I run a 12 Ah jump start battery from Supercheap Auto. Cost me $90, and comes with the charger. It also has an LED strip, 2 cigarette sockets, a USB port for charging phones etc. Well worth it (and it'll jump strt your car too
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Never had one run out during a night yet, provided I remember to charge them the day before (as soon as I finish each dawn, I put it back on the charger).
I have 2 - one to run the mount, the other runs an inverter for the laptop and camera.