portable power supply???

[lookus]

i am wondering what size battery i would need to run a heq5 mount, a laptop (running stellarium) and possibly a dew heater.

i am considering a 36a/h agm battery at th moment, but i am wondering if it will be enough. i can always get a larger capacity battery but it will be much larger and heavier and therefore less portable that the 36 a/h battery. will a 36a/h be enough to run for a night(approx 6-7 hours)?

[RobF]

I bought a 33ah AGM to run my laptop and a HEQ5Pro recently. The longest night I've run them both for so far was about 8hrs. Judging by the time to charge I'd taken 15 to 20ah out - bit more than I would have preferred. My laptop has a DVD drive, and seems to draw about 2ah guiding etc. The Heq5Pro I've usually run off a jumpstart battery pack in the past. If you're doing dew as well you might be pushing it to go a really long night. I'm not up on dew heaters and how much juice they draw however - I'm sure someone else can comment.

Then again, with one of the newer atom processer-based netbooks that draw a lot less current you might be ok.....