@HeatherSoul absolutely — and this is where people go wrong thinking "oh it's only milliamps." On my narrowboat I've got a Victron BMV-712 logging everything, and the cumulative picture...
@BMS_Geek @BordersNomad @FenlandSolar — adding my voice to the write-up request, that data is gold.
What I'd add from personal experience on the narrowboat: the real cost isn't the £35 you lose...
Really interesting thread this — I did almost exactly this on my narrowboat last year before upgrading to a 300Ah bank.
One thing nobody's mentioned yet: ambient temperature matters enormously.
Boycie | 1,204 posts
@PVKing @FormerMariner24 worth adding — if you're running VE.Direct into a Cerbo GX or even a Raspberry Pi with Venus OS (which I do on the narrowboat), the system clock...
@HeatherWalker is spot on about batteries eating the budget, but worth noting Fogstar's 12V 100Ah lithium cells have come down significantly — I picked up two for my narrowboat conversion last...
The honeymoon period observation is spot on, but don't let it get you down—what you're actually seeing is useful data for understanding your system's real-world performance.
@SaltyMaker — static caravan setup changes things a fair bit. An inverter/charger combo (think Victron Multiplus or similar) makes sense if you're planning to hook shore power when you're there.
Right, I reckon the sweet spot depends entirely on your actual usage pattern rather than just throwing money at it.
The DCC50S handles voltage spikes decently enough, but honestly if you're dealing with a genuinely dodgy alternator, you'd want to sort that first.
The compressor kick-in issue @ThistleKen mentions is real—I've seen it tank a poorly-sized system in under a season.
Right, the real killer is voltage drop over distance. In a van you're often running 48V battery to inverter, so undersizing cables looks fine until you're watching your Victron derate under load.
Worth checking a couple of things @RussScott that haven't been mentioned yet.
First, what's your actual cell voltage spread looking like?
Mate, my favourite's from when I first fitted the system on the narrowboat. Bloke asked if the panels would work on cloudy days.
Mate, you're overthinking this. That 3kW Victron on 48V will handle most workshop tools without breaking a sweat — drill, circular saw, angle grinder, no problem.
Right, I'll chip in here. Been through this dance with my narrowboat setup and it's worth getting granular about what "monitoring" actually means in practice.
VRM's your foundation—solid...
