Adding Solar - Victron MPPT to MultiPlus

Been running a Victron MultiPlus-II 24/3000 on my narrowboat for about 18 months now, and recently added a SmartSolar MPPT 100/30 to the mix. The integration via VE.Direct is genuinely impressive once you get your head around it.

The key thing most people miss is setting up DVCC (Distributed Voltage and Current Control) correctly in Venus OS. Without it, the MPPT and MultiPlus can end up working against each other — particularly around absorption and float transitions. Took me an embarrassing amount of forum reading to sort that out initially.

A few things worth noting for anyone doing the same:

• Make sure your battery BMS is also on the VE.Can or VE.Direct network if it supports it — Fogstar Drift LiFePO4 cells work nicely here
• Set SVS (Shared Voltage Sense) on so all devices are reading from the same reference point
• Check your charge current limits are correctly aggregated — the MultiPlus won't automatically know the MPPT is contributing unless DVCC is active

One gotcha on a narrowboat specifically: alternator input via the MultiPlus shore power port means you need to be careful about simultaneous charge source limits. The VictronConnect app makes monitoring straightforward but the initial config really benefits from VRM portal access.

Has anyone else found the Cerbo GX worth adding for this kind of multi-source setup, or is a basic CCGX sufficient? Curious whether the touchscreen display justifies the price difference for a static installation versus something you're moving daily.

@PN_Camper yeah the VE.Direct comms is where Victron really earns its money tbh. Once it's all talking through VictronConnect (or even better, a Cerbo GX if you go that route) you get proper system-level stuff — DVCC kicked in on mine and suddenly the MPPT and MultiPlus were actually coordinating rather than just doing their own thing.

One thing worth checking — make sure your charge profile is consistent across both devices. Had a weird situation in my shepherd's hut setup where the MultiPlus was set to one absorption voltage and the MPPT slightly different. Nothing catastrophic but not ideal for the Fogstar Drift lithium I'm running.

What batteries are you on? Makes a difference to how you dial it all in.

@PN_Camper welcome to the forum — good first post, straight into the technical detail, that's exactly what we like here.

One thing worth adding that nobody's mentioned yet: once you've got your MPPT and MultiPlus both visible in VRM, set up a shared voltage sense if you haven't already. The MultiPlus can use the MPPT's battery voltage reading (or vice versa) which tightens up your charge curves considerably — especially relevant on a narrowboat where cable runs between your alternator, MPPT and inverter can introduce real voltage drop discrepancies.

Also make sure your DVCC settings in Venus OS are configured correctly if you're running a Cerbo or similar. Wrong DVCC setup is the single most common cause of the two units "fighting" each other on charge control.

@PN_Camper nice setup! One thing worth mentioning if you haven't already discovered it — make sure you've got the charge profiles synced properly between the MPPT and the MultiPlus. The MultiPlus takes priority as the "master" charger, so if your absorption voltage on the MPPT is set differently you can end up with the two fighting each other a bit. Best practice is to let the MultiPlus lead and configure the MPPT to follow via the shared voltage sense.

Also, are you running a GX device in the mix? A Cerbo or even a Venus GX makes the whole system genuinely brilliant to monitor, especially useful on a narrowboat where you're moving around and conditions change constantly. VRM portal then gives you remote monitoring which is handy if the boat's moored somewhere whilst you're away.

Had a Victron setup in my static caravan for three years now and the VE.Direct/VictronConnect ecosystem is either the best thing ever or a rabbit hole that swallows entire weekends — sometimes both simultaneously.

Fair warning: once you start seeing all that lovely live data, you will end up sitting in the garden at 11pm watching the