Why is an EV's backup power less than it's driving power?
Nov 17, 2022 Last reply: 3 years ago 48 Replies
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Commander Kinsey
If an EV has an output power of say 80kW to drive the motors when driving, why is the backup power (to power your house in a power outage) only about 10kW? It's the same battery!
And why do people say it costs thousands of dollars to fit something to do this? Surely a 10kW invertor doesn't cost much, just something to make 400VDC into 240VAC. I'd say more like 500 dollars.
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Commander Kinsey
Rewrite all that considering I know the difference between power and energy, I have a f****ng physics degree. When I said 80kW I meant 80kW, not 80kWh. Do you seriously think a car motor only draws 10kW?
And that last link doesn't tell you how to do it, just sales waffle about Ford are getting to it.
Pretty easy really, you find the 400V battery wire and connect a convertor to it to make 240VAC.
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Commander Kinsey
Cables don't cost much, especially if they're short.
It's a pest, you have to switch stuff off.
Not if it's bursts, like cooking a meal or having a hot shower.
They usually are. If it was plugged in when the powercut started, it would have just been charging.
A Nissan Leaf would power the average house for 3 days. And decent electric cars have a battery 3 times bigger.
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Commander Kinsey
That's only for convenience.
$13.
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Then fit it yourself.
Rules are for the obedience of fools.
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Commander Kinsey
If you have 24kW in the house, you might aswell fit a charger as such.
Park the car nearer the house.
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Commander Kinsey
This is a newsgroup, so I'm talking to whoever reads the post.
You need to shop around. I can get one for half the price that does 8kW. Anyway they have electronics to communicate with the car.
A grand actually.
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Commander Kinsey
Why would you do that knowing you can only get 10kW at a time? You'd spread the usage out.
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Commander Kinsey
Do you like being ripped off? $1K
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Commander Kinsey
Finally, you understood and answered my question. The difference between 10kW backup mode and 80kW driving mode is sustainability.
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Commander Kinsey
You're the one getting mixed up with kW and kWh.
Arrested for using your car battery for something else, yeah right.
And you too, or you would have written them down.
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Commander Kinsey
And in sensible countries with a proper voltage, the slowest charger plugs into a proper 13A 240V socket and gives out 3kW.
So use it next week then.
You have dryers that use 6kW?! I know American clothes are much larger, but still....
Just go for it and have a 24kW charger.
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Commander Kinsey
A post can be read and responded to by anyone. When I said "And why do people say it costs tho.....", you didn't seem to know who I was talking to, I can't tell to help you out now, since you snipped the attributions.
But you weren't talking about invertors, you said EVSE.
Because I live cheaply on Chinese stuff. 99p for an 18650 battery charger!
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Commander Kinsey
You switch one off while you cook. It's only for the duration of the power outage.
I did no such thing. If you believe I did, show me where I did.
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Commander Kinsey
If you join the outputs together from three of those, would they phase synch?
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Commander Kinsey
I fit what I want to fit, not what they want to fit. My house, my wiring. Easy enough to get a 24kW commercial charger destined for a car park and wire it to your house.
A garage is for storing things and for a workshop. The car lives outside.
You do that at 240V, so not expensive.
Don't use surplus words.
No, use the same cable, electrons will go both ways.
Noisy, and prone to not starting. I hate one cylinder "engines".
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Commander Kinsey
Nobody checks that s*it, just fit it. You can have a manual switch which will obviously do the same job. In the UK technically it's illegal for me to fit a new 13A outlet. WTF?!
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Commander Kinsey
You misunderstand. A manual switch would also do the same. And a power transfer switch is just a relay, very cheap indeed. I had one when I tried solar power (which is a dead loss in Scotland, no sun).
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Commander Kinsey
Why do you run your house on DC?
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Commander Kinsey
At 240 volts, the cable will be cheap as it's thinner than a 12V one. Or you could run it at 400V DC from the car to there for even less, and put the invertor near the panel.
And if there's a powercut while they're already on? Now you trip the thing and your meal is half cooked and other stuff goes off like your computer and the DVR that was recording stuff.
More like 1500.
To have the full 24kW would be more convenient, you carry on regardless.
That's a weak 8kW charger you're talking about. And assuming you came home with an empty battery.
If you're out you don't need power.
I want 24kW, not 80. And I don't use that continuously.
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Commander Kinsey
I guess most 220V stuff will run DC or AC.
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