EV / Backup
Generator vs hybrid solar — which should power my EV in South Africa?
For everyday kilometres, a hybrid solar + battery + AC wallbox is almost always cheaper per kWh than a diesel or petrol generator. Keep a generator (if at all) for rare deep backup — not as your daily “EV fuel.” Fuel cost, noise, maintenance and CoC reality all argue against genset-as-charger.
Updated 27 October 2026 · Illustrative ranges — not a formal quote, tax ruling or legal advice.
Answer first: An EV shifts energy demand from petrol stations to your DB. Meeting that demand with a generator turns cheap electrons into expensive, noisy fuel. Size solar and storage for commuting kWh first; treat the genset as a contingency for multi-day grid failure if you truly need it.
Cost per 100 km (directional)
A commuting EV using ~16–18 kWh/100 km:
- Home / workplace AC on metro rates ~R3.30–R4.70/kWh: roughly R53–R85 per 100 km.
- Solar self-use: often far below that once the system is paid — you are burning surplus PV instead of exporting at ~108–185 c/kWh credits.
- Public DC: commonly ~R6–R8/kWh on many apps (with outliers such as reported SAEV Richmond ~R3.49/kWh).
- Small diesel generator: fuel alone often lands several rand per kWh after efficiency and partial-load penalties — easily worse than grid, before oil, servicing and the capital cost of the genset. Measure litres × fuel price ÷ kWh delivered; do not trust brochure “prime power” at ¼ load.
When a generator still makes sense
- Farms / clinics that must ride multi-day outages beyond battery autonomy.
- Buildings where solar roof area is blocked and NMD upgrades are years away.
- Temporary site power during construction — not as the long-term EV fuel plan.
Even then, prefer auto-start gensets on the essentials board with proper changeover (ATS), CoC and ventilation — ATS / changeover. Do not back-feed the municipal grid through a DIY changeover.
Hybrid solar + wallbox pattern (default)
- ~7.4 kW Type 2 wallbox on a dedicated circuit with load management — home charger cost.
- Hybrid inverter + LiFePO₄ sized so daytime PV covers house + a chunk of charging.
- Charge the car on surplus first; avoid draining the house battery into the EV unless designed that way — charge EV from solar.
- Register SSEG; keep CoC. Generator (optional) only on non-paralleled essentials with interlock.
Fleet / workplace twist
Diesel-generating a DC depot “because the NMD is tight” is usually the wrong first move — load management, overnight AC diversity, PV carports and battery-buffered DC deserve a spreadsheet first (fleet charging). Fuel logistics for ten vans on genset power will show up on the P&L immediately.
Fuel arithmetic you can repeat at home
Example method (plug in your numbers): a generator that burns 1.5 ℓ/h to deliver a measured 4 kW into a charger at R23/ℓ diesel costs R34.50/h ÷ 4 kWh ≈ R8.60/kWh in fuel alone — before oil, filters, capital recovery and the fact that partial loads waste fuel. At 17 kWh/100 km that is ~R146 per 100 km, worse than many public DC tariffs and far worse than home AC on metro rates. If your genset is older or overloaded by a kettle + charger together, the effective R/kWh climbs again.
Electrical safety non-negotiables
- Registered contractor; CoC for fixed wiring.
- Proper ATS / interlock — never a double-male cable into a wall socket.
- Neutral-earth arrangement compatible with the hybrid inverter maker’s instructions.
- Ventilation and exhaust routing that will not kill anyone in a garage while “just topping up the car.”
Hybrid-first build order
Follow the same savings-led stack as the rest of this desk: fix water heating, size PV for self-use, add battery for evening/essentials, then the wallbox with load management. Generator last, if ever. Guides: home solar · EV charging · install order.
Public DC as the “generator alternative” for travel
For road trips, public CCS2 is usually saner than towing a genset. Compare live app rates — GridCars network upgrades and CHARGE N3 hubs are expanding capacity on corridors (GridCars, CHARGE N3). Home/work AC remains the everyday fuel.
Quick questions
Can I charge my EV from a portable inverter-generator?
Sometimes in an emergency at low kW, but it is expensive, noisy and easy to get electrically wrong. Not a daily plan.
Will a generator void my hybrid warranty?
Poor paralleling / neutral-earth faults can damage inverters. Use a compliant ATS design from the installer.
Is hybrid always cheaper than grid-only charging?
Once installed, self-used solar kWh usually beats retail grid and thrash public DC — run your tariff numbers.
When a generator still earns a place beside solar
A hybrid solar + battery system is the daily driver for EV charging and Stage evenings: quiet, no fuel queue, and daytime PV can fill the car for free. A portable or standby generator still helps on multi-day outages, cloudy winter weeks, or sites where the battery was sized only for essentials. The catch is integration — many hybrids need a correctly wired generator input or an ATS, and dirty generator power can trip inverter protection. Never back-feed a wallbox from a generator without an electrician confirming earthing, neutral bonding and transfer switching.
Cost sense-check: diesel for 200 kWh of EV miles is expensive and noisy compared with off-peak Homeflex or solar surplus. Keep the generator for rare deep-backup hours; let PV and the wallbox handle the commuting kWh. See also TOU and prepaid EV charging.
Quick decision table
| Need | Lean hybrid solar + battery | Keep / add generator |
|---|---|---|
| Daily EV commute kWh | Yes — daytime PV or off-peak wallbox | No — fuel cost and noise lose |
| Stage 2–4 essentials | Yes if battery sized for essentials | Optional backup if battery is small |
| Multi-day rural outage | Partial — sun + storage help by day | Yes — fuelled runtime for cloudy stretches |
| Quiet estate / complex | Preferred | Often restricted by HOA rules |
Fuel maths when the wallbox is the load that hurts
A 7.4 kW wallbox running three hours is roughly 22 kWh. On a petrol or diesel generator that is a serious fuel stop plus noise and maintenance — often several times the cost of the same kWh from the grid or from a hybrid battery charged on daytime solar. Generators shine for short, high-power backup of essentials; they are a poor “nightly EV charger” plan unless fuel is free and neighbours never sleep.
Hybrid solar with a correctly sized battery lets you charge the car from surplus or from cheap off-peak grid into the pack, then discharge to the wallbox under load management. That is the savings path for most suburban homes. Keep a small generator only if you need multi-day resilience for medical loads or a borehole when Stage 6 coincides with empty batteries — and interlock it so it cannot back-feed. Quotes that add both a large generator and a large battery without a coincidence study are usually overselling fear.
If you already own a generator, ask the hybrid designer for an ATS / changeover scheme that prefers solar+battery, then grid, then generator. Document the sequence on the CoC pack. Related: ATS / changeover, TOU EV charging.
Sources
- Solar News 24 — cost to charge an EV in SA
- DriveElectric / MyBroadband reporting on SAEV Richmond DC tariffs (secondary)
- Solar News 24 — changeover / ATS