man i totally get the anxiety... frying a body right before a big gig like that would be a nightmare. honestly, for the X-H2S, i really think you should play it safe. ive seen those cheap dummy batteries cause some weird glitchy behavior and it just isnt worth it when youre on a time limit in that miami sun. here is what i have tried and what i would be careful with:

• USB-C PD Power: This is the safest way to go imo. It bypasses the dummy battery risks entirely. if you use something like the Anker 737 Power Bank 24000mAh 140W it can definitely keep the internal battery topped off even at 4k 60p. the main downside is that usb-c ports can be fragile, so you really need a cable clamp to keep it from snapping.
• V-Mount with Plate: If you want to use your big batteries, maybe look at the SmallRig V-Mount Battery Plate with Crab-Shaped Clamp 3204. it has better regulation than those super cheap d-tap cables you find on amazon. just make sure the cable is rated for the fuji specifically, dont just grab a random one.
• Extra NP-W235s: i know it sounds old school, but just carrying four or five Fujifilm NP-W235 Li-ion Battery might be the move for a festival. no cables to trip on or snap off in the crowd. just be careful with the internal heat too. charging while filming 4k makes the camera way hotter. i would suggest keeping that screen flipped out the whole time to help it cool down... maybe even look into a cooling fan if you have money left. stay safe out there.

To add to the point above: I had the exact same panic before my first desert shoot! I was so stressed about the heat killing my X-H2S but it ended up being totally fine. USB-C PD is honestly a lifesaver and so much simpler than those scary cheap dummy batteries. I love how modern cameras can just take power directly now, its amazing! Here is what I found works best after experimenting:

• Nitecore NB20000 Gen 2 Power Bank : This thing is fantastic because it is so light! It handles 4k 60p like a champ and fits right in a pocket or strapped to the cage.
• Fuji CP-W235 DC Coupler : If you really want peace of mind, go official. It is pricey but you wont worry about voltage spikes frying your sensor at all.
• Baseus Blade 100W 20000mAh Power Bank : Fantastic value and the super thin design is great for mounting. You are gonna crush that Miami festival!! Just keep an extra cable handy in case one gets snagged!

Like someone mentioned, USB-C PD is the safest interface for the X-H2S, but i would argue against using consumer-level power banks for a professional multi-day festival. In high-heat environments like Miami, consumer electronics often throttle output to manage thermals, which might lead to the camera losing its external power handshake mid-recording. For a $300 budget, the Core SWX Powerbase Edge Lite for Fujifilm is a more methodical choice. It provides a regulated 8.4V supply and 14V outputs, specifically designed to prevent those voltage spikes seen in unbranded dummy batteries. Looking at brand comparisons, the FXLION NANO TWO 98Wh V-Mount Battery offers professional-grade circuitry that handles heat dissipation much better than a plastic power bank tucked in a pouch. Its compact enough for a cage setup and provides a stable USB-C PD output. These dedicated cinema batteries are engineered for continuous high-draw scenarios, which is exactly what 4k 60p recording requires. They cost a bit more than a standard battery bank, but the reliability during a live set is worth it tho.

That Miami sun is a nightmare for gear honestly. I would be so careful with whatever you choose because the heat changes everything...

• My old mentor actually had a disaster like this at a music fest back in the day.
• He was so paranoid about running out of juice that he built this massive custom power array.
• It worked for the first day but by day two the humidity just soaked into the wiring.
• Right in the middle of a huge set the whole thing shorted out and his camera never turned on again.
• He ended up having to borrow a point and shoot from a tourist just to get a few shots for the client. It was a total mess and ngl i still get nervous thinking about it whenever i see someone prepping for a humid shoot. Just gotta be really careful out there tho.

Saw a rig fry in high humidity once. I've used the SmallRig VB99 Pro V-Mount Battery 99Wh since.

• 14.8V regulated
• 65W PD Dont risk the spikes.

Saving this whole thread. So much good info here you guys are awesome.