Why is my Victron Energy 50 amp dc-dv charger drawing 16.2 volts, no amps, no watts from my starter

Odd one this — had something similar crop up on my static caravan setup last summer and it had me scratching my head for a good while.

The 16.2V reading with zero amps/watts is almost certainly the charger doing its input voltage sensing before it actually begins drawing current. Victron units will often probe the source first, especially if there's a protection threshold being triggered. Worth checking whether the unit thinks it's seeing an overvoltage condition — 16.2V on a 12V starter battery is pushing into alarm territory for most chargers.

A few things worth looking at:

• Is the starter battery actually healthy? A failing battery can throw weird open-circuit voltages, particularly if a cell is playing up
• Check your cabling and connections — a poor connection can cause voltage to read high with no current flowing
• Look in the VictronConnect app — it'll often log error codes that don't show on the display itself
• Input voltage range settings — some Victron DC-DC units have configurable input thresholds, make sure it's set for 12V systems not 24V

On my shepherd's hut build I had a Victron Orion-Tr Smart doing something similar after a firmware update — turned out the protection settings had reset to defaults and it was refusing to engage below a certain state of charge on the source.

Anyone else seen this behaviour specifically on the 50A model? Wondering if it's a known quirk with a particular firmware version. Would be good to know before I pull all the wiring apart looking for phantom faults.

@BoatMick had the exact same head-scratcher with my garden office setup last year. That 16.2V with no current flowing is almost certainly just the charger sensing/probing the source battery before deciding whether to engage — Victron's DC-DC units do this to check the alternator or source battery is actually "live" and above threshold before pulling any amps through.

Worth checking:

• Is your starter battery actually above the minimum input voltage threshold? (usually ~13.2V under load)
• Any loose connections or high resistance on the input cable run?
• What's the actual resting voltage on that starter battery under load?

Mine did something similar when I had a slightly corroded negative terminal on the source side — showed voltage present but zero current. Cleaned the terminal and it immediately started pulling amps properly. Simple fix but easy to overlook.

Seen this exact thing on my narrowboat. That 16.2V is the charger's detection voltage — it's essentially knocking on the door to sense whether a battery is there, but not committing any current until it's happy with what it finds.

Worth checking your starter battery's internal resistance first. If it's an ageing lead-acid that's sulphated, the Victron will see that detection voltage bounce back oddly and refuse to engage properly.

Also double-check your cable connections at the starter terminals — I had a corroded ring terminal on Selene (my 57ft trad) that was causing almost identical behaviour. Looked fine visually, but had enough resistance to fool the charger's sensing circuit completely.

Pull up the Victron Connect app and check the charger's history tab — any fault codes showing?

To add some precision here — the Victron Orion-Tr (I'm assuming that's the unit in question, worth confirming the exact model) uses a detection/sense voltage before it commits to actually drawing current. It's essentially confirming the source battery exists and is within acceptable parameters before enabling the converter.

Worth checking:

• Is your starter battery actually above the input voltage lockout threshold? Even 16.2V detection won't trigger current flow if the charger deems the source marginal
• Have you configured the input current limit correctly in VictronConnect?
• Is the remote on/off wire properly handled?

The zero amps/watts suggests the charger is seeing the battery but refusing to engage for a reason. Pull up VictronConnect and check the device state — it'll tell you exactly which condition is blocking it rather than leaving you guessing.

If the charger's just sniffing around at 16.2V with nothing to show for it, your alternator or starter battery might not be hitting the threshold to trigger actual charging — mine did this when a dodgy connection was dropping just enough voltage to fool the Victron into thinking nowt was worth collecting. 🔌

Good point from @KatePrice about the source battery — worth checking what the actual voltage at the starter battery terminals is under load, not just static.

One thing nobody's mentioned: if you're running this in a static caravan setup like mine, check your cable gauge and run length. The Orion-Tr needs to see sufficient voltage at its input terminals, not just at the battery. Voltage drop on undersized cable can fool the unit into thinking there's no valid source.

Also confirm the "engine running detection" threshold in VictronConnect — by default it's set to something like 14.4V, so if your alternator isn't pushing above that, the charger parks itself in standby and you get exactly this behaviour.

What's the actual measured voltage at the Orion's input terminals directly?