AIO inverter on trailer with high voltage solar controller, 11/100 watt panels in series producing about 200 volts at 6 amps. Is this dangerous?

Mate, 200V open-circuit from 11 panels in series going into an AIO not rated for that input is basically a very expensive way to turn your trailer into a bonfire. 🔥

Most budget AIOs — and even some of the decent ones — have an absolute maximum PV input voltage, usually around 145V or maybe 150V if you're lucky, and exceeding that will fry the MPPT controller internally, often without any dramatic warning, just a quiet death and a voided warranty.

A few things worth checking:

• What's the actual AIO model? Some higher-end units (certain Victron MultiPlus combos with a separate Smarts Solar, for instance) can handle it, but they're wired differently
• VOC at cold temperatures — in a British winter your panels will push higher than the 200V you're seeing now, so factor that in
• Series vs parallel — could you reconfigure to 2S5P or similar to bring voltage down and current up to something more manageable?

I had a similar head-scratcher with my shepherd's hut build — ended up reconfiguring from a long series string to a shorter one and chucking a Fogstar battery in the mix, sorted it nicely without cooking anything.

The short answer to your thread title question: yes, it's dangerous, but fixable without buying new kit.

What AIO are you actually running? That's the crucial bit — someone here will know the spec sheet inside out.

Smithy51 | ⭐⭐⭐ | Posts: 847

@BatteryJason is spot on about the voltage risk, but worth adding — it's not just the AIO that'll cop it. At 200V you're also in a genuinely lethal territory for anyone working on or around that system, not just equipment damage territory.

DC at that voltage doesn't let go like AC does. If you're on a metal trailer chassis and something arcs or you touch the wrong terminal, that's a serious electrocution risk, not just a tingle.

What AIO have you actually got? Most budget units top out at 145V PV input, some of the better Growatt or Victron-compatible units handle higher, but it'll be clearly stated in the specs.

Honestly mate, get that string voltage down before you power anything up. Reconfigure to parallel or split into two smaller strings. 🙏

ExBrickie | ⭐⭐ | Posts: 312

Had a mate do something similar on his narrowboat — fried the MPPT input stage on a perfectly decent unit, warranty void obviously because the manufacturer could see the fault was overvoltage.

The maths isn't complicated: check your panel's Voc at low temperature, not the STC figure. On a cold morning that 200V could easily creep to 220V+. Most budget AIOs cap out at 145V input, some at 120V.

@Smithy51 makes a fair point too, though I'd add that even if you technically stay within limits, running close to max Voc continuously stresses the input capacitors.

Honestly? Reconfigure to two parallel strings rather than one long series string. Halves your voltage, keeps your current manageable. Victron's string calculator is free to use and takes about 3 minutes.

FenlandSolar | ⭐⭐⭐⭐ | Posts: 2,341

Worth being precise about the actual risk here. Open-circuit voltage rises significantly in cold weather — your 200V figure is presumably STC or a warm-day measurement. On a crisp January morning those 11 panels could easily push 220-230V OC. If your AIO's absolute maximum input is, say, 145V (common on budget units), you're not just risking gradual degradation — you're looking at instantaneous MOSFET or diode failure the moment the controller powers up.

@ExBrickie's point about the MPPT stage is exactly the failure mode I'd expect.

For a trailer setup I'd seriously consider reconfiguring to a lower-voltage string — 4-5 panels in series with a proper Victron SmartSolar handling the array separately, feeding your AIO on the battery side. Far safer, and the Victron's Bluetooth monitoring is genuinely useful for a mobile setup.

What's the actual AIO model? Specs matter here.

QuietTrekker | ⭐⭐⭐ | Posts: 156

Yeah this is a proper gotcha — cold mornings make it worse too. My panels hit noticeably higher Voc in January than the spec sheet suggests, caught me off guard first winter with my garden office setup.

The bit people miss: even if your AIO survives the overvoltage momentarily, you've likely stressed the MOSFETs and you won't know until it fails at the worst possible moment.

Practical fix — either:

• Drop panels into parallel strings to keep voltage sensible
• Swap to a standalone Victron SmartSolar MPPT with a proper Voc rating, then feed the AIO from battery side only

The Victron 150/35 handles up to 150V input and isn't outrageously priced. Much safer architecture for a trailer anyway where wiring takes a beating.

@FenlandSolar's point about Voc rising in cold is the critical bit here — don't ignore it.