Please note this is advice for Amber customers involved in the ARENA project only. Full support of Zappi chargers for all Amber customers will be announced in time.
Amber for EVs (A4EVs) is all about making your EV charging smarter and simpler, allowing you to make the best use of your own solar and cheap grid prices.
It's purposely-designed to get you as many free or super-cheap charging opportunities as you can get.
And the tech is also free to take advantage of for Amber customers!
Some of the key benefits of using Amber for EVs with your Zappi include:
- Easy excess solar charging: a smart way to get more free kilometres - A4EVs enables you to charge from your excess solar only (if you have it).
- Charge at the cheapest times: Automatically take advantage of times when energy from the grid is cheapest and greenest (handy if your solar falls short, or if you don't have solar)
- Smart battery coordination: We're Australia's most popular battery manager and so it only made sense we make an EV charging solution that works well with your home battery (if you have one).
How it works
A4EV's can switch your Zappi between modes - ECO+ (solar-only) and FAST (max-rate) automatically.
The Zappi will be kept in ECO+ to use excess solar where possible. In this mode, charging pauses if excess solar drops below the minimum charge rate (about 1.5 kW on single‑phase; ~4.5 kW on three‑phase), and resumes when excess solar rises again.
In some situations Amber will override to FAST or STOP charging, in this priority order:
- Charge Until Disconnected (manual override in Amber) → FAST
- Grid usage price falls below your Opportunity Charge Price → FAST
- Inside a charge schedule window (and, if set, price is below your Max Price) → FAST
- Feed‑in price (FiT) rises above your Maximum Feed‑in (optional setting) → STOP (so you can export instead)
- All other times → ECO+ (excess‑solar only)
When you first plug in, the Zappi may start in FAST briefly from a previous session; Amber usually switches it to ECO+ within ~1 minute.
Amber supports ECO+ for automation. You can use ECO manually if you prefer, however you may experience issues when also using Amber for EVs due to competing controls.
Charging from the grid
If the live price drops below the price threshold you set, Amber switches your Zappi to FAST so you charge quickly at the cheap rate.
If you’ve also set a Charge Schedule, Amber will charge FAST within that window (and only if price is below your Max Price cap, if set).
Charging from the grid rules take priority over solar‑only charging.
To charge when the price is cheap, in the A4EV settings you can:
- Set your Opportunity Charge Price (c/kWh threshold for cheap grid charging).
- Add a Charge Schedule and a Max Price cap for that window.
- Manually charge for a set period of time, when you think the price is cheap.
Solar Charging - Equipment Requirements
To use Zappi solar charging with Amber, your Zappi must be installed to support ECO and ECO+ mode charging. In particular:
- a Zappi CT clamp must be connected on your home’s supply cable(s)
- a Zappi CT clamp on your solar inverter cable is optional
Most Zappis are installed in this way on homes with solar.
If you have been using your Zappi in ECO or ECO+ mode then it meets the requirements to work with Amber.
To charge from solar, in the A4EV settings you can
- Turn on Excess Solar charging
- Set a maximum feed in tariff (optional - but a good idea if you want to export when you'd be paid a lot to do so)
Solar curtailment
If you have you have a solar inverter connected to SmartShift that supports curtailment, Amber will curtail (ie reduce or stop) your inverter’s solar generation when the grid feed-in price (FiT) is negative.
However, this curtailment would prevent the Zappi from charging from solar as there would be no excess solar detected by the Zappi.
To allow solar charging during periods of negative FiT, Amber will disable curtailment automatically when the following is true:
- the EV is plugged in and can accept charge (ie the battery has not reached the charge limit)
- solar charging is enabled and no other feature is causing charging at max power (eg the Opportunity Price feature)
The Amber app will show a message when curtailment has been paused to allow solar charging.
Please note that it can take 5 to 10 minutes to enable or disable curtailment depending on your inverter.
Solar charging may cause some unwanted exports
If your solar system can generate more power than your EV charger can deliver then you may experience some unwanted exports during solar charging.
For example, consider the following situation:
- solar generation: 7 kW
- household load: 1 kW
- EV load: 3.5 kW (max power)
- grid exports: 2.5 kW (7 - 1 - 3.5) (unwanted if feed-in is negative)
Since it’s not possible to perform solar charging whilst curtailment is enabled, this situation involves a trade-off. Charging the EV from solar generally means you don’t have to charge the EV from the grid at another time, thus avoiding import costs. But it may mean you incur a small loss due to the “spilled exports” during negative FiT.
In most cases, the benefit of solar charging will significantly outweigh the cost of the “spilled exports”. For example, consider solar charging for 3 hours with the power flows described above:
- assume the price to charge the EV from the grid at another time is 15 c / kWh
- charging the EV from solar thus avoids costs of 3.5 kW * 3 hours * 15 c / kWh = $1.58
- assume the negative FiT price is -4 c / kWh (in most cases, the negative FiT is closer to zero than this)
- the “spilled exports” at negative fit incurs a cost of 2.5 kW * 3 hours * 4 c / kWh = $0.30
In this example, it is better to charge from solar despite the small cost of the unwanted “spilled exports” during negative FiT, since the benefit of $1.58 is greater than the cost of $0.30.
Battery coordination
If you have a home battery, the way Zappi solar charging works depends on whether you have an AC-coupled battery (eg Powerwall) with a Zappi CT clamp attached, or not.
AC-coupled with Zappi CT clamp
When the Zappi has a CT clamp attached to an AC-coupled battery, an advanced setting is available on the Zappi that controls how the Zappi interacts with the battery.
The choices are as follows (from the Zappi User Guide):
The setting is adjusted on the Zappi’s control panel, under Advanced → Supply Grid → Battery.
The default PIN to access the settings is 0000.
DC-coupled or no CT clamp
If your home battery is DC-coupled, or it’s AC-coupled but there is no Zappi CT clamp installed on it, you can make some setting changes on the Zappi to prevent it from charging the EV from your home battery.
This video explains how to setup your Zappi to avoid discharging your DC-coupled home battery into your EV when solar charging: https://www.youtube.com/watch?v=ZbfSrsR8iwQ
Configuring your Zappi per the above video will ensure that:
- the home battery will charge from excess solar before the Zappi does
- the Zappi will not discharge the home battery into the EV
The disadvantage of setting an Export Margin is that it will lead to continuous grid exports of 100W when solar charging. However this should be outweighed by the advantages.
Default behaviour
If the changes described above have not been made to your Zappi, then the behaviour will be unpredictable: the Zappi will sometimes charge from the home battery, and sometimes not. Usually the home battery will charge from excess solar first, but sometimes the Zappi will.
SmartShift battery dispatch
If your home battery is connected to Amber SmartShift, there is an additional consideration.
During periods when SmartShift instructs your home battery to discharge to the grid to take advantage of high feed-in prices, the Zappi will see this as excess solar and will start charging the EV, even if you have set an Export Margin. To prevent this, you can either unplug the EV or use the manual control in the EV section of the Amber app.
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