AA lthium replacement batteries?

Ian_Edwards

Ian_Edwards

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I bought 2 sets of 8, Li AA replacement batteries with chargers, in 2019.
I use them in small torches, WiFi connected temperature loggers and similar gadgets.
They have started to fail to recharge properly. They appear to charge, the charger light goes from red to green, but they discharge quickly, in days, rather than weeks or month in some devices.
They are nominal 3000mah.
I'm not complaining about the effective life time, they've saved many times there own weight in conventional AAs, and been good value for money.
Question, what replacement AA Li batteries should I buy.
I'm looking for 16.
 
What charger do you have? Most AA chargers only charge in pairs which can lead to an imbalance between the cells which eventually looks like what you describe.
If you find a charger that definitely does each battery individually you may get better results.
I use standard Duracell and they’ve been going for many years with no degradation

Edit: this is the charger I have
https://www.amazon.co.uk/gp/aw/d/B08HLRP6GM
 
I'm using the charger that came with the set of 8 batteries, it has 8 docking points.
But normally I only need to charge an odd one at a time, often weeks appart.
How would I tell if the charger only works with pairs of batteries? And if it is limited to pairs which pair would I use, or find out which of the 8 docking points work as pairs?
I have multimeter and I although reluctant I could take them appart. I wouldn't want to do anything to the charger to make it dangerous.
 
It ought to say in the manual. Some refuse to charge one battery on its own. Others just parallel the slots. You can charge an uneven pair until “charged” and then check the voltage which ought to be the same.
Using the batteries individually or in threes can lead to this, if you keep and use them in pairs it’s normally OK.

Fwiw I had three Duracell chargers and all charged in pairs and killed batteries.
 
Thanks for the reply.
I bought these in 2019, I've no idea where the manual is, it most likely got thrown out years ago.
Almost all the low power Bluetooth device only use 1 battery.
I could try charging them in pairs to see if that works.
However, at approximately £30 for 8 including a new charge, it's marginal as to whether it's worth the time and effort.
But thanks for the replies, now I know that some chargers only work with pairs of batteries, I'll bear that in mind when buying Li replacement batteries and chargers.
 
I am a bit confused by all the AA rechargeable batteries available. I may be out of date on what is available. I did not realise you could get 1.5v rechargeable lithium.
I have a few 14500 rechargeable lithium (same physical size) rated at about 600 maH. But that is as 3.7 to 4 volts. I have also 18650 cells at 2200maH.
Situation a few years back was that about 700maH for 14500 and 2500MaH for 18650 was near max possible with this battery chemistry.
At the time Chinese 18650 were sold claiming 9900maH when on testing they were more like 600maH.
This all lead to my doubt that your cells were ever 3000maH. Be careful also that they often refer with lithium batteries to WattHour which of course is much more than maH. (maH multiplied by voltage) Of course they may be NICad batteries at 1.2v but higher maH.
You can get quite cheaply from China a battery capacity tester which discharges to set point and counts ma produced. Might be useful to you.
ol'will
 
Take a look at YouTube channel Project Farm. Excellent reviews throughout and the guy recently thoroughly compared AA batteries, including lithium.
 
Cell voltages of all Li-ion chemistries are around 3.5v, so to replicate an AA cell it has a voltage regulator and needs a charging circuit/BMS within the battery.
 
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