Inverter limit my battery charge current to 15A-20A problem

Had almost exactly this on my narrowboat a couple of years back. Turned out the charge current limit in the Victron MultiPlus settings had been knocked down during a firmware update — it just quietly reset itself to a conservative default and I didn't notice for weeks. Worth checking your charger profile first before assuming anything's physically wrong.

A few things worth poking at:

• Battery type setting — if it's on AGM/gel profile when you've got lithium, it'll throttle back hard
• Input current limit — sometimes the shore power or generator input limit drags the charge current down as it tries to protect the AC side
• Temperature compensation — a dodgy sensor can cause the unit to back off thinking the batteries are getting warm

On my static caravan setup I've got a Fogstar Drift 200Ah and the Victron is perfectly happy pushing 40A+ once the profiles are sorted. Night and day difference.

What inverter/charger are you running and what batteries? That'll narrow it down a lot. Also — are you seeing this on shore power, solar, or both? Makes a difference to where the fault likely sits.

@DerekDixon worth also checking the DC input current limit separately from the charge current — they're distinct settings in VEConfigure and people frequently conflate them.

On my cabin setup I had a similar head-scratcher where the absorption current was being throttled because the battery capacity figure in the charger profile was set absurdly low (someone had entered Ah instead of the correct value during commissioning). The MultiPlus was doing exactly what it was told — protecting a battery it thought was far smaller than it actually was.

If you're running Fogstar or similar lithium cells, also double-check whether a BMS communication signal is actively capping charge current via the VE.Bus BMS or a DVCC override in Cerbo/Venus. That'll override everything else you've set manually and can be genuinely baffling to diagnose without a GX device showing you the live DVCC status.

@WezWhite72 makes a fair point — had something similar in my shepherd's hut setup where the absorption voltage was also quietly throttling things before I'd even looked at current limits, so worth a poke around the full charge profile whilst you're in VictronConnect rather than just the one setting.

Good shout from both @DerekDixon and @WezWhite72. One thing nobody's mentioned yet — if you're running a MultiPlus, check the assistant configurations in VE.Configure. I had my motorhome setup inexplicably capped because a current limiter assistant was still active from a previous configuration I'd forgotten about entirely. It was overriding the main charge current setting, so changing the obvious parameters made no difference whatsoever.

Also worth connecting via VictronConnect or VE.Configure and doing a full settings export before you start poking around — gives you a clean baseline to compare against if things get worse.

The Fogstar Drift LiFePO4 cells I'm running have their own BMS current limits too, so if you're on lithium, don't overlook the battery-side BMS parameters potentially throttling things independently of the inverter/charger settings.

Really useful thread this — jumping in because I had almost the same head-scratcher with my motorhome setup last year.

One thing nobody's touched on yet: check your battery BMS communication settings. If you're using a Victron MPPT or MultiPlus alongside a lithium bank (I run Fogstar Drift cells), the BMS can actively tell the charger to throttle back via the VE.Bus or VE.Direct protocol. Took me ages to realise my BMS was flagging a cell imbalance and quietly capping charge current as a protective measure — nothing obviously wrong on the surface.

Worth pulling up VictronConnect and checking the "why is the charger in this state?" flag under the charger status screen. It'll often tell you exactly what's throttling it rather than guessing through settings menus.