A Victron energy meter measures AC power at a point in your system and sends it to a GX device. Most people need one for ESS (Energy Storage System), so the MultiPlus-II knows how much power the house is pulling from the grid and can cut grid import or export. Meters also measure a PV inverter’s output or AC loads. Victron offers several models, and the right one depends on your phases, your current and how you connect it.
Victron Energy Meters Compared
| Meter | Phases | Max current | Measurement | Connection | Refresh |
|---|---|---|---|---|---|
| ET112 | 1 | 100A | Direct | RS485 | 750 ms |
| ET340 | 3 | 65A per phase | Direct | RS485 | 2000 ms |
| EM540 | 3 | 65A per phase | Direct | RS485 | 100 ms |
| EM24 Ethernet | 3 | 65A per phase | Direct | Ethernet | 600 ms |
| VM-3P75CT | 3 (also split-phase) | 75A rated (CTs included) | CTs | VE.Can / Ethernet | 100 ms |
| VM-3P5A | 3 (also split-phase) | 5A per phase (external CTs) | CTs | VE.Can / Ethernet | 100 ms |
Source: Victron Energy Meters Selection Guide and product page.
How to Choose
Victron’s selection guide starts with phases:
- Single-phase up to 100A: ET112.
- Three-phase up to 65A per phase: ET340, EM540 or EM24.
- Split-phase, or anything over 65A per phase: VM-3P75CT or VM-3P5A with current transformers.
- Single-phase grid plus a PV inverter to measure: Victron recommends the ET340.
Victron notes that most three-phase meters also support single-phase use.
VM-3P75CT: The Easy One for North America
The VM-3P75CT is the simplest choice for US split-phase homes. Victron says it connects over VE.Can or Ethernet and works out of the box with no configuration. It comes with its CTs, which have 640 mm leads. It runs from 85-265V line-to-neutral, draws 1.45W, and is rated for indoor use only (IP20). Victron’s page lists a maximum of 80A per phase.
ET112, ET340 and EM540: RS485 Meters
These connect to the GX device over RS485. You can wire them with an RS485-to-USB interface, or go wireless with Zigbee converters. Their data then shows on the GX device and in VRM.
Who It’s For
- Grid-tied ESS systems that need grid metering.
- Systems with a PV inverter you want to monitor.
Who Doesn’t Need One
- Measuring a PV inverter only. Victron notes that most PV inverters support direct readout by the Victron system, so in many cases you don’t need an extra meter for their output.
- Off-grid systems with no grid connection to meter.
Good to Know Before You Buy
- Picking the wrong phase type is a common mistake.
- RS485 meters need an interface cable.
- Indoor only.
Victron’s energy meters product page has the full datasheet and manual downloads.
Scenario: A US Split-Phase Home With ESS
A 120/240V home with two MultiPlus-II 120V units in split-phase and a CAN-bus battery:
- The VM-3P75CT measures the two service legs with its included CTs, placed around the conductors after the main breaker.
- It connects over VE.Can or Ethernet to the Cerbo GX and needs no configuration, as Victron describes it.
- With the 100ms refresh rate, ESS reacts quickly when a large load like a dryer switches on.
- The VM-3P75CT’s 80A per phase maximum suits many homes. For services with higher currents, the VM-3P5A pairs with external CTs.
Scenario: A Three-Phase European Home
A 230/400V three-phase home with three MultiPlus-II units, one per phase:
- An EM540 at the grid connection measures all three phases, up to 65A per phase, at a 100ms refresh rate.
- The EM24 Ethernet is an alternative where a network cable is easier to run than RS485.
- The ET340 also measures three phases, and Victron recommends it where a single-phase home also needs to meter a PV inverter, since it can measure the grid on one phase and the PV inverter on another.
Scenario: A Small Single-Phase Home
A 230V single-phase home with up to 100A service and one MultiPlus-II GX:
- The ET112 is the simplest fit, direct-connect up to 100A, with RS485 to the built-in GX.
- If the panel is far from the inverter, a Zigbee link replaces the RS485 cable.
Why Refresh Rate Matters
ESS adjusts the inverter based on the meter’s readings. A faster refresh lets it follow quick load changes more closely, so less power briefly comes from or goes to the grid when a kettle or pump switches on or off. Victron’s guide lists 100ms for the EM540 and the VM-3P meters, 600ms for the EM24 Ethernet, 750ms for the ET112 and 2000ms for the ET340.
Direct vs CT Measurement
- Direct meters (ET112, ET340, EM540, EM24) carry the current through their own terminals, so the electrician wires them into the supply.
- CT meters (VM-3P75CT, VM-3P5A) measure through current transformers placed around the conductors, so the load current never passes through the meter itself. That suits higher currents and split-phase services.
Installation Notes
- Mount the meter in the main panel or a nearby enclosure, since they’re indoor devices.
- Place it at the grid connection point so it sees every import and export.
- Set its role on the GX to Grid meter, or PV inverter for a PV meter.
- Have a licensed electrician do the work, and check grid feed-in rules with your utility.
Quick Picker
| Your supply | Good fit |
|---|---|
| — | — |
| 230V single-phase, up to 100A | ET112 |
| 230V single-phase plus PV inverter to measure | ET340 |
| 230/400V three-phase, up to 65A per phase | EM540 or EM24 Ethernet |
| 120/240V split-phase | VM-3P75CT |
| Any supply above the CT meter’s included range | VM-3P5A with external CTs |
Reading the Data
Whichever meter you choose, the GX overview shows grid import and export live, and VRM charts history over days and months. Comparing those charts with your utility bill is a simple way to see how much ESS is shifting.
FAQ
Which Victron energy meter do I need for ESS in the US?
For a split-phase panel, Victron’s guide points to the VM-3P75CT or VM-3P5A.
Does the ET112 work on three-phase?
No. It’s single-phase, up to 100A.
How does it connect to the Cerbo GX?
The VM-3P75CT uses VE.Can or Ethernet. The ET112, ET340 and EM540 use RS485.
Do I need a meter for an off-grid system?
No. There’s no grid connection to measure. A battery monitor is the key instrument off-grid.
Can a CT meter measure single-phase?
Yes. The VM-3P75CT can be used on single-phase as well as split-phase and three-phase supplies.
Which meter updates fastest?
The EM540, VM-3P75CT and VM-3P5A, all at 100ms in Victron’s selection guide.
Can I add a meter later?
Yes. A GX device detects a new meter once it’s connected. Set its role, then enable or adjust ESS.
Sources: Victron Energy Meters Selection Guide; Energy Meter VM-3P5A + VM-3P75CT datasheet; Energy Meter product page, victronenergy.com, accessed Oct 2026.
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