Power for mobile field setup

[EdwardArcher]

Hey everyone,
I'm just looking for some advice about powering my astrophotography setup for when I am in the field. Currently, I have a 12v 80 ah lead battery. I am hoping to power the following items off of the battery:
Laptop- 20v 3.25 A
Skywatcher HEQ5 mount- 12v 6 A
powered USB hub- 12v 4 A
Note: all these numbers are taken from the adaptors.
My plan at this stage is to use a 240v inverter between the battery to the rest of the gear. I just wanted to make sure that this would work before wasting money on something that won't work. So any advice, recommendations or corrections would be valuable to me.
Regards,
Edward

[AdamJL]

Hi Edward. The only thing that would benefit from the inverter is your laptop. But you’ll be going from DC to AC and back to AC again so a lot of wasted energy as heat (a good AC to DC can be a 20% efficiency loss so you’d still only get 80% of the DC being fed)
If you can, why not try and see if you can just get a USB Power Delivery battery? You only need 60wh by the sounds of it which is well within the range of decent laptop power delivery batteries. Some will even do +100w
Then you just run your current battery as DC only

Your mount, by the way, is likely to never ever draw 6a even when slewing which is when it draws the most amps. During tracking you’ll barely break an amp

[xelasnave]

Everything Adam says is good advice.
However I do think having everything 240 a better approach for various reasons getting polarity wrong being one:D..but what I would be doing is get another battery to have as a spare...or a small genny.
I would hard wire the inverter to the battery...now one should not get polarity wrong ever but it has happened to me too often..late at night and tired you can stuff up...well anytime really. I would leave my battery in my car ( this is when I am coming up from Sydney) with the inverter hard wired and then run a 240;vlt lead to the gear..besides eliminating mistakes I just found it easier to set up..At that point I did not have a spare battery or genny as it was near the house so I could charge if needed.
Alex

[Mickconn77]

Adam is right.
Keep everything 12v. You can buy a 12v laptop power supply from Jaycar for around $70 (maybe more now).
My Microsoft surface is 15v so I bought a 12-15v upstep and power it via a USB adapter.
Inverters are incredibly inefficient, so would be a waste of power, time and money in this set up.
I did a full 12v system on my caravan and only have the inverter as an emergency backup for whatever reason. It’s been 2 years and never used.
Im in the process of designing my own portable power station for astro so will share pics once complete.

[JimsShed]

Get an adapter and try running your laptop from the 12 volt battery. Chances are it will run fine. If not, do as Mick suggested and get a Jaycar 12v PS.
Regarding the battery, I'd ditch the lead acid battery and get a 100ah lithium. Light weight and will run for at least twice as long as the lead acid, and without the linear voltage drop. Check out 4WD and caravan accessory suppliers for the most competitive prices on complete battery boxes with a lithium battery and all the ports you need.
You don't need an inverter.

[pmrid]

I have switched one of my rigs across to a wholly ZWO setup (except for the mount itself and scope). ASi1600MM, ASi EFW (mini - 1.25” filters), ASi EAF focuser, ASi120M guide cam all running out of an ASIair Plus mounted on the scope. Early experiments with a deep cycle battery have been been encouraging. At the moment I am using a 38 AmpHour Deep cycle from ALDI but I think I will need to scale that up to 100AH. The battery runs everything including the mount and I use my IPad to operate the ASiair. No laptop until the session ends and I transfer images for processing.

It took a bit of nail-biting to cut the laptop out of the loop but it has increased my ability to operate away from home by orders of magnitude.