Anyone else finding the dark mornings a good excuse to finally sort the battery monitoring out?

Funny how it takes sitting in a dark static caravan at 7am, squinting at a phone torch to find the kettle, before you finally think right, something has to change.

That was me three weeks ago. After two years of vaguely guessing my battery state by whether the lights looked "a bit dim," I finally fitted a Victron BMV-712 across my 200Ah Fogstar lithium bank. Honestly cannot believe I waited this long. Seeing actual state-of-charge percentages rather than operating on pure optimism has been a revelation.

The darker mornings have been the real test — solar input is practically nothing before 9am at the moment, and I can watch exactly how much the overnight heating draw has taken. Turns out my diesel heater's control panel was quietly nibbling away far more on standby than I'd ever realised. Wouldn't have spotted that without proper monitoring.

Now I've got the BMV talking to my phone via Bluetooth while I'm still in bed, which my late husband would have called "completely unnecessary" but I call brilliant.

For anyone still umming and ahhing about whether battery monitoring is worth it — particularly those of you running emergency backup systems or motorhomes heading into winter storage — I'd genuinely say just do it. The peace of mind alone is worth every penny.

Anyone else had a similar "why didn't I do this sooner" moment this autumn? And has anyone gone the whole hog with a Cerbo GX setup, or is that overkill for a modest leisure setup like mine?

@RetiredNurse58 ha, nothing focuses the mind like genuinely not being able to see your kettle!

Been there. My turning point was a particularly grim November morning in the motorhome, watching my Victron BMV-712 show 11.8V whilst simultaneously trying to convince myself "it's probably fine." It was not fine.

The BMV-712 changed everything for me — not just because it shows voltage, but because state of charge and consumed amp-hours together finally told me a story I could actually act on. Voltage alone on LiFePO4 is basically useless across 80% of the charge curve anyway.

If budget's tight, even a cheap Bluetooth shunt from Fogstar gives you proper visibility. The key thing is getting it on the house battery, not just relying on whatever the leisure controller claims.

Dark mornings are genuinely the best teacher in this hobby.

Victron BMV-712 — sorted mine out after one too many mornings watching my Fogstar batteries get quietly murdered by a clueless PWM controller that thought "low voltage" was somewhere around 10.8V. The Bluetooth sync to your phone means you can see exactly how doomed you are without leaving the duvet.

Really resonates this, @RetiredNurse58! There's something about those grim October mornings that cuts through all the "I'll get round to it" procrastination sharpish.

I ended up going the Victron route like @Rob1963 (the 702 rather than the 712 since I don't need Bluetooth on mine), but honestly the bigger game-changer for me was finally sitting down and properly calculating my actual consumption versus what I thought it was. Turns out my assumptions were embarrassingly optimistic 😄

The monitoring just makes the reality unavoidable in a way that's actually quite useful. You stop guessing and start managing properly. Worth the afternoon it takes to wire it in correctly - just make sure your shunt placement is right or the readings will be all over the shop.

@RetiredNurse58 the static caravan scenario is basically identical to what happened on my narrowboat two winters ago — except it was 6am, I was trying to find the gas lighter, and I genuinely didn't know if my bank was at 40% or 4%. Massive difference in terms of whether you're about to flatten your cells.

What sorted it for me was pairing the BMV-712 that @Rob1963 mentions with the Victron app via Bluetooth — you can literally lie in your bunk and check state of charge before committing to the kettle. Game changer.

One thing worth noting for static caravan setups specifically: make sure your shunt is wired to capture all loads, including any parasitic draws from inverters on standby. That's where a lot of folk go wrong and the monitor reads incorrectly optimistic all winter.