My trap is completely wireless using Yongnuo 603ii variously hacked a bit or standard. Over the last year I’ve upgraded the battery capacity from the standard AAA to 2xAA then 2xC and I’ve just gone to 6x AA (wired 2S 3P to still give 3V). This latest setup gives me 7500mAh at 3V and a solid 2 week duration. That about does what I need though when I started I thought a 2 to 3 days would be fine!

I’ve just now added up the number of AAs this set up uses and it is 38. Of course, they are rechargeable (Eneloop or Amazon High Capacity).
4x6 for the transmitters
4x2 for 2 strobes
6x1 for IR sensor

About GBP 80 for a full load. I don’t have a spare set!

Add in 2 camera batteries in grip and that’s a round 40.

I sure didn’t expect that when I started out. Oh well.

I know what you are saying I just spent $500+ on AA Eneloop batteries and need to spend another $400+ so I will have enough to run half a dozen camms. If I want to swap the batteries over in the field then I will need to buy another bunch. So $ outlay to be able to continuously run my 6 hb cams will be $1800+ that's a hell of an investment in batteries lol.....

That's A LOT of batteries! I wouldn't be able to do it if I was using that many batteries. Others have more experience but for my SLR set I have 8 batteries for the flash, 8 for the camera, and 4 for a wireless trigger (Total: 16 rechargeable, 4 non-rechargeable). Could get it down to 17 with a little re-wiring. I am also using wired flashes.So at $2USD it's ~$40USD of batteries at my SLR set at any given time.

A few other options out there like solar panel (not my cup of tea), build a more efficient system, make a large battery back and then have grab the voltages you need off of it with voltage regulators (90% efficient) so you can use one large battery. I'm guessing there's something that usually dies first? How soon after the first system dying from low battery would the second one fail?

Head to Ikea, they have NIMH batteries that are similar to Eneloops (basically made in the same factory). I've used them in my set ups and normal photography and have seen zero difference.

Until very recently, Ikea was quite a trek for me. I’ve been using the Amazon basics High Capacity (2500 mAh) which are a OK price. And I don’t have to brave the Ikea experience!

It’s the 24 I need for the wireless transmitters that are a bit painful. But I will live with it. The compactness of the setup, their robustness, lack of wires to be careful with and trip over at setup, ease of waterproofing and no need to hide / camouflage those wires, have all persuaded me that wireless works reliably. Bigger powerpacks would require wires and solar cells are both too obvious and just don’t work under trees. It’s a compromise on battery cost and endurance but everything else just works nicely now!

Ouch. That makes me feel a whole lot better to know that it’s not just me. I also bought a 16x AA battery charger. Tedium of feeding two, 4x AA battery, chargers now overcome!