Charging the 1.5V rechargeable AA/AAA Li-ion batteries properly

XTAR Light

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Some customers asked the questions about charging 1.5V rechargeable AA/AAA Li-ion batteries. For example, could these batteries be charged on a regular battery charger, such as, VC4SL, Energizer AA/AAA charger, etc.? As for the dedicated chargers LC4/LC8, designed for xtar 1.5V Li-ion batteries with indicator, can they charge other different Li-ion or NiMH batteries smoothly?

The answer is No. To charge these 1.5V AA/AAA Li-ion batteries, it needs standard charging voltage around 5V, and keeps constant voltage charge. Not same way as a regular 3.6V Li-ion batteruy charging, or 1.5V as NIMH battery needs. Besides, you also couldn't charge AA/AAA NIMH batteries on the LC4/LC8, because it will send around 5V straight to the batteries and destroy them.

So please don't try to charge the special 1.5V Li-ion batteries with other chargers, or do mix-charging with other batteries. That would damage the batteries and chargers, even bring with other safety hazards.
 

KITROBASKIN

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Good to remember.
I have 4 of these Li-ion 1.5V, and the dedicated charger (though my BC4 model says it can charge NiMH as well). My son is not complaining about abrupt shutdown these days; not sure why but they do last longer than NiMH and alkaline in his X-Box controller. (I have not measured precisely due to variance in controller behavior. There is a haptic feature that activates irregularly)
 

Bambuino

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Yes this is good info, and thank you for posting. I been a AA/123 user for so long, and have little knowledge of newer batt chemistries and charger technologies.
 

mrqzz

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Actually, today I accidentaly put one of my KENTLI 1.5V Li-po batteries into the Nitecore D2 charger. I realised my mistake only upon removal of the battery from the charger. To my greatest shock+surprise, it actually 'successfully' charged the battery!

At least, by 'successful' I mean the following:

1) Upon putting the battery into the charger's slot, the charger appeared to detect and display the approximately correct voltage readings of the flat battery: 2.97 Volts. (Can't confirm though, as my multimeter read 0.00V as probably the battery was so flat that the protection kicked-in.)

2) The charger recognized the battery as 'Li-ion' type so this also worked correctly.

3) When I released the battery after approx. an hour, the charger was displaying voltage of 4.09 Volts. However the real voltage was 3.79 Volts only as measured by my multimeter. The battery was moderately warm/hot when removed, but it didn't feel unusually hot for any battery freshly removed from a charger...

Contradicting points of the described event:

1) When the battery was flat, the battery's upper positive terminal read only 1.5V (by design, for a 1.5V Li-ion). However the charger read 2.97V as put into the slot. This is interesting as the charger's positive terminal was in contact only with this upper terminal of the battery that outputs 1.5V only. The battery's secondary, lower positive terminal is the one that should read the actual Li-ion cell voltage.

2) Despite the 'seemingly correct' charging process, after the one-hour period the battery spent in the charger, the multimeter-read voltage of the lower terminal was 3.79V only, in contrast with the charger's reported voltage that stood on 4.09V)

3) Apart from the above, both the battery and charger successfully went through the process without any apparent damage. I subsequently tested the charger with several different types of its supported batteries and it wortked OK and for the moment the battery works OK in my mouse and also charging it in its own Kentli-made charger doesn't flash an error, and voltage ramps up correctly after charging there for another 10 minutes.

Conclusion: looks like even that the KENTLI design is two positive terminals on the battery, the upper one standing for outputting 1.5Volts and the lower one for charging (through standard Li-ion CC-CV charging method). However it looks like the battery nevertheless 'accepted' the charging through it's upper, 1.5V output terminal and made it possible to reveive the charge from the standard Li-ion charger. Also the battery 'somehow' reported the Li-ion-ish voltages (albeit inaccurate by ~0.3 Volts) to the charger trough its output-only 1.5V terminal... (Which for the multimeter reads 1.5V only.)

I'm curious if anyone has any further experience/explanation regarding this occurence so that we might have a better understanding on what is going on when NiteCore D2 charger is charging the 1.5V Kentli battery?
 
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