Here is a convenient way to have a spare battery. Just add the 4-pin socket. The light comes in handy too. The manfacturer recommends not to deep-cycle the battery.

What happened to Tekkeon??

The Tekkeon battery would be okay for the Mini head, finder and screen alone but at 50w. (2.5Ah???) it might be a bit small for the full recorder unit assembled to draw from. Might be only good for about 35 minutes at what the full recorder unit draws. Unlikely to endure any longer than the ABs I already use.

The blue battery is a jump starter for cars, will always be aboard, has a little worklight built-in and all that was needed was a 4-pin socket. I was using a cigarette lighter plug in the socket already provided but those plugs are notoriously resistive and not reliable.