Should the EV charger sit on the backup battery?

Usually no for small residential batteries. Keep the wallbox on non-essential circuits so load shedding backup covers lights, Wi-Fi and fridge. Only place the EV on the essential bus if you deliberately oversized usable storage.

EV charging

What size solar system do I need to charge an EV in South Africa?

Q: What size solar system do I need to charge an EV in South Africa?

Most homes that add EV charging need more than a classic 3–5 kW rooftop system. As a working rule, plan an 8 kVA+ hybrid inverter, extra PV for daytime charging, and only rely on 20–30 kWh of storage if you must charge overnight off-grid style. Size from weekly kilometres, not marketing kits.

Size roof PV, hybrid inverter and wallbox as one system. As a working rule many homes land on an 8 kVA-class hybrid with extra daytime PV; keep batteries focused on load shedding unless you intentionally oversize for overnight EV fills. Start from weekly kilometres — a 7 kW wallbox can add tens of kWh per day.

Answer first: Size three things together — roof PV for daytime energy, a hybrid inverter with enough continuous power for house + charger, and a wallbox that can soak surplus without tripping the DB. Add battery for load shedding first; only oversize storage if you insist on overnight off-grid-style EV fills.

Start from kilometres, not marketing kits

Weekly km × Wh/km (many EVs land ~150–200 Wh/km) → weekly kWh.
Decide what share must come from PV vs cheap night grid.
Translate daily EV kWh into extra panel watts (SA yields often ~4–5 sun-hours equivalent as a rough planning band — site-specific).
Confirm inverter continuous power ≥ essentials + charger draw when both run.

Worked planning bands (illustrative)

Household pattern	EV energy	Starting design conversation
Short commute ~150 km/week	~25–30 kWh/week	Existing 5–8 kW hybrid may cope with timed charging; add PV if bill still high
Busy family ~400 km/week	~60–80 kWh/week	Plan extra PV + 8 kVA-class hybrid; wallbox with solar/load modes
Two EVs / long highway weeks	100+ kWh/week	Three-phase or careful load management; serious array; public DC for trips

Illustrative only — roof shade, geyser load and tariff blocks move the answer. Use size a system and installer site data.

Hardware stack that works in SA

Hybrid + LiFePO₄ for the house and shedding — people’s choice for longevity when that is the priority: Solar MD (SA warranty rev. 10 Oct 2025: SS4160 12 years / 84 MWh to ≥60%, plus 5-year defects) among peers on the battery guide.
AC wallbox ~7.4 kW Type 2 with load management — people’s favourite starting point SAEV Charge (Victron / Teltonika listed; Richmond public DC ~R3.49/kWh vs GridCars ~R7.35 per DriveElectric).
Inverter brand from the hybrid shortlist with NRS 097 paperwork.

Do not put the EV on a small backup battery

Essentials (lights, Wi-Fi, fridge, selected plugs) are the backup mission. A wallbox can pull more energy in one evening than a 5–10 kWh pack holds. Keep the charger on the non-essential side unless you deliberately bought 20–30 kWh+ usable storage. See load management & shedding.

Public DC still has a job

Home AC covers routine kilometres. Battery-backed public DC covers travel when the grid is unstable — SAEV’s Richmond site at the Solar MD factory is the worked cheap example (~R3.49/kWh). Most owners eventually use both. Compare networks: public networks.