Running out of (HV) battery in an EV

[mg4mc]

The AA had a stand at the Fully Charged show in Harrogate. They were showing their onboard recharging system, and their universal free wheel "wheels" that allow EVs to be towed by their regular vans with a single axle lift.

 

[Rolfe]

I've only seen one person run out of charge in real life.

About a year and a half ago-ish, I was at an Ionity charger when a recovery lorry with a then, just released, Audi Etron 55 on the back.

The Etron driver looked a bit sheepish but I suspect it was a journalist as that Etron model had only just been released for sale and the reviews had just been on Youtube a week or two earlier.

I wonder what led to that? Didn't they give it to him charged up?

 

[Rolfe]

If you look on Andrew Till's Youtube channel, "Mr EV", he once ran out of charge accidentally in his old LEAF and had to be flatbedded home.

That's the sort of thing I thought had probably happened sometimes - these Leafs only had a pretty short range, didn't they?

 

[Rolfe]

The AA had a stand at the Fully Charged show in Harrogate. They were showing their onboard recharging system, and their universal free wheel "wheels" that allow EVs to be towed by their regular vans with a single axle lift.

I know they have these, and it would be absolutely mad for them not to have them, and of course it's a great selling point that they have them, but I wonder how often they actually use them for real, rather than for people making YouTube videos about what happens if you drive a car to a standstill.

 

[Gadget Geek]

Found the video. It wasn't his LEAF, it was his e-Niro.


EDIT: Watch this one first.

 

[Rolfe]

Thanks for the link, great find. I see it was two years ago, but that's not that long ago, it's more recent than the link I posted above, where the cars were behaving as he was saying he would have liked the Niro to behave.

His GOM was lying to him, which is the main take-home message. I do wonder about that first reading he gives. 15% battery to cover 26 miles isn't something I'd want to rely on in my SR, especially in cold conditions - I don't think he mentioned it, but the external temperature on his dashboard was showing only 6C. But his GOM thought he could get 39 miles out of 15% battery at that temperature, which seems ridiculous. What size of battery does that thing have? I mean, I would have thought it was obvious it was lying even at that stage.

The way the range was dropping was also a big indicator of danger, as he admits. He's quite candid about being an idiot, first by setting off at such a low SoC, and secondly by not taking a charging opportunity he had when he passed his friend's house. And he also mentions electricity being everywhere, but he was too bashful to ask a random house to let him charge.

He's quite right that the GOM ought to give you a fair estimate of the miles you have left at a reasonable driving speed, without including miles where the car will be limited to 10 mph. But that already seems to be how most EVs behave, certainly the ones tested in the "How far will they go?" videos.

He also didn't mention the car giving him the option to hypermile at a relatively early stage in this process. My MG definitely did that, somewhere round about Abington, which is about 23 miles from home. I didn't take it up on that, because my GOM was showing 28 miles at that point, which seemed safe enough, so I don't know how much the range could have been extended with that feature. (I suspect this happened at around 15% SoC.)

If it's any comfort to anyone, as well as Bjorn driving the Trophy down and finding that it had a pretty decent buffer still there after 0 miles range was showing, my experience with my SR was very reassuring.

I started at Moffat car park (the site of the broken charger) which is 34 miles from home by the shortest route, but 44 by the motorway. I had 52 miles on the GOM at that point, I think. I was certain I could get home the short way (the A701), especially if I limited my speed, but I wanted to see what would happen. The advantage of going M74/A702 was that, although ten miles longer, there are chargers there - a full service station, Gridserves, Applegreen, the lot, at Abington. There are also some type 2 chargers in Biggar, about 11 miles from home. So by that route I knew I had options if the range started to drop precipitously as happened in that video.

I started off on the motorway with the ACC at 60 mph but it was driving me mad. I increased that to 65 and then to 70. I reasoned that the GOM was making its estimate on the basis of how I had already been driving on that trip, and I had driven to Moffat on the motorway with the ACC set at 75. So it should be good to get home driving the same way.

I got to Abington and was a bit confused about the distance, because the number 30 was in my head and if it was actually 30 miles still to go I was in a bit of trouble. However when I checked Google Maps, having pulled over by the service station, I saw it was only 23 miles, and remembered that the number 30 was actually "30 minutes driving". GOM was still behaving consistently, no precipitous drops, and showing (I think) 28 miles, so I went on.

It was just after that that the car asked me if I wanted to hypermile and I said no. The car went on driving normally and the GOM went on behaving consistently, and the projected range was always in line with the % charge, at roughly 2 miles for every 1% charge.

I got to Biggar and everything still seemed fine, GOM still telling me I had more range than I knew I needed, car not limiting power, so I passed up on the type 2 chargers there too.

