DVCC issue - 150A limit exceeded with multiple MPPTs

Been scratching my head over something similar on my narrowboat setup and wondering if anyone else has run into this.

Running a Victron system with a Multiplus-II 48/5000 and two SmartSolar MPPT 100/30s — all talking nicely through VE.Can with DVCC enabled. I've got DVCC set to cap system charge current at 100A to protect my Fogstar 48V LiFePO4 battery.

The problem? On a cracking sunny morning when both MPPTs are going full chat and the Multiplus decides to run an absorption cycle simultaneously, I'm consistently seeing the actual current going well above my configured limit. We're talking 115-120A showing in VRM. Not catastrophic, but it's not what DVCC is supposed to do, is it?

From what I understand, DVCC is meant to coordinate all charge sources so the combined total stays within limits. But it feels like the MPPTs and the inverter/charger aren't quite agreeing on who's responsible for backing off.

A few questions for the collective brain here:

• Does anyone know whether DVCC aggregation actually works reliably across mixed VE.Can and VE.Direct devices?
• Is there a known firmware version on the Cerbo GX that addresses this? (I'm on v3.14)
• Would splitting into separate battery banks with individual BMS limits be a cleaner solution, or just overcomplicating things?

Genuinely not sure if this is a configuration issue on my end or a known quirk. Would love to hear from anyone who's wrestled with multi-MPPT DVCC setups, especially on boats where you can't exactly call an electrician round

@CopperRoamer had exactly this on my cabin setup last summer. The DVCC shared current limit is supposed to cap the combined charge current but with two MPPTs it can get confused about which device "owns" the limit.

Worth checking a couple of things:

• Are both MPPTs on the same VE.Can or VE.Smart network? They need to be to coordinate properly
• What firmware are you on? There was a known bug a while back where DVCC wasn't distributing the limit correctly across multiple chargers
• Check the SVS (Shared Voltage Sense) is enabled — sometimes that's the culprit

In VictronConnect, look at the "network status" on each MPPT individually and confirm they're actually seeing each other. Mine were showing as networked but one had silently dropped off after a firmware update.

What does your GX device show for each charger's individual current limit under DVCC?

Classic DVCC gotcha — the 150A shared current limit applies to charging sources collectively, but if your MPPTs aren't all on the same VE.Can or VE.Direct network talking properly to the GX device, they'll cheerfully ignore the cap and do their own thing.

Check your Venus OS version first (3.x handles multi-MPPT DVCC considerably better than older firmware). Each SmartSolar needs to be visible in the Device List on Cerbo/CCGX, not just paired via Bluetooth — Bluetooth doesn't participate in DVCC.

Also worth checking: on a 48V narrowboat bank, your actual battery BMS current limit needs to be correctly set in DVCC → SVS/SCS/STS settings, otherwise the GX is just guessing. What GX device are you running and what's your battery chemistry? That'll narrow it down sharpish.

@CopperRoamer worth double-checking your DVCC Shared Voltage Sense is actually enabled — I've seen setups where SVS is off and each MPPT just does its own thing, ignoring the shared current limit entirely.

Also, which firmware are you on? There was a known issue a while back where the 150A cap wasn't being respected properly with multiple MPPTs on VE.Can vs VE.Direct. My narrowboat runs two SmartSolar 100/30s and I had grief until I got everything on the same comms bus.

Quick checklist:

• All MPPTs visible in VRM?
• DVCC on, SVS on, SCS on?
• BMS (if fitted) actually asserting the charge current limit?

If you've got a Lynx Shunt in the mix, that changes things too. What's your battery comms setup?

@OldSailor makes a fair point but I'd also check your BMS current limits are actually being passed to the GX device properly. Had a similar headache at the cabin — my Cerbo wasn't receiving the charge current limit from the BMS so DVCC was basically flying blind.

Pop into VRM → Device List and confirm your BMS shows up and the CCL value looks sane. If it's reading 0 or missing entirely that's your culprit.

Also worth checking you're on recent firmware — there were some DVCC fixes in the Venus OS 3.x releases that sorted weird multi-MPPT behaviour for a few people.

@CopperRoamer had almost identical grief on my motorhome build with a pair of SmartSolar 100/30s feeding a Fogstar Drift 100Ah 48V bank.

The bit that caught me out: DVCC's SVL (Shared Voltage Limit) and the 150A CCL are only as reliable as your CAN-bus or VE.Direct topology allows. If either MPPT is connected via VE.Direct and your GX device is under load processing multiple data streams, you can get brief windows where the charge controllers haven't yet received an updated CCL from the BMS — and they'll revert to their own internal charge profile momentarily.

Worth checking in VRM > Advanced > Device List whether both MPPTs show consistent CCL values in real time, or whether one occasionally drops to ---.

@Lefty31's point about BMS passthrough is crucial — what BMS are you actually running? That'll determine whether you need to manually cap MPPT max current as a belt-and-braces measure.