A Salutory lesson to all i3 BEV owners
Discussion
Don't believe everything you read on the internet!!!
In an earlier thread it was mentioned that someone had conducted a test to see how much ACTUAL range their car had after zero and the conclusion was 10-15 miles post zero before the car conked out.
With the recent drop in i3 mileage due to the cold weather, yesterday i found myself pushing my luck...
I knew that i could conclude all my chores in the nearest town and get home, and i reckoned i would get back with -3 or -4 miles in the tank. close, but i should make it, says i....
How wrong could i be. at +1 mile the throttle became treacly recalcitrant, throttle response was barely present and the seat heaters stopped working, same for zero miles, after zero, you get "--" on the mileage readout, and a mile after that (on a dual carriageway) the epower side of the dash went down to half "oh s
t, this isn't going to end well" thinks i. Within a few hundred yards, the bars start counting down alarmingly quickly until you are left with neutral and regen only, at that point all i could do was keep the foot buried so i didn't regen and coasted to a side turning 1 mile from my front door.
Wifey wasn't amused!!!
walked home, got the 4x4 and car trailer and self recovered home. FYI, once i had coasted downhill (i was parked on a slight slope) to the bottom of the trailer, i had enough juice to get onto the trailer and i was able to back off the trailer at home, but after about 10 yards it refused to move.
So the lesson to be learned by you lot is that you have about 2 miles past zero and once it stops, you have about 20 yards of manoeuvring power, that's your lot!!!
In order to get it charged, i had to run an extension lead out the garage and plug the included 3 pin charger in for half an hour to get enough charge in to back it into the garage for a 'proper' charge.
What a berk......
In an earlier thread it was mentioned that someone had conducted a test to see how much ACTUAL range their car had after zero and the conclusion was 10-15 miles post zero before the car conked out.
With the recent drop in i3 mileage due to the cold weather, yesterday i found myself pushing my luck...
I knew that i could conclude all my chores in the nearest town and get home, and i reckoned i would get back with -3 or -4 miles in the tank. close, but i should make it, says i....
How wrong could i be. at +1 mile the throttle became treacly recalcitrant, throttle response was barely present and the seat heaters stopped working, same for zero miles, after zero, you get "--" on the mileage readout, and a mile after that (on a dual carriageway) the epower side of the dash went down to half "oh s
t, this isn't going to end well" thinks i. Within a few hundred yards, the bars start counting down alarmingly quickly until you are left with neutral and regen only, at that point all i could do was keep the foot buried so i didn't regen and coasted to a side turning 1 mile from my front door.Wifey wasn't amused!!!
walked home, got the 4x4 and car trailer and self recovered home. FYI, once i had coasted downhill (i was parked on a slight slope) to the bottom of the trailer, i had enough juice to get onto the trailer and i was able to back off the trailer at home, but after about 10 yards it refused to move.
So the lesson to be learned by you lot is that you have about 2 miles past zero and once it stops, you have about 20 yards of manoeuvring power, that's your lot!!!
In order to get it charged, i had to run an extension lead out the garage and plug the included 3 pin charger in for half an hour to get enough charge in to back it into the garage for a 'proper' charge.
What a berk......
The stand out thing in this post is that you noticed the heated seats switching off.
You knew you were super low on juice but your arse remained cold enough to justify the risk of leaving the seat heaters switched on. If you had forgone a toasted rear end might you have nursed it home. Did you have the heater and a/c turned on too?
You knew you were super low on juice but your arse remained cold enough to justify the risk of leaving the seat heaters switched on. If you had forgone a toasted rear end might you have nursed it home. Did you have the heater and a/c turned on too?
snotrag said:
What dave said - I can't understand knowing you are so low on charge, yet still having the heated seats on!
I'm also surprised the car let you get that low without either warning you, or turning things like that off itself.
It wasn't so much the seat heaters that caused the problem, moreso, going to B+Q the other side of town to get a box of screws and a countdown timer probably didn't help, or that blast down the dual carriageway earlier on in the day, or frankly, anything else i did with that charge.I'm also surprised the car let you get that low without either warning you, or turning things like that off itself.
My point was that, i had been informed that the car should be alright for about 10 miles past zero, i was about 4 miles from home and had a mile left, i expected to get back and i didn't.
Woulda coulda shoulda doesn't apply, i was pretty comfortable with arriving home on -3 and at least i now know what happens past zero. i just thought i would pass it on for the benefit of the group.
Electrical heating elements use a *lot* of power, so your heated seats very probably were the sole reason you didn't make it home easily.
I'm a bit baffled why you didn't turn them off as soon as you thought it might be a bit tight... the more toys you have turned on, the more juice they'll use.
If it had been me I'd have had everything I could turned off - radio, lights (if safe to do so), heater, fans etc.
Try it next time it happens
I'm a bit baffled why you didn't turn them off as soon as you thought it might be a bit tight... the more toys you have turned on, the more juice they'll use.
If it had been me I'd have had everything I could turned off - radio, lights (if safe to do so), heater, fans etc.
Try it next time it happens
Greg_D said:
It was an i3. That's why I wasn't surprised when the epower display started changing. I'd read that they do that
I'm surprised that an i3 owner thought they had 10 to 15 miles extra mileage hidden away when the range on the display hit zero. EV's are all about range, it's probably the single most important stat to think about when you're considering buying one so it's hard to imagine that BMW have engineered in any spare battery capacity above what is shown in-car.Saying that, it's useful info to learn what happens in this situation so thanks for getting the grief off your wife on our behalf
shandyboy said:
Electrical heating elements use a *lot* of power, so your heated seats very probably were the sole reason you didn't make it home easily.
