Led Lenser Battery Pack

dvd8n

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My old Led Lenser head torch is refusing to charge properly. The battery pack is (I presume) on it's last legs.

The numbers on the pack are ICR18650 2S1P 7.4V 2200mAh.

I went to buy a new battery but they seem to be obsolete. I can find similar battery packs but with different connectors; the Led Lenser has three connectors on one end labelled - - +

I suspect that it's just two Li-ion cells with some wiring and maybe some circuitry inside but I'm a bit loath to cut it open when there's still some life in it.

Does anyone have any advice?
 

dvd8n

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theshorelinemarket-2615-1773395785.jpg


Looks like this.
 

lightfooted

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theshorelinemarket-2615-1773395785.jpg


Looks like this.

It looks like it could be three 18650s wrapped together but I'm not sure if they are all connected in series or parallel or a combination. Maybe you should dissect it to see. I know I would.
 

dvd8n

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It looks like it could be three 18650s wrapped together but I'm not sure if they are all connected in series or parallel or a combination. Maybe you should dissect it to see. I know I would.


It feels like there is something going on down the middle that's not a cell. But I think that you're right - I'll need to cut it open to find out. I'll get my explosion containment pie dish out.
 

DIWdiver

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Based on the markings on it (2S1P, 7.4V), it is most definitely two 18650 cells in series. The thing running down the middle would be a battery protection circuit.

The reason for it to have 3 connections is so that the charger can balance the cells. Balancing is a requirement for LiIon cells charged in series. It is possible to put the balancing circuit in the battery pack (I've done this, and gotten it UL approved), but I very much doubt this one has that.

If it's nearly dead, it isn't likely to explode, as there's not much energy there. It could burn, though even that's unlikely. You might want to carefully cut away the shrink wrap so you can re-attach the markings after you re-build it. What you want to avoid is shorting anything with the knife. It looks like there's a connector strip running along the edge of the pack. See that flat section under the LED LENSER name? That's insulated from the cell it runs alongside, by an inner shrink wrap on the cell.

Have you looked into what it takes to re-build a battery pack?
 

dvd8n

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Have you looked into what it takes to re-build a battery pack?

I hadn't but I watched a couple of videos and it doesn't look too hard. I don't have anything to spot weld the batteries but I'd be willing to try soldering them - maybe outside though.
 
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