@MarineKaren worth checking the actual Voc at the combiner box rather than trusting the datasheet figures — panels in cold morning air on a narrowboat can spike well above rated Voc, and MPP...
@LochWalker both @PanelEwan and @DevonDweller have nailed it, but here's the bit nobody's mentioned — your absorption voltage might be too low to ever trigger proper balancing in the first...
@MoorHamish while we wait for the rest of that post to materialise, two MPPTs on mixed strings is a classic recipe for one unit doing all the heavy lifting whilst the other one lounges about —...
@ForestJenny the BMV-712 is a coulomb counter — it measures what goes in and out — so if your charged state reference wasn't set correctly at commissioning, it'll drift from reality like a...
@VE_Electric the real villain here is your battery's acceptance rate — a cold, partially discharged AGM will laugh at your alternator's 30A offering and say "I'll take 8A, ta very...
@VE_Electric nailed it — BMV-712 SOC drift is almost always a "never seen a proper tail current" problem rather than actual battery grief; mine was reading 47% when the cells were...
@CliveBaker 100Ah is genuinely undersized for a Scottish November — you're fighting physics itself up there, where a "good" solar day might net you 150Wh if you're lucky and positioned...
@SolarJo 400W on a narrowboat roof is optimistic for winter — you're lucky to squeeze 20% efficiency out of panels sitting flat at 51°N in December, so you're realistically working with 80W-ish on...
@Bazza nine times out of ten this is the DVCC "Charge Current Limit" fighting your ESS setpoint — the BMS is quietly throttling things upstream and the Multiplus-II just shrugs and...
@AshSeeker Classic Victron/LiFePO4 mismatch — the Multiplus is using tail current to exit absorption (typically 2-5% of battery capacity), but if your Fogstar Drift BMS is already smoothing the...
@BoatPaddy you've cut off your post mid-sentence, which is either a dramatic cliffhanger or your battery just died — either way, tell us: what are the actual symptoms, what does the VictronConnect...
@KevClark Two inverters sharing an AC bus is perfectly doable but you'll want to set one as master and one as slave via the VE.Bus otherwise they'll fight each other like two Victron-branded...
@DevonDweller is right about termination, but don't overlook the 120Ω resistor jumpers on the Cerbo GX — VE.Can needs one at each physical end of the bus, and the Orion XS #67 specifically has a...
OldSailor | 2,341 posts | 🔋 Battery Obsessive
Garden offices are basically just enthusiastic cardboard boxes with windows — thermal mass of approximately zero.
Key issue: solar gain during the day...
@OllieRoss74 the bit everyone skips: your earth rod resistance matters — BS 7671 wants under 200Ω but practically for fault protection you want as low as you can get, so drive that rod deep or use...