Zappi, Hypervolt or Ohme: the right EV charger for a solar home in Scotland

We all want the easy win. Free miles from your own roof. A charger that behaves. An app that doesn’t nag. A cable long enough to reach the car without a wet shuffle in your slippers.

Easy to want. Harder to live with the trade‑offs: the pauses when a cloud parks over Stirling, the odd firmware foible, the 60 A main fuse that won’t budge, the CT clamp (a clip‑on current sensor) that only works if it’s actually on the right tail. That’s the real test of a charger in Scotland.

What matters for us in Scotland

• DNO rules and export caps. Most single‑phase homes sit under G98 at 3.68 kW export unless you’ve got G99 or an export limiter. Your charger, inverter and battery need to cooperate or you’ll be chasing nuisance trips.
• Weather and siting. Mostly wet and windy with the odd sunny spell. Aim for IP65–IP66 (weather‑resistant enclosures). Shade dark housings where you can. Keep cable glands (sealed cable entries at the box) and drip loops (a downward loop so rain drips off before the box) neat to avoid problems later.
• Small supplies and flats. Looped services and 60 A fuses are common. Dynamic load management (automatic power throttling) isn’t a nice‑to‑have; it keeps the lights on. Sometimes we cap to 16 A if an upgrade isn’t realistic.
• Cable length. Scottish driveways are often a touch longer than standard leads. Hypervolt’s 7.5 m and 10 m tethers solve real issues. Zappi comes tethered or untethered. Ohme is usually 5 or 8 m.

The chargers

MyEnergi Zappi v2.1

Why folk pick it: it’s built around solar. ECO blends grid and PV. ECO+ waits for true surplus and pauses when the sky turns grey. The floor is about 1.4 kW, so smaller arrays still dip into the grid unless you let ECO+ stop and start.

What to get right: CT placement (where the current sensor sits). In a PV + battery home, the import/export CT needs to see the whole house, not just the battery leg. Get that wrong and your battery quietly feeds the car and your “free miles” aren’t free. We often add a mini consumer unit (small fuse board) to keep things tidy and serviceable.

Protection and build: integrated open‑PEN (built‑in earthing fault protection) and 6 mA DC detection (RDC‑DD) on board; Type A AC protection is provided in the installation. No earth rod for typical houses. UK‑made, IP65, 7 kW single‑phase or 22 kW three‑phase. The 2.1 revision has Wi‑Fi built in. Note: MyEnergi have moved to a “2.1 Multiphase” range—22 kW units can be set in firmware for single‑ or three‑phase use.

Day to day: the buttons and small screen are handy when your phone’s inside. The app’s plain but dependable. If it has to live on a sun‑soaked south wall, pick the white casing or give it a bit of shade.

Hypervolt Home 3 Pro

Why folk pick it: it’s solid kit and the app is genuinely usable. Solar modes are simple: Super Eco (solar‑only), Eco (blend), Boost (just get charge). It supports CTs for load limiting (protects your main fuse); fit a second CT on the PV leg if you want a clearer picture of what’s going on.

What to get right: hard‑wire the CT data on longer runs. EV Ultra (power and data in one) keeps things clean and avoids flaky readings. On 60 A services and flats, set firm limits and test them before we leave.

Protection and build: integrated open‑PEN, IP66 enclosure (good weather protection), UK‑made. Tethered only, with 5, 7.5 and 10 m options. That extra reach often seals the deal.

Day to day: schedules are clear, the stats are useful, and you can dim the LED ring if it shines into a bedroom. It feels sorted.

Ohme Home Pro

Why you may pick it? tariffs. If you live on Octopus Go or Intelligent Go, Ohme makes life easy. The small screen on the unit helps when you are not on the app.

It can use a CT and be solar aware, but it’s not a full diverter like Zappi. If solar is the main use, use the right tool. If it’s a not then Ohme’s fine.

What to get right, the CT clamp (the clip‑on sensor that measures current). Load balancing (auto‑throttling to protect the main fuse) without a good reading often leaves you stuck around 16 A. Fit it, face it the right way, check the numbers. Most “slow charge” issues end there. If everything looks right and it still won’t budge past ~16 A, check for a firmware update in the Ohme app or raise a ticket, an earlier version briefly caused this and was fixed over the air.

Protection and build: open‑PEN compliance is handled in the wider install design (earthing and protective devices as per the site). For flats and tariff‑first homes, day to day ownership is straightforward.

How to decide without overthinking it

• “I want my car to eat surplus solar, even if it pauses when a cloud parks over.” Then choose Zappi v2.1. Use ECO+ on steady days. If your car hates frequent restarts, widen the ECO+ thresholds or use ECO on patchy days.
• “I want one unit that does most things well, with a long cable and a solid app.” Then choose Hypervolt Home 3 Pro. Ask for two CTs if you want both load limiting and PV visibility. Go 7.5 or 10 m if the car sits a stretch away.
• “I’m chasing cheap night rates and I don’t want to babysit schedules.” hoose Ohme Home Pro. That’s its sweet spot. Make sure the CT is in and reading.

Making PV, batteries and the EV connect nicely

• Start with CTs (current sensors). Put the import/export CT on the main tails so the charger sees the real surplus. Add a PV CT where supported. Don’t clamp only the battery leg or you’ll empty stored kWh into the car without meaning to.
• Respect export limits. Under G98 you are capped at 3.68 kw export unless you’ve got G99 or a limiter. We set inverter and charger limits and note them for SPEN/SSEN (your local DNOs).
• On Octopus Go or Intelligent Go. With Zappi or Hypervolt, schedule the car in cheap hours and keep the home battery for the evening peak. With Ohme, let the app organise it, but still check your car and charger show as compatible in the app.

Flats, tenements and tight supplies

• Looped or 60 A mains. Turn on dynamic load management (automatic current limiting) from day one. If an upgrade isn’t happening, a 16 A cap can be the right call. Better that than a blown main fuse in January.
• Long cable runs. Use EV Ultra (power and signal in one cable) to keep power and CT/data together. Fewer boxes, fewer gremlins.
• No PV (yet). In tenements and flats, go for tariff control and a clean, durable install. Ohme is great here. Hypervolt is close if you want the longer tether. Zappi still makes sense if you’re future‑proofing.

Other chargers we fit

• Pod Point Solo 3. Straightforward and reliable. Not a solar diverter, but it fits a lot of homes and budgets.
• Wallbox Pulsar Max. Compact, with dynamic load balance and solar via add‑ons if you use the right meter/CT.
• Tesla Wall Connector (Gen 3). Ideal for Tesla owners and very tidy installs. Best inside the Tesla ecosystem, especially if you plan on “Charge on Solar.”

If you’re torn between two options, we’ll come out, look at your supply, your PV and battery layout, and how you park. We’ll match the box to the house, not the other way round.

FAQs

Last checked: 2025-09-06. Features and firmware move on; we’ll keep this page current.

Serving Central & West Scotland: Stirling, Perth, Falkirk, Dunbartonshire, Glasgow and beyond.