as I don't trust the trickle charge once it's considered full. It's pretty much only single battery capable Panasonic branded chargers with a 300 mA charge.

 

[wrcsixeight]

I've got some eneloops from 2010 or earlier.

One of them I soldered into an Andis hair clipper in 2017 or so, whose own internal AA battery failed. I never bothered checking the output of the transformer based heavy wall wart charger that came with the clippers, but the eneloop performed well inside ever since.

I recently moved and the charger wall wartdid not make it.

I use an XL4005 based 5 amp voltage bucker for speed controllers for 12vDC fans and LEd lights and used one with an appropriate barrell plug in order to charge the eneloop inside the Andis.

The Andis green 'charging' light did not light up until I turned output voltage upto 2+ volts. I settled at 2.37 volts to get an ~ 0.15 amp charge rate, and let it go for hours and hours, occassionally removing source voltage to the bucker and checking the battery voltage, and also using infrared gun to check for significant temp rise, which I never observed.

One thing I found interesting, was that turning the Andis' motor on, at 2.37 volts, was drawing 9+ amps through the 5 amp rated bucker.

I declared it to be 'charged enough', when the battery itself read 1.39 volts.

I am impressed with the Eneloops longevity, and remaining capacity after at least 12.5 years of ownership, I think mine say 1900mah.

Loose Eneloops get charged on my Nitecore I4v2 charger. I've dedicated the one Xl4005 voltage bucker with its own barrell plug just for the Andis clippers.