Gregory Baskin wrote:

> 15 minutes of idling is 15 minutes of idling,

Greg,
Yes, it is. But most of us will find a reason to run the engine the
equivalent of 15 minutes a day for other reasons, whether it be to find
a new campsite, heat the van on a freezing day, or whatever. Maybe it's
an hour's drive every fourth day. Efficient use of the aux battery
should keep it up that long. If not, then plan on spending a wad for PVs
big enough to handle whatever you're running.
Larry