(Rod Mollise) wrote in message ...
OTOH I suspect the deep cycle batteries might be better for higher
current drawing equipment, like a dew heater system.


Hi:

Or maybe not even then. I've been using one of the Walmart yellow "Prestone"
jump start packs for a couple of years to power a goto scope and a Dewbuster
heater system. Never have had a problem. I do recharge in the mornings, though,
and if the setup includes a CCD camera, computer, etc., a big deep-cycle
battery is definitely recommended.

Same here. For a "normal" weekend (of visual) I find I can use just two of
the jump-start systems on an LX200 with no problem: one for the scope and the
other for the dew heater system (though I'll always bring two more for backup).

Once CCD imaging comes into play, however, out come the deep-cycle batteries
given the much higher current requirements for the gear and ancillary support
equipment.

(Expected) temperature at one's viewing site(s) should be factored-in, too,
given battery efficiency/voltage decreases as the temperatures plummet. If I
go to a site where the temps hover around freezing (of water) or below, the
deep-cycle batteries are the only ones I'll use.