EVs in a jam.

Author
Discussion

grumpy52

Original Poster:

5,565 posts

165 months

Friday 14th February 2020
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Think about this

w1bbles

986 posts

135 months

Friday 14th February 2020
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That’s very shouty.

InitialDave

11,856 posts

118 months

Friday 14th February 2020
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I've been stuck for a couple of hours in a big jam in an EV. It's no worse than a petrol car. Better, in fact, as running the heating or AC only uses enough power to do that one task, rather than needing the engine going to generate heat or run the compressor.

Stop reading/believing/sharing inane ste written by people who don't know what they're talking about.

Patrick magooagain

9,909 posts

169 months

Friday 14th February 2020
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InitialDave said:
I've been stuck for a couple of hours in a big jam in an EV. It's no worse than a petrol car. Better, in fact, as running the heating or AC only uses enough power to do that one task, rather than needing the engine going to generate heat or run the compressor.

Stop reading/believing/sharing inane ste written by people who don't know what they're talking about.
I would like to see proof of this please.

Witchfinder

6,250 posts

251 months

Friday 14th February 2020
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Patrick magooagain said:
I would like to see proof of this please.
But you don't need proof for the claim made in the original post?

InitialDave

11,856 posts

118 months

Friday 14th February 2020
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Patrick magooagain said:
I would like to see proof of this please.
I'm not voluntarily repeating the experience!

Does it cut into your range a bit? Yes, of course it does, and I was in a first-gen Zoe, so it didn't have the largest battery capacity to start with. But it really wasn't that bad, and compared to when I've been stuck in similar jams in a petrol car, the unpleasantness of the experience was entirely the same, and down to the frustration of being stuck in a jam rather than any worry over how I'd get home.

With the far higher range the newer EVs seem to be getting, it's not even something I'd consider as a point of concern.

Zad

12,695 posts

235 months

Friday 14th February 2020
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I would spend the time going through the paper underlining random words with a ballpoint pen. Or taking screen grabs of random news stories and drawing wiggly lines under words with the phone equivalent of Microsoft Paint.

Mudgey

682 posts

173 months

Friday 14th February 2020
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You don't need proof, you can work it out easily enough.

Now, I am using stats I can't confirm as I have never tested this personally (and why would I want to?). A vehicle uses 0.6 ltr/hour per litre engine capacity, so for example a 2ltr car would be 1.2ltr/hr, say 50ltr tank, would give us approx. 33hrs idle time to power heater or AC.

A typical air source heat pump in a vehicle has what say 2.6 COP efficiency? You probably only need 1.5kw to maintain temperature in a car, but lets say 2kw. So 2kw / 2.6 gives us a consumption of 0.76kwh's to power the heat pump. A full 64kwh battery out of a Kona or Kia would give you 84 hours of heat less system consumption when stationary <- this I don't have figures for either but can't imagine it's more than 100w/hr.

Either way, if a person is stupid enough to let the car run out of fuel or battery power then that would happen no matter whether they were driving an ICE or BEV.

mcm87

110 posts

132 months

Friday 14th February 2020
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People camp in EVs as it uses so little energy to heat the cabin. Non issue.

Perhaps 1kw of energy to keep the cabin warm with a heat pump. In extreme conditions. In even a modest 30kwh battery that’s 30hours of climate control from full.

Tesla’s and the more recent gen EVs with 80-100kwh batteries will be fine for days.

If you’re very low on charge you might need to think about it, but that’s no different to being caught low on fuel. And if you lower the cabin to say 12-15 degrees you can probably reduce power consumption to a few 100w and stretch out even a few kWh for ages. Might be uncomfortable but not freezing to death cold.

People don’t realise how much electrical energy these cars store. The motors for driving the car are massively powerful. A heater is insignificant in comparison. Even a modest car battery could run our house for days.

Search YouTube for TeslaBjorn and he camps in his Tesla in crazy temps like -20. Doesn’t use that much capacity overnight.

