Why the myenergi Zappi Is the Best EV Charger for Solar Panel Owners

If you have solar panels on your Scottish home, or you are planning to add them, the EV charger you fit matters far more than most homeowners realise. The wrong charger will simply pull from the grid like any other appliance. The right one will route your free, self generated solar electricity straight into your car. The myenergi Zappi EV charger and solar panels combination is the gold standard for this in 2026, and this guide explains exactly why, how it works, and what it saves a typical Scottish household across a year.

Why solar plus EV is such a powerful combination

Solar PV and electric vehicles are good on their own. Stacked together they are something else entirely. The key insight is timing. A typical Scottish household uses very little of its solar generation while the panels are actively producing. Most occupants are out at work or school during the peak generation window, lights are off, the dishwasher and washing machine are usually off, and the home draws maybe 200 to 400 watts from the panels for fridges, routers, and standby loads.

That leaves a huge amount of generated solar surplus during sunny hours. By default, that surplus is sold back to the grid via the Smart Export Guarantee at roughly 4p to 15p per kWh. Useful, but not a great deal. The same kWh used in your home is worth 27p to 32p, the price you would otherwise pay your energy supplier.

An EV gives you somewhere to put that surplus. A typical Scottish family car needs 12 to 15 kWh per day to cover an average commute. A 4 kW solar array on a sunny Aberdeenshire afternoon can produce 3 kW of surplus for 4 to 5 hours. That is enough to feed almost an entire day’s commute back into the car, for free. The Zappi is the unit that makes this happen automatically, with no thinking required from you.

For a wider charger comparison covering all three of the units we install most, see our breakdown of Zappi vs Ohme vs Easee.

The Zappi feature that changes everything: Eco+ mode

Every smart EV charger can schedule charging to off peak hours. The Zappi can do that too. What sets it apart is its three charging modes, and specifically the third one.

Fast mode

This is the default behaviour of any home EV charger. The Zappi pulls a fixed current from the grid (up to 7 kW on single phase, up to 22 kW on three phase) until the car is full. No interaction with solar at all.

Eco mode

The Zappi watches your home’s net export to the grid through a small CT clamp around your meter tail. When it sees surplus solar being exported, it adds that surplus into the EV charge cable. When other appliances kick in (kettle, oven, electric shower), it backs off so the home draws from solar first. The car always gets charged eventually, even if it has to top up from the grid at the end.

Eco+ mode

This is where the magic happens. In Eco+ mode, the Zappi will only charge the car when there is genuine solar surplus available. The moment the surplus drops below a configurable threshold (typically 1.4 kW, the minimum the J1772 charging standard allows), the charger pauses. As soon as the surplus comes back, charging resumes. The car only charges from your roof. Zero grid electricity.

For a Scottish solar owner, Eco+ mode is the difference between a charger that costs you 7p per kWh on a smart tariff and a charger that costs you nothing at all on bright days. Across a sunny Aberdeenshire summer week, an Eco+ Zappi can deliver 200 to 400 free miles into the EV.

How solar diversion actually works

Under the bonnet, solar diversion is simpler than it looks. The Zappi installer fits a small CT clamp (a current transformer) around the meter tail going into the consumer unit. That clamp measures the direction and magnitude of current flowing past the meter. When current is flowing out of the house (export, surplus solar), the Zappi knows there is excess generation. When current is flowing in (import, drawing from the grid), the Zappi knows the home is consuming more than it produces.

The Zappi’s onboard logic uses that signal to modulate the EV charging current dynamically. It can adjust in real time, every few seconds, so when a kettle boils for 3 minutes, the Zappi notices, drops the EV charge rate to compensate, and ramps back up when the kettle clicks off. The car driver sees nothing. The energy meter logs nothing extra. The home runs as normal.

This level of dynamic load management is what separates the Zappi from a basic smart scheduler. A scheduler can charge during a fixed window. It cannot react to a cloud passing overhead, a kettle boiling, or your neighbour deciding to start a load of laundry on a shared meter.

Real Scottish numbers: a 4 kW solar array plus Zappi

Let us run a worked example for a typical Aberdeenshire family. South facing 4 kW solar array, generating roughly 3,400 kWh per year (the actual figure varies by location, with better outputs in coastal areas with clearer skies and worse outputs inland). Two adults working at home or hybrid. One EV doing 10,000 miles per year, requiring around 3,000 kWh of charging.

Without the Zappi

The home consumes roughly 35 percent of its solar generation directly during the day, exports 65 percent back to the grid at the Smart Export Guarantee rate of around 8p per kWh. The EV charges entirely from the grid, off peak, at around 7p per kWh on Octopus Go.

• Solar self consumption: 1,190 kWh saved at 28p per kWh = £333.
• Solar export: 2,210 kWh sold at 8p per kWh = £177.
• EV charging cost: 3,000 kWh at 7p per kWh = £210.
• Net annual position: minus £210, plus £510 of solar value = positive £300.

With a Zappi in Eco mode

Solar self consumption rises to roughly 65 percent, because the Zappi diverts surplus into the EV instead of exporting it. EV charging draws less from the grid.

• Solar to EV via Zappi: 1,400 kWh, replacing 1,400 kWh of grid charging, saving 1,400 × (28p minus 8p export rate avoided) = £280.
• Reduced grid EV cost: 1,600 kWh × 7p = £112 (instead of 3,000 × 7p = £210).
• Annual saving versus no Zappi: roughly £200 to £300.

That saving compounds across the 8 to 12 year ownership of a charger and an array. Across a decade, a Zappi delivers thousands of pounds of additional value to a Scottish solar household compared with a non solar friendly charger. For a wider Scottish solar context, see our forthcoming guide on whether solar panels work in Scotland.

