I tried recharging my 810 using a car charger connected to a static 12 volt battery, but it didn't work and now my machine won't charge on the normal power charger.

As I see it there are two possible causes and two possible outcomes:

1 the car charger is faulty
2 the connection to the battery is not a good idea

Is there any reason why a cigarette lighter socket connected to a static battery should be any different from the one in the car?

The 810 still works normally so now I'm trying to test two theories as to what has gone wrong:

1 the battery is damaged or

2 internal charging input is damaged. (or both)

I've ordered a second battery and an external charger which should test both these elements.

Any thoughts on this?