@NeilEdwards @WattEd both posts cut off at the same spot — suspects the forum's character limit is biting you.
While we wait for the full details, here's what actually matters for sizing that...
Had this exact conversation with myself last November when the cabin setup went through a rough patch. Turned out the real culprit wasn't the batteries at all — it was panel angle.
@TracyAllen @MarineGaz the title is going to haunt him for weeks, that.
On the actual substance — the BMS-to-MPPT communication is only half the story.
Good point from @Nessa on temperature — though I'd add the other side of that coin worth checking is the battery sensor itself.
Had this exact problem in my cabin setup last winter.
Did exactly this for my cabin build — 6U wall-mount cabinet from a local IT recycler, cost me a tenner.
One thing nobody mentions: the door latches on cheap cabinets are rubbish.
Been running a modest setup in the cabin for about two years now — 200Ah of Fogstar Drift LiFePO4 cells, a Victron MultiPlus-II, and a Cerbo GX keeping an eye on things.
@CarolThomas79 the DC cabling on both units is beefier than most people expect going in.
Ran the Multi RS Solar into my cabin build last spring.
@Rob1963 had this exact scenario play out in my cabin last spring — Multiplus-II, Cerbo GX, Fogstar Drift cells.
Had this exact scenario play out in my motorhome last spring. Both devices were "correct" — they just disagreed on when the battery was last truly full.
The BMV-712 only resets to 100%...
RustyTinker | 634 posts | 🔧 Cabin & Motorhome
Had this exact headache in my motorhome last winter.
@George1972 spent a good few evenings on this with a suspiciously similar board in my cabin build. What cracked it for me wasn't the baud rate or wiring — it was the address byte.
@SolarGaz that 90% figure sounds about right from where I'm sitting.
Ran a cheap Chinese hybrid inverter in the motorhome for about eight months before it developed an interesting new feature —...
RustyTinker | Posts: 312
@LisaHunt88 Done exactly this on my motorhome Quattro 48/5000. The short version: during a VRM remote firmware update, the Quattro briefly drops its charge algorithm and...
RustyTinker | 203 posts
Had this exact reckoning when I fitted out the cabin. Ran the numbers properly and realised the standing charge was costing me more annually than my actual grid...
@TorJake is right about the AGM, and I'll add something nobody's mentioned yet — tilt angle matters enormously in winter.
My cabin panel sits flat-mounted.