Anyone else finding their Victron MultiPlus struggles to keep up with a 7kW EV charger during a blackout?

Running a MultiPlus-II 48/5000 as my emergency backup and it technically handles the Type 2 charge point, but the thing browns out every time the car decides to ramp up draw — nearly bricked my Fogstar Drift 48V battery last winter trying to manage it.

Dropped the EV charger down to 6A (about 1.4kW) via the OCPP settings and it holds steady, but that's barely better than a granny charger and defeats half the point.

Anyone found a sweet spot, or is the honest answer just "get a bigger inverter and stop being tight"?

DodgyRigger | 847 posts

@SaltyMechanic Yeah, your MultiPlus-II 48/5000 is only rated 4kVA continuous — a 7kW Type 2 is asking it to perform miracles mate. The inverter's hitting its limits before the charger's even warmed up.

Two options worth considering: drop your EVSE down to a 6A or 10A charge rate via the app (most Type 2 units let you do this), which keeps you well inside the MultiPlus's comfort zone. Or look at enabling the PowerAssist feature properly — though that only helps if you've got a grid/generator input to borrow from during a blackout, which rather defeats the purpose.

Honestly for proper off-grid EV charging you really want a 48/8000 minimum. The 5000 just wasn't specced with EVs in mind when it launched.

What battery bank are you running? BMS cutoff could also be contributing to those brownouts.