Six hours in a traffic jam...

[Rolfe]

... and all the electric cars were running out of battery.

Well, that's the story I was told in the Post Office this afternoon. Of course it was second-hand and I don't even know where this immense traffic jam is supposed to have happened.

I mused that EVs don't use much energy at very low speeds, so I was surprised. Oh well, came the answer, the traffic was constantly inching forward, just a wee bit at a time, and it was a shame really, all these electric cars were stranded because their batteries were empty.

This smells a bit like an urban legend to me. Is it even likely that an EV battery would drain in six hours under these conditions? If it is an issue, and you're stuck in a jam like that and you see your charge going down, what should you do? Switch of the AC/heating and audio systems for a start, I assume. In an ICE car, if I was low on petrol, I'd switch off the engine until a gap had opened up in front of me then switch it on, drive to close the gap, then switch it off again, rinse and repeat. Even then, though, I've sometimes wondered whether constantly restarting the car might be counterproductive.

Thinking about it, if this was me and I was getting worried by the car eating electrons and I couldn't see a way out, I think I'd try to get it in to the side of the road, power off and simply sit it out until the road cleared, however long it took, rather than let the battery drain. If I couldn't get to the side of the road I'd simply sit where I was and let other vehicles do what they liked. Anything but allow the battery to run down. But would that even happen? Interesting intellectual exercise.

 

[meicd]

I can only just drain the battery with 6 hours of driving let alone standing still. Wouldn’t use hardly any battery.

 

[Lucky5]

I’ve done a couple of hours in a jam in summer so aircon rather than heating and the drain was so small I can’t remember how little it went down

 

[Rolfe]

I can only just drain the battery with 6 hours of driving let alone standing still. Wouldn’t use hardly any battery.

What if your battery was only at 50% or lower to start with, or maybe you had a car with a very short range like my neighbour's Zoe? What if it was very cold and you kept your heater and fan on?

I'm still not really buying this story though.

 

[Rolfe]

I’ve done a couple of hours in a jam in summer so aircon rather than heating and the drain was so small I can’t remember how little it went down

Interesting. I've not been in a jam of any sort yet, so I don't know how the car would behave. I was reluctant to tell Sandra, who told me this tale, that she'd been fed a line, but that was my immediate reaction.

Maybe one car, a low-range model, that was already getting low when it got caught in the jam?

I'm wondering if it's a story made up and set loose to discourage people thinking about EVs.

 

[DenisG]

Interesting. I've not been in a jam of any sort yet, so I don't know how the car would behave. I was reluctant to tell Sandra, who told me this tale, that she'd been fed a line, but that was my immediate reaction.

Maybe one car, a low-range model, that was already getting low when it got caught in the jam?

I'm wondering if it's a story made up and set loose to discourage people thinking about EVs.

IMHO this is not correct. I was waiting in a car park (Eurotunnel) with the heating on last night for two hours used 1% (64kw LR luxury/trophy - mine has a heat pump though!).

 

[tsedge]

An EV can run for days without moving, especially if AC and lights are off. They can run the average house for up to a week.

So this is urban legend nonsense. It is the ICE cars that would have flat 12V batteries and run out of petrol first.

 

[Rolfe]

An EV can run for days without moving, especially if AC and lights are off. They can run the average house for up to a week.

So this is urban legend nonsense. It is the ICE cars that would have flat 12V batteries and run out of petrol first.

That's what I thought. But having owned an EV for the grand total of two weeks (I was actually in the Post Office to cash the cheque the DVLA sent me as a refund on my previous car's road tax), and knowing nothing at all about them before the beginning of this month, I didn't want to jump right in and say so.

I was just about prepared to credit that it might have happened to one person who was already low when they got into the traffic jam and didn't have the sense to turn off the AC and lights and kept inching forwards the whole time, but even there I was sceptical. The "all the electric cars ran out of battery" part was just incredible from the start. (It's also something that I think would have been all over the news and social media if it had actually happened.)

 

[StackH]

I can actually counter this with real life experience. Only a few weeks into owning my EV I was caught in a road closure - about 500m from the accident that closed the road on a dual carriageway.

This was January, and I was sat there from just before 7am until midday, when the police finally started turning traffic around and back up to the nearest junction.

It was snowy weather, so I had the heater on all the time and obviously the infotainment (during which I found I could watch Netflix and Disney+, which was a bonus) but in those five hours I think I lost 2-3 percent of battery.

My biggest worry wasn't the battery, but my bladder. I'd stopped at Starbucks on the way to work and had finished my large latte around 07:30 so by midday my eyeballs were floating.

