The Victron SmartShunt comes in four current ratings: 300 A, 500 A, 1000 A and 2000 A. Each one also comes in a water-resistant IP65 version. All of them do the same job and use the same app. So which do you need? The answer depends on how much current flows through the shunt, not on how big your battery is. This guide shows how to work out that current for a typical RV and what you give up by oversizing.
What stays the same across every size
Victron's datasheet gives all four sizes the same features and the same specs:
- Bluetooth to the VictronConnect app, plus a VE.Direct port for a GX device such as the Cerbo GX
- A second input that can read a starter battery's voltage, a battery bank's midpoint or (with the optional sensor) temperature
- Supply range of 6.5 to 70 VDC, so it works on 12, 24 and 48 V banks
- Battery capacity setting from 1 to 9,999 Ah
- Current resolution of ±0.01 A and accuracy of ±0.4%; voltage accuracy of ±0.3%
- Current draw under 1 mA
So a 300 A SmartShunt on a 1,000 Ah bank is fine. The battery capacity is just a setting. What the rating limits is current.
What changes with the size
| SmartShunt | Dimensions (h x w x d) | Connection bolts | Zero offset |
|---|---|---|---|
| 300 A | 44 x 120 x 44 mm | M8 | under 10 mA |
| 500 A | 46 x 120 x 54 mm | M10 | under 10 mA |
| 1000 A | 68 x 168 x 75 mm | M10 | under 20 mA |
| 2000 A | 68 x 168 x 100 mm | M10 | under 40 mA |
The offset is the small error the shunt can show when almost no current is flowing. On a big shunt it is a bigger share of a small reading. Take a rig parked overnight drawing 0.5 A: a 40 mA offset is 8% of that reading, while 10 mA is 2%. That is a good reason not to buy a 2000 A shunt for a 1,500 W inverter.
Step 1: find the most current that flows through it
Victron's manual says every DC load, inverter, battery charger, solar charger and other charge source must connect to the "system minus" side of the shunt. So all of the system's current passes through it. Add up what can run at the same time, in each direction.
The inverter is almost always the biggest number. A rough DC current is the inverter's continuous watts ÷ (battery voltage x efficiency). These estimates use Victron's continuous ratings at 25°C and its maximum efficiency figures. Real current rises as the battery voltage sags, so treat them as a floor.
| 12 V inverter | Continuous output (Victron) | Max efficiency (Victron) | Approx. DC current |
|---|---|---|---|
| Phoenix Inverter 12/1200 VE.Direct | 1,200 W | 91% | about 110 A |
| MultiPlus 12/2000 | 1,600 W | 92–93% | about 145 A |
| MultiPlus-II 12/3000 | 2,400 W | 93% | about 215 A |
| MultiPlus-II 12/4000 | 3,400 W | 93% | about 305 A |
Inverters also surge. Victron rates the MultiPlus-II 12/3000's peak power at 5,500 W. At 12 V and 93% efficiency, that is close to 490 A for a moment. Victron does not publish a short-term overload rating for the SmartShunt, so we size on continuous current and leave headroom for surges.
Check the charging side too. A MultiPlus-II 12/3000 charges at up to 120 A and the 12/4000 at 160 A. Add any solar and DC-DC charging that can run at the same time. On most RVs the inverter number is still the larger one.
Step 2: pick the size
Here is how we would match those numbers to a shunt. It is our rule of thumb, not a Victron table:
- 300 A: small systems, such as an inverter up to about 1,200 W plus solar and a fridge. It is the most compact and the only size with M8 bolts, so check your cable lugs.
- 500 A: the usual pick for a 12V RV with one inverter/charger up to 3000 VA. It is the size in our MultiPlus-II Inverter Core Kit and our Lynx DC Distribution Pack. Our Victron solar charging kits include a SmartShunt as well.
- 1000 A: a 12 V MultiPlus-II 12/4000, two inverters in parallel, or a 3000 VA inverter plus heavy DC loads such as a 12V air conditioner.
- 2000 A: large banks feeding several big inverters at 12 V. Most RVs never need it, and it has the largest zero offset.
At 24 V or 48 V the same power draws half or a quarter of the current, so a smaller shunt often does.
Standard or IP65?
The standard SmartShunt is rated IP21. Victron's manual says it is not waterproof and must be mounted in a dry place. The SmartShunt IP65 comes in the same four sizes and is water resistant, for spots where the standard model could get wet. Its leads are 1.5 m cables, including one with a VE.Direct socket. To connect it to a GX device you still need a VE.Direct cable, which is not included. Both versions are on one listing: Victron SmartShunt 300 A to 2000 A, standard and IP65.
SmartShunt, BMV-712 or Lynx Shunt?
The BMV-712 Smart comes with a 500 A shunt and a wall display. Victron lists "shunt selection capability up to 10,000 Amps", so on a big system it can run from one of Victron's larger stand-alone shunts, such as the 1000 A or 2000 A. Victron says the SmartShunt differs from the BMV-712 in having no programmable visual and audible alarm and no programmable relay. Our BMV-712 vs SmartShunt guide covers that choice in full.
If you are building a Lynx busbar line, the Lynx Shunt VE.Can is the alternative. It is rated 1000 A, holds the main fuse and reports to a GX device over VE.Can. See Victron Lynx explained.
Installing it
The battery negative goes to the "battery minus" side, and nothing else connects there. Victron's manual is plain about why: anything connected on that side is left out of the state-of-charge calculation. Torque the main bolts to a maximum of 21 Nm (10 Nm on the 300 A). Our step-by-step guide on how to install a Victron SmartShunt walks through the wiring and the first settings.
FAQ
Can a 500 A SmartShunt handle a 3000 W inverter?
On a 12 V system, a MultiPlus-II 12/3000 draws roughly 215 A continuous by our estimate, so 500 A leaves room for surges. On a 12/4000 or two inverters, step up to 1000 A.
Does a bigger battery need a bigger SmartShunt?
No. You set the capacity, from 1 to 9,999 Ah, in the app. The shunt rating is about current.
Do I need a GX device?
No. The SmartShunt has Bluetooth, so your phone acts as the display. A GX device adds a wall screen through a GX Touch and remote monitoring on VRM.
Can it show my starter battery too?
Yes. The auxiliary input can read a second battery's voltage instead of temperature or midpoint. See our answer on wiring the SmartShunt Aux input.
What is the Bluetooth range?
Victron quotes 10 to 15 m in most cases, less near a metal chassis. If the range is poor, Victron suggests adding a VE.Direct Bluetooth dongle and switching off the shunt's own Bluetooth.
Browse the full Victron Energy range. Found it cheaper? We'll beat it.