Multiplus force la tension de charge des Pylontech à plus de 52,40V

Noticed something a bit odd this week after updating my Multiplus-II to the latest firmware — charge voltage crept above what I'd expect for my Pylontechs.

I'm running four US5000s on the boat, managed through the DVCC stack with a Cerbo GX, and historically the system has been rock solid. The BMS handshake keeps everything playing nicely together. But after the update I caught the charger pushing noticeably higher than the 52.4V ceiling I'd mentally filed away as the upper boundary for these cells.

Worth noting — Pylontech's own documentation for the US5000 does specify charge voltage limits, and I'd always assumed DVCC + the CANbus link meant the Multiplus couldn't really go rogue on that front. Apparently that assumption needs revisiting.

A few questions for anyone who's seen similar:

• Has anyone else clocked this after a recent firmware revision?
• Is this a DVCC override issue, or is the BMS simply reporting a higher CV request at a certain SOC that the Multiplus is now actually honouring rather than capping?
• Could it be cell balancing behaviour at the top of charge that's pushing the headline voltage up temporarily?

For context, my setup runs primarily on solar with occasional shore power on the marina — so the Multiplus isn't hammering the pack constantly, but I'd still rather not be stressing the cells unnecessarily over winter when I'm also running the shepherd's hut off the same bank occasionally via a long umbilical.

Anyone with Victron + Pylontech experience who's dug into the VRM logs on this, I'd be very interested to compare notes.

Saw something similar with my setup in the static caravan — not Pylontechs but after a firmware update the Victron was behaving slightly differently with absorption voltage. Worth checking in VictronConnect whether the DVCC settings have reset to defaults, that caught me out once. The Pylontech CAN comms should theoretically be overriding the Multiplus charge parameters anyway, but I've read that certain firmware versions have a bug where DVCC wasn't properly honouring the BMS limits.

Also check ESS Assistant version if you're running ESS — sometimes updating firmware doesn't automatically update the assistant and you can end up with a mismatch.

The Victron community forum has a few threads on this exact issue. @ExFirefighter11 what firmware version are you on? Might be worth rolling back temporarily if you're seeing voltages consistently above 52.4V.

@ExFirefighter11 mine did the same thing after a firmware update last year — Pylontechs screamed blue murder and the BMS cut out faster than my ex leaving on a Saturday night.

Check your DVCC settings in VRM; there's a known quirk where firmware updates can reset the CVL override so the Multiplus ignores what the BMS is actually requesting and just does whatever it fancies.

Specifically look at:

• SVS (Shared Voltage Sense) — make sure it's enabled
• SCS — same

If the BMS is talking to the Multiplus properly via CAN, the Pylontechs should be dictating that 52.4V ceiling themselves. When DVCC gets scrambled it stops listening. Classic Victron — brilliant kit, occasionally has the memory of a goldfish.

@NotAnElectrician80 "screamed blue murder" is doing a lot of heavy lifting there, but honestly my US3000s had the same meltdown until I rolled back the firmware and let the CAN-bus actually tell the Multiplus what to do rather than letting it freelance like a rogue builder.

@ExFirefighter11 worth checking whether the DVCC settings got reset during the firmware update — this catches people out more often than you'd think. After an update, DVCC can revert to "SVS" (shared voltage sense) mode rather than deferring properly to the BMS, which can let the Multiplus push voltage beyond what the Pylontechs want.

Head into VictronConnect or VEConfigure, confirm DVCC is enabled and that "BMS control" is active. The US5000s should be commanding charge limits directly via CAN-bus, and the Multiplus ought to respect those. If the BMS is correctly connected and still being overridden, it's worth logging a ticket with Victron support — they've been reasonably responsive about firmware-related regressions in my experience.

What firmware version did you land on? Might help narrow it down.