Using a 3rd party battery with myenergi devices

Overview

A very common question is "How do I set up my myenergi devices so that they work with a battery?"

Although we can't control a third-party battery directly, the myenergi devices have been designed so that they "play nicely" with a battery if one is fitted. As the battery and the myenergi devices are both trying to control the power flowing to/from the grid they can fight each other, leading to unexpected results.

The exact answer depends on what sort of battery has been fitted:

A standalone battery that is completely separate from a PV panel or other renewable generation.
A "hybrid" battery where the battery and the PV panels both feed into a single "inverter".

In both cases, most customers want to avoid emptying their battery into their EV or hot water when the myenergi devices should be working from any spare PV (or other) generation that this available.

Bosting or FAST Mode

If zappi or eddi is "boosting", or zappi is in FAST mode then power will always be taken from your battery unless the battery is turned off.

The Simplest Setting

The simplest way to stop your eddi or zappi from draining the battery is to set an "Export Margin".

This means that the myenergi devices will not start to divert power until they measure power being exported that exceeds this level. The battery then has a chance to control first, taking the surplus generation.

There is a small drawback in this approach as, once the battery is full, you will see a small amount of power being exported to the grid.

To set an export margin, the menu is

Zappi: Settings - Advanced - Supply Grid - Network - Export Margin
Eddi: Setting - Advanced - Supply Grid - Export Margin

A value of 50W or 100W should be suitable.

If you have more than one myenergi device this setting needs to be set on the "master" device.

NOTE: If you have the Export Margin set then, on zappi, the "Minimum Green Level" or "MGL" needs to be set at 100%.

Standalone Battery (AC Coupled)

With a standalone battery, you have the option to install an extra-current transformer (CT) on the wire from the battery to your consumer unit. With this CT, your myenergi devices can measure the power flowing to/from the battery and then ensure that the zappi / eddi does not take power from the battery when they should be using any surplus renewable generation.

The CT will normally need to be installed by an electrician and should be connected back to your zappi / eddi - either connected directly or via a harvi wireless transmitter. If needed, extra CTs can be bought through the myenergi website at myenergi.com.

Once the battery CT has been connected, the following needs to be set in the zappi/eddi:

Set the CT type to "battery".
Tell the zappi / eddi to "avoid draining" the battery via the following menu:
- zappi: Settings - Advanced - Supply Grid - Network - Battery
- eddi: Settings - Advanced - Supply Grid - Battery

When you have a battery CT fitted, you will also be able to see the live battery power flows in the myenergi App.

NOTE: If you have more than one myenergi device the battery setting needs to be set on the "master" device.

Battery combined with Solar (Hybrid/PV)

With a hybrid battery system, your myenergi devices can't work out whether the power is coming from the PV panels or the hybrid battery. In this case, the only option is to set the "Export Margin" (see Hybrid PV and Battery - How to stop your myenergi devices draining the battery in ECO+)

If you decide to fit a CT on the output from the hybrid inverter then you can still monitor the live power flows from the inverter in the myenergi app. The CT type should be set to "Generation + Battery"

You will see the Device locally will not show your power coming out of the inverter, (see DC/Hybrid PV not showing on device display but does on app?)

Depending on where the battery and myenergi devices are connected in your electrical system it may be possible to wire them so that they work better together. This article provides examples from two myenergi customers: Hybrid Battery Installation - Alternative Connection Arrangements

myenergi libbi - Full control

If you did want to have full control over how other myenergi products use the power from your battery. The best solution is to purchase our libbi. libbi is our Intelligent home battery storage solution.

We created libbi to store your electricity, to use it when you need it most. It allows you to capture as much surplus solar electricity as possible, whilst integrating with your existing myenergi devices.

libbi is modular by design. Each module can store up to 5kWh of electricity, so combining 4 of them would provide up to 20kWh of storage.

For more info see here-> libbi

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