Synregie - charging via lighter socket

[Richard_C]

I have an ancient Synergie 1.9TD which often lies unused in the garage for 3 - 4 weeks at a time. If I know it has been idle and plan ot use it I give it a few hours of trickle charge with my even more ancient battery charger the day before.

That is a bit of a palaver, I need to move a car, find somewhere to park it and open garage door to be able to open the bonnet, door wont close with bonnet up and so on. As the fuse (#16 I think) can be placed to keep the cigarette lighter sockets always live, I could easily charge it via the rear socket, I could even leave it plugged in, with a timer so it gets a couple of hours every week.

Is there a downside to doing it that way?

As a general question, what is the best way to look after a battery of an infrequently used vehicle?