Anyone else running a Victron Multiplus II with a Pylontech battery stack — what SOC settings are you actually using?

Just finished wiring up a Multiplus II 48/3000 with two Pylontech US3000C batteries (about 7kWh usable) and I'm second-guessing my charge/discharge limits in VEConfigure. Currently I've got it set to charge to 95% and cut off discharge at 10% SOC, but I'm wondering if I'm being too conservative or not conservative enough.

The Pylontech BMS is handling the low-level cell protection, so in theory it'll step in before anything goes badly wrong. But I've read conflicting things about whether you should let the Victron settings do the heavy lifting or just trust the BMS. Some people say set the Victron to 20% discharge floor, others say 5% is fine because the BMS will save you anyway.

Also curious about the absorption voltage — I'm running 52.4V as Pylontech recommends, but a few posts I've found from European forums suggest backing it off slightly for longevity. Not sure if that's relevant in a UK climate where we're not exactly hammering the batteries with solar every day for eight months straight.

Has anyone done any actual cycle testing or noticed real-world capacity degradation over a year or two with these setups? Would love to know what settings people have landed on after running them for a while.

CaddyBuild | 847 posts

@WonkyWarden nice setup! With that exact combination I'd let the DVCC system handle most of the heavy lifting honestly — once you've got your Cerbo or Venus device talking to the Pylontechs via CAN bus, the batteries tell the Multiplus what they actually want.

That said, for a fallback/manual config I run:

• Charge voltage: 53.2V
• Float: 52.4V
• Low battery cutoff: 47.0V

The US3000C BMS will ultimately protect itself anyway, but keeping your manual settings slightly conservative means if CAN comms drop for any reason you're not hammering the cells.

What are you using as your GX device? That'll affect how much you can rely on managed charging versus manual parameters.

PylontechMaster | 2,341 posts

@WonkyWarden good shout checking this before you run it hard. One thing worth knowing — the US3000C will actually communicate its own charge/discharge limits to the Multiplus II via CAN bus through Venus OS, so you don't need to be too precious about manually restricting things in VEConfigure.

That said, I'd personally set a low SOC warning around 20% and a minimum discharge cutoff at 10% as a belt-and-braces measure. For daily cycling, staying between 20-90% will preserve longevity considerably.

Make sure your DVCC is enabled in Venus OS and that "Use charge current limiter" is ticked — the Pylontech BMS will then handshake properly with the inverter. Also double-check your battery capacity is entered correctly in the system settings, as that affects SOC accuracy noticeably. What firmware are you running on the Cerbo/CCGX?

WelshVanLifer | 34 posts

Not exactly the same setup — I'm running mine on a boat rather than a fixed install — but curious whether the DVCC approach @CaddyBuild mentioned actually honours the Pylontech's own BMS limits properly? That's the bit I've always been unsure about.

On my setup I've been a bit conservative manually, sitting around 90% max SOC and not letting it drop below 20%, partly because marine environments add a bit more stress I reckon. But I genuinely don't know if I'm being overly cautious and leaving usable capacity on the table.

Does the Multiplus II just trust whatever the BMS reports via CAN bus, or is VEConfigure still the final word on cutoff limits? That hierarchy confuses me with Victron kit.

Taffy42 | 156 posts

@WelshVanLifer snap — narrowboat here too, and Pylontech US3000Cs talk to the Multiplus II via CAN bus so beautifully you'd almost forgive Victron for the price tag. Let the BMS do the heavy lifting on cutoffs; I've got my DVCC charge voltage at 52.4V and honestly the batteries just tell the Multiplus what they want anyway. Only thing I'd add that nobody's mentioned: if you're in a tidal mooring or anywhere with dodgy shore power, set your AC input current limit conservatively in VEConfigure — my stack got a bit grumpy the one time grid quality went wobbly and it started cycling unnecessarily.

PeteDixon89 | 847 posts

@WonkyWarden the good news is you don't need to overthink this too much — with proper CAN bus comms between the Pylontechs and the Multiplus II, the BMS is actually managing those limits dynamically anyway. What you set in VEConfigure becomes a safety backstop rather than the primary control.

That said, I'd still recommend setting your DC input low shutdown no lower than 47V and keeping your absorption voltage around 53.2V. The Pylontech BMS will pull the reins before those limits kick in under normal operation.

Are you running the batteries via CAN bus or just the Victron cable kit? Makes a big difference to how much manual tweaking you actually need. If you're on CAN bus and running Venus OS, honestly let DVCC do the heavy lifting — it's what it's there for.

WrongFuse | 212 posts

@WonkyWarden @PeteDixon89 is right about the CAN bus doing the heavy lifting, but worth mentioning — make sure your DVCC settings in Venus OS are actually enabled, otherwise the Multiplus can ignore what the BMS is requesting and just do its own thing. Caught me out on my first build.

One thing I'd add: with only two US3000Cs I'd be a bit conservative on the lower end in practice. Pylontech spec allows discharge down to around 10% but I personally set a low SOC alarm at 20% and a shutdown at 15% just to keep cycles healthy long-term. More relevant if you're not grid-tied and might genuinely flatten them on a bad weather run.

What Venus OS version are you on? There were some DVCC quirks on older firmware worth knowing about.