I got to the Dolphinton straight on the A702, which was only 2-3 miles from home. Car still behaving normally at 5% charge. GOM still telling me sensible things. So I overtook another car, taking the MG4 up to 80 mph, which it did without any reservations whatsoever.

Got to the rapid charger in West Linton on 4% battery and GOM showing 8 miles remaining, which isn't a kick in the pants off what one might have predicted from the readings I set off from Moffat with. Lots of dashboard warnings to charge NOW please, but no power limitation and no turtle seen.

I can easily see how a lying GOM could trick you into doing something stupid, but if the GOM is giving you a range that seems wildly improbable from the % charge reading, you should know something's up.

 

[jackois]

Reserve petrol tanks on cars were very popular back in the day, I seem to remember that that some of the Rover cars had them and it could be operated by pulling out a “choke” like cable by the centre console ?.
When the manufacturers stopped fitting reserve tanks, for a while people would carry a can containing a gallon of fuel in the boot !.
Motor bikes have had a reserve tank for as long as I can remember.
As EV battery packs improve and get smaller, I guess it could be possible to have a “Get you home” section like a reserve tank ?.

Been there, got the tee shirt, Rover 2.2TC. Overtaking another car up a hill, cough, splutter, grab the reserve pull and listen for it catching again...

 

[Gadget Geek]

I like Andrew's videos as he is very candid and honest. His wife, Flaviana is Italian and is very . . . shall we say forthright in her opinions.

I never faithfully follow a Sat-Nav and always start looking for a charger when I'm down to 20% and look to be charging when it's at no less than 15%

 

[Rolfe]

I like Andrew's videos as he is very candid and honest. His wife, Flaviana is Italian and is very . . . shall we say forthright in her opinions.

I never faithfully follow a Sat-Nav and always start looking for a charger when I'm down to 20% and look to be charging when it's at no less than 15%

I should watch a few more, he seems a nice chap and very informative. Still not sure why the discrepancy between what his GOM was telling him and the % charge reported didn't ring warning bells, mind you.

In the saga recounted above, I had intended to charge at Moffat because that charger was only 25p a unit, but it was broken. Rather than sit on one of the type 2 chargers on the other side of the car park, or pootle home on the A701 at 50 mph, or pay motorway service station prices at Abington, I decided to see what would happen. Very reassuring, but I don't intend to make a habit of driving down to 4%, I assure you.

 

[Lovemyev]

I like Andrew's videos as he is very candid and honest. His wife, Flaviana is Italian and is very . . . shall we say forthright in her opinions.

I also like watching Andrew & Flavian’s video’s, great content !.

 

[Ian Key]

Going back to the Triumph Herald's reserve tank. The "switch" was a lever that lowered the fuel pickup tube further into the bottom of the tank.

As mentioned in another thread, many years ago I helped a friend of mine fit a 3.8l V8 Range Rover engine into a series 2A Land Rover and while we were at it we fitted a second fuel tank and filler on the other side of the car. The look on the petrol station attendant's face when we'd pull up between the line of pumps and fill both fuel tanks at once.

 

[Rolfe]

I suspect the motorbike reserve tank works in much the same way. It certainly worked, although I do remember wondering if it was possible to carry a small bottle of petrol in a saddlebag anyway!

 

[Lovemyev]

Going back to the Triumph Herald's reserve tank. The "switch" was a lever that lowered the fuel pickup tube further into the bottom of the tank.

As mentioned in another thread, many years ago I helped a friend of mine fit a 3.8l V8 Range Rover engine into a series 2A Land Rover and while we were at it we fitted a second fuel tank and filler on the other side of the car. The look on the petrol station attendant's face when we'd pull up between the line of pumps and fill both fuel tanks at once.

Triumph Herald …… Wow that takes me pack in time a bit !.
I have sat on the front wheel of those cars a few times, while serving my time ?.
The access to the engine was absolutely brilliant, the whole front just hinged up out of the way.
Nice comfortable place to sit while changing the plugs & points ( 25 & 15 thou ) then reset them noisy tappets ? ( All Triumphs are 10 thou ).
It’s crazy after all these years, that you retain some this useless stuff now, in the memory bank called your brain.
The Buick 3.5 V8 engine was a fantastic almost a bulletproof motor.
They should have fitted it into the Triumph Stag ( I know some had the conversation done ).
One of those detuned V8 engines squeezed into the MGB body was a complete widow maker.
The rear of the car was always wanting to over take the front of the car, by going sideways.
I remember doing an insurance write off, complete body-shell replacement on a 3 month old maroon coloured car, what a complete nightmare of a job !.
There was no room to work under the bonnet, how the hell they got that motor in there was a work of art.
Thank you for bringing back the memories Ian ?.

 

[Rolfe]

I actually prefer the series of tests on Carwow. There are several, this is the first one I know about.



