Victron Connect showing low amps on Smart charge controller

Had the exact same head-scratcher with my Victron SmartSolar 100/30 on the shepherd's hut last summer — panels were supposedly pumping out decent wattage but VictronConnect was reading like I'd accidentally installed a potato as a charge controller.

Turned out a few things were ganging up on me:

• Panel voltage vs. actual conditions — a partly cloudy Shropshire morning means your theoretical max is basically fiction
• Battery state of charge — if the bank's nearly full, the MPPT intentionally backs off; it's not broken, it's just doing its job
• Temperature derating — panels get hot, output drops, VictronConnect tells no lies

Worth checking your absorption/float voltage settings are correct for your battery chemistry too. I had mine set up for AGM when I'd swapped to Fogstar lithium and basically wasted a week wondering why the numbers looked odd.

Also — and this catches people out — VictronConnect shows output amps to the battery, not input amps from the panels. So if you're expecting panel-side figures you'll always be disappointed.

Anyone else running a bigger array on a UK setup and finding the app readings confusing? Curious whether this is a display/settings issue or something deeper for folk with higher-voltage arrays.

@Pete1994 classic case of your panels lying to you like a used car salesman — check if you've got the PV voltage set correctly in VictronConnect, because if the controller thinks your open-circuit voltage is lower than it actually is, it'll throttle the amps faster than a marina harbourmaster kills a good time. Had the exact same drama on my boat last season with a Victron SmartSolar 75/15 — turned out my cable runs had more voltage drop than a dodgy chandlery's prices, so the controller was working with phantom numbers. Run a Renogy inline meter directly at the panel output and compare what VictronConnect's actually seeing — the truth will either fix your problem or properly ruin your afternoon.

Great thread — had almost identical with my 100/20 last spring. Before you go too deep down the rabbit hole, worth checking your battery absorption voltage settings in VictronConnect. If the batteries are already near full, the controller will naturally throttle back the amps regardless of what the panels could theoretically deliver — it's doing exactly what it should.

Also worth a look: are your panel cables adequately sized for the run length? Undersized cabling causes voltage drop that doesn't always show obviously but absolutely hammers your actual delivered amps.

What's your cable run length from panels to controller @Pete1994? And what are the batteries showing as state of charge when you're seeing the low readings? That'd help narrow it down considerably rather than chasing the wrong culprit. 🙂

@Pete1994 had this exact farce with my static van setup — turned out my MC4 connectors had corroded faster than my faith in British summers, dropping just enough resistance to make the whole thing look like a chocolate teapot.

Shove a multimeter on the PV input terminals at the controller itself and compare it to what you're getting directly at the panels — if there's more than a volt or two of difference, your cabling or connectors are robbing you blind.

Also worth checking your panel orientation isn't giving you partial shade losses; VictronConnect's history graphs will show suspiciously flat curves if that's the culprit rather than a steady climb and drop.

@Pete1994 had this with my garden office setup — Fogstar battery was full and the controller was just loafing about in float doing absolutely nothing, which VictronConnect helpfully displays as "suspiciously low amps" rather than "job done, mate."