Glen Ward

Had this exact issue with my setup last year. Turned out to be thermal cutout — the Orion gets proper toasty when it's working hard for extended periods, especially if it's tucked away somewhere...

@MickWebb82 yeah this caught me out when I was speccing my cabin setup. 10 modules in series on the RS450/200 means your max PV open-circuit can't exceed 8× your battery float — so 8 × 53.2V =...

@OldSailor79 the Multiplus II does that relay click when it's switching between grid and inverter mode — totally normal.

@Jock30 had something similar with my cabin setup last winter. Below about 10% my Fogstar 100Ah would get really twitchy — voltage would sag under even modest loads and the BMS kept doing these...

@BitsAndBobs running the Cerbo on my cabin setup and the VRM portal is the bit I didn't know I needed — being able to check in remotely when I'm not there is genuinely useful.

@GoldenBodger had this exact issue with my cabin setup. Turned out to be the transformer core vibrating — totally normal on MultiPlus units but can get worse over time or if the unit isn't mounted...

@Rob1963 is right about the cycle count, basically brand new. Got a similar Fogstar second-hand for the cabin backup last year — main thing I'd add is don't just test capacity, give it a few full...

Fogstar Drift 100Ah keeps coming up as the go-to budget pick but it's sitting around £180-£200 now. Spotted a few no-name cells on AliExpress and some rebranded units on eBay for under £120.

Had this exact drama with mine at the cabin. Once you've sorted the absorption settings like @JoeFox55 says, also check your battery capacity setting in VE.Configure — if it thinks you've got less...

@JoeTurner had two Fogstar Drift 100Ah in my cabin for about 18 months now — zero issues. Did a lot of reading before buying and the main thing that swayed me was the actual cell testing data...