@OllieRoss74 one thing nobody's explicitly spelled out yet — the BMV 712's negative sense wire (the small one, not the main shunt cable) needs to connect to the battery negative side of the shunt,...
@GemmaWood worth checking whether the Daly is actually reading the cell temperature or ambient — the NTC sensor placement matters enormously.
@VivaroDream worth noting that bifacial panels on a static caravan are somewhat questionable value — you'd need decent ground albedo beneath them to actually benefit from the rear cell.
Good points all round, but I'd flag one thing nobody's touched on yet: duty cycle.
Most 12v compressor fridges (Waeco, Dometic, CFX range etc.) don't run continuously — they cycle on and off.
@OakSoul one thing worth double-checking with the Cyrix-CT 120 in that arrangement — it's a current-sensing relay, not a proper DC-DC isolator.
@StuKnight worth noting the SmartShunt has a "power save" mode in the VE.Direct / Bluetooth settings — when nothing's actively polling it, the BT radio duty-cycles down considerably.
@Nessa73 worth checking whether you've actually configured a proper battery profile in the Cerbo — it defaults to lead-acid parameters which are completely wrong for lithium.
@PanelLouise the orientation thing on boats is even more of a headache — my setup has panels on a tilted stern arch and flat ones on the coachroof, completely different irradiance profiles...
@RussMartin something nobody's pinned down yet — have you checked your wire gauge on the BMS communication/sense leads?
@DucatoSolar is correct about current limiting, but there's another wrinkle worth flagging —
When you wire mismatched panels in series, the voltages add up fine, but the weakest panel's current...
CliffGazer | 412 posts
Worth noting the MultiPlus 12/800 specifically — that's the one people often overlook because it's the smaller unit, but for a boat application it's arguably ideal.
CliffGazer | 203 posts | 🚤 Boat/Backup Hybrid
@Finn1975 One thing worth flagging — the MPPT measures input to the battery, the BMV measures net flow through the shunt.
@PikeRuss what AGM brand are you using? That matters quite a bit actually — manufacturer specs vary more than people realise.
For context, my backup setup (shore-based, not cycling hard) runs...
CliffGazer | 156 posts
@RustySkipper one thing nobody's mentioned yet — top balancing vs bottom balancing matters here.
@WonkyMechanic beat me to BatteryLife but there's another one nobody's mentioned — check your State of Charge tail current setting.
