40% LOSS OF BATTERY RANGE

BMW i3 Forum

Help Support BMW i3 Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
K

kentheteaman

Well-known member
Joined
Oct 20, 2013
Messages
77
Location
County Surrey, UK
As soon as I bought i3Rex in March 2014 my work circumstances changed unexpectedly. Suddenly I found myself driving 100km (60miles) to work and 100km back home on 3 or 4 days week. So I use to go by battery and return by Rex.

The mileage as of today is 28,000km.

I use to get 120km per charge until Mid October. Then I started to notice Rex was finding it difficult to maintain the state of charge to 5kw/h. Then during the early November the SOC simply fell to 0kw/h.

Now in the last one week my battery charge range has drastically dropped. I only get 70km for full charge !!! That is almost 50% drop for the same type of driving. Loss of 55km.

Last week while was driving back home using Rex, the SOC dropped to 0kw/h and the speed of the car dropped from 70miles to 45miles while I was climbing a small rolling hill. I wont call it a mountain it was just a small hill. Then the car simply crawled at 40miles speed until it reached the top and picked up speed to 60miles while driving down hill.

Took the car to BMW and showed them the video of the dash board when the car speed dropped and crawling. They could not figure out what was wrong.

I think the battery has become weak and not able to hold charge. May be it is the winter cold makes it to perform less efficiently.

What ever it is, only getting 70km/charge is not what I bargained for.
i3 is the best car I have driven, so smooth and lovely.
But at 70km/charge, it is nothing but an expensive electric toy.

Hope BMW will be able to find a fix.

regards,
ken
 
Sounds like your battery is not getting hunky-dory cozy, which didn't matter when the weather was warmer; or maybe the battery heater recently conked out. Are you able to pre-condition the car and at that point monitor the battery temperature? Has your dealer?
 
At least in the USA, the battery warranty is 100K miles or 8-years, and it must still hold at least 70% as read out from the diagnostic display. Find out what yours is reading...you might end up with a new battery.

The colder temperature from my observation using a volt/amp meter during preconditioning is that you could lose easily 4-miles just because of the cold, and that's each time it needs to do that from cold (probably at least twice - once when you leave in the morning, and again when coming home. Extra stops long enough for things to cool off a bunch, could each take a 4-mile chunk out of max range. If you can precondition while still on the EVSE, you don't lose anything to the cold (or much) at least for the outgoing leg.

Many people have said, and you've just proved it yourself, that the REx's sweet spot while driving up a hill is around 56mph or slower. Go faster, you'll drop the charge, and if your battery was low enough, it just can't keep up. WHen you're essentially out of battery capacity, keep in mind the only thing driving the car is the 34-hp generator pack...when was the last time you drove a car with 34-hp? You can use the full 170hp of the electric motor only when there is enough current to make it turn, and with nearly zero SOC, it's just not there.

If you turn the REx on earlier to keep the SOC up, you may not run into that scenario...something the US version can't do right now, at least as delivered.
 
jadnashuanh said:
...when was the last time you drove a car with 34-hp?
Click to expand...

OK, you asked: Last summer in Italy I drove a 1961 Fiat 500D. It had a whopping 17hp, but navigated the rolling hills of Tuscany surprisingly well with a family of 4. Yes, you have to enjoy double-clutching. And yes, it only weighs ~500kg, but this was the most fun I've had driving in a long time...

They need to make an EV version of this car... oh wait, they did.
 
There are important data missing:
What speed are you driving at?
What mode, Comfort, EcoPro?
Do you precondition the car?

The reason that your car dropped speed is that the battery level was too low to support the rex. The rex itself cannot supply enough power to drive the engine at full speed, especially when climbing hills. Your dealer should know that. BMW says that it is working on this problem.
 
The battery pack had a high voltage air conditioner unit, when you pre-condition the car, it will warm up not only your cabin but the battery itself. It helps the range of the car, it is very normal if you own an iphone, try leave it outside in winter and you will see your battery drains much faster, compare the same when you put in your warm pocket.

