Victron SmartShunt and Boat Battery Monitor Installation
A voltage reading only tells you so much about a battery. A shunt-based monitor such as the Victron SmartShunt or BMV-712 counts every amp going in and out, so it can show state of charge, time remaining and history. We fit marine battery monitors so the numbers are accurate, and set them up for the bank you actually have.
Most of the problems people have with a boat battery monitor come from installation, not the monitor: a shunt fitted in the wrong place, a load wired around it, or a capacity setting that never matched the bank.
We are a Victron installer based at Shoreham Airport, working aboard at the berth from Brighton to Southampton.
What is a Victron SmartShunt?
The SmartShunt is a battery monitor without a screen. It sits in the main negative cable and reports over Bluetooth to the VictronConnect app, or to a GX device for remote monitoring. The BMV-712 does the same measuring with a panel-mounted display, which suits owners who want to glance at the battery without reaching for a phone. Choosing between them is mainly about whether you want that display.
How a battery monitor should be installed
Every negative connection except the battery itself must go to the load side of the shunt. If a single charger, inverter or bilge pump bypasses it, the monitor drifts and the percentage cannot be trusted. We trace the negatives, consolidate them where needed, fit a fused supply for the shunt and keep the cable short.
- Shunt placed so all charge and discharge current passes through it
- Battery capacity, chemistry and charged-voltage settings entered
- Optional temperature or midpoint sensing
- Connection to a Cerbo GX or display where fitted
Why is my Victron shunt always showing 100%?
This usually means the monitor keeps resynchronising because the charged-voltage setting is lower than the voltage your charger holds, or because current is bypassing the shunt so it never sees the battery being used. Wrong capacity settings and a lithium bank set up with lead-acid parameters cause similar confusion. We check the wiring and settings together rather than resetting the unit and hoping.
Victron Cerbo GX installation · Lithium battery upgrades
Quote and handover
The cost depends on the bank, how the negatives are currently arranged and whether a display is wanted. We give a written quote first. At handover we show you how to read state of charge and how to reset or resynchronise the monitor correctly.
Monitors on boats and vans
The same SmartShunt and BMV-712 work just as well in a campervan or motorhome leisure system. Whatever the vehicle or vessel, the rule about every negative passing through the shunt stays the same, and so does the value of a reading you can rely on before a night away from charging.
Frequently asked questions
Do I need a Victron SmartShunt?
If you want to know how much battery you really have left, yes. Voltage alone is a poor guide, especially with lithium, where the voltage barely changes until the bank is nearly empty.
SmartShunt or BMV-712?
They measure the same way. The BMV-712 adds a display; the SmartShunt relies on the app or a GX device.
How do I reset my Victron battery monitor?
It can be synchronised to 100% from the app or display after a full charge. If it keeps going wrong, the wiring or settings need checking.
How much is a Victron SmartShunt installation?
It depends on how your battery negatives are arranged. We look first and give a written quote.
Want readings you can trust?
Send the boat details, where it is kept and what you have in mind, and we will come back with the next step and a written quote.