My old campervan refused to start the other day ( keep it on the road during the winter as it's still good fun to take out on a sunny winter's day ) got the RAC Homestart out to get it going - they tested the battery and the alternator charge and found no problem but suggested a trickle charger due to lack of use. Good old Amazon came up with a solar one for £15 ( free delivery ) that you can plug in to the power/lighter thingee and believe me it works a treat . The quality is excellent and you have no wires to worry about and the old van starts up instantly now. Can be used on all cars so would be good for zeds that are not used as much as they should ( clearly not for those tucked up in a garage under cover but if kept outside or natural light available an effective cheap convenient means of keeping your battery in optimum charge.
Thought it worth a mention.
Thought it worth a mention.