You may need to ask the dealer to check if this special AC unit is bad one, at least for me, after less than 5k miles, my AC unit is with problem and cause the check engine light error, and the dealer is importing parts from Germany to fix it.
 
Lecram said:
There are important data missing:
What speed are you driving at?
70miles/h on cruise control.

What mode, Comfort, EcoPro?
Ecopro

Do you precondition the car?
I did not as I do not have access to charging away from home.

The reason that your car dropped speed is that the battery level was too low to support the rex. The rex itself cannot supply enough power to drive the engine at full speed, especially when climbing hills. Your dealer should know that. BMW says that it is working on this problem.

To start with the SOC was 15kw/h when I started.
That slowly dropped down to 0 with in 15mts of driving at 70miles/h in cruise control.
Click to expand...
 
old4d said:
You may need to ask the dealer to check if this special AC unit is bad one, at least for me, after less than 5k miles, my AC unit is with problem and cause the check engine light error, and the dealer is importing parts from Germany to fix it.
Thank you, Tony, I shall do that.
Click to expand...
 
jadnashuanh said:
At least in the USA, the battery warranty is 100K miles or 8-years, and it must still hold at least 70% as read out from the diagnostic display. Find out what yours is reading...you might end up with a new battery.
It is the same here in UK.
Hope it doesn't end up in that situation.
One never knows.

The colder temperature from my observation using a volt/amp meter during preconditioning is that you could lose easily 4-miles just because of the cold, and that's each time it needs to do that from cold (probably at least twice - once when you leave in the morning, and again when coming home. Extra stops long enough for things to cool off a bunch, could each take a 4-mile chunk out of max range. If you can precondition while still on the EVSE, you don't lose anything to the cold (or much) at least for the outgoing leg.

I will try that.

Many people have said, and you've just proved it yourself, that the REx's sweet spot while driving up a hill is around 56mph or slower. Go faster, you'll drop the charge, and if your battery was low enough, it just can't keep up. WHen you're essentially out of battery capacity, keep in mind the only thing driving the car is the 34-hp generator pack...when was the last time you drove a car with 34-hp? You can use the full 170hp of the electric motor only when there is enough current to make it turn, and with nearly zero SOC, it's just not there.

If you turn the REx on earlier to keep the SOC up, you may not run into that scenario...something the US version can't do right now, at least as delivered.
Now I engage the Rex when the SOC at 25% to prevent the same situation again.
It is kind of working well for me now.
I engage the battery again when I am closer to home to use the rest of the battery.

jadnashuanh,
Thank you for your suggestions.
Click to expand...
 
I'm afraid I might also be loosing battery range after only 6 months and 4,000km / 2,500 miles travelled. Since I purchased my i3 BEV back in May, I make a weekly round trip to a town that is exactly 50 km/31miles away. 80% of the driving is on a highway at an average speed of 120 km/h / 75mph. In the first months after buying the car, I'd arrive back home after the round trip with about 5 km left in battery. But starting a few weeks ago, I can no longer make that round trip at those speeds. In order to make it, I now have to travel at around 90kmh /55 mph in the highway, with no AC. When I do that, I also end up with about 5 km left in the battery... but again at a 25% reduction and speed an no AC... If I made the trip at the 120kmh I used to, there is absolutely no way I'd make it back home.

This post is not about finding techniques to reduce my consumption (I'm reading other posts for that), but simply about trying to understand why I can no longer make a trip the same way I was 3-4 months ago. The only factor that has changed is the weather, which is not extreme here, so we went from an average of 28 deg celsius / 82 F in the Summer to 18 deg Celsius / 64 F this time of year. If anything, you'd think my consumption would have been higher during the Summer months because my AC was set at pretty high levels then.

Any help is appreciated.
 
Yes, I second that, the battery life is every owner's concern here, and I also find the 20% difference between August and November reading here on my mileage.

I am only at less than 5000 miles here also, and if the battery degrade so much so soon, it should be every one's concern.
 
