How far does harvi reach?

How far harvi reaches: plan for 20 to 25m in a straight line. Some installs work past 50m with no interference, but results vary. See what harvi does and does not do, how walls, metal and foil-lined insulation cut its signal, and test your layout on a floor plan. Includes why some harvi units seem to stop working after an update, and the rules for G100 sites.

myenergi

harvi guide

How far does your harvi reach?

harvi sends CT readings to your master device by radio. In a straight line with nothing in the way, plan for 20 to 25m. Some installs reach past 50m with no interference, but results vary. Walls, metal and foil-lined insulation shorten the reach.

Plan for 20 to 25mPast 50m seen, results vary868 MHz radio, no Wi-FiWalls cut the signalMetal and foil insulation block it

Did harvi stop working after an update? Your harvi has not failed.

On this page

The basics

What harvi does and does not do

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The CT clamp powers harvi and gives it the reading. harvi sends the reading to the master device by radio.

harvi does

  • Read current from a myenergi CT clamp.
  • Send the reading to your master device by radio.
  • Power itself from the CT clamp. It needs no battery and no mains supply.
  • Take up to three CT inputs, on single phase and three phase sites.
  • Measure grid import and export, solar generation and battery storage, to a typical accuracy of ±2%.
  • Work with zappi, eddi and libbi.
  • Suit retrofit jobs where new cable is hard to run.

harvi does not

  • Use Wi-Fi. It talks by radio only, at 868 MHz (915 MHz in some regions).
  • Pair with secondary or follower devices. It pairs to the master device only.
  • Work with other CT clamps. Use only clamps supplied with myenergi devices.
  • Pass through everything. Walls, floors, metal and foil-lined insulation cut the signal.
  • Guarantee a range. Plan for 20 to 25m in a straight line. Some installs work past 50m with no interference. Results vary.
  • Suit outdoor fitting on its own. Fit it indoors, or in an IP rated enclosure outside.

Range

Plan for 20 to 25m in a straight line

Radio signal travels in straight lines. The best case is a clear line between harvi and the master device, with nothing in the way. Plan for 20 to 25m. With no interference, harvi reaches further. We have seen installs work past 50m. Results vary, so do not rely on it.

Every wall, floor and metal object on the line takes signal away. Foil-lined insulation counts as metal, because the foil backing is metal. More walls means less signal. So 20 to 25m is a planning figure for the best case. It is not a promise for the whole house.

Try it on a floor plan

harvi sits at the meter box on most sites. The master device sits somewhere else, in the garage or outside the front of the house. Drag either one, or pick a spot below. The line shows what the signal crosses on its way. Every wall it crosses lights up.

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Drag harvi or the master device. Tap the plan to move the one you used last. Arrow keys work too. Hold Shift for bigger steps.

GoodA good spot. The walls on the line take some signal.
Distance
5.8mInside 20m
Walls on the line
1 wall1 brick
Metal or foil on the line
NoneAdd some below

Inside walls

Put the master device

How the bars work

A clear line gives four bars out to 20m. Between 20m and 25m the bars fall. Past 25m the model shows no bars. Real installs sometimes work past 50m with no interference, but results vary. Each wall takes bars away: plasterboard half a bar, brick or block one bar, reinforced concrete two bars. Outside walls count as brick. Metal takes two bars. Foil-lined insulation is metal backed, so it adds two more bars of loss to each outside wall it sits in. The model compares spots. It is not a measurement.

Illustration only. The bars combine the usual 20 to 25m range with the effect levels in the table below. Real signal depends on what your walls are made of, and some installs reach further. The shaded band marks 20 to 25m from harvi.

What cuts the signal

Plasterboard and timber stud walls Lower effect
Brick and block walls Medium effect
Reinforced concrete walls and floors High effect
Large metal surfaces, such as switchboxes, shelving and roller doors High effect
Foil-lined insulation and foil-backed plasterboard. The foil backing is metal. It sits in walls, floors and roofs. High effect
Other devices on 868 or 915 MHz Adds interference

Count a floor or ceiling on the line as a wall.

Commissioning checks

0 of 5 checked

Metal

Metal blocks the signal

Metal reflects radio signal. A closed metal box stops most of it leaving. Large metal surfaces nearby weaken it too. So does foil-lined insulation, because the foil backing is metal.

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Almost noneA closed metal box keeps most of the signal inside. Move harvi out.

Where is harvi?

Move harvi in and out of the box. Inside, the signal bounces back and little reaches the master device. Next to the box, it reaches the master. Add the shelf or the foil-lined wall to see metal on the line weaken it. Add both and almost nothing gets through.

Do

  • Fit harvi on the wall, outside any metal box or cabinet.
  • Keep it away from switchboxes, shelving and roller doors.
  • Check the signal after you close an enclosure.
  • Check the walls for foil-lined insulation before you choose where the master device goes.

Avoid

  • A closed metal box around harvi.
  • Large metal surfaces next to harvi.
  • A metal door or shelf on the line to the master device.
  • Foil-lined insulation on the line to the master device.

After an update

Did harvi stop working after an update?

Your harvi has not failed. After a software update, some harvi units appear to stop working. The update did not break them.

The weak signal has always been there. We did not show it to customers before. The Radio Equipment Directive (RED) changed the rules, so it now shows.

What to do

  1. Measure the distance from harvi to the master device. Stay inside 20 to 25m.
  2. Count the walls and floors on the straight line between them.
  3. Look for metal on the line, including foil-lined insulation, and around harvi.
  4. Move harvi or the master device closer, or to a spot with fewer walls. The floor plan above shows the effect.
  5. Still not working? Send us the details.

G100

harvi and G100

Engineering Recommendation G100 Issue 2, 2022 Amendment 2 confirms you use harvi at the grid point in a G100 installation, under conditions.

Every G100 site The master device runs firmware V5.4x or newer.
Property fused to 60A harvi works at full capacity.
Fuse above 60A, with the full power range wanted Hardwire the grid reading into a zappi V2.1, eddi V2 or libbi V1.
CLS with a 60A Maximum Import Limit (MIL) harvi works under G100. Maintained load-controlled devices lose 20A, so they get 40A.
Setup wizard. The wizard asks whether you are in the UK and whether the property must be G100 compliant. Then it asks for an import limit (60A, 80A or 100A) and an export limit (16A, 22A, 32A, 60A or 100A).

Unsure about setup or compliance? Contact us and we check it with you.

Fitting

Fit harvi in the right place

Where it goes

  • Indoors, in a dry place.
  • Relative humidity of 95% or less.
  • Temperature from -30°C to +50°C.
  • Altitude of 2000 metres or less.
  • Outdoors only in an IP rated enclosure.

Before you leave

  • Use only CT clamps supplied with myenergi devices.
  • Pair harvi to the master device.
  • Check the status LED. It flashes green within two minutes once the monitored circuit is energised.

Still not working?

Check the distance, the walls and the metal first. Then send us the details.

myenergi Customer Careharvi range guide

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