Myenergi Zappi: The Solar EV Charger

What makes the Zappi different?

Most EV chargers are simple devices: they deliver power from the grid to your car. The Myenergi Zappi does something fundamentally different — it monitors your solar generation in real time and diverts surplus solar power to your EV.

Without a Zappi (or similar solar-aware charger), your surplus solar exports to the grid at SEG rates — around 12p/kWh as of early 2026. With a Zappi in Eco+ mode, that same surplus charges your car. Since grid electricity costs ~24p/kWh, every kWh diverted to your EV instead of exported saves you 12–14p.

Over a year, for a typical solar household with an EV, this can add up to meaningful savings — and a much lower cost per mile.

The three charging modes

Fast mode

Full-power charging from the grid, ignoring solar generation entirely. Use this when you need the car charged quickly and don't care about optimisation. The Zappi draws the maximum your supply allows (7kW single-phase, up to 22kW three-phase).

Eco mode

The Zappi uses surplus solar first, then tops up from the grid to maintain a minimum charge rate. This is the practical everyday mode. If your panels are generating 2kW surplus, the Zappi uses that 2kW from solar and draws ~4kW from the grid to maintain a steady charge.

The minimum charge rate is 1.4kW (6A at 230V) — below this, EV charging protocols won't function. Eco mode ensures you always charge at least this minimum.

Eco+ mode (pure solar)

The Zappi only charges when there's enough surplus solar to meet the minimum 1.4kW threshold. No grid electricity is used at all. When a cloud passes and surplus drops below 1.4kW, charging pauses. When the sun returns, charging resumes.

This mode maximises your use of free solar electricity but charges more slowly and unpredictably. On a sunny summer day with a 4kWp system, you might add 15–25 kWh to your EV (50–80 miles of range). On a cloudy day, you might add very little.

How the CT clamp works

The Zappi needs to know how much solar surplus is available. It gets this information from a CT (current transformer) clamp — a small sensor that clips around your main electricity supply cable.

The CT clamp measures the net flow of electricity at your meter point:

• Negative flow = you're exporting (surplus solar) → Zappi can use this for charging
• Positive flow = you're importing (using more than panels generate) → Zappi knows not to draw grid power in Eco+ mode

Installation of the CT clamp is straightforward but must be done by a qualified electrician, usually as part of the Zappi installation.

If you have a Myenergi Eddi (hot water diverter) as well as a Zappi, they share the CT clamp and prioritise surplus solar between them based on your configured priorities.

Specifications and versions

Most UK homes are single-phase, so the 7kW version is the standard choice. The 22kW three-phase version is for homes with a three-phase supply — typically larger properties or those with specific electrical requirements.

Tethered vs untethered: The tethered version has a permanently attached cable — more convenient (no plugging in a cable each time). The untethered version has a socket — better if you have multiple vehicles with different connector types, or want a tidier look when not in use. See our full comparison.

myenergi Zappi 22kW EV Charger

£780

max charge rate kw

22

single phase kw

7.4

three phase kw

22

modes

fast,eco,eco_plus

View on Amazon

Affiliate link — we may earn a small commission at no extra cost to you

Installation and costs

Unit cost: £800–£1,100 depending on version and retailer Installation cost: £300–£500 depending on cable run distance and electrical work needed Total installed cost: £1,100–£1,600

Installation must be done by a qualified electrician and should comply with BS 7671 (IET Wiring Regulations). The OZEV grant can contribute up to £350 toward the cost if you qualify.

The installation includes:

• Mounting the Zappi on an external wall (usually near your consumer unit or driveway)
• Running the electrical supply from your consumer unit
• Installing the CT clamp on your main supply cable
• Configuring the Myenergi Hub for smart features and app connectivity
• Testing and commissioning

Real-world solar charging performance

Summer scenario (4kWp system, sunny day):

• Solar generation: 20kWh over the day
• Household consumption: 8kWh
• Surplus available for EV: 12kWh
• Zappi Eco+ charges: ~12kWh (about 40 miles of range)
• Cost: £0

Winter scenario (4kWp system, overcast):

• Solar generation: 3kWh
• Household consumption: 10kWh
• Surplus: 0kWh
• Zappi in Eco+ mode: no charging
• Switch to Eco or Fast mode, charge from grid

Annual solar EV charging on a 4kWp system: approximately 1,200–1,800 kWh (depending on your driving pattern and how often the car is home during solar hours). At avoided grid rates of ~24p/kWh, that's £288–£432 of free fuel per year.

Zappi vs standard EV chargers

A basic 7kW charger costs £400–£700 installed. The Zappi costs £1,100–£1,600. Is the premium worth it?

The £400–700 premium buys you:

• Solar-aware charging (Eco and Eco+ modes)
• Smart scheduling via app
• Integration with Intelligent Octopus Go
• Energy monitoring
• Compatibility with Eddi for whole-home solar management

Payback on the premium: If the Zappi diverts 1,500 kWh of solar to your EV annually (instead of exporting at 12p), the value of that diverted solar is ~1,500 × 12p (24p saved minus 12p lost export) = £180/year. The £500 premium pays back in under three years.

Complete your myenergi solar ecosystem with the Eddi for hot water diversion:

myenergi Eddi Solar Diverter

£185

max power w

3000

modes

power_divert,timed_boost

outputs

2

priority

configurable

View on Amazon

Affiliate link — we may earn a small commission at no extra cost to you

Ohme Home Pro 7.4kW EV Charger

£600

max charge rate kw

7.4

modes

smart,scheduled,manual

solar divert

false

wifi

true

View on Amazon

Affiliate link — we may earn a small commission at no extra cost to you

Tips for Zappi owners

1. Park your EV during peak solar hours — if you work from home or can charge during the day, Eco+ mode harvests the most free solar
2. Use scheduling for overnight top-ups — if solar didn't fully charge the car, schedule a grid top-up during cheap overnight tariff hours
3. Set priorities with Eddi — if you have both a Zappi and an Eddi, decide which gets surplus solar first. EV charging is typically more valuable than hot water heating
4. Connect the Hub — don't skip the Myenergi Hub. Remote monitoring and smart tariff integration add real value
5. Keep firmware updated — Myenergi regularly releases updates that improve solar tracking algorithms and add new features

Share this article