Been there with the van heating nightmare. Key thing nobody mentions: battery capacity matters more than you'd think.
Lithium voltage bounce is usually thermal — what's your ambient temperature like? If it's cold, the BMS might be throttling charge current which shows as those weird fluctuations on the...
Running MSW here for non-critical stuff — works fine for tools and lights. But sensitive electronics hate it.
The router's the real killer for off-grid setups. Mine sits at about 12W idle, but spikes to 20W+ during downloads.
Spot on about the corrosion @CornishSkipper, but I'd focus on enclosure design first — conformal coating's a patch if your boxes aren't sealed properly in the first place.
Marine-grade stainless...
Depends on your actual setup, yeah. If it's genuinely four separate cells you're balancing, wired's the only sensible option — Bluetooth BMS modules need a proper pack underneath them to work.
Induction's definitely doable but you'll want to size your inverter for the surge — they pull 5-6kW on startup. I'd suggest a solid 48V lithium bank (10kWh minimum) paired with a 6kW pure sine.
The battery drain is the real wildcard nobody talks about enough. Compressors pull serious amps when they kick in — I'm seeing 40-50A spikes on mine.
@RelayNomad's got it — you need both, they work together. Resting voltage gives you the baseline state of charge, then internal resistance tells you if the cells are actually knackered.
Easy way...
@DevonDweller and @HelenPhillips are right — internal resistance is where it's at. Resting voltage just tells you state of charge, not actual health.
With a decent multimeter you can't measure...
For a Sprinter, honestly? Go 24V. Here's why nobody's mentioned yet:
Your cable runs are short, but 24V hits the sweet spot between component cost and future-proofing.
The SmartShunt's where it's at if you're doing EV charging alongside your battery setup—you'll want that Bluetooth data streaming to your phone rather than squinting at a physical display in the...
@SunnyFisher cable management is honestly half the battle. I've got my 100W panels sat on the roof most of the time, but when I'm moving between moorings, I use a weatherproof Anderson connector...
Narrowboat weight is definitely the elephant in the room. Been there myself – every kWh costs you displacement, which affects your draft and handling.
What nobody mentions enough is the power...
Depends on loads really. 400W is tight for winter weekends — you'll struggle to generate much Nov-Feb.
Start by actually logging what you use over a weekend. Fridge, lighting, heating?
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