This guide is for installers. It covers how to pair multiple myenergi devices into one eco-system, how load balancing works across them, and how to balance the load across phases on three-phase sites.
Load balancing
CTs allow multiple zappis to manage the current they draw to prevent the switchboard from overload. This is called load balancing, or load curtailment. You set a Import Limit, which is the maximum current that can be drawn from the grid connection. The zappi and devices paired with it then reduce their current draw to stay under it.
Example: a property has a 63A grid supply, with regular energy use (refrigerator, lighting, appliances) it is drawing 6A (1.4kW). If two EVs are both start charging a EV at 32A, the total grid draw will immediately go over the 63A supply limit and trip the supply or blow a fuse. With a Grid Limit of 63A, the zappi automatically reduces its charging current to both zappis so the supply isn't overloaded.
Related article: How do myenergi products balance the grid in your property
Planning your site
- Each zappi must be installed on its own dedicated circuit with circuit protection
- Choose which zappi will be your Load Controller first. Every other device pairs with it
- Only one Load Controller per eco-system
- Only one Gateway Device per eco-system. It manages communication outside the site.
- All devices must use the same radio channel.
myenergi offer pedestals that hold two zappis mounted back-to-back. This suits sites with two chargers in one spot, such as a shared car park or driveway.
Limitations
- CTs hard-wired to the device: load balancing up to 100 A per phase.
- CTs connected through a harvi: load balancing up to 65 A per phase.
- One zappi set as Load Controller is able to pair up to 4 secondary zappis
Pairing devices
There are three different roles that the devices can have:
The Load Controller manages the group
The Secondary Device follows instructions from the Load Controller
The Gateway Device connects to internet and handles communication outside the site.
The Load Controller and Gateway Device (vHub-enabled) do not need to be the same device. If one zappi is closest to the switchboard, and another zappi is closest to the network router, you can make the zappi closest to the switchboard the Load Controller, and the zappi closest to the router the Gateway device
Pairing links your myenergi devices into one eco-system, so they can share information and work together. Every device pairs with the Load Controller. Devices can connect in three ways: radio (RF), Wi-Fi or Ethernet.
Radio Frequency (RF)
- Devices talk to each other directly over 868MHz o 915MHz radio. No router or internet is needed.
- Keep every radio-paired device within 15 metres of the Load Controller. Do not go beyond this.
- Walls, metal and other obstructions can reduce the range, so allow some margin when you choose where to mount each device.
- All devices must use the same radio channel.
- Radio pairing is off by default. Turn it on in Installer Settings, then Communications Mode, before you pair (see below).
Wi-Fi
- Use Wi-Fi when radio pairing is off, or when a device is too far from the Load Controller for radio.
- All devices must be connected to the same 2.4GHz network.
- A strong, stable Wi-Fi signal at each device is important. Check it before you start.
Ethernet
Use Ethernet where you have a wired connection available. It is the most stable option, because it doesn't depend on Wi-Fi signal or radio range. As with Wi-Fi, all devices must be on the same network.
A note on terminology
We've updated the terms used in our products and documentation to be more inclusive and to better describe what each device does. You may still see the old names in older manuals, videos, forum posts and device menus, so here is how they match up:
- Load Controller (formerly Master)
- Secondary Device (formerly Slave)
- Gateway Device (formerly vHub Device)
Related article: Pairing Devices
Three-phase sites: managing phase rotation
A single-phase EV connected to a three-phase zappi always draws from the zappi's L1 phase. With more than one zappi, every charger can load the same phase while the other two sit idle. This can overload that phase.
To spread the load, set a different phase rotation on each zappi, so each zappi's L1 terminal corresponds to a different supply phase.
Related article: Managing Phase Rotation and CT Connections for Three-Phase zappi Installations
Paid charging (multi-user and commercial sites)
If your customer wants to charge drivers for using the zappis, for example at an apartment building, workplace or business, there are some things to know first.
The zappi was not designed for paid charging. It can be integrated with paid charging through OCPP and a third-party platform, but the platform is not a myenergi product.
How it works:
- When a zappi is connected via OCPP, the Charge Point Operator (CPO) takes over management of the zappi. The zappi then works as hardware only.
- The CPO's platform handles the charging, pricing and payments, not the zappi's own settings.
Who to contact:
- Any troubleshooting of paid charging must be coordinated with the CPO.
- myenergi is only responsible for the zappi hardware once it is connected to a CPO.
Costs:
- A CPO may charge ongoing fees for access to their platform. Make sure your customer knows about these before you set up paid charging.
Before you commit to a paid charging setup, check with the CPO what they support and what it will cost.
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