Charging Lithium batteries

[mark]

Can Lithium AA batteries be charged in a normal charger?

mark

[fred]

In article , mark writes

Unless something has changed very recently, I'd expect any AA size lithium cell to be primary so not rechargeable at all.

Any link to the cell concerned?

[Andy Dingley]

No.

There are half-a-dozen rechargeable lithium technologies, a few of which are available in AA sized cells, and each one needs a particular charger. At present they're so different that you might as well get a new charger, from the same supplier, with each batch of cells. The cell voltage is also such that they're incompatible with AA cells.

There are also some lithium technologies that are resolutely primary. Trying to recharge these is likely to start a fire. These are the more common forms in AA format.

If you had lithiums that were safe to put near a charger, I think you'd already know.

[ericp]

I do not know if you can charge them or not but I would think there is probably some preventative in them to stop it.

And from a practical point of view using the crappy normal chargers would appear foolish unless you put said batteries and charger outside where they could burst into flames harmlessly.

It would be an interesting experiment though.

[dent]

The only rechargeable ones I can think of that are close to AA (the

14500 cell) are 3.6V and need a special charger.

dan.

[Rod]

And I have a torch that can use anything from 1.2 to 4.5 volts (or something like that). Can run on rechargeable or primary cells, alkaline, NiMH or Lithium - so long as they are AA size. But what I don't seem able to find out is whether there is anything to be gained by using 14500 lithium cells.

I really don't want to buy another charger unless there is a significant gain. (Especially as many of the cheaper ones have US plugs.) Like last much longer. Remain charged for ever. Provide higher current. Anyone tell me?

14500 cells, chargers and 'flashlights' here:

[mark]

I think that's lithium batteries knocked on the head.My Nickel m-h ones are getting to be useless, hence the question

Thanks all.

mark (OP)

[The Natural Philosopher]

primary or secondary?

If secondary, I doubt they will be AA since they are about 3.8 v per cell.and need special cahrers

If primary, you shouldnt be charging them at all.

[Dave Liquorice]

I haven't looked at all the torches in your link but only one of those I looked at will work over that range and the light output is only quoted for 14500 battery...

Looking at the batteries themselves they all have less than 1000mAHr capacity. The new hybrid Ni-MH batteries are around 2000mAhr and will charge in a normal Ni-MH charger and have a long shelf life. The easy way to tell the hybrid Ni-MH batteries is that they are rechargeble batteries come ready to use, no need to charge before use.

I'd also be a bit cagey about having physically indentical batteries with such a large difference in terminal voltages. Far too easy to fit a set into something designed for a nominal 1.5v/cell and let the magic smoke out.

[mark]

I was thinking of my Makita rechargeable screwdriver which has lithium.

mark

[Rod]

Obviously I don't know which ones you looked at. I actually bought this one:

Have to agree it is stonkingly bright on alkaline.

There are at least three with the sort of range I mentioned - even 0.8 to 4.5V. Totally agreed about the capacity as claimed. Just wondered if perhaps you could use the whole capacity where NiMH (or whatever else) fades out more quickly.

And also about the magic smoke release. Another reason I decided not to bother. But there are all sorts of mentions of using small magnets to make some batteries the right size - never did measure to see if they are exactly same size as AA.

[Mike]

In the 1990's there was an HSE report on an incident, possibly in the USA with a non-rechargeable lithium cell that was accidentally 'charged' when if I recall correctly a forensic examination indicated a blocking diode fitted the wrong way round. Despite it being the size of around half a PP3 cell it destroyed a substantial sized room with the resulting explosion. Internal cell protection devices have improved significantly since then, but fiddling with something you don't have intimate knowledge of can be very dangerous.

Even if you *think* you know what you are doing and have done something similar many times before it can still go very wrong, I 'exploded' a Nicad pack a few years back when I had a very senior moment last thing at the end of a very long day regarding charge rates and ampere hours and a newish bench power supply. The big 'bang' happened overnight when no one was around but I didn't destroy the lab with an explosion...I instead contaminated the place with cadmium residue.