SBMS0/Victron mppt smart solar controller 100/50 /Victron Non-Inverting cable.

So I've been going round in circles on this one and wondered if anyone here has hands-on experience with the SBMS0 paired with a Victron SmartSolar 100/50?

I'm in the process of setting up my tiny house build and I'm trying to work out the correct wiring between the SBMS0's load/charge control outputs and the Victron MPPT. Specifically around using the non-inverting cable — I've seen conflicting info about whether the SBMS0 output signal is compatible straight out of the box with the Victron's remote on/off port, or whether you need to account for the logic inversion.

From what I can gather:

• The SBMS0 outputs a low signal to disconnect
• Victron's remote port wants a high signal to enable charging
• So in theory you'd need the non-inverting cable rather than a standard one?

But then I've seen some builds where people just wire it direct and claim it works fine, which has me scratching my head a bit.

Is anyone running this exact combo? Does the non-inverting cable actually sort the logic issue cleanly, or is there something else going on with the Victron's internal pull-up resistor that makes it behave differently to what you'd expect on paper?

Also — does it matter which firmware version the 100/50 is running? I've seen mentions of behaviour changing across updates.

Would love to see how others have actually wired this up, even a rough diagram would be brilliant. Trying to get this right before I start pulling cable through the build! 🔌

Hey @DucatoLife! Yes, running almost exactly this setup in my van. The key thing with the SBMS0 and the 100/50 is making sure you're using the non-inverting cable between the SBMS0's EXT IO port and the Victron's remote on/off terminals. Without it the logic is inverted and the MPPT won't shut down properly when the SBMS0 triggers a protection event - which rather defeats the point!

Also worth checking your remote on/off jumper is removed on the 100/50 before connecting. Caught me out first time round.

The Victron Connect app still works fine for monitoring alongside the SBMS0 - you don't lose any functionality there. What cells are you running? LiFePO4 I'd assume? Makes a difference to how you configure the SBMS0 thresholds. Happy to share my settings if useful.

Running this combo on my boat. One thing worth flagging that @Gazza22 probably covered - the non-inverting cable between SBMS0 and the Victron is critical. The SBMS0's remote on/off output needs to match Victron's H/L logic, and without that cable you'll get inverted behaviour where the SBMS0 enables the MPPT when it should be cutting it off for protection.

Victron's own Non-Inverting Remote On-Off cable (part ASS030550300) sorts this. Double-check you've got that specific one rather than a generic RJ45 lead.

Also worth connecting via VictronConnect and disabling the built-in battery protection on the MPPT itself - let the SBMS0 handle all cell-level protection, otherwise you risk them fighting each other at charge cutoff voltages.

@DucatoLife — worth knowing that on my narrowboat I had a frustrating episode where the SBMS0's load output signal was perfectly correct, but the 100/50 was still behaving oddly at the transition point between absorption and float.

Turned out the issue wasn't the non-inverting cable wiring at all — it was the VE.Direct TX port function on the SmartSolar. You need to set it to "Normal communication" rather than one of the pulse-width options, otherwise the SBMS0 misreads the signal entirely.

Took me an embarrassingly long afternoon with a multimeter to work that out.

Also worth double-checking your remote on/off pin logic — the SBMS0 pulls the line low to disconnect, so polarity matters enormously here. Getting that backwards is a very common gotcha with this pairing.

Something I'd add that hasn't been mentioned yet — double-check your VE.Direct comms if you're planning to monitor the 100/50 through the SBMS0's interface. I had a right headache initially where the controller kept dropping connection intermittently, turned out to be a dodgy VE.Direct cable rather than anything to do with the SBMS0 itself.

Also worth noting: the 100/50 will happily absorb the SBMS0's charge enable/disable signal via the remote on/off terminals, but make sure you've configured the tail current settings correctly in VictronConnect — if it's set too low it can confuse the SBMS0's SoC calculations something chronic.

@KevWatson57 makes a good point about the non-inverting cable — that caught me out too when I first wired mine up. Fogstar cells with this combo have been rock solid for me.