I’m looking for something I can make up that will power my P7 light head while I wait for a replacement battery to arrive.

Unfortunately, I didn’t heed all the dire warnings and let the original one get wet. It’s shagged, but I figure if I can just get something that will provide vaguely the right ammount of current and volts into the head unit I’ll have some sort of lighting available until the new battery arrives.

Any clues?

It’s 7.4v (4 x 3.7v cells, 2s2p) but AFAIK the current draw protection is built into the PCM on your old battery – probably the bit that is shagged tbh, and possibly replaceable (though it will take as long to arrive as your battery unless you can find a UK source).

I don’t know what protection is built into the head unit having never taken it apart – if there’s no driver in it I’d be a bit wary.

Yeah.. I’d been running the head unit directly off of the cells – bypassing the protection unit that was knackered. It worked quite well! Until I let the cells completely discharge at the weekend – I think the protection unit prevents this? Unfortunately, it looks like I’ve now run the battery down into a deep discharge, from which it will now never return..

The head unit has its own transformer thingy, which I think will protect it from any current spikes, maybe..

Cheers!