EV Charging for Multi-EV Households UK 2026

How it works:

• One 7kW home charger services both cars.
• Cars alternate or share charging slots overnight.
• Schedule coordination via app (Intelligent Octopus Go schedules each car separately).

When this works:

• Both cars do <40 miles/day average → each needs ~10-12 kWh/day → ~3-4 hours charging.
• Combined daily kWh needs: ~20-25 kWh.
• Single 7kW charger over 6-hour cheap-rate window: 42 kWh available - more than enough.
• Alternative: each car charges every other day to 80%.

Practical scheduling:

• Car A plugs in 23:00 - 03:00.
• Car B plugs in 03:00 - 06:30 (next morning).
• Both finish before peak rate starts.
• Requires manual plug-swap (not automated).

Pros:

• Lower install cost (no second charger).
• No supply upgrade needed (single 7kW draws ~32A, well within 80A supply).
• Simple electrical infrastructure.

Cons:

• Manual plug-swap required overnight.
• Both cars must be home at the right times.
• Limits flexibility (can't charge both during a daytime cheap window simultaneously).
• Workplace charging fallback needed if both cars at low charge + need same morning.

How it works:

• Two 7kW chargers installed (one per car).
• Both cars charge simultaneously if needed.
• Dynamic load balancing OR supply upgrade required for shared 14kW combined draw.

When this works (vs single):

• Both cars do >60 miles/day average.
• Both cars need full overnight charge.
• One+ household member does irregular hours (can't reliably plug-swap).
• Larger battery EVs (75 kWh+) that take longer than 6-7 hours full charge.

Electrical supply considerations:

• Standard 80A supply: 7kW + 7kW = 14kW = 58A combined EV load.
• Plus household baseline (~3-5 kW): brings to ~17-19 kW.
• Cooker + heat pump + EV × 2 at peak: ~22-26 kW → exceeds 80A (19kW) supply.
• Solutions: 100A supply upgrade (more headroom); dynamic load balancing.

Dynamic load balancing:

• Both chargers monitor whole-house current draw.
• If household + EV combined approaches supply limit: one or both chargers throttle.
• Typically: each charger drops from 32A to 16A when household is at peak.
• Total charge time extends but never trips the main fuse.
• Examples: Ohme Pro + Ohme Pro pair, Zappi + Zappi, Easee Home + Easee Home with shared CT clamp.

Intelligent Octopus Go for two EVs:

• Octopus allows TWO separate IO agreements - one per EV.
• Each car has its own app account + schedule.
• Both cars charge during 23:30-05:30 cheap window at ~7p/kWh.
• Cars typically share the 6-hour window without conflict (sequential charging).
• Total household electricity costs are the same as single-EV (off-peak window is the same).

Octopus Cosy for two EVs:

• Multiple cheap-rate windows per day (04:00-07:00 + 13:00-16:00 + 22:00-00:00).
• EV + EV + heat pump + appliances all run during cheap windows.
• More flexibility for mid-day work-from-home + EV charging.
• Costs comparable to IO for typical 2-EV usage.

Octopus Agile (advanced users):

• Half-hourly rates; cheapest typically 02:00-06:00 + 13:00-15:00 + 22:00-00:00.
• Both EVs scheduled via Home Assistant or similar automation.
• Potential GBP 100-300/year extra savings vs IO for active management.
• Best for: technically-comfortable users.

Shared single charger (no extra cost):

• Existing 7kW charger: assumed.
• Tariff registration of second EV: GBP 0.
• Scheduling: manual or via Octopus app.
• Net additional cost: GBP 0.

Dual chargers + dynamic load balancing:

• Second 7kW charger (Ohme Pro / Zappi / Easee): GBP 800-1,200.
• Install: GBP 400-700.
• CT clamp / load-balancing config: included if same brand.
• Net additional cost: GBP 1,200-1,900.

Dual chargers + 100A supply upgrade:

• Second 7kW charger: GBP 800-1,200.
• Install: GBP 400-700.
• Supply upgrade 80A → 100A: GBP 300-900 (DNO charges).
• Consumer unit upgrade if needed: GBP 700-1,500.
• Net additional cost: GBP 2,200-4,300.

Both cars do <40 miles/day average:

• Single 7kW shared charger sufficient.
• Manual plug-swap workable.
• Each EV on Intelligent Octopus Go.
• Net cost: GBP 0 extra.

Both cars do 40-60 miles/day average:

• Either approach works; consider lifestyle preference.
• Manual swap acceptable if both partners flexible.
• Dual chargers if convenience matters.
• Net cost: GBP 0 or GBP 1,200-1,900.

Both cars do >60 miles/day average:

• Dual chargers + load balancing recommended.
• Avoid forced supply upgrade unless household otherwise needs it.
• Net cost: GBP 1,200-1,900.

Combined with heat pump + induction cooker:

• 100A supply upgrade often justified (future-proofs household).
• Even single-EV households may want this for resilience.
• Net cost: GBP 1,500-3,000 supply + consumer unit work.

1. Two separate non-balancing chargers: risks supply trip when both run + household load is high. Always specify load-balancing capability.
2. Mixing different brands of chargers: load balancing typically requires same-brand pair. Stick with one brand for both chargers.
3. Standard variable tariff for two EVs: ~GBP 1,500-2,500/year wasted vs Intelligent Octopus Go. Switch immediately.
4. Single Octopus IO account for two EVs: works but car-charge tracking gets confused. Use separate accounts per EV.
5. Plug-swap reliance with frequent travellers: schedule failures = morning surprise. Either dual chargers or strict charging discipline.

By 2030-2035, UK 3+ EV households (parents + adult children with multiple cars) become common:

• Single 7kW charger insufficient.
• Two 7kW chargers + load balancing handles most cases.
• Three chargers + load balancing: rare but possible.
• 3-phase 22kW supply for premium households: requires DNO 3-phase upgrade (rare in UK residential; costs GBP 5,000-15,000).

For 2026 planning: install with capacity headroom but don't over-spec for hypothetical future needs.