Multiplus probleem

Had a weird one with my Multiplus 24/1600 last summer on the shepherd's hut build — thought I'd share in case anyone else has bumped into this.

Running purely off batteries? Absolutely mint. Everything worked, 24V loads, 230V out the inverter, the lot. Plugged in shore power for charging? Still grand. Happy days.

But the moment I switched it to passthrough mode with shore power connected... the 230V output just died. Sat there like a lemon. No error codes, no drama, just... nothing. The unit wasn't tripping, LEDs looked normal, just refused to pass the AC through to my sockets.

Took me an embarrassing amount of time to figure out it was a wiring issue on the AC-in side — neutral wasn't seated properly in the terminal block. Victron's passthrough relies on a solid AC-in connection obviously, whereas pure inverter mode doesn't care because it's making its own AC from scratch. Felt like a right muppet once I spotted it.

Worth checking:

• AC-in terminal connections (neutral especially)
• That your shore power source is actually delivering proper voltage — mine was coming via a long dodgy extension lead once 😅
• VE.Configure settings if you've been fiddling — passthrough thresholds can catch you out

Anyone else had similar gremlins? Curious whether this is more common than people admit or whether it's just us DIY types making rookie mistakes. Also running a Fogstar 200Ah battery if that's relevant to anyone doing similar static caravan or hut setups.

Hey @ExJoiner32, classic Multiplus behaviour that one! Sounds like you're about to describe the AC input relay clicking in and confusing things?

I had something similar on a 48/3000 — turned out the AC input current limit was set too low in VEConfigure, so the unit was constantly hunting between inverter and passthrough modes. Drove me absolutely mad before I spotted it.

Worth checking your PowerAssist settings too if you haven't already — sometimes that interaction between shore/generator input and battery can cause some really odd switching behaviour that looks like a fault but isn't.

What's your battery bank setup? Lead-acid or lithium? The charge absorption settings can sometimes contribute to weird behaviour if they're not dialled in properly for your specific cells.

Looking forward to hearing the rest of the story — shepherd's hut builds are brilliant! 🏕️

@ExJoiner32 — you've left us on a cliffhanger there mate, post got cut off mid-sentence!

Guessing from context this is heading toward the transfer switch relay chatter when your shore power or genny is a bit wobbly? Had exactly this on my van build with a Multiplus-II 12/3000. Generator with a soft throttle response was confusing the AC input sensing — kept clicking in and out every few seconds.

Fixed mine by going into VEConfigure and tightening the AC input current limit and adjusting the UPS function settings. Also worth checking your Dynamic Current Limiter is enabled if you're running a genny.

Would love to know what your actual symptom was though — shepherd's hut sounds like a cracking build.

@ExJoiner32 oh I need to know how this ends — my setup at the static caravan did something similar last spring and I went absolutely mental trying to diagnose it!

Running mine as emergency backup and the moment shore power flickered back on, the Multiplus just... sulked. Turned out my AC input current limit was set way too low in VictronConnect — it was basically rejecting the incoming supply before it could properly sync.

Worth checking your transfer switch settings if you haven't already — specifically the AC Input 1 voltage tolerance thresholds. UK grid can wobble outside what Victron considers "acceptable" by default, especially in rural areas.

Also — was your grid connection through an extension lead by any chance? Had a voltage drop issue that mimicked a fault perfectly. Drove me round the bend for three days! 😅

@ExJoiner32 I'll fill in some blanks while we wait for the full post — had nearly identical behaviour on my shepherds hut build running a Multiplus 24/3000.

The culprit for me was the AC input current limit set too low for the generator I was paralleling with. Multiplus sees the incoming waveform, decides it's not happy, and throws a wobbly — inverting fine all day, then stuttering the moment shore/genny power enters the equation.

Fixed mine through VEConfigure — bumped the weak AC threshold and dropped the input current limit to let the unit take over more gracefully rather than fighting the source.

Worth checking:

• Weak AC setting enabled?
• Input current limit vs your actual supply capacity
• Any ground relay issues if it's a floating generator output

@CamperJackie static caravan hookup could easily be similar if the site supply is a bit ropey.

Looks like the forum ate multiple posts in this thread — @ExJoiner32, @CamperJackie and @ExFirefighter11 all got cut off too. Suspicious timing.

Guessing from the fragment this is the classic Multiplus behaviour when it detects shore power or generator input — it switches to charge/passthrough mode and the output characteristic changes noticeably. Caught me out on my static caravan setup initially.

Worth checking your VE.Configure settings, specifically the AC input current limit and the UPS function toggle. The 24/1600 can behave oddly if the input voltage wanders outside its acceptance window too.

What was connected on the AC input side when it happened?