If you're going to have to change the battery, you could also add a charger connection lead at the same time. I'm not too keen on using the cigarette lighter - the fit of plug into socket frequently is not too good. Cheers,
Graham (G4FUJ)
Sold L44FOR 4/4 Giallo Fly '11 MINI Countryman Cooper D All4 '90 LR 90 SW