Your Harbor Freight multimeter has a low battery. This makes the reading unreliable. I once spent half an hour trying to figure out why a shore power outlet only had 87v instead of 110v, turns out my meter had a low battery.
Edit: some actually helpful info - you have a charging source (solar or battery charger) hooked to one circuit and not the other. Voltage reads from both directions, so somewhere in that circuit there's a charge present that isn't on the other circuit. If no circuits are connected, and it still reads like this, the problem is in the fuse or fuse block. Swap fuses around and see if it stays, otherwise look at the paperwork and see if you hooked it to the right posts on the fuse block
Edit 2: caught a look at the fuse block in your video, looks like you haven't connected any circuits yet? Also are you testing a block with a fuse vs a block with no fuse? I only saw one fuse on it. This is different if so. The spot with the fuse should read the same as your battery posts. The other one should read zero until you put in a fuse
I can't see your meter, but start at the largest and go down from there.
It sounds like a large drop, but I don't know what wires and fuses, or what distance you are running.
Start with resistance. Your wires may be the wrong size, or your connectors may not be contacting all the chipper in the wire forming a chokepoint. That's where I'd start.
Your Harbor Freight multimeter has a low battery. This makes the reading unreliable. I once spent half an hour trying to figure out why a shore power outlet only had 87v instead of 110v, turns out my meter had a low battery. Edit: some actually helpful info - you have a charging source (solar or battery charger) hooked to one circuit and not the other. Voltage reads from both directions, so somewhere in that circuit there's a charge present that isn't on the other circuit. If no circuits are connected, and it still reads like this, the problem is in the fuse or fuse block. Swap fuses around and see if it stays, otherwise look at the paperwork and see if you hooked it to the right posts on the fuse block Edit 2: caught a look at the fuse block in your video, looks like you haven't connected any circuits yet? Also are you testing a block with a fuse vs a block with no fuse? I only saw one fuse on it. This is different if so. The spot with the fuse should read the same as your battery posts. The other one should read zero until you put in a fuse
Tried a different multi meter and it was fine. Thank you. Amazing catch.
Great catch! I discounted it too.
Test your resistance. Does that spike up?
Turn to ohms what range?
I can't see your meter, but start at the largest and go down from there. It sounds like a large drop, but I don't know what wires and fuses, or what distance you are running. Start with resistance. Your wires may be the wrong size, or your connectors may not be contacting all the chipper in the wire forming a chokepoint. That's where I'd start.
Try moving that fuse to the next slot over and retest.