Anyone else finding the dark evenings a good excuse to finally sort the battery setup?

Every autumn it's the same story on my narrowboat — the solar just can't keep up once the days shrink, and suddenly every inefficiency in the system becomes painfully obvious. This year I finally stopped ignoring the warning signs and pulled apart my whole battery bank.

Swapped out the tired AGM setup for a pair of Fogstar Drift 100Ah LiFePO4 batteries, and honestly it's transformed things. The Victron SmartShunt is now showing me accurate state-of-charge for the first time in years rather than just lying to me optimistically.

The catalyst was wanting to charge the car at the marina — even modest EV top-ups were absolutely murdering the old batteries. Now with the lithium bank I can actually pull a decent chunk of charge across without panic.

A few things I'd flag for anyone doing similar:

• Check your charger is actually lithium-compatible before you just swap the batteries
• The Victron app is worth setting up properly — the default profiles aren't always right out of the box
• If you're on a boat, think about where the heat goes; lithium doesn't love being cold any more than AGMs do

What's everyone else tackling this winter? Curious whether people are prioritising generation or storage first — I always end up doing storage and then wishing I'd added another panel.

@MarineOllie mate my garden office Fogstar 280Ah LiFePO4 basically laughed at me from September onwards until I finally cabled everything properly — turns out "good enough" wiring is just "expensive mistake" written in 6mm² twin core.

@MarineOllie know exactly what you mean — three winters on the cut taught me more about battery management than any YouTube video ever did.

What's your current setup? On my narrowboat I ended up adding a 40A DC-DC charger from the alternator as backup when the panels give up around November. Game changer for those grey weeks when you're getting 20W peak if you're lucky.

Also worth checking your Victron BMV data from last winter if you logged it — you can usually spot exactly where the losses crept in. Mine showed I was losing significant capacity overnight to phantom loads I'd completely forgotten about.

@LazyRanger LiFePO4 definitely helps but it won't fix a fundamentally undersized system — I learned that the hard way before I upgraded the solar array last spring.

Yep, same thing happens every year with my static caravan setup. The short days basically act as a free audit — suddenly you notice the phantom loads you'd completely forgotten about, the dodgy connection that was "fine in summer," all of it.

Got a Victron SmartShunt fitted last spring and honestly the data it throws up in autumn is eye-opening. Running a 200Ah Fogstar LiFePO4 and I can now actually see what's dragging it down overnight rather than just guessing.

@MarineOllie the narrowboat context sounds brutal though — at least my van isn't moving around and introducing vibration issues on top of everything else. Have you looked at adding a small wind element? Not always practical on the cut I know, but might take the edge off those grey November days when solar is basically decorative.

@MarineOllie same thing happened to me last autumn with the garden office. Running a Victron SmartSolar and a 200Ah Fogstar Drift, and the moment October hit I realised I'd been coasting all summer on long days and not actually sorting my consumption properly.

Ended up setting proper absorption and float voltages rather than just leaving it on defaults — made a noticeable difference. Also added a small 100W panel I'd had sitting in the garage doing nothing for two years. Embarrassing how long I put that off.

The dark evenings are genuinely useful as a forcing function though. If your system survives November to February without you reaching for the generator every five minutes, you've actually built something decent. Everything else is just summer holiday performance.

@LazyRanger what BMS are you running with that 280Ah? Curious how it handles sustained low-input periods.

@MarineOllie dark evenings absolutely expose bad wiring and undersized capacity — no argument there. What I'd add is that it's also the time people realise their BMS settings are completely wrong for winter discharge curves. Had that exact problem last year with my Fogstar Drift cells; the low-voltage cutoff was set for summer ambient temps and the BMS was tripping out prematurely once the garage dropped below 8°C.

Worth checking your temperature compensation settings if you've got a Victron MPPT — most people leave it on default and wonder why they're losing 15-20% effective capacity come November.

@GoldenSocket curious what capacity you're running alongside that SmartSolar — 200Ah sounds tight for a garden office through a proper British winter unless you're being very disciplined about loads.