I'm a bit baffled why you didn't turn them off as soon as you thought it might be a bit tight... the more toys you have turned on, the more juice they'll use.
If it had been me I'd have had everything I could turned off - radio, lights (if safe to do so), heater, fans etc.
Try it next time it happens
I would have thought the electricity consumed by the seats would be really low compared to the motor. Also I bet they run off the 12v system, not the main motive battery, so there would be a delayed effect anyway. If I turn my seats on with a full battery, then the range usually reduces by nothing or a mile at most so about 1-2%.I'm a bit baffled why you didn't turn them off as soon as you thought it might be a bit tight... the more toys you have turned on, the more juice they'll use.
If it had been me I'd have had everything I could turned off - radio, lights (if safe to do so), heater, fans etc.
Try it next time it happens
Thanks for the heads up Greg!
RossP said:
I would have thought the electricity consumed by the seats would be really low compared to the motor. Also I bet they run off the 12v system, not the main motive battery, so there would be a delayed effect anyway. If I turn my seats on with a full battery, then the range usually reduces by nothing or a mile at most so about 1-2%.
1-2% would be anything from 8-20 miles wouldn't it? Admittedly it would obviously be a lot less than that if we're not talking about fully charged.
I once flattened a car's 12v battery quite quickly by having the lights and radio on with the engine off whilst the other half collected a pizza from pizza hut (chivalry's not dead!), I know the batteries will be a *bit* bigger...
Edited by shandyboy on Tuesday 18th November 17:24
The thing to realise is the predicted range is a hugely complicated thing to get correct all of the time, so therefore some wiggle room is built in. This ensures that at worst case 0 miles range remaining means just that, but best case is there's still some usable energy to be had out the pack. Hence on some days you'll get to -10 miles, but on others you won't - as you found out!
I think this is one area where the OEMs will have to refine things significantly, we're all used to relatively linear fuel gauges that consistently show empty at the same point every time. With a range prediction it's a bit like asking the fuel gauge to do the same thing, but with a fuel tank that expands and contracts depending on environmental conditions; driving style and drive cycle, with a hidden fuel tank pixie occasionally stealing or donating fuel in parallel. A key input into this process is market data - both data from vehicles to understand how they behave out in the wild, and feedback from customers on how they expect them to behave.
I think this is one area where the OEMs will have to refine things significantly, we're all used to relatively linear fuel gauges that consistently show empty at the same point every time. With a range prediction it's a bit like asking the fuel gauge to do the same thing, but with a fuel tank that expands and contracts depending on environmental conditions; driving style and drive cycle, with a hidden fuel tank pixie occasionally stealing or donating fuel in parallel. A key input into this process is market data - both data from vehicles to understand how they behave out in the wild, and feedback from customers on how they expect them to behave.
Yes it is highly complicated, but with 10 miles left it will be a LOT more accurate than +/- 10 miles! I'd expect the reading to be easily within 20%.
Nissan have changed the Leaf software, so apparently now there is more "hidden" reserve, but I'm too chicken to try it.
Nissan have changed the Leaf software, so apparently now there is more "hidden" reserve, but I'm too chicken to try it.
amstrange1 said:
The thing to realise is the predicted range is a hugely complicated thing to get correct all of the time, so therefore some wiggle room is built in. This ensures that at worst case 0 miles range remaining means just that, but best case is there's still some usable energy to be had out the pack. Hence on some days you'll get to -10 miles, but on others you won't - as you found out!
I think this is one area where the OEMs will have to refine things significantly, we're all used to relatively linear fuel gauges that consistently show empty at the same point every time. With a range prediction it's a bit like asking the fuel gauge to do the same thing, but with a fuel tank that expands and contracts depending on environmental conditions; driving style and drive cycle, with a hidden fuel tank pixie occasionally stealing or donating fuel in parallel. A key input into this process is market data - both data from vehicles to understand how they behave out in the wild, and feedback from customers on how they expect them to behave.
I think this is one area where the OEMs will have to refine things significantly, we're all used to relatively linear fuel gauges that consistently show empty at the same point every time. With a range prediction it's a bit like asking the fuel gauge to do the same thing, but with a fuel tank that expands and contracts depending on environmental conditions; driving style and drive cycle, with a hidden fuel tank pixie occasionally stealing or donating fuel in parallel. A key input into this process is market data - both data from vehicles to understand how they behave out in the wild, and feedback from customers on how they expect them to behave.
Depends on the strategy/model being used and what conditions are used to remove all available power and prevent drive. If you're using lower cell voltages as a dominant cut-off criteria then battery pack balance can have a significant effect, as well as the load on the vehicle at the time. With heavy damping on the predicted range calculation, but relatively quick-acting de-rate/cut-offs to protect the battery it's challenging to integrate and calibrate.
Edit to add - I've read this as the OP's i3 conked out pretty much as it claimed to have 0 mile range left, whereas some other i3 bloke on the internet said he got a further 10 miles out of his after that point.
Edit to add - I've read this as the OP's i3 conked out pretty much as it claimed to have 0 mile range left, whereas some other i3 bloke on the internet said he got a further 10 miles out of his after that point.
Edited by amstrange1 on Tuesday 18th November 21:31
Good on you for pushing the car to its limits, for the benefit of the rest of us owners!
On the i3 forum, someone else did similar, and found that the car went about 5 miles extra:
"So on EcoPro+ I managed to get within 3 miles of home after the point where the sat nav said I was 15 miles away with 7 miles of range showing."
On the i3 forum, someone else did similar, and found that the car went about 5 miles extra:
"So on EcoPro+ I managed to get within 3 miles of home after the point where the sat nav said I was 15 miles away with 7 miles of range showing."
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