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.
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.
He clearly said that the battery can deliver 80 KW of power. No 80 KWH car is going to be limited to 10 KW into the motors. Ecars are all about acceleration.
You need to learn how to read and how to discuss.
I don't know who you are talking to. Many people talk about stuff they don't actually know much about. An EVSE which does zero energy conversion, costs around $400 for 5 kW handling capability. 10 kW is around 42 amps. So I can see a 10 kW inverter being much more expensive than $500. If you think you can make and sell them at a profit, for $500, you need to go into that business!
That doesn't necessarily follow. If you run an electric stove, and electric water heater and a heat pump at the same time, you can easily overload a 10 kW power source and still not reach 10 kWh.
In the UK, perhaps. In the US, lots of homes have gone to 100-amp 220 Vac split phase, or 22 KW. Some have twice that.
My house has 100 amp service. But we have a gas stove and water heater, and oil heat. No electric heat. My shop runs off 220 Vac, but the big machines are only used intermittently, but will need a lot of power when doing something heavy.
Most appliances (including air conditioners) are 120 Vac and 15 or 20 amps. Things like clothes dryers are 220 Vac. Many people have electric water heaters. also 220 Vac.
Joe Gwinn
No home in the US have gone to 100-amp, 220VAC split phase. The nominal voltage in the US is 240V. I expect very few homes in the US have been built with 100 amp service in the last 50 years. In the 70s, there was a big push to use more electric appliances, including electric radiant heat! You aren't getting that with 100 amp service.
Do you have a 240V to 220V transformer? If not, you have excessive voltage drop coming to your house and should ask the power company to fix that.
If you have 120V on the low voltage outlets, how do you get 220V on the high voltage circuits? Is your line not balanced with one at 120V and the other at 100V?
They don't list an electric range.
He is probably like me. Says 110 and 120 or 220 and 240 at different times when he talks about the low or higher voltage.
Over the years in the US the voltage went from 110/220 to 115/230 to
120/240. There was even some 117 volts. People as old as I am remember their dads talking about 110/220 so sometimes they may say any of the above.Now most of the time my voltage is 125/250, sometimes even more. This was measured with 2 different Fluke meters that had been calibrated at a seperate test lab.
Even that is a lot.
If i drive at 60MPH for an hour, i burn 20kWhr. So, average is 20kW. My motor is 80kW, but usually 30 to 40kW to accelerate.
The only time I've seen 117V was on appliance rating plates. As far back as I can remember (including my teenage years) the nominal household outlet voltage was 120V. I believe 120V was the official standard in 1967. That was a long time ago. I think it's time to forgive and forget!
The misunderstanding was yours. The nastiness too.
The question made sense. Why a 10 KW inverter? The answer is probably, it's enough for a house backup and a bigger inverter would cost more.
Battery cooling could be involved too, for a parked car.
3 miles per kwhr is a good rule of thumb. So, if you need to drive 60MPH, then you need around 20kW drive power. I don't know why people need 150kW, unless they are driving 450MPH.
Yes if you are discharging 50A. 20kW is around 50A @ 400V.
Absolutely, when you push the performance of the car. I saw a video of a German guy on the autobahn, driving as fast as he could. This involved not only acceleration, but deceleration, which ultimately overheated the car. I can't say for sure if it was the motor or battery, but the continued high current, in and out of the battery will absolutely raise the battery temperature and the cooling is important to the longevity of the battery.
3 miles per kWh is a good number for an electron guzzler like my X. The less bloated cars like the 3 and Y get more like 4 miles per kWh and I'd lump the Nissan Leaf into 4 miles per kWh group from everything I've heard.
Your Leaf has no battery cooling, right?
So, 150kW drive power can get up to 600MPH.
Not for my #1 battery, but #2 and #3 are A/C cooled.
??? The power of the battery voltage and current is either input to the battery for charging, or it's the power out to the circuit. The only dissipation would be losses which are very similar between charge and discharge. There are ohmic losses in the conductors in the battery, but there's also some loss in the chemistry, in that it requires diffusion. At higher currents the diffusion does not keep up as well as it might and the battery appears to have some extra losses.
There is zero reason to think that there are no losses on discharge. But there's no good way to measure the actual energy in the battery, so the losses on charge and discharge are hard to separate. I suppose you can consider the energy to be the useful coulombs in the battery, times the open circuit voltage. The voltage while discharging will be lowered by the net losses of discharge, in a similar manner to how the voltage when charging will be higher than the open circuit voltage, so that increase represents the losses of charging.
It is certainly not reasonable to consider that the conductors have losses in charging and none when discharging.
Hmmm... There are always I2R losses in the motor. You don't need to worry with the details of "spinning up". The more power the motor is handling, the higher the current and the more I2R losses. Notice the '2' in I2R? The waste power goes up with the square of the current. So higher road speeds, and especially accelerating and decelerating will heat up the motor and battery quickly.
Some of their values seem rather high to me but otherwise mostly OK.
Typically 6-8kW if all the halogen rings are on at once from cold.
About 2kW per ring when they are actively heating. Once each one is hot they pulse on and off. I expect induction ones to be a bit less but near continuous whereas halogen hobs are very bang bang regulation.
Obviously it has to be wired to cope with the worst case scenario. Ovens by comparison have become so well insulated now that 1kW suffices (and once it is up to temperature the average is even lower).
The kitchen supply for the electric cooker got its own dedicated thicker cable in most installations. It is a bit overkill now that ovens have become so much more thermally efficient.
Since US domestic power is nominal 110v I'd have thought that 100A per live feed was about right (bordering on the low side). OTOH high power devices like aircon are run phase to phase on 220v.
My feed is 60A @ 230v ~ 14kW modern build here would be 100A ~ 23kW
Base load 24/7 is 70W typical daytime load ~300W peak maybe 6kW.
UK says it has 240v but in reality all of Europe uses a ~230v nominal voltage with an asymmetric tolerance band see for example:
It is likely that as in the UK confusion reigns about actual mains voltage - so few consumers ever measure it and think they have 240v. It could in reality be as low as 216 or high as 253 and still (just) in spec.
In most of Europe it is likely to be 230v nominal 115v-0-115v balanced or it could be full three phase supply to industrial premises.
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