Victron MultiPlus-II 48V vs 24V for EV charging – anyone made the switch?

Been running a 24V system with a MultiPlus-II 3000VA for a couple of years now, mostly for the van and a small static setup at home. Works fine for general loads but I'm hitting a wall when it comes to EV charging. Currently pushing through a 7kW Type 2 EVSE but the inverter can't sustain that draw without the DC side struggling under load — I'm seeing voltage sag on the 24V busbar dropping to around 22.8V under peak demand, which is obviously hammering efficiency and causing the Victron to throttle back.

The obvious move seems to be jumping to 48V — halving the current for the same power makes a massive difference to cable losses and battery stress. I've got four 200Ah Fogstar Drift LiFePO4 cells that I could reconfigure from 2S to 4S without buying new hardware, which is tempting. The MultiPlus-II 48/5000 would give me the headroom I need and Victron's ESS assistant should handle the grid-tied side cleanly when I'm at my static site.

What I'm less sure about is the DC-DC side of things — everything else in the van runs at 12V (lighting, fridge, USB hubs), so I'd need a decent 48V→12V converter. Victron do an Orion-Tr Smart 48/12 but the 30A (360W) version feels a bit marginal for simultaneous fridge and lighting loads. Anyone running the 45A version or daisy-chaining two 30A units?

Has anyone here actually done this 24V→48V migration with a similar Fogstar/Victron stack, particularly with EV charging as the primary driver? Curious whether the real-world gains match the theory before I start pulling connectors.

@RetiredSquaddie I made exactly this jump last year — was on a 24V MultiPlus-II 3000VA setup for the garden office and honestly the EV charging was a nightmare. Kept tripping the inverter under sustained load.

Moved to a 48V MultiPlus-II 5000VA and it's a different world. The lower current at 48V means far less heat in the cables and battery connections, and the Victron handles the sustained draw from even a modest 3.6kW EVSE without breaking a sweat.

One thing worth mentioning — if you're using Fogstar Drift cells, they're already configured for 48V packs which made the battery build straightforward.

The wiring cost savings alone on thinner cable almost offset the inverter price difference. Go 48V, you won't regret it.

Great thread, this. @RetiredSquaddie I'd echo what @ExFarmer90 has touched on, but worth adding — the 48V system genuinely opens up your cable sizing options considerably. Lower current for the same wattage means you can run thinner cable runs without the voltage drop headaches that plague 24V at higher loads.

For EV charging specifically, I'd strongly recommend pairing a 48V MultiPlus-II 5000VA with a proper MPPT like the SmartSolar 250/100 if you're expanding your array. The efficiency gains at battery level are noticeable once you're regularly pulling 3kW+.

One thing nobody mentions enough — the transition isn't cheap. Budget for rewiring your battery bank properly and don't cut corners on the BMS if you're going lithium. Done it twice now and wish I'd gone 48V from the start. Happy to share my component list if useful.

Something worth flagging that I don't think's been mentioned yet — if you're going down the 48V route specifically for EV charging, have a proper look at the MultiPlus-II 48/5000 rather than jumping straight to the 48/3000. The power assist and AC coupling headroom makes a real difference when your car's onboard charger starts pulling hard. I learned the hard way with undersizing. Also, on the battery side, moving to 48V means your cable runs and fuse ratings become far more manageable for the same wattage — that alone made my install considerably tidier. @RetiredSquaddie what type of EV are you charging? That'll affect which charge rate you're realistically targeting, and whether the inverter sizing even matters as much as your battery bank capacity does.

Really useful thread. One thing I'd add from my own experience — when I moved to 48V (running a MultiPlus-II 5000VA now), the cable sizing headache dropped significantly. Half the current for the same power means you can actually use sensible cable runs without your wallet crying.

For EV charging specifically, worth looking at whether your car accepts AC Type 2 directly from the inverter output. Mine does, but some vehicles get fussy about the waveform or earthing arrangement with off-grid setups — had to sort a proper neutral-earth bond before my Zoe would negotiate properly.

Also, if you're sizing a new 48V battery bank, Fogstar Drift cells are worth a look for the price point. Decent BMS comms with Victron kit over CAN if you go the DIY route.

Good points all round, but one thing nobody's touched on yet is the cable run implications for a motorhome specifically.

Going 48V halves your current for the same wattage, which means you can realistically use slimmer cable runs between your battery bank and the MultiPlus without the voltage drop penalty killing efficiency. In a motorhome where you're routing through tight conduit runs and every kilogram matters, that's not trivial — I dropped from 70mm² to 35mm² on my main run when I made the switch and gained meaningful headroom back in the battery bay.

@RetiredSquaddie also worth checking whether your existing Fogstar or whatever cells you're running are 48V-configurable — some folk assume a full rebuy when actually a series reconfiguration of existing cells covers it.

The MultiPlus-II 48/3000 and 48/5000 both sit on the same footprint too, which matters in cramped habitation areas.

@Curly raises something I kept underestimating during my own 24V-to-48V migration on my Hymer. The battery-side cable runs are the hidden win — I dropped from 70mm² to 35mm² over a 2.5m run to my Fogstar Drift cells and the voltage drop at peak draw went from embarrassing to negligible.

Specifically for EV charging: the MultiPlus-II 48/5000 paired with a proper AC-coupled inverter arrangement gives you a sustained output that 24V systems genuinely can't sustain thermally. I was throttling at around 2.2kW continuous on the 24V setup; the 48V system sits comfortable at 3.5–4kW without the unit even getting warm.

One caveat — your DC bus architecture needs revisiting entirely, not just the battery bank voltage. Fusing, busbars, and the Cerbo GX configuration all need attention before you energise anything.

Jumping in here as someone who made exactly this transition last spring. @MistyTinker and @Curly are spot on about cabling, but what caught me off guard was the BMS communication side when I paired a 48V lithium bank with the MultiPlus-II 5000VA. Getting the DVCC settings dialled in via VictronConnect took a fair bit of head-scratching before charging profiles behaved properly. @RetiredSquaddie, if you're considering the jump, factor in that your existing 24V battery bank almost certainly won't carry over — that's realistically your biggest single cost.

Really useful thread this. One thing worth adding to what @CotswoldVanLifer and the others have covered – if you're seriously considering EV charging, it's worth looking at the MultiPlus-II GX variant rather than bolting on a separate Cerbo. Saves you a mounting headache in a confined van install and the integrated Venus OS gives you proper DVCC control, which becomes genuinely important when you're pushing higher charge currents through a BMS. @RetiredSquaddie, what battery chemistry are you running currently? That'll likely influence whether a direct bank upgrade makes sense or whether you're better off starting fresh.