MPPTS 250/100 scheinbar nicht richtig im ESS Betrieb eingebunden

Been having a similar head-scratcher with my setup and wondering if anyone else has run into this.

I've got a Victron SmartSolar MPPT 250/100 connected via VE.Can to a Multiplus-II, and ever since I started experimenting with ESS I've noticed the MPPT doesn't seem to be playing ball properly. Specifically, it feels like the solar isn't being factored into the overall system load calculation correctly — the inverter seems to be pulling more from the grid than it should when there's clearly decent PV available.

A few things I'm trying to work out:

• Does the MPPT firmware version matter here? I've seen mentions that older firmware causes ESS integration issues
• Is VE.Can definitely the right bus for this, or should I be using VE.Direct and a separate data cable to the Cerbo GX?
• Anyone using a CCGX rather than a Cerbo had different results?

My system is primarily for a garden office so it's not a massive install, but I do want ESS working properly before I consider adding a second MPPT next season. The whole point is to minimise grid draw during daylight hours.

I've been through the Victron ESS design guide but honestly some of it assumes a level of familiarity I'm still building up. Would really appreciate hearing from anyone who's got multiple MPPTs running cleanly in ESS — particularly curious whether the CAN version of the 250/100 behaves differently to the standard one in this context.

Hey @Macca97, welcome to the forum! Your post seems to have got cut off there, so we're missing the actual details of what's going wrong - worth editing it to fill in the rest!

That said, the 250/100 on VE.Can with ESS is a combination I know reasonably well. One thing worth checking straight away is whether the MPPT is showing up correctly in the VRM portal and whether it's set to the right network mode. If it's not appearing as a "networked" device in VEConfigure or the GX device, it'll essentially behave as a standalone charger rather than being properly coordinated within the ESS.

Also, which GX device are you running? Cerbo, CCGX? Sometimes firmware mismatches between the MPPT and GX device cause odd behaviour. Post the full symptoms when you get chance and we'll dig into it properly! 👍

@Macca97 @CraftyWelder is right that we're missing the meat of your issue, but I'll take a punt at what you're likely seeing — classic ESS/MPPT integration grief.

On VE.Can setups, make sure your MPPT is set to the correct VE.Can profile (not the default). In VEConfigure, check that the ESS assistant is actually recognising the MPPT as a networked device rather than treating it as invisible. Common culprits:

• DVCC not enabled on the Cerbo/CCGX — without this, ESS can't properly hand charge current control to the MPPT
• Mismatched battery voltage profile between the Multiplus-II and the MPPT
• CAN termination resistor missing if yours is the last device on the bus

My cabin setup ran into the DVCC issue specifically — the MPPT was producing power but ESS wasn't accounting for it in the charge algorithm. Fill in the rest of your original post and we can narrow it down properly.

Hey @Macca97, looks like we've got a classic case of the forum eating your post mid-sentence! 😄 While you sort out the full details, I'd say check a couple of things in the meantime: make sure your DVCC settings are properly configured in Venus OS, as this is often the culprit when the MPPT isn't playing nicely within ESS. Also worth confirming the VE.Can termination resistors are seated correctly at both ends of the bus - a surprising number of integration headaches trace back to that. What firmware version are you running on the MPPT and the GX device? That'd help us narrow things down once you've posted the rest of your description.

@Macca97 worth noting that the thread title mentions ESS specifically — if you're running ESS mode, the MPPT behaviour via VE.Can can be quite different to what you'd expect. In ESS the system deliberately curtails solar to match load + charge requirements, so the MPPT won't always be running flat out even on a cracking sunny day. Looks like throttling but it's actually working correctly.

On my boat I had this exact confusion before I understood the ESS logic properly. Check your VictronConnect and look at whether the MPPT shows "ESS" in the reason for its state — that's usually the giveaway.

Finish your original post when you get a chance and we can give more targeted advice.

@BPH_Boats is correct and this point doesn't get made enough. In ESS the MPPT is deliberately throttled by the GX device — it's not a bug, it's by design. The Multiplus-II controls overall system power balance, so if grid is present and batteries are full, the MPPT gets told to back off. People see this and assume a wiring fault or firmware issue.

@Macca97 before chasing your tail, check VRM or the Cerbo/CCGX console and look at what state the MPPT is actually reporting. If it's showing "ESS" under its operating state, it's working exactly as intended. Also verify your BatteryLife settings — if that's enabled with a conservative SOC ceiling, you'll see curtailment constantly.

What GX device are you running and what's your battery chemistry? Makes a significant difference to how aggressive the throttling gets.