Solar and EV Charging in Singapore: What It Actually Saves

Solar EV charging means using electricity your own rooftop panels generate to charge your electric vehicle, instead of drawing that power from the grid. For a Singapore landed home with solar already installed, charging during the day from your own panels avoids the S$0.3478 per kWh retail tariff entirely for every kWh self-consumed.

Most EVs use roughly 15 to 20 kWh per 100km, a range that varies by model and driving style rather than a fixed figure.

A well-sized system on a landed home usually has enough surplus daytime generation to cover most of a typical commuter's charging needs, on top of the household's own usage.

• Charging entirely from the grid costs about 6.3 cents per kilometre at current tariffs; self-consumed solar charging costs nothing marginal per kilometre.
• Timing decides the saving: daytime charging draws from panels first; overnight charging draws entirely from the grid at full price, solar system or not.
• A 7kW home charger can use more than half of a single-phase home's roughly 10 to 13kWp solar capacity ceiling at once, so sizing both together matters.
• Three situations genuinely reduce the benefit: overnight-only charging, a household that already self-consumes most of its generation, and low monthly mileage.

How does solar EV charging actually work?

Solar panels feed a single supply point at a home, the same one that powers air-conditioning, lights, and every other socket. There is no separate solar circuit for the car. When an EV charger draws power during daylight hours and the panels are generating, that demand is met by solar generation first, before drawing any additional power from the grid.

Why does charging time matter so much?

A car plugged in and charging at 9pm draws entirely from the grid at the full S$0.3478/kWh retail rate, because panels stop generating after sunset. The same car charging at 1pm on a sunny day draws mostly, sometimes entirely, from the home's own panels. This single difference, more than system size or panel brand, determines how much of a driver's charging solar actually covers.

What does an EV charger add to my electrical setup?

A home EV charger is a meaningful electrical load in its own right, separate from anything solar-related, and it changes the system sizing conversation beyond simply adding panels.

The two decisions, panel count and charger capacity, are easiest to get right together, during the same site visit, rather than solving one and revisiting the other later.

What EV charger types are realistic for a landed home?

Level 1 charging uses a standard household socket and adds only around 10 to 12km of range per hour, too slow for daily reliance on a typical commute.

Level 2 AC charging, using a dedicated 7kW wallbox, is the practical standard for landed home charging, adding roughly 35 to 40km of range per hour and comfortably recharging most EVs overnight or substantially during a sunny afternoon.

DC fast charging is a public-charger technology, not something installed at a typical home.

Does adding an EV charger mean upgrading my electrical phase?

Possibly, though it depends on existing capacity rather than a fixed rule. Single-phase electrical supply commonly caps a home in the 10 to 13kWp range for solar, a ceiling SP Group confirms case by case rather than one universal number, and a 7kW EV charger alone can use more than half of that at any given moment.

Checking the specific approved capacity for a property, rather than assuming a round figure, is the only way to know for certain.

Can I charge two EVs from one solar system?

Yes, though total charging demand then competes for the same limited surplus generation and electrical supply capacity. Two 7kW chargers running simultaneously can draw 14kW, which very likely requires three-phase supply regardless of solar system size, and splits whatever solar surplus is available between both cars rather than doubling it.

Does property type affect how easily I can add an EV charger?

Mostly through existing electrical headroom rather than the charger itself. A larger bungalow or GCB more often already has three-phase supply or spare capacity to add it, while a terrace or semi-detached home is more likely sitting close to the single-phase ceiling once solar is factored in.

Porch and driveway layout also varies enough between property types that cable routing is worth confirming during the same site visit that scopes the solar installation.

What does an EV charger actually cost?

Charger hardware and installation together typically run from a few hundred to a few thousand Singapore dollars, varying by charger brand, amperage, and how far the cable needs to run from the distribution board to the parking area. A straightforward run to a nearby porch costs meaningfully less than routing power to a driveway further from the meter box.

This cost sits alongside the solar system's own installed cost, not instead of it, and the saving calculated below should be weighed against the charger's own cost specifically. The solar system's payback already stands on its own regardless of whether an EV is involved.

How much does charging from solar actually save?

Every kWh self-consumed from a home's own panels instead of bought from the grid saves the full retail tariff, currently S$0.3478/kWh including GST.

Every kWh that would otherwise have been exported and used for EV charging instead saves the difference between the retail rate and the lower export credit rate of S$0.2581/kWh, since the alternative is a purchase avoided, not an export credit earned.

For a driver doing 1,000km a month at 18kWh per 100km, that is roughly 180kWh of monthly charging. Shifting that entirely from grid to self-consumed solar saves about S$63 a month, or roughly S$750 a year, on top of whatever the system is already saving on household electricity.

How does this compare per kilometre rather than per month?

At 18kWh per 100km, grid-only charging costs roughly S$6.26 per 100km at the current S$0.3478/kWh retail tariff, or about 6.3 cents per kilometre.

