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Cordless drill battery pack cell upgrade
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drummerdimitri:
I'd like to upgrade the cells in my Bosch's cordless drill battery as they are originally rated at 1.3 Ah but according to my electronic load they are around 1.05 Ah today. (10 year old batteries).

I got frustrated today as I was drilling 4 deep holes in a concrete wall and had to swap the battery out after just two holes!

Today's high end 18650s are around 3400-3500 mAh as battery tech has gotten much better over the last decade so I thought it would be a fun and beneficial project to take the pack appart and upgrade the cells within.

The only issue is, the original ones are Samsung  INR18650-13Q and according to the datasheet, they are rated at a max continuous discharge rate of 15A while the ones I'm thinking of replacing them with are Panasonic NCR18650B with a max continuous discharge rate of 6.8 A only.

Not sure why this is the case but will this be an issue? I don't want to run out of power while drilling deep holes in concrete with hammer action so should I look at another cell that at least matches the 15A rating of the original battery?
Monkeh:
You definitely want to get appropriate cells - the ones you're looking at are aimed at lower power applications. 2.5Ah is probably the limit for appropriate cells.

You might find it better to just buy a new battery.
wraper:
There are some higher capacity high discharge current cells like INR18650-30Q, ICR18650HG2
wraper:
Note that soldering those batteries is a bad idea, especially soldering bottom side. It may cause battery degradation or even explosion/fire in the worst case. You should either spot weld them or buy batteries with spot welded tabs already present, then solder to those tabs.
drummerdimitri:

--- Quote from: wraper on March 26, 2020, 12:24:04 am ---Note that soldering those batteries is a bad idea, especially soldering bottom side. It may cause battery degradation or even explosion/fire in the worst case. You should either spot weld them or buy batteries with spot welded tabs already present, then solder to those tabs.

--- End quote ---

I always assumed that higher capacity battery also come with a higher discharge rate as well.

That's obviuosly not the case and thanks for clearing that up.

Those look like excellent contenders thanks.

Don't worry, I have experience tab welding battery banks so that shouldnt be an issue. Need 0.3 mm nickel strips though as the ones I have are only 0.15 mm which makes sense for the high current draw.
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