Vehicle-to-home is extra inverter work, not free kWh
Many 2026-class electric cars ship with traction packs labelled between about 60 kWh and 100 kWh. A common stationary home battery in the 13.5 kWh class (Tesla Powerwall-class or Enphase 5P-class nameplates) stores far less energy on the sticker. The tempting sentence is: why buy a wall pack when the car already holds 5 to 7 times more kWh? The original FoxyEco article was right to call that a hardware problem, not a slogan problem.
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Bidirectional power is not a default Level 2 charger. Energy must move from a high-voltage DC pack into a 120/240 V split-phase panel. DC off-board designs (public examples named on the prior page: Wallbox Quasar 2-class, Ford Charge Station Pro-class) send DC out of the car and use a wall inverter. Public price bands quoted on that page for inverter hardware — on the order of $4,000 to $6,500 before install — stay as previously published desk figures to confirm live, not as a FoxyEco invoice. AC bidirectional designs put the inverter in the car. That can cheapen the wall box and add vehicle mass. This desk installed neither.
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Stationary systems in the EcoFlow / Enphase neighbourhood are typically LFP, with manufacturer cycle language often in the 4,000 to 6,000 full-cycle band to a retained-capacity clause. Traction packs may be NMC or LFP depending on the model year. Do not paste a cycle count from a wall pack onto a car warranty. Open the live warranty PDF.
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Round-trip, isolation, and who should not V2H yet
Round-trip efficiency is a chain: pack, inverter, panel, then back. Every conversion drops Wh. A stationary LFP cube that only does home backup has fewer conversions than a car that also has to drive tomorrow. Isolation matters: a V2H setup that cannot legally island from the utility is not a blackout kit. Look for an automatic transfer path and a stated continuous watt rating that covers the loads you actually run (well pump, heat pump compressor, refrigerator). Continuous watts and surge watts are different lines.
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Who should skip: drivers whose lease or warranty forbids export, apartments without a panel the installer can island, and households that need 24-hour medical loads without a documented failover. Photograph usable kWh, continuous watts, and the export-allowed clause. A 75 kWh car label is 75,000 Wh of nameplate arithmetic — not 75 kWh of guaranteed backup after inverter losses.
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Cons / limitations
- Inverter hardware and install can erase the ‘free kWh’ story. Public price bands on the prior page must be re-checked live; this desk has no installer quote.
- Traction-pack cycle life and stationary LFP cycle life are different warranty objects. Mixing them is a math error.
- Without a documented islanding path, V2H is a bill-management toy, not a blackout plan.
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Desk metrics (11 September 2026)
These figures are methods, public-source labels, or counts from this desk check. They are not a FoxyEco calorimeter run, dynamometer loop, or invented field trial. Desk timers on this pass: 8 minutes to open a spec or policy page and 15 minutes to walk a methods PDF — a reading method, not a lab stopwatch contest.
- Label arithmetic: 13.5 kWh wall pack = 13,500 Wh; 75 kWh car pack = 75,000 Wh. Not usable-energy tests.
- Prior desk price band retained as a check-live item: inverter hardware $4,000–$6,500 class, not a FoxyEco invoice.
- Documents to open: vehicle warranty, charger manual, interconnection / islanding notes. Count for this snapshot: 3 document types.
- V2H systems installed by this desk: 0.
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A short who-should-skip list for V2H shoppers
Skip V2H shopping if your parking is on the street, your utility interconnection queue is closed, or your vehicle app still lists export as ‘coming soon’. Do the stationary LFP comparison first: nameplate kWh, chemistry, and whether the cube can start a 240 V well pump. Then decide whether the car is a complement or a substitute. Confirm every dollar and every Wh on live pages.
FAQ
Is a 75 kWh car five home batteries?
On nameplate kWh, sometimes. After inverter losses, warranty export limits, and the fact you may need to drive, no.
Can I skip a stationary pack if I buy V2H?
Only if islanding, continuous watts, and warranty export are documented for your panel. Many households still want a small LFP cube for nights the car is away.
What Wh should I photograph?
Usable kWh on the wall pack or car, plus continuous watts on the inverter. Convert kWh to Wh by multiplying by 1,000 if you are comparing portable gear.
If you are comparing field or household energy hardware after this desk check, open the live partner listing for EcoFlow home battery hardware and read the nameplate Wh or kWh on that page. Do not treat the listing as a FoxyEco lab result.