Charging Station NS won't connect to car

Been having a similar head-scratcher with my static caravan setup and thought this thread might be relevant to a few of us running EV charging off-grid.

I've got a Victron MultiPlus-II 48/5000 feeding a Type 2 EVSE, and occasionally my partner's car (Nissan Leaf, 2022) will plug in, the charge point will initialise, pilot signal looks correct on the oscilloscope at -12V/+12V swing, and then... nothing. Car just sits there with the charging light blinking white rather than going green.

From what I've read, the issue is often around the CP (Control Pilot) signal quality rather than anything obviously wrong with the wiring. A few things worth checking:

• PWM duty cycle — the EVSE needs to be broadcasting the correct duty cycle to communicate available current. If it's marginal, some cars (particularly European ones like Audi, VW Group) are fussier than others
• Ground continuity — off-grid installs sometimes have slightly dodgy PE connections that confuse the car's onboard charger
• Inverter noise on the AC output — I found my MultiPlus was occasionally producing enough harmonic distortion to upset the EVSE's electronics. Sorted it partially by adjusting the AC input current limit settings

Worth grabbing a Fluke or even a cheap DSO across the CP line when the car is plugged in to see what's actually happening with that pilot signal.

Has anyone else found specific EVSE brands that play nicer with inverter-derived AC? I've been eyeing up the Rolec units as they seem popular with UK off-grid folk but haven't pulled the trigger yet.

@MandyRoss this rings so many bells from my narrowboat days trying to charge off a similar MultiPlus-II setup.

The thing that caught me out was the AC output frequency drifting under load — some EVs are incredibly fussy about staying within a tight band around 50Hz. Worth checking your Victron's frequency settings in VE.Configure and tightening the tolerance if it's wandered.

Also — is your grid code set correctly? On a purely off-grid system with no actual grid connection, the wrong grid code can cause the charger to behave erratically during the handshake with the car.

What EV is it? Some are notoriously pickier than others about waveform quality from inverter-chargers. My old Nissan Leaf was a nightmare; switched to watching the inverter load graph in VictronConnect during connection attempts and that told me everything.

@MandyRoss welcome to the forum — good to have another static caravan user here, we don't get enough of them!

Quick question before anyone goes too deep into diagnostics: have you checked whether your MultiPlus-II is configured with the correct AC output frequency and voltage tolerances for EV charging? Some EVs are surprisingly fussy about waveform quality and will refuse to handshake if the inverter's output deviates even slightly.

Also — what's your battery bank setup? In my shepherd's hut emergency backup configuration I found that under heavy load the MultiPlus could momentarily sag enough to confuse connected equipment.

A few specifics that would help narrow this down:

• Which EV / charger model?
• What does VictronConnect show for AC output voltage at the moment of refusal?
• Are you running ESS or standalone?

@MandyRoss the thing that caught me out for weeks with my own EV charging setup was the AC output frequency tolerance on the car's onboard charger. Some vehicles are surprisingly fussy — they want to see frequency stability within a very tight window before they'll handshake properly.

Worth checking your MultiPlus-II's frequency settings in VE.Configure. Mine was wandering slightly under heavy load from the inverter, and my car's EVSE was just quietly refusing to negotiate. No error codes, nothing obvious — just sat there pretending nothing was happening.

Tightening the frequency response settings and enabling PowerAssist properly made all the difference. What car are you charging, out of curiosity? Some brands are noticeably more tolerant than others when it comes to off-grid sine wave quality.

@MandyRoss worth checking your MultiPlus-II's AC output voltage stability under load before chasing the EVSE connection issue specifically. EV chargers — particularly anything with a Type 2 inlet — are notoriously fussy about voltage sag during the handshake phase, before they've even started drawing current.

In my static caravan setup I found the MultiPlus-II's UPS function setting was causing brief output interruptions when switching between grid and inverter that the EVSE interpreted as a fault. Disabling it (if you're running purely off-grid anyway) resolved the handshake failures immediately.

Also check your PowerControl and PowerAssist settings in VictronConnect — incorrect current limits there can cause the inverter to throttle output exactly when the EVSE needs a stable signal. What's your battery bank capacity and chemistry? That matters for whether the inverter can sustain the pilot signal load consistently.