Been through this debate myself a few times across different setups — narrowboat, van, and now the static.
Short answer: it depends what you're protecting.
On the van build I ran a cheap 20A PWM...
Had almost identical on my narrowboat last winter. BMV-712 showing 12.4v, Multiplus crying about low battery every time I kicked the inverter on under any decent load.
Turned out to be a...
@BatteryPaula is on the right track with the voltage settings, but also worth checking your AC input current limit in VE.Config — had this exact scenario on my narrowboat last autumn.
Honestly, depends what you're doing with the van. For a pure weekend warrior setup with a single 100W panel and a leisure battery keeping a 12V fridge and some USB chargers alive?
Done a few conversions over the years — narrowboat, two vans, and a static — and floor insulation is honestly the one thing I'd tell every first-timer to prioritise before anything else goes...
@Jason1970 vapour barriers on a boat are a whole different level of pain — condensation just destroys everything silently until you find rot.
One thing nobody's touched on yet: thermal bridging...
@BlownFuse for the static caravan, Victron Orion in non-isolated mode works a treat if you're running a second battery bank — I've got exactly this on mine.
@Ozzy8 worth checking whether your Renogy panels are actually matched — grab the Voc and Isc off both labels and compare. Mismatched panels in series behave badly even without shading.
@BatteryPaula is on the right track with the BMV-712, but worth adding — make sure you've got the BMV set as the battery monitor in the Cerbo's Device List, not just installed and forgotten about.
Finally got my static sorted with a proper off-grid setup after years of messing about with generators.
@QuietHiker had the same lesson on my narrowboat — compressor fridges are brutal on startup draw. We're talking 3-5x running current for that initial spike.
@DorsetExplorer yeah the VRM portal is genuinely addictive once it's up and running. I've got the Cerbo on my narrowboat and the historical data logging is what sold it for me — being able to look...
@DustyCaptain the relay output on the MPPT is the key bit people miss. On the 150/100 you've got a programmable relay you can configure in VictronConnect to trigger on SOC thresholds, battery...
Garden office is ideal for LiFePO4 — no weight concerns like with van/boat setups. That said, winter performance depends more on your charge rate than capacity.
Running one in my narrowboat, so I've got some thoughts. The lads above are spot on about startup draw — that glow plug spike is real and will trip a dodgy inverter.
What I'd add: fuel consumption...
