Problems with MPPT RS 450/100 – Errors 27, 201, 215

Been having a nightmare with my Victron MPPT RS 450/100 at the static caravan and wondered if anyone else has seen similar.

Getting error codes 27, 201, and 215 popping up intermittently. The unit's installed on a fairly remote site — no mobile signal worth speaking of, so remote diagnosis is a pain. I've got VRM set up but it only syncs properly when I drive within range, which isn't exactly ideal for catching faults in real time.

Few questions for anyone who's dealt with these:

• Error 27 — I've seen this flagged as a calibration or internal fault? Mine seems to clear itself after a reset but keeps coming back
• 201 and 215 — less sure about these, the Victron documentation isn't exactly plain English on what's actually causing them vs just describing them
• Is this a firmware issue? I'm running what I think is a relatively recent version but haven't updated in a while

The array feeding it is about 4kW of panels (mix of older Renogy and some newer ones I picked up), going into a 48V LiFePO4 bank — Fogstar Drift cells. Wiring all seems solid, checked terminations twice.

What I can't work out is whether it's a panel mismatch causing the RS to throw a wobble, or something deeper with the unit itself.

Has anyone managed to get Victron support to actually engage with something like this or is it all bounced back through the dealer? My dealer's helpful enough but slow.

Anyone seen these three errors together specifically, or know if there's a known combination that points to something obvious?

@SmartSolarNerd those three together are a pretty telling combo.

• Error 27 = charger temperature too high (thermal protection)
• Error 201 = internal DC voltage error
• Error 215 = internal error (usually firmware or comms related)

The 201 and 215 often appear because of the thermal issue triggering a cascade rather than being independent faults. The RS 450/100 runs hot — mine in the garden office needed proper ventilation sorting before it settled down.

Few things worth checking:

• Is it wall-mounted with adequate clearance? Victron spec 10cm minimum but more is better
• Ambient temp in the caravan cupboard/enclosure?
• Firmware up to date via VictronConnect?
• Any loose DC connections causing resistance/heat?

Update the firmware first, it's fixed some 215 gremlins. If errors persist after that, worth logging via VRM and sending to your Victron dealer — could be a warranty job.

@CE_Builds has covered the error definitions well so I won't rehash those.

One thing worth checking that catches people out on the RS 450/100 specifically — ventilation clearances. Victron spec 10cm minimum on all sides but I've seen installs where it's been boxed in tight and the thermal sensor trips repeatedly even in mild weather.

Also worth pulling the history data from VictronConnect and checking whether the 201/215 errors correlate with high irradiance periods. On my narrowboat install I had similar phantom comms errors that turned out to be a dodgy RJ45 cable on the VE.Can network rather than anything fundamental with the unit itself. Swapped it for a quality shielded cable and it cleared up completely.

What's your PV array configuration — string voltage and how many panels? That might help narrow down whether the 215 is genuine or noise.

My MPPT RS ran hotter than a vindaloo until I shoved a small 12v fan on it — sorted the Error 27 nonsense overnight, though mind you check that your battery cabling is adequately rated for the 100A output because undersized cable adds resistance, generates heat, and then everything starts throwing a wobbler simultaneously which sounds suspiciously like what you're describing. 🔥

@RetiredNurse49 the fan trick is a solid workaround but worth also checking the mounting surface itself — I had Error 27 recurring on my boat install until I realised the backing plate was acting as an insulator rather than a heatsink. Switched to mounting directly onto an aluminium plate bolted to the hull and temps dropped noticeably.

On errors 201 and 215 specifically, these often appear because of the thermal issue rather than independently — the unit starts throttling and that cascades into the comms/internal faults. Fix the cooling first and see if 201/215 clear themselves.

Also make sure your VE.Can termination resistors are properly seated if you're running a network — loose terminators can trigger 215 intermittently even when everything else is fine.

@RetiredNurse49 @PanelJulie both right, but if you're still chasing 201 and 215 after sorting the thermals, check your string voltages haven't gone rogue on a cold morning — my RS 450/100 threw a wobbler in January when the panels hit near-limit voltage at -3°C before the batteries had warmed up, classic rookie trap that cost me a morning of head-scratching.