Best Practice Question for Battery Temperature Monitoring to Control Multiple Victron Charge Sources

Running a Victron setup across my garden office and tiny house build, and this question has been nagging at me for a while now.

I've got two MPPT controllers (a 100/30 and a 75/15), a MultiPlus 24/3000, and a Cerbo GX all talking to each other nicely via VE.Can and VE.Direct. My battery bank is Fogstar Drift 24V LiFePO4.

Here's what I can't quite work out — where is the "correct" place to connect the battery temperature sensor for best practice?

Options as I see it:

• Direct to the Cerbo GX temperature input
• Direct to one of the MPPT controllers via the VE.Smart network
• Direct to the MultiPlus via its own temp sensor input

The Cerbo can obviously share temperature data across the whole system, but I've read conflicting things about whether the MPPTs actually act on that data for charge limiting in the same way they would if the sensor was wired directly to them.

Does the VE.Smart Networking properly propagate temperature compensation to all charge sources when the sensor is on the Cerbo? Or is there a risk that one source is throttling correctly while another is blissfully ignoring the cold?

Worth noting I'm in the north of England, so winter temps in the unheated garden office do drop below 5°C fairly regularly — so getting the low-temperature charge cutoff working reliably across all sources matters quite a bit to me.

Has anyone actually tested this properly rather than just assuming it works? Curious what setups others are running.

Good question @Liz1979. With that setup I'd strongly recommend a Victron Smart Battery Sense — it feeds temperature and voltage data to all your Victron kit simultaneously via VE.Smart Networking. All three charge sources (both MPPTs and the MultiPlus) can then compensate based on actual battery temp rather than guessing.

One thing worth knowing — the MultiPlus gets its temp data differently. You'll want to check whether your 24/3000 has a VE.Bus BMS in the loop or if you're running the temp sensor cable directly to the unit.

Did my van with a similar arrangement and the Smart Battery Sense made a noticeable difference to absorption behaviour in winter. Fogstar cells especially benefit from tighter temp-compensated charging when it drops below 5°C.

What battery chemistry are you running? LiFePO4 changes things considerably.

Good shout from @CoveMick on the Smart Battery Sense. One thing worth adding — if your MPPTs and MultiPlus are all on the same VE.Smart Network, they'll all pull from that single temperature reading automatically. No extra wiring faff.

Done this on my van conversion with a 100/50 and a MultiPlus — works a treat once it's all talking properly in the Victron Connect app.

Main gotcha I'd flag: make sure the Sense is mounted on the battery (or as close as practical), not somewhere ambient like a wall. Obvious maybe, but easy to overlook during a build when you're rushing. Temperature offset from a poorly placed sensor can mess with your charging curves more than people realise.

@WonkyMender and @CoveMick have covered the Smart Battery Sense nicely, so I'll just add — if your batteries have their own internal temp sensor outputting via a dedicated wire (common on decent lithium packs, Fogstar Drift included), wire that directly to the MultiPlus temp sense port rather than relying solely on the Smart Battery Sense for the inverter/charger side.

The Smart Battery Sense broadcasts over VE.Smart networking for the MPPTs, but the MultiPlus actually prefers a hardwired signal — belt and braces being rather important when you're asking 30 amps to know when to back off.

Seen rigs where the wireless dropout during RF interference caused the MultiPlus to fall back to worst-case assumptions. Not catastrophic, but not ideal at 2am in a Scottish winter either.

Dead handy thread this. One thing nobody's mentioned yet — placement of the Smart Battery Sense matters more than people think. Stick it on the coldest battery in the bank if you've got multiple units, not just wherever's convenient. Otherwise your compensation is based on the warmest and the others get undercharged in winter.

Learned this the hard way on my narrowboat last January. Batteries read fine, actual cold-end cells were sulphating quietly. Not fun.

Also worth checking your VE.Smart Networking is actually syncing — go into the VictronConnect app and confirm all devices show the shared temperature data. Easy to assume it's working when it isn't. 🔧