Bi-directional EV charger

[kevm14]

https://www.motortrend.com/news/wallbox ... 4A6BED04A4

Summary: They think it will cost around $4,000 and will handle up to 7.4kW/32 amps (I assume 240V).

This will enable not just selling some of your EV power back to the grid (perhaps you charge free at work and sell power back to the grid...oh boy that's a racket), but backup power to your house.

The 2017-2019 Chevy Bolt has a 60kWh pack. Let's assume the pack starts at 90% and we don't drain past 20%, so we're accessing 70% of the total capacity. That's pretty safe and realistic but also doesn't leave much for actual driving if necessary. In any event, that's 42 kWh of energy available to power the house. That's enough to provide 1.75kW of continuous electrical power for a 24 hour period. There are going to be some conversion losses through the charger. It would be nice if the car side was a DC interface but if not there will be inverter loss on the car side as well. Let's say 85% efficiency total. That would change to 1.3kW of continuous draw for 24 hours. You may be able to extend that to the 48 hour mark with more judicious use of electrical loads.

However at the end, you cannot just go out and fill your 5 gallon cans with electricity and "dump" it into the car. Conclusion....this is not practical except perhaps in communist CA where blackouts are a thing, and due to regulations, the utility may be required to pay astronomical rates for your EV juice.

[Bob]

A couple weeks ago, I saw a 2011 Leaf that had a recent battery replacement for $2600 on Nextdoor. That's getting to the price point where EV ownership starts to make sense, especially if you combine it with something like this.

https://www.nissan-global.com/EN/TECHNO ... _home.html

https://jalopnik.com/your-nissan-leaf-m ... 1836311220

[kevm14]

What is the financial case for the home connection? I don't really see one, unless your grid pays an astronomical amount for borrowing some of your juice.

[Bob]

Charge at work for free and power my house at night? Actually, that would probably only get me about $30-40 a month savings at current rates, which would be way less than my fuel, tire and depreciation avoidance savings by commuting in the Leaf over the Vsport.

Probably the biggest value would be having it available as a backup power source during power outages. Of course, a gen 1 Leaf might get me 24 hours of house operation then I have a car that won't move and a house with no power

[kevm14]

Yeah you're making my point. For most people, idling their car while they charge their phone is good enough. For everyone else, they get a generator or tough it out. I don't see this moving the needle on anything.

[kevm14]

There are going to be some conversion losses through the charger. It would be nice if the car side was a DC interface but if not there will be inverter loss on the car side as well. Let's say 85% efficiency total. That would change to 1.3kW of continuous draw for 24 hours. You may be able to extend that to the 48 hour mark with more judicious use of electrical loads.

I think it is DC. So whatever the efficiency of the charger inverter is. The efficiency could be above 85% but not sure how much more. Maybe Bob knows?