 

[Ian Key]

A quick Google produced the ammunition you need to tell her she was spun a lie...

Fact Check-Electric cars not more likely to get stuck in traffic jams

A graphic circulating online has claimed electric cars run out of power in three hours when stuck in traffic jams, leaving people stranded with no heating. However, electric cars use little power when not moving and would likely last longer than petrol cars with the heating...

www.reuters.com

 

[Rolfe]

Thank you both for that. I'll have the confidence to tell her that someone spun her a line when I see her next. (I see inflation has struck. It was six hours in the jam when I heard it!)

 

[Rolfe]

I can actually counter this with real life experience. Only a few weeks into owning my EV I was caught in a road closure - about 500m from the accident that closed the road on a dual carriageway.

This was January, and I was sat there from just before 7am until midday, when the police finally started turning traffic around and back up to the nearest junction.

It was snowy weather, so I had the heater on all the time and obviously the infotainment (during which I found I could watch Netflix and Disney+, which was a bonus) but in those five hours I think I lost 2-3 percent of battery.

My biggest worry wasn't the battery, but my bladder. I'd stopped at Starbucks on the way to work and had finished my large latte around 07:30 so by midday my eyeballs were floating.

I used to live in the south-east of England. I remember several traumatic episodes on the M25, including one where my Fiesta's engine overheated and I had to be rescued by a mechanic in a yellow truck who wired my fan so that it ran constantly. In another one I was stuck for ages on a raised flyover section in exactly the situation you describe. If it had been on a normal section I could have made it to a grass verge or somewhere and dropped my pants, but there was nothing. I was thinking guys might have it easier...

I managed to make it to South Mimms, stopped the car just anywhere, and sprinted for the Ladies.

 

[gus]

Had to laugh @Rolfe, guys would be playing fountains off the flyover

I have just got stuck in a traffic jam at our local traffic lights (3 cars, well I am rural) I was watching the current demand as I pulled to a stop 20 amps, turned the heater off 0 amps, hence demand is very low when stationary, last time I got stuck in a jam in an ICE I was more concerned about fuel level and if my battery would continue to start the car if I kept switching off and on.

 

[Rolfe]

It's interesting that the "oh noes!" tenor of the posts highlighted by the Reuters fact-check was all about how everyone would freeze to death because EVs don't have much heating. That's probably a bigger worry with ICE cars as you have to keep the engine running to get heating, and if you're stuck all night there's a good chance you could indeed run out.

There wasn't any mention of the fact that if you run out of petrol in an ICE car then you'll be OK so long as someone brings you a can of the stuff, whereas an EV with a dead battery is a great deal more difficult to deal with. It suggests that whoever dreamed it up didn't know much about EVs at all.

 

[Rolfe]

So the advice for the EV driver caught in a long jam is, sit there, use whatever you need to stay warm (or cool) and don't worry about it. Which is a lot less stress than you'd be under in an ICE car, in just the way gus indicates.

 

[gus]

Just thinking, dont even need the heating on - just turn the heated seat on, uses even less energy.

 

[Ayoull]

AC compressor at full tilt pulls 6.4kW, SE SR pulls 0.2-0.3kW just being turned on.

So if we take 6.7kW as worst case stationary with it that hot the Aircon had to be on full constantly it would be 7.58hrs to drain the useable 50.8kWh SE SR battery.

But Aircon is an intermittent load so would last longer.

 

[Rolfe]

Just thinking, dont even need the heating on - just turn the heated seat on, uses even less energy.

If you have heated seats, sure.

 

[Rolfe]

AC compressor at full tilt pulls 6.4kW, SE SR pulls 0.2-0.3kW just being turned on.

So if we take 6.7kW as worst case stationary with it that hot the Aircon had to be on full constantly it would be 7.58hrs to drain the useable 50.8kWh SE SR battery.

But Aircon is an intermittent load so would last longer.

I suppose we can't assume that the car would have a full battery when it got caught in the jam, but even at 50% you'd be safe for a while.

It's telling that the original criticism wasn't apparently that you'd drain your battery, but that you'd freeze to death because the car was incapable of being effectively heated. That's obvious nonsense.

 

[Mr Savage]

My Nissan Leaf 30kWh could maybe drain 1-2% on a 40-minute ferry with heater and music on so it has to be a long traffic jam to drain an EV battery.

Bjørn Nyland (Teslabjørn) spent the night in a 2021 Model 3 in "camping mode" at -20c. He drained 20% during the night while keeping the temperature inside the car at 19-20c and watching Youtube on his car monitor.

Started at 87%, and ended at 67% (8:51)