If they come back to Australia, a Jackery 500 is perfect. Also keep an eye out on Bluettipower.com.au, they should be bringing one of their Lithium batteries here shortly.
Me, I don't advocate for lead acid at all. They're heavy, cumbersome, have too many "quirks" when it comes to power and longevity compared to Lithium
I would choose either standard Li-ION like I mentioned above, or a LiFe-PO4 system, which you can build yourself using say a battery from Solarking or wait for Bluetti to release their LiFe-PO4 range here.
For what it's worth, I have
- Jackery 240. This is the main right that powers everything during the night
- Since 240 isn't enough juice, I top it up during the night with one (or more) of my LiFe-PO4 batteries: 12Ah, 15Ah and 20Ah. This is enough for two nights of shooting.
If you choose Li-ION, make sure it's a regulated unit to guarantee 12V power. If you choose LiFe-PO4, that spits out around 13V all the way to about 5% capacity so you're fine with that.
There's also an Aussie option at 40Ah, which uses LiFe-PO4 cells:
https://www.snowys.com.au/rover-lith...-power-station
I believe they also sell a 70Ah version.