Can an electronics guru give me advice on AA battery chargers. My limited knowledge tells me that charging AA batteries slowly will prolong their life so I have been using the 4-way Uniross chargers where you can select 200, 500, 750, 1000mA and using it on 200 whenever possible and they've seemed fine. Does 200 or 500mA really make any difference to the life of the battery?

I now have a need for a bigger charger so would like a 16-way one. I found these which always charge at 500mA...
https://www.ebay.co.uk/itm/253785866774

Happy to spend more money but there doesn't seem to be many 16-way options that look much better.

Any advice / recommendations?

There is the weird thing to do with charging them at too low a rate can lead to overcharging. For 2500 Eneloops, you would think it should be 500 or 700 mA initial rate. It doesn?t make much difference to how long they take to charge. You could use 1000mA just fine, possibly not a lot more if you worry much.

I believe it is generally held that Eneloops don?t misbehave, others might.

ooooo a charge rate question, very interesting, most say a low rate is bad for Nickel based chemistrys.

https://batteryuniversity.com/learn/

Assuming you are charging AA NiMH cells? The problem for NiMH cell is the end of charge is detected by a voltage drop called -dv, negative delta voltage, which occurs near charge capacity.  the NiCD -dv is quite pronounced and that technology is repurposed for the NiMH but the NiMH -dv is signifcantly lesser and so can be missed leading to overcharging/overheating.  Some chargers will have a timer cut off for this reason and then also if you've a good one a temperature cutoff too.  so when buying a charger check how it cuts off charging.

Please read this site, I like it a lot, although it doesn't have many 16 cell reviews but gives a great idea of what to look for.  I imagine there are other sites like it but this is the one I like.

https://lygte-info.dk/info/roundCellChargerIndex%20UK.html


Regarding Youshik as a brand, I won't buy one after they ripped off the Technoline design of the BL-700 which was regarded as the top of the range 4 berth charger.

https://www.youtube.com/watch?v=-e0uZbxBQnw

https://www.youtube.com/watch?v=QkErCpNA0q4


I've bought from this company in the past and they offer a japcell 16 berth.  If it's like the Technoline and Youshik setup of decent design nicked and cheapened then I'd go for the japcell every time.

https://www.batterylogic.co.uk/nimh-battery-chargers.asp

This prompted me to take a look at the charger I normally use for AA?s and read the back properly for the very first time. Pithy.

I use it for AAA?s, but it is over 1C, which is a bit much.

I like the advice to read the instruction before taking them to court.

Nitecore Intelli chargers are worth a look too.  Don't think they do one that charges 16 at at time though.

There is this one which would be OK I imagine. They claim independant control of each slot. It is 500mA and does a discharge cycle.

https://www.amazon.co.uk/Youshiko-YC1600-Intelligent-batteries-Including/dp/B07D2BLVNG/ref=psdc_431408031_t1_B07BKV5Y82?th=1

I recommend the Watts Clever SBC1001 smart battery charger which can recharge standard AA and AAA sized alkaline batteries.  Unfortunately it is currently unavailable from Amazon from where I bought mine at the moment but I suggest you Google similar "Alkaline battery chargers" for something similar.

https://www.amazon.co.uk/SBC1001-Battery-Alkaline-Batteries-Rechargeable/dp/B00872D8WU

I've had good use out of the Powerex/Maha 4 cell AA/AAA charger. They do others which sem to e liked. It seems to 'look after' the batteries quite well.