Self-consumed solar charging costs nothing marginal per kilometre, since the electricity was already generated regardless of whether the car uses it.

What does this add up to over the life of the system?

Applying the same 0.5% annual panel degradation used for household savings, S$750 a year in EV charging savings compounds to a meaningful sum across a panel's 25-year life, since it is simply an additional slice of the same self-consumed generation, not a separate calculation. See the total cost of ownership framework for how this fits into the full 25-year return.

What actually determines how much of your charging solar can cover?

Two households with identical solar systems and identical EVs can end up covering very different shares of their charging from solar. The difference comes down to timing and how much surplus generation is actually left over: charging during generation hours captures the full retail-rate saving, charging outside them does not, and that gap plays out consistently across a full year rather than just one sunny afternoon.

Should EV charging coverage be planned around a conservative or optimistic generation estimate?

A conservative estimate is the safer basis specifically for EV charging coverage, more so than for general household savings. Planning around an optimistic generation figure risks a driver expecting more free charging than a real year of Singapore weather reliably delivers, while a household's general electricity savings still land somewhere reasonable either way. See the P50 versus P90 estimates guide for how Sunnify's own figures reflect this distinction.

When does solar EV charging not make much sense?

Three situations genuinely limit how much solar EV charging actually saves: an inflexible overnight-only charging schedule, a household with little surplus generation left over, and low monthly mileage.

What if my charging schedule genuinely cannot shift to daytime?

A household needing the car ready very early each morning, charged fully overnight, gets little benefit from solar EV charging specifically, even though the household's other daytime usage still saves normally. The charging itself simply draws from the grid at the standard retail rate, the same as it would without solar.

What if my household already self-consumes most of its generation?

A home already running significant daytime loads, a home office, aircon, a pool pump, may have little true surplus left for EV charging even when the sun is out. The EV then draws partly from the grid even during daylight hours, reducing but not eliminating the saving.

Does a low-mileage driver still benefit meaningfully?

The saving scales directly with charging volume. A driver doing 300km a month sees roughly a third of the S$750 annual figure used as the reference in this guide, real, but proportionally small next to a system's overall household savings.

Should I size my solar system around EV charging?

Only if charging is genuinely flexible enough to happen during daylight hours, and only up to the point where generation still exceeds household usage during those hours. A system sized for a household that self-consumes 25% of generation, Sunnify's reference assumption, has real surplus most sunny afternoons.

Oversizing further adds little value if charging happens overnight regardless, since a bigger system generates no power after sunset.

A smart charger that schedules charging to daylight hours, or simply a habit of plugging in when arriving home in the early evening, captures most of the available saving without needing to oversize the system at all.

Does a home battery help EV charging more than solar alone?

It can, specifically for a household whose charging is unavoidably in the evening or overnight. A battery charged during the day from surplus solar can then supply the EV charger after sunset at no additional grid cost, though this adds the battery's own separate cost and payback calculation on top of the solar system's.

This is a genuinely separate decision from whether solar itself makes sense, worth evaluating on its own numbers rather than folded into the solar payback calculation. See the battery sizing guide for whether this specific household's evening-charging pattern actually justifies the extra cost.

Does charging from solar affect my EV's battery warranty?

No. An EV's battery warranty is based on charge cycles, depth of discharge, and time, not on which specific electricity source supplied the charge. A kWh delivered by a home AC Level 2 charger behaves identically to the battery regardless of whether it originated from solar panels or the grid.

The manufacturer's warranty terms are still worth checking directly and independently of any solar-related claims, since exclusions when they exist are typically tied to charging speed or discharge habits, not to electricity source.

What is the actual next step?

Confirming electrical phase and available capacity comes first, since it determines whether a charger, a larger solar system, or both are realistic without an electrical upgrade. See the EMA and SP Group approval process for how phase confirmation fits into the standard solar approval steps.

Does the charging point need separate approval from the solar system?

Yes, though it runs alongside the solar approval rather than replacing it. LTA sets the technical standards a home EV charging point in Singapore needs to meet.

A Licensed Electrical Worker handles the actual circuit installation for both the charger and the solar system.

Coordinating the two with a single competent installer is simpler than treating them as unrelated projects, since the same electrical supply and distribution board capacity questions apply to both, and asking twice rarely produces a different answer.

What does the physical installation actually involve?

A dedicated circuit runs from the distribution board to the charger's mounting point near where the car parks, which on a landed home porch or driveway is often only partly covered.

The cable run and any exposed wiring need the same electrical safety standards applied to the rest of a solar installation, given Singapore's rain and humidity.

A homeowner who already has solar and is only now planning an EV should re-run their sizing numbers rather than assume the original estimate still applies. An estimate built around a household's electricity usage before an EV existed does not account for the new daytime load a charger adds, and whether the existing system is still well-sized can genuinely change.

Run the solar inverter comparison to check compatibility with EV charger scheduling features, then the Sunnify solar estimate to see a specific roof's generation and self-consumption numbers before sizing a system around EV charging.