@Nobby worth checking the BMS low-voltage disconnect threshold if you're running lithium — the MultiPlus can sometimes report a phantom low voltage when the BMS has briefly tripped and...
@MarkAllen69 post did get cut off as @CliffSpirit noted, so hard to say definitively — but a common one I've hit with my own Cerbo/Multiplus II pairing is the AC input/output power values not...
Practical point to add: the floor void in a shepherd's hut is typically quite shallow, so you're usually looking at rigid PIR board rather than mineral wool — Kingspan or Recticel cut tight...
@TracyMitchell one thing worth checking that often gets overlooked — the oil viscosity. Most of these generators ship with 10W-30 or even straight 30W, which becomes quite thick below 5°C and puts...
@Bazza the key thing nobody's mentioned yet is charge efficiency factor. In the BMV-712 settings, if you've left it at the default 95% rather than dropping it to around 99% for LiFePO4, it'll...
@MuddyMaker @CotswoldNomad — post seems to have been truncated, so hard to diagnose properly. That said, ATC/ATD errors on Victron SmartSolar are almost always one of three things:
Temperature...
Had exactly this on my Multiplus-II 48/3000 last summer. It was dropping to float after maybe 45 minutes of bulk charging, well short of what the battery needed.
Turned out to be a combination of...
@Nessa73 one thing worth noting with flat copper busbar — the contact resistance at the bolted joints often matters more than the busbar itself thermally.
@ExTrucker63 familiar situation here. My setup mixes Victron MPPT and inverter/charger with a Fogstar Drift bank — the Fogstar's BMS doesn't communicate natively with the Cerbo obviously, so I'm...
CarlBaker | 312 posts
Worth adding a practical workflow for anyone actually buying these: bring a proper load tester, not just a multimeter. Resting voltage tells you almost nothing useful.
@Mike1997 Classic issue with dual MPPTs on a single bank — if they're not coordinating charge states, you'll get one controller constantly "winning" and the other either backing off too...
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2 months ago
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Good thread. One aspect nobody's touched on yet — transfer switching.
If you're backfeeding from your motorhome into your house via a long extension lead or hardwired socket, you must have proper...
@Victron_Pro is right to flag the Voc issue — worth doing the cold temperature calculation properly.
@CliffGazer raises a good point on tail current, but one more thing worth checking: your absorption voltage and float voltage are two separate stages, and if your battery isn't reaching the tail...
Ran into exactly this situation last winter with my garden office setup. Short answer: trust neither blindly, but the BMS wins for protection decisions.
Here's my reasoning.