"Chuck Cox" wrote in message
...
Yes, this is an old thread coming back to life...

Back in December I wrote:
As part of a non-boating-related product, my company is
designing what amounts to an automatic 500w DC self-starting
gasoline battery charger. The charger is designed to be
portable, unobtrusive and easy to maintain. If the battery has
sufficient charge, it can self-start, but it can also be
hand-started easily when necessary. It is designed to
automatically start and stop as necessary to keep a battery
charged.

I've used petrol gennys for charging (not auto) and like the idea,
and also agree the preference for diesel. Nice if it's portable -
but that means air cooling - usually noisier.

One factor you haven't mentioned is the desirability of charging
at the maximum feasible rate (minimum running time). Perhaps
you've already got that idea in mind.

Just in case you haven't, I achieved best results charging by
taking my (European) 240v through an intelligent charger, one that
sensed battery voltage direct, and delivered up to 14.4v (variable
depending on battery type) stepping to 13.6v once the main charge
had been delivered (there was also a 16v option for de-sulphating
the batteries. Add water afterwards!).

A shortcoming of most petrol gennys on the market which supply 12v
nominal is that they're usually regulated to 13.4v or so maximum,
which gives a very slow re-charge once you reach 75% or so of
battery capacity. Especially if you're pumping it down a long line
.. . .

JimB