A SmartShunt is the most accurate way to know your battery's true state of charge. It installs on the battery negative, measuring every amp in and out so you see exactly how full your bank is — not a voltage guess. Wiring it is straightforward: all main negative loads connect to one side of the shunt, the battery negative to the other, plus a small sense wire to the battery positive. This guide walks the install and the VictronConnect setup.
Why a shunt beats a voltage readout
Voltage alone is a poor fuel gauge for batteries — it sags under load and rises at rest, so it can't tell you the real state of charge. A SmartShunt counts the actual current flowing in and out, giving you a true percentage, time-remaining, and history. For lithium especially, that accuracy matters.
What you'll need
- Victron SmartShunt (500A is the common RV size) — shop Victron battery monitors
- The supplied positive sense wire + inline fuse
- A heavy cable to connect battery negative to the shunt (sized to your system's max current)
- Lugs and a crimp tool
Step 1 — Mount the shunt
Mount the SmartShunt near the battery on a dry surface. It needs to sit in the negative path, so locate it where the battery negative cable can reach one stud and all your negative loads connect to the other.
Step 2 — Wire the negative path (the key step)
- Disconnect the battery before working.
- Connect the battery negative to the shunt stud marked "BATTERY ONLY".
- Connect all other negative loads and charging sources (inverter, busbar, chassis ground, charger negatives) to the other stud ("SYSTEM MINUS").
- Nothing except the battery negative should touch the "BATTERY ONLY" side — that's what lets the shunt measure everything.
Step 3 — Connect the positive sense wire
Run the supplied red sense wire from the shunt to the battery positive, through the small inline fuse. This powers the shunt and lets it read battery voltage. Keep the fuse close to the battery positive.
Step 4 — Configure in VictronConnect
- Open VictronConnect on your phone and connect to the SmartShunt over Bluetooth.
- Set the battery capacity (total Ah of your bank) and battery type (e.g. LiFePO4).
- Set charged-voltage and tail-current parameters per Victron's guidance for your battery.
- Optionally connect it to a Cerbo GX via VE.Direct to show on your system display and VRM.
Common mistakes to avoid
- Loads on the "BATTERY ONLY" stud — only the battery negative goes there, or readings will be wrong.
- No fuse on the sense wire — always fuse the positive sense lead.
- Wrong battery capacity entered — the percentage is only as good as the Ah figure you set.
- Undersized negative cable — the battery-to-shunt cable carries full system current.
Frequently asked questions
Where does the SmartShunt install — positive or negative?
On the battery negative. All negative loads pass through the shunt so it can count current in and out.
What size SmartShunt do I need?
The 500A SmartShunt covers most RV systems including those with large inverters; choose a higher rating only if your peak current exceeds it.
Do I need a Cerbo GX to use it?
No — the SmartShunt works standalone over Bluetooth in VictronConnect. Connect it to a Cerbo only if you want it on a system display and the VRM portal.
Will it work with lithium and lead-acid?
Yes. Set the correct battery type and capacity in VictronConnect and it monitors any battery chemistry.
Get accurate battery data: Shop Victron SmartShunt & monitors — in stock, ships from Upland, CA.