Battery fix

While looking around for something to do that didn't mean too much moving around I remembered the troubles I was having with my battery powered drills. I found that after 6 months or so the battery life is not too good and they self discharge overnight! A 12volt drill battery is rated at about 1200mAh, since I had a number of old Lipo batteries I will never use again, (they sag under load) this is what I've done.
First discharge the battery completely! Not hard to do!


This is the type of battery, Ryobi (Australian) is common here as budget tooling.
Remove 4 screws.


and this is what you find.
Using a disc cutter in a pencil grinder cut the negative strap.

I hesitated to say Dremel!
Now unsolder the positive and tin the negative contact because we need this widget that holds the sliding contacts.

One at a time solder the new battery wires onto the widget, I've left it sitting on top of the old battery pack so it's easier to work with.


Once done we can discard the old battery.

The sliding connector block fits in the 'tower' of the case.


And we need a block of non conductive (wood) material to stop the contact block from sliding down. Note the 4mm hole for the balance plug wires.


I put a dab of glue to stop the block from moving during assembly.


Job done, I still have one battery with the original batteries but I'm going to modify one of the charger sockets to fit my Lipo charger.

I claim no original thought for this, it came from a site called 'Instructables', the MO is mine.
A caveat, don't run this new battery flat, there is no 'auto disconnect' that you get with the new Lipo powered portables.

Guilty as well! Replacement OEM batteries here cost over 50quid each. Apparently the voltage of the new battery is not that critical since the only difference between a 12volt and an 18volt drill is the battery, there may be a slight drop in maximum revs but these things don't rev that high anyway.

I vaguely remember doing something similar with an ancient old B+D 9v drill, with the nicads built into the handle. When the battery pack 'died', i discarded it, used an external 'car-racing' pack (because it wouldn't fit inside), and fed it via the 3.5mm charging jack.
It worked great for a while, but when I was drilling a larger diameter hole for something - long forgotten what - the socket melted! Made some lovely sparks before I cut the wire!

I accidentally blew up a nicad 500mah button cell. I'd left it (a four cell pack) on the usual 50mah overnight trickle, having done it many times before, then at Oh-God-o-clock, tremendous BANG! from the model room.
When I went to investigate, black powder all over everything! One button in the middle of the pack had decided it had had enough! It took weeks to get the black stain off everything!