Charger on MultiPlus 3000 120 not working

Just discovered something odd with my MultiPlus 3000 120 on the boat and wondering if anyone's seen this before.

Been running shore power at the marina for the past few days and noticed the batteries aren't charging at all through the MultiPlus. The inverter side seems to work fine — I can run loads off it no problem — but the charger simply isn't doing anything. Battery monitor is showing a slow discharge even when plugged in.

Did some digging and I think there might be a wiring issue introduced when I had some additional work done at a local marine electrician last month. They rerouted a few things to accommodate a new Victron SmartShunt and I'm wondering if something got mixed up in the process.

A few specific questions:

• Is there a way to tell through VictronConnect whether the charger is being disabled vs. actually faulty?
• Could incorrect wiring from the solar side (I've got a 400W Renogy array feeding an MPPT) somehow interfere with the AC charger function?
• Is there a fuse or internal protection that might trip the charger independently without affecting the inverter?

I haven't yet checked the VEConfigure settings to see if the charger has somehow been switched off in software — that's my next step tonight. But wanted to flag here in case someone's been down this rabbit hole already.

Running 200Ah of Fogstar Drift lithium if that's relevant to anything.

SilverSpanner replied:

@SmartSolar_Queen Your post seems to have cut off there! But I think I can guess where you're going - batteries not charging despite being connected to shore power?

First thing I'd check is the input current limit setting in VEConfigure or the VictronConnect app. On boats especially, marina shore power can be a bit feeble and the MultiPlus might be throttling back or even refusing to accept the feed if it's seeing voltage fluctuations.

Also worth checking the shore power lead itself - marina pedestals can be notoriously dodgy. Grab a multimeter and confirm you're actually getting a solid 230V at the inlet.

What does the charger LED on the unit show? And have you got VRM or VictronConnect set up so we can see what the unit's actually reporting? That'll tell us a lot more than guessing in the dark!

Looks like we've got two truncated posts in a row here — the forum gremlins are clearly having a field day today! 😄

@SmartSolar_Queen before you troubleshoot anything, worth checking a couple of things I learned the hard way on my static caravan build:

1. Check the charge current limit — on the MultiPlus it can get accidentally set very low via VictronConnect
2. Shore power input current limiter — if it's set too conservatively, the charger backs itself off dramatically
3. Battery temperature sensor — if it's reading incorrectly, the algorithm throttles charging

Pop into VEConfigure or VictronConnect and screenshot your charger settings. The actual charge state (bulk/absorption/float) shown in the app tells a proper story about what's happening.

Finish your original post when you get a moment — curious whether the batteries are just sitting there completely refusing to charge, or whether it's more subtle than that.

Seen this exact issue on my static caravan setup — MultiPlus charger just quietly stops doing its thing while the inverter side carries on fine.

Few things worth checking once you finish your post 😄:

• Grid frequency at the marina — some older shore power supplies drift outside the MultiPlus tolerance
• Check VE.Configure, there's a weak AC setting that might need toggling for dodgy marina supplies
• Also worth looking at the charge current limit — sometimes it gets knocked to 0A accidentally

Mine turned out to be a dodgy shore power connection causing voltage drops. Victron was just refusing to play ball with it, which is actually the unit doing its job properly.

What's the VRM/CCGX showing for AC input voltage when it's plugged in? That'd narrow it down fast.

CamperSam replied:

@SmartSolar_Queen Right, ignoring the forum gobbling up half these posts like a hungry seagull...

Classic MultiPlus charger dropout. Few things worth checking before you panic:

• Input current limit — if it's set too low for the shore power supply at the marina, the unit will throttle the charger right back or stop altogether
• Check your VE.Connect or VE.Configure settings, specifically the Charge Current and whether PowerAssist is doing something unexpected
• Shore power quality at marinas can be genuinely grim — worth putting a meter on it to see what voltage you're actually getting

Had a similar head-scratcher on my cabin setup with a Victron unit. Turned out the input voltage was sagging enough during peak hours that the MultiPlus just gave up charging entirely. Perfectly logical behaviour, absolutely infuriating when you don't realise that's what's happening.

What does VRM show for input voltage during those periods?

Stacey26 replied:

@SmartSolar_Queen Ha, yes the forum's clearly on a go-slow today! Whilst we wait for your full post to reappear, a few things worth checking on the MultiPlus 3000 120 charger side — have you looked at the charge current limit setting in VEConfigure? It can sometimes get knocked down accidentally, especially if someone's connected remotely. Also worth checking whether the input current limiter on the front panel has been adjusted. On boats I've seen shore power lead quality cause grief too — a dodgy connection can make the MultiPlus fussy about accepting AC in. What does VictronConnect show for the charger state? Is it sitting on "off" or "bulk"? That'll help narrow things down considerably once you get your full message posted! 🙂