Mommabear - Out of interest, what solar and leisure battery have you got? I've always found that running the engine for a short(ish) while is usually enough to keep give the battery a kick. We've not actually got solar at the moment but, hopefully, the panel is being stuck to the roof as I type this and I will be getting the van back with the job done tomorrow.
Just remember bud that idling, especially from cold is where the majority of engine wear comes from. Not a problem, but if you are doing it regularly just drop the oil a bit sooner.