Lithium Ion Drill battery retrofit?

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Lithium Ion Drill battery retrofit?

Post by Jarod » Sun Sep 29, 2013 6:55 pm

Just read on hackaday about a guy that converted his cordless drill batterys to lithium ion.

I have several dewalt drills, a reciprocating saw, and circular saw. all of which are useless due to all the battery's I have being shot.

New batterys cost about $50 each, lithium ion packs are around 80 if i remember correctly.

I have at least 3 battery cases with no good cells left inside. I have found these cells: ... _Pack.html

which I can fit 2 of in each battery pack. totalling 22.2 V per pack. which is a little over the 18V that the factory batteries are specified at.

So for about $20 per battery pack I can convert to lithium-ion. I can then charge them with this: ... oduct=7028

So here comes the problem. Undervoltage protection. these are RC packs. which means they have no undervoltage protection at all. you can drain these until they are $10 paperweights.

If I end up buying some and converting my drills then I need to find a way to prevent destroying these batteries. looking into purpose-built ICs as well as circuits of discrete components. there is plenty of leftover space in the packs to put a bunch of extra hardware.

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