I mentioned it in other threads, but based on the volt/amp meter I installed feeding my EVSE, when it is cold out, and I precondition so I can see how much it takes to warm things up for optimum performance and comfort, it appears to me that the car is using the equivalent of about 3-4 miles of range. If you need to do this without the EVSE being attached, it is coming directly out of the batteries, and may need to happen multiple times over the course of the day between opportunities to reattach to your EVSE...so, 4-miles or so each warmup cycle. Once preconditioned, the actual battery useful capacity I think is the same, but getting there on battery use alone verses the EVSE and line voltage available means less in your battery to start with.

There is a service menu that shows SOC, and is what the dealer will use to determine if you have a warranty claim because your battery has lost too much. Keep in mind that that is 100K miles, or 8-years and the battery must still hold at least 70% of original as indicated by that service menu.

Until spring or summer when it warms back up again and the vehicle doesn't need to spend as much energy protecting the batteries and make you comfortable, you'll probably not know if the battery itself has lost any capacity. It certainly will move you a shorter distance in the winter unless you can park it where it is warm or you can precondition while still attached, but don't confuse that with loss of battery capacity.
 
The following applies to my Smart ED, and may apply to the BMW i4.

The lithium ion battery pack has an internal resistance which is greater in colder weather. The colder the electrolyte, the more resistance. Even if it is subtly more, maybe 10%, it still matters. Plus the car is conditioning the battery pack and cabin.

The loss in very cold weather exceeds 40%, the loss in midly cold still reduces range by 20%. It is absolutely noticeable, and only a few degrees Celcius is all that is needed to change the efficiency of the car.
 
I'm only showing 65 miles on a full charge at 3k miles on the odometer. It doesn't make any difference if I precondition. I think my battery has already degraded significantly as well. I accelerate really slowly on flat land, with no accessories on and drive in Eco pro plus. It's been in the 60s here in the Dallas area. I get the same Max rabge indicated at 35 degrees and my car is garaged.
 
Pixelpro said:
I'm only showing 65 miles on a full charge at 3k miles on the odometer. It doesn't make any difference if I precondition. I think my battery has already degraded significantly as well. I accelerate really slowly on flat land, with no accessories on and drive in Eco pro plus. It's been in the 60s here in the Dallas area. I get the same Max rabge indicated at 35 degrees and my car is garaged.
Click to expand...

I take it you have a REX?
 
Pixelpro said:
I'm only showing 65 miles on a full charge at 3k miles on the odometer. It doesn't make any difference if I precondition. I think my battery has already degraded significantly as well. I accelerate really slowly on flat land, with no accessories on and drive in Eco pro plus. It's been in the 60s here in the Dallas area. I get the same Max rabge indicated at 35 degrees and my car is garaged.
Click to expand...

Check your tire pressure to make sure they are at the right setting. I found mine were low and my range increased after I put them up to the correct pressure, plus in the winter month's I inflate them to about 1 to 2 psi over recommended because as the temperature drops so does the tire pressure. I do this only after the car has set and the tires are cold at home. After you drive the tires heat up and they even heat up faster if they are under inflated.

My dealer delivered the car with the front tires under-inflated by 9 psi.
 
I gave my REX to the dealer because of a range loss problem and they have been told by BMW to change the KLE. Should get the car back tomorrow.
 
MikeS said:
I gave my REX to the dealer because of a range loss problem and they have been told by BMW to change the KLE. Should get the car back tomorrow.
Click to expand...

Will be real interested in hearing the results of the new KLE, just don't quite see how the battery charger would impact range since it just takes longer to charge and you still should be getting a full charge.
 

Similar threads

T
Preconditioning of the battery while driving
Replies
2
Views
327
mojo
M
I
Our 2015 i3 BEV
Replies
0
Views
249
izak
I
M
Rex Works, tested several times by BMW (maintenance mode and driving), but...
Replies
8
Views
2K
spartacus68
S
B
Second BMW i3-REx
Replies
4
Views
1K
JohnnyCakes
J
bmwni3
Seeking Advice on Annual Maintenance, Battery Check, and Long-Distance Suitability for 2016 i3 REx
Replies
2
Views
232
bmwni3
bmwni3

Latest posts

Back
Top