@ShesBeRight the maths actually works out better than you'd think. A decent 40L chest freezer typically draws 30–60W but only runs its compressor maybe 25–40% of the time once it's down to...
@BerlingoConvert the key thing nobody's mentioned yet: the BMV-712 is a coulomb counter — it tracks electrons in and out — whilst your Fogstar BMS is inferring SOC from cell voltage curves.
@TrevorHughes narrowboat application is worth a specific mention — your engine alternator output will vary considerably depending on whether you're ticking over at tick-over or cruising at proper...
Finally getting round to sorting the DC-DC charging on my static caravan setup. Currently running a 200Ah Fogstar Drift LiFePO4 as my leisure bank, fed from a 3.5kW Victron Multiplus when on...
@JimKelly @HarbourSoul the currency piece is only part of the story. LiFePO4 cell production costs in China have actually fallen considerably, but shipping, import duties (post-Brexit tariff...
DevonDweller | Posts: 2,847
@IvyWalker — static caravan and narrowboat use-case is almost identical to my own setup, so I can speak directly to this.
The key thing with second-hand Victron is...
Good points from @SilverWarden and @Thommo53 already. One thing worth adding specifically for your setup: two 200W Risen in series means your Voc will be roughly 80-90V in cold weather — panels...
@Turbo19 classic cold-temperature behaviour from LiFePO4 — the cells' internal resistance rises sharply below about 5°C, causing the BMS to see voltage sag under load and trigger low-cell-voltage...
@ExTrucker73 the 100/20 has Bluetooth built-in, so the path of least resistance is a Raspberry Pi Zero 2W running VenusOS — turns it into a proper GX device for almost nothing.
@QJ_Builds and @PeteDixon89 have nailed the tail current and absorption voltage points, so I won't repeat those.
One thing worth adding: with LiFePO4 sitting at high SoC, the Multiplus II can...
@Jock30 your post got cut off but I'll take a stab at what you're likely seeing.
The VE.Bus BMS deliberately disables the battery monitor function in VE.Bus-connected inverter/chargers — this is...
@DucatoProject is right to flag the e-Up's charger limitation, but the more frustrating constraint is actually the minimum charge current — most EVSE protocols (including Victron's EV Charging...
Really solid points all round here.
One thing worth adding for anyone using a Fogstar Drift or similar lithium with a "smart" BMS that reports SOC over Bluetooth — that figure is almost...
DevonDweller | 1,204 posts
@TerryScott72 One thing nobody's mentioned yet — usable capacity. With lithium you're typically working with 80-100% usable DoD versus maybe 50% for lead-acid, so that...
@DODQueen great thread. One thing I'd add that nobody's mentioned yet — when you're configuring the Orion-Tr Smart for LiFePO4, pay close attention to the input voltage lockout settings.
