Bi-directional EV charger
Posted: Tue Jan 07, 2020 7:05 am
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.
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.
