Bosch battery pack dead

I have a Bosch PSB 12 VSP-2. It is a 12 Volt hammer drill and the battery pack is as dead as the proverbial dodo. All the cells are short circuit and I have never come across this before.

Was it the battery pack dying or has the charger fried them? I need to know so that I can arrange a new drill or not.

At this point, what battery hammer drill should I buy for economic reasons?

TIA

Dave

Reply to
Dave
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Dave explained :

Crystals grow across the poles inside of the cells and short circuit it. This results from leaving the cells uncharged for an extended period.

You can blow them clear with a source of high DC current, such as a large power supply or a car battery. You simply connect the source across the cells briefly, and it will clear the internal shorts enabling them to be charged once again.

Reply to
Harry Bloomfield

Be VERY CAREFUL sparking a car battery or similar high-current source across a dead nicad. There is a large current flow and this may weld your bit of wire to the battery terminal,. If this happens, the electrolyte will boil and the cells can explode - and it only takes a few seconds! I would suggest making up a rig with a 35 or 50A fuse in series, so if the wire welds, then hopefully the fuse will blow before the cells... K.

Reply to
Ken

Yes - a car battery is a bit much. You want something like 10-30A, maybe a car battery with a halogen headlamp bulb in series with it - this will give a high initial current surge but then limit the current as the filament heats up.

Do one cell at a time.

Reply to
Mike Harrison

Yes, I know that, but what I wanted to find out, was why all ten of the cells went short circuit :-)

If I can determine that, I can re-battery the pack and convert the charger to 14 hour charge and save the school the cost of a new drill.

73

Dave

Reply to
Dave

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