Charging batteries with the engine

Desert Captain wrote:
One of the many advantages of a large gasser vs the Mercedes {or other diesel} is the ability to let the gasser idle for extended periods of time. {Don't even think about trying this with a diesel}.

This bit of wisdom is at best overstated and in many cases flat out wrong.

It's not good for either gas or diesel to only be run at idle, so if you are boon-docking for months on end and the only use is an hour a day of idling, it causes problems. Basically the engine doesn't get hot enough to burn the fuel cleanly and carbon deposits can coat the cylinder and score the piston.

As long as you periodically get the engine up to full operating temperature, those carbon deposits get burnt off before they are enough to do any damage. So if you drive out for a long weekend, run the engine to charge for a couple hours on saturday and then drive back at the end of the weekend, no issues as the engine will reach operating temps during the drive. Even a stray week won't have any measurable impact. (look at truck stops where historically they would just idle the engines all night long and get 500-1000k miles out of an engine because the next morning the engine gets up to temp and addresses the issue).

Still not the best option if you have a generator or other source to charge with but this is rarely a consideration.