Other Zappi smart features beyond solar

Solar diversion is the headline feature, but the Zappi has a long list of useful capabilities that benefit any household, solar or not.

• Smart tariff scheduling. The Zappi can schedule grid charging to your tariff’s off peak window, even on Octopus Go, EDF GoElectric, British Gas EV, and most other UK smart tariffs.
• Boost mode. If you forget to plug in early and need a guaranteed top up before you leave, Boost mode forces a charge regardless of solar status.
• Time of use plus solar. The Zappi can layer scheduled grid charging on top of solar diversion, so the car gets free solar during the day and tops up off peak overnight.
• Eddi compatibility. If you also have a myenergi Eddi solar diverter feeding your hot water cylinder, the Zappi and Eddi coordinate so neither competes for the same surplus. Hot water and EV charging both benefit.
• Hub and remote monitoring. The optional myenergi Hub gives you remote monitoring of the entire home energy system from anywhere with internet access.
• Built in O PEN protection. Most homes do not need a separate earth rod, which simplifies the install.

Setting up a Zappi with solar: what is involved

A standard Faithful Spark Zappi install for a Scottish solar home looks like this on the day.

1. We arrive, confirm the parking and cable route, and isolate the consumer unit.
2. We fit the dedicated 32A circuit from the consumer unit, with the correct RCD protection (typically Type A) per BS 7671 18th Edition.
3. We mount the Zappi on the wall and complete the cable termination.
4. We fit the CT clamp around the appropriate meter tail. For most homes this is the live tail going into the consumer unit. For homes with the solar inverter on a separate circuit, we may also fit a second CT clamp on the inverter output.
5. We commission the unit, walk you through the app, and demonstrate Eco, Eco+, and Fast modes by triggering each one with the EV plugged in.
6. We notify the install through NICEIC to Building Standards and email you the Electrical Installation Certificate.

The whole job typically takes 4 to 5 hours for a single phase domestic install. Three phase Zappi installs (less common) typically take 5 to 7 hours.

Common solar plus Zappi questions we get on site

Three things come up at almost every solar plus EV survey. Worth covering them upfront.

“My solar is on a separate consumer unit. Will Eco mode still work?”

Yes. The CT clamp can be fitted on either the meter tail (measuring net import or export) or directly on the inverter output. We will pick the right configuration during the survey based on your wiring layout. The result is the same: the Zappi sees solar surplus and acts on it.

“Can the Zappi use battery storage as well as solar?”

Yes, with a configuration choice. By default, the Zappi will divert surplus to the EV before it hits a home battery. If you would prefer the home battery to fill up first and then the EV, we can configure the priorities accordingly. Most Scottish solar plus battery homes opt to charge the home battery first, the EV second, with both happily filled on a typical sunny summer day.

“What happens in winter when there is no solar surplus?”

Eco+ pauses charging. Eco still tries to use any surplus available, even small amounts, but most charging shifts to the grid. We typically configure a smart tariff schedule on top, so winter charging is still off peak and cheap. You get the best of both worlds across the year.

Frequently asked questions

Can I add a Zappi later if I already have solar?

Absolutely. Many of our Aberdeenshire customers had solar fitted years ago and are only now adding an EV. The Zappi simply needs the CT clamp on the right cable. No changes to the solar inverter or panels are required.

Does my solar inverter brand matter?

No. The Zappi works with any inverter brand because the CT clamp measures current at the meter, not at the inverter. SolarEdge, GivEnergy, Solis, Growatt, Tesla, Sunpower, Enphase, all are compatible.

Can I install a Zappi if I do not yet have solar but plan to add it?

Yes, and this is increasingly common. We fit the Zappi now in Fast or smart tariff scheduled mode, then when solar is added later, the same CT clamp is repositioned to enable Eco and Eco+ modes. Faithful Spark can carry out both jobs as one connected project.

How much surplus solar do I need for Eco+ to be worth using?

The minimum charging current under the J1772 standard requires roughly 1.4 kW of available surplus. Most 3 kW or larger Scottish arrays will reach this threshold for several hours per day from spring through autumn.

Will my Zappi affect my Smart Export Guarantee payments?

Yes, modestly. Diverting surplus into the EV instead of exporting it reduces your SEG income. But the value of using that energy in your car (saving 28p per kWh of grid electricity) is much higher than the value of exporting it (8p per kWh on most SEG tariffs). You come out well ahead.

How long do Zappi units last?

The Zappi v2 has been on the market since 2020 and the original Zappi since 2017. We have seen field units running cleanly past their 5 year mark with no issues, and myenergi expects 8 to 12 year operational life with normal maintenance.

Do I need a special tariff to use a Zappi?

No. The Zappi works on any tariff, including standard variable. For solar diversion, the tariff is irrelevant because you are using your own electricity. For overnight grid top ups in winter, a smart EV tariff like Octopus Go pays back fastest.

Book a Zappi plus solar consultation

If you would like a free, no obligation Zappi quote, whether you already have solar or are planning to add it, get in touch. We will assess your supply, your existing setup (or planned setup), and recommend the right Zappi configuration for your home. Across Aberdeen, Peterhead, Ellon, Fraserburgh, and the wider Aberdeenshire area, the Zappi remains our most installed charger for solar households, and the easiest unit to set up correctly.

Book My Zappi Plus Solar Consultation

Faithful Spark Electricians. NICEIC approved. OZEV listed. myenergi authorised installer. Serving Aberdeen, Peterhead, Ellon, Fraserburgh and across Aberdeenshire.