Leaf as a Home Battery
Many Nissan Leafs sit parked at home for 20+ hours a day. That's a large lithium battery doing nothing. This project is about changing that, using the Leaf's existing CHAdeMO port to move energy in both directions between the car and the house.
The idea
All Nissan Leafs have a CHAdeMO DC fast-charge port. What most people don't know is that CHAdeMO is a bidirectional protocol. With the right hardware on the other end, you can move energy back out of the car through that same port.
The idea is to build a small V2X DC charger that sits in an enclosure, connects to a home hybrid inverter on one side and to the car's CHAdeMO port on the other. When the car is parked and plugged in, it becomes part of the home energy system: charged up from solar during the day, drawn on in the evening, or kept as backup power. Combined with the 52kWh battery upgrade, you get aproximately 10kWh of usable storage from the old car battery which could be ustilised as a home battery also.
Paired with the 52kWh battery upgrade, you'd have more storage capacity than most residential battery systems at a fraction of the cost per kWh. The AZE0 (2013–2017 Gen1) and ZE1 (Gen2) Leafs support V2X natively via CHAdeMO. The older ZE0 (2010–2012) doesn't have native V2X support, but I'm working on a solution for that separately.
This is early stages. I'm working through the hardware design and the interaction with hybrid inverters before committing to a prototype. But the concept is solid and the CHAdeMO protocol is well documented.
How it would work
Solar charges the car or home battery
Excess solar generation during the day charges the Leaf through the CHAdeMO port, rather than exporting to the grid at a low rate.
Car powers the house
In the evening, or during an outage, energy flows back out of the Leaf through the same port and into the home via the hybrid inverter.
Car is ready to drive
A departure schedule ensures the battery is at the right charge level before you leave. The car never gets flattened for house loads.
Rough numbers (indicative)
What about the old battery?
When a Gen1 Leaf battery is removed during an upgrade, it still has capacity left, typically around 10kWh of usable storage depending on how degraded it is. Throwing that away seems wasteful, and the obvious idea is to repurpose it as a dedicated home battery.
The appeal is real. You'd have the upgraded car for driving and V2X, plus a separate stationary battery from the old pack sitting in the garage. Combined storage, no additional battery purchase.
The catch is NZ regulation. Second-life battery installations in residential settings involve building consents, electrical certification, and compliance with battery safety standards that aren't designed with repurposed EV packs in mind. The path through that is unclear and likely more effort than it's worth for most people.
The more practical option for most customers would be a certified home battery system that connects directly to the hybrid inverter with a known compliance pathway. The old Leaf pack would need a different disposal or commercial reuse route. That's a separate problem worth solving, but not part of this project for now.
Where it's at
This project follows the Leaf-Upgrade. The plan is to trial it in full before considering it as a product. If you have a Leaf and a hybrid inverter and want to talk through the idea, get in touch.