Power packs?

[fwm891]

As the trees (not mine) encroach further into my already restricted fov I'm beginning to pull together a small (ish) kit to take to broader horizons!

The kit: Skywatcher AZ-GTi mount (EQ mod) on tripod, Altair Ascent 80mm triplet with 1x and 0.8x flat/red, ASi585,  Hypercam 26C and ASi120mini (guide cam) and mini guide scope plus dew bands to suit 80mm and mini guider scope and an ASiAIR Plus.

I will also have a laptop with me but its own battery runs for 6 hours+ if I keep the screen brightness right down and that will more than suffice my needs.

My cooling of the camera will be down to -10°C max more normally -5°C.

Dew straps only when needed

Working away probably looking at 3-4 hours run time

What sort of power pack would suit this set-up with a small fudge factor?

I'm sure many of you have a similar outlook to me. The photo shows my skies - I'm backed against the obsy looking south. Neighbours wall takes out all my north view (no Polaris and only a few degrees from zenith).

Cheers Francis

[Elp]

Depends on ambient temperature. My Celestron Lithium LT in recent weeks has lasted over 3 hours, probably will go to 4.5, similar setup but any dew bands I power with a separate usb power bank, though haven't needed them the past few weeks. In winter it usually only last 3 hours or less. Alt az usually lasts around 6+ hours. An even better battery recently bought is the Talentcell 72W 100WH one, this thing just keeps going, and can power my gem28 rig on its own with the air, though I don't think it also likes a cooled cam attached, uncooled cam works fine with this setup and the one battery. I generally don't like using two batteries per setup so have been fine tuning it all, without looking at great big hulking batteries which are not portable at all, the ones mentioned truly are portable.

[ONIKKINEN]

You could measure how much power all the kit needs with an ampmeter while its running. I think that gets you to the best estimate without guessing.

But guessing anyway: Without the dew straps you will probably average around 20 watts of power drawn (safe estimate). Could be more if ambient temperatures are high and the cooler has to work harder. Lets add 5w average for the dew straps at minimum power only when needed.

So for 4 hours you need at minimum a 100wh battery. In practice you should never drain a battery all the way and if its cold outside (below 0) you can have as little as half the rated output available. To be on the safe side i would be looking at a 150+wh battery pack of decent quality. If you want to save money and go for a lead acid battery you might want to double that. Gets bulky really fast...

The most convenient option (not the cheapest) is a jackery/Ecoflow river/similar power station with good battery chemistry: LiFePo or Li-ion.

[fwm891]

Thanks @Elp and @ONIKKINEN looks like 100wh is a minimum. I wasn’t fancying lead acid batteries. At present I won’t be using the 26C as it’s not compatible with the ASiAIR PLUS and I may well sell it and get something that is compatible. But that’s all in the future…