They do several cars at once, driving in convoy, then the various drivers have their strategies to try to be near a charger when they conk out. The banter between the drivers is fun, and the various scrapes they get into as the cars give up are amusing. I think my favourite was the time someone begged to plug the granny lead into someone's domestic supply.

It was watching a bunch of these that got me thinking. They really had to work at it to get these cars to the point where they bricked. Just how likely is it that someone who didn't want to brick their car would actually manage to do it anyway?

I actually watched that again, and a couple of things struck me. Although the e-Niro was one of the cars, and it went second-furthest (behind the Tesla), and it did a decent percentage of its stated range, there was one car that was already in turtle and reducing power before it was showing zero range, and didn't get much beyond it. It's hard to say, given the format, but I think it might have been the Kia, the car that let Mr EV down. It certainly has a big battery, the range was quite impressive, but it could be badly set up so that it really means the zero range rather than "once you're past this the car will only crawl".

Second, at the beginning, they say they charged all the cars to 100% the evening before they set out, but some (all?) of them had lost a bit of charge overnight. One was only on 96%. My SE SR has been sitting at 100% for two days and it's still at 100%. Is it common for cars to leak charge overnight to that extent?

 

[Ian Key]

If the weather has been cold overnight that can affect the charge percentage until it warms up to the same temperature as it was when they were charged.

 

[Gadget Geek]

Second, at the beginning, they say they charged all the cars to 100% the evening before they set out, but some (all?) of them had lost a bit of charge overnight. One was only on 96%. My SE SR has been sitting at 100% for two days and it's still at 100%. Is it common for cars to leak charge overnight to that extent?

Some cars "wake up" and top up the 12V battery from the traction battery, reducing the % slightly.

Also, just a heads up, battery manufacturers warn against leaving them at 100% for long periods of time as it can cause dendrite formation in the lithium anode which shortens the useful life of the battery.

 

[Rolfe]

Also, just a heads up, battery manufacturers warn against leaving them at 100% for long periods of time as it can cause dendrite formation in the lithium anode which shortens the useful life of the battery.

Mine is the LFP battery. They're fine about sitting at 100% for a bit, and MG advises using them that way.

(I would have thought that losing 4% of battery overnight was a bit much just from topping up the 12v. And they all did it, and they had all been driven the day before. How much topping up would have been needed?)

 

[Rolfe]

If the weather has been cold overnight that can affect the charge percentage until it warms up to the same temperature as it was when they were charged.

It was quite a cold day, so that was possibly it.

 

[Rolfe]

EDIT: Watch this one first.

I only just saw your edit. So it had happened to him before, and this was FOUR years ago!

Again, his GOM was lying to him, and fell very rapidly after having told him he was OK for range. He said something interesting, that the car doesn't display battery %, just a linear or dial indicator. He realised if he'd been watching the battery % he'd have twigged that something wasn't right, but I think he said you have to press extra buttons to get it. (I noticed on that Peugeot e208 that I had the other day the display was the same. Just estimated range and a vague sort of line on a virtual dial.) MG have got this one right, anyway, the battery % is shoved in our faces, in duplicate.

That is a definite danger situation, missing a turnoff on a motorway. That was how I ran out of petrol once, when I was blocked from my exit, in the dark and rain, by a long HGV. (Fortunately I wasn't on the motorway when I ran out, they were still building the M74 at the time, but when I ran on to the old A74 I discovered that the next petrol station up had shut up shop, presumably in preparation for being swept away by the advance of the new road.)

Of course if that happens you should probably drop your speed right down, maybe even drive slowly on the hard shoulder if it's safer, but as he said, he still thought he was OK until the GOM suddenly changed its mind.

Moral of that story, as he says, is watch the battery % as well as the GOM, and cut your speed right down if you're in any doubt. It's interesting that he again didn't say much about the car going into turtle mode or giving him fair warning of what was about to happen. I think that particular model is a bit problematic in that respect, although it does have a great range if it's charged.

You'd have thought, after that experience, that he'd have been a lot more wary the day he took his little girl to the park.

 

[awbugritt]

Went out in my Zero electric motorcycle, arrived at my destination with 52%. Plenty thought I as I've run it to 0% and still done 5 miles in the past. Not on this day though! Started pushing 3 miles from home which on a very hot day in leathers is particularly unpleasant, until I had a brainwave: Knowing that batteries can recover slightly I thought that I could carry on pushing with a little judicious throttle input. The bloody thing took off like a scalded cat, buried the front wheel in the hedge and threw me on my back like a stranded tortoise! Fortunately a passing couple came to my rescue and I was able to actually ride the bike at about 2 mph along the cycle path and home. Moral? Factor in the terrain -it was mostly downhill on the outward trip !