MOBB

3,575 posts

126 months

Friday 14th February 2020
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The poor women and children :-(

Simpo Two

85,149 posts

264 months

Friday 14th February 2020
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mcm87 said:
Even a modest car battery could run our house for days.
Are you allowing for the step up to 240V? Raise the voltage and suddenly you need a shedload more current, thanks to Mr Ohm.

gangzoom

6,253 posts

214 months

Friday 14th February 2020
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Patrick magooagain said:
I would like to see proof of this please.
We choose one of the hottest days of the year last summer to visit the west Midlands safari park. Arrived at the park with 61% battery, after spending nearly 2 hrs crawling around in what ended up over 30 degrees C, had 54% battery left. So running air con full blast used 3.5% battery per hour.

If you are down to the last 10% battery and get caught in a horrific 2hr+ jam you will get stuck, but thats the same as in any combustion car running with the fuel light on.

Anyways with the way temperatures are going needing to keep the aircon on is far more likely than needing the heater on in a blizzard.




Witchfinder

6,250 posts

251 months

Friday 14th February 2020
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Simpo Two said:
Are you allowing for the step up to 240V? Raise the voltage and suddenly you need a shedload more current, thanks to Mr Ohm.
Sure, but modern household smart chargers are capable of V2G. Electricity usage for a usual UK home is about 10kWh per day, and a decent EV has a battery with many times that capacity.

InitialDave

11,856 posts

118 months

Friday 14th February 2020
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Aren't EV batteries more like 400v anyway?

Cledus Snow

2,088 posts

187 months

Friday 14th February 2020
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I sat through a Mercedes eVito training course yesterday. It advised just using the seat heater rather than the climate control as the HVAC system uses a lot of power and reduces range.

150km range at 80km/h drops to 100km.


bloomen

6,854 posts

158 months

Friday 14th February 2020
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I would support electric scooters stationed every five miles to hand out cyanide pills in this scenario.

LimSlip

800 posts

53 months

Friday 14th February 2020
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mcm87 said:
People don’t realise how much electrical energy these cars store. The motors for driving the car are massively powerful. A heater is insignificant in comparison. Even a modest car battery could run our house for days.
Which is why such large currents need to be drawn to charge them in a reasonable time, and even an overnight charge is a heavy consumer by household standards.

fatboy b

9,492 posts

215 months

Friday 14th February 2020
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Cledus Snow said:
I sat through a Mercedes eVito training course yesterday. It advised just using the seat heater rather than the climate control as the HVAC system uses a lot of power and reduces range.

150km range at 80km/h drops to 100km.
But why should you be limited? I’d rather drive a 5.0 petrol and fill it as required.

kambites

67,461 posts

220 months

Friday 14th February 2020
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I'm not convinced an EV will flatten its battery keeping the cabin warm any faster than an ICE will empty its fuel tank? Yes, an EV battery stores a lot less energy than a petrol tank, but it's a damned slight more efficient at turning it into something useful, be that cabin heating or motion.

Whilst EV heaters can draw several kw for brief periods, maintaining comfortable cabin heat is going to be in the hundreds of watts rather than the kw range (unless you intend to take your EV to somewhere it's minus 70 outside, I suppose). That realistically means something like a Kia Niro EV could keep its cabin warm for several days on a full battery in UK sorts of temperatures. I have no idea how long a typical petrol engine can idle on a tank of fuel?

Personally if I was going to be stuck in a traffic jam for ages, I'd rather that jam was made up of EVs than of petrol/diesel cars running their engines to keep warm!

Edited by kambites on Friday 14th February 19:35

xjay1337

15,966 posts

117 months

Friday 14th February 2020
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Mudgey said:
You don't need proof, you can work it out easily enough.

Now, I am using stats I can't confirm as I have never tested this personally (and why would I want to?). A vehicle uses 0.6 ltr/hour per litre engine capacity, so for example a 2ltr car would be 1.2ltr/hr, say 50ltr tank, would give us approx. 33hrs idle time to power heater or AC.

A typical air source heat pump in a vehicle has what say 2.6 COP efficiency? You probably only need 1.5kw to maintain temperature in a car, but lets say 2kw. So 2kw / 2.6 gives us a consumption of 0.76kwh's to power the heat pump. A full 64kwh battery out of a Kona or Kia would give you 84 hours of heat less system consumption when stationary <- this I don't have figures for either but can't imagine it's more than 100w/hr.

Either way, if a person is stupid enough to let the car run out of fuel or battery power then that would happen no matter whether they were driving an ICE or BEV.
My Fiesta has a display to show L per hour at idle.
It's 0.1L /pHR.