I charged the battery for my E30 BMW...

[Legacywr]

I had had it on trickle charge for a couple of days, I put it in the car, connected the positive terminal, but when I connected the earth it sparked, which it shouldn't have, and my alternator burnt out!???

Why? Have I done something stupid and charged the battery the wrong way round?

[stevieturbo]

Legacywr said:

which it shouldn't have

And why do you think it shouldnt ?

If there are any electrical loads still turned on, then it's very likely it will spark.

[Legacywr]

stevieturbo said:

Legacywr said:

which it shouldn't have

And why do you think it shouldnt ?

If there are any electrical loads still turned on, then it's very likely it will spark.

Yes, sorry, it was a much stronger spark than you would expect. Maybe it was the alternator that had shorted while the car has been out of use?

[Mr2Mike]

Are you certain you didn't accidentally connect the battery backwards? That would certainly give a large spark and burn out the alternator coil pack.

[Legacywr]

Mr2Mike said:

Are you certain you didn't accidentally connect the battery backwards? That would certainly give a large spark and burn out the alternator coil pack.

It was the right way round, but is it possible that I charged it the wrong way round and reversed the polarity?