battery cable & fuse question -> Epoch V2-T 12v 460 ah

Running a pair of these in parallel in my motorhome build and trying to nail down the cabling spec before I commit to anything.

Each battery is rated for 200A continuous discharge, so theoretically with two in parallel I'm looking at 400A available from the bank. My inverter (Victron Multiplus-II 3000) pulls up to around 250A peak at 12V under heavy load.

Cable sizing question: I've got 70mm² tinned copper running from each battery to a busbar, then a single 95mm² run to the inverter. Is that sufficient, or should I be upsizing to 95mm² throughout? Runs are fairly short — roughly 600mm per battery to busbar, then about 800mm busbar to inverter.

Fuse placement:

• ANL fuse directly at each battery terminal (so two fuses total) — what rating? The Epoch V2-T has an internal 200A BMS but I presume I still need external fusing?
• Then a second ANL or MIDI fuse on the main positive leaving the busbar toward the inverter?

Victron's own documentation is a bit vague on parallel battery setups and I've not found anything Epoch-specific for UK installations.

Also wondering whether anyone's used Fogstar or another UK supplier for pre-made cable assemblies at these gauges, or whether it's worth getting them crimped locally.

Primarily concerned about getting the protection scheme right rather than just "it works" — want proper fault protection at each battery independently.

@Chalky90 with 200A continuous per battery, your parallel combined capacity is 400A — but the fuse on each individual battery cable should protect that cable, not the total system.

So if you're running 70mm² cable from each battery to your busbar (rated ~280–320A depending on run length and routing), fuse each battery leg at around 250A to protect the cable rather than the battery's max output.

Then put your main system fuse between the busbar and your loads/inverter, sized for that equipment.

Key questions worth pinning down before you buy anything:

• What's your cable run length?
• What inverter are you running?
• Are both batteries physically close to the busbar?

Victron's cable sizing guidelines are worth checking — their documentation on parallel battery setups is solid and will sanity-check your calculations. Equal cable lengths between each battery and the busbar is non-negotiable for proper current sharing.

@BlownFuse has covered the per-battery fusing nicely, but one thing that's bitten me on my narrowboat setup — don't forget your inter-battery link cables need to be the same spec as your main cables. I made the classic mistake of undersizing those and ended up with one battery working harder than the other like a lazy coworker.

Also worth considering: where exactly are these batteries sitting relative to your inverter/charger? On a motorhome the cable runs can get surprisingly long, and voltage drop on 400A combined is no joke. A 30cm run versus a 1.5m run is a very different conversation for cable sizing.

What Victron kit are you running downstream? That'll affect what your busbars need to handle too.

What @BlownFuse and @SunnyFisher said, but nobody's mentioned cable length matching yet.

Running parallel batteries? Both cables from battery to busbar need to be identical length. Even a few centimetres difference causes one battery to do more work than the other — guarantees uneven wear and shortened lifespan.

Did this properly in my shepherd's hut build with Fogstar Drift cells. Cut both runs to exactly the same length, same gauge, same terminals. Both batteries charge and discharge at near-identical rates.

Also — what cable gauge are you actually planning? 200A per battery means you want minimum 35mm² on each battery's positive run, ideally 50mm² if your runs are longer than a metre or so. Don't cheap out on cable. It's the bit that catches fire.

Good points all round. One thing I'd add from bitter experience on my narrowboat — terminal torque matters more than most people realise with these higher-capacity LiFePO4 builds.

Epoch spec their terminals at a specific torque value; ignore it and you get micro-arcing under sustained load that'll heat the connection and skew your current sharing between the parallel cells. I use a proper torque screwdriver now rather than "feels tight enough."

Also worth checking whether your busbars are tinned copper rather than bare — on a motorhome you'll get condensation cycles and bare copper oxidises faster than you'd expect, adding resistance asymmetrically across your parallel strings. Fogstar and Victron accessories are decent for this. Small detail, big consequences at 400A combined.