Weather change... reduced range

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noakey

Well-known member
Joined
Jan 27, 2014
Messages
398
Location
Swindon UK
Hi all..

Just wanted to share my observations re my BEV... All driving below is done on ecopro.

My normal daily commute is a total of 60 miles, and I always return home with about 30 miles range left, indicating a total range of 90 miles on my charge. Its always been dry, light and no air-con, with cabin heating at 19celcius.

Today it was dull and raining and cold and steamy.. so the same commute now included headlights, wipers and air con. I returned home with 10 miles range remaining... or a range of 70 miles.

So the headlights, wipers and aircon in total consumed 20 miles of range over a 2 hour period...

Just saying...
 
You have to take into account the ambient temperature. The colder it is outside, the less miles you will get on each charge. The use of the accessories further reduces the range.
 
That's about what I get here in Los Angeles with the a/c on constantly. My default driving mode is Eco Pro for the soft throttle, but with the climate control set to Comfort in the iDrive. If I run with everything in Comfort it drops even more, still with the REx I don't really worry. As summer turns to fall here, (it was 97/36 today) I hope to be able to drive in full Eco plus and see what kind of range we get.
 
noakey said:
So the headlights, wipers and aircon in total consumed 20 miles of range over a 2 hour period...
Yep, and we can expect that range to drop further when winter really sets in.

On Sunday night I drove the 200'ish miles back from parents which is something I've already done several times in my i3 and I usually arrive back with plenty of juice in the tank (after a fill-up midway). This time it was noticeably colder and as I was getting closer to home I realised it was going to be quite tight and I arrived with 9 miles remaining. It looks like, when the temps start dropping, I'll be having to slow down a bit from the 75mph that I set the cruise at.
 
I've got a 62 mile commute. In the summer I could comfortably do this with 30% range left. So about 90 miles range.

Last night the weather was appalling - very heavy rain. Not too cold though.

I managed to get 60 miles before the Rex kicked in. And the traffic was heavy so driving slower than normal.
 
The weather has definitely turned in the UK. The past couple days we have had about 10% less battery remaining when getting home. Our round trip is 74 miles, of which 37 miles is on the motorway and we set cruise to 60mph (if possible, usually traffic is going more like 50-55).

We find that we have to run the air just to keep the windows from fogging up. Temperature-wise we are fine/comfortable, air is on solely to keep the windows clear.

There was discussion somewhere where people concluded that heated seats are generally more energy efficient than heated air for the reason that seats heat just you versus the whole cabin for air.
 
:) Too new to the i3, but with my Prius Plug In, with the drivers heated seat on, no noticeable effect on the 10 mile EV range. Heated seats for the i3 as a $350 option is a bargain.
 
elptex said:
There was discussion somewhere where people concluded that heated seats are generally more energy efficient than heated air for the reason that seats heat just you versus the whole cabin for air.

So you get a comfy warm bum but crash into everything in front of you! :D

I think for sure the heated seats will be more efficient at keeping bodies warm, and would imagine that running the fan on max/window instead of AC the same might be more economical?
 
Rain, I suspect, is the main culprit in range loss during foul weather, more so than cold or humidity. Most ICE drivers won't notice it (because they're not looking out for it), but I have driven a Honda Insight, with hard narrow skinny tires, since the dawn of the century, and it absolutely struggles in the rain and fuel consumption rises steeply. I suspect what I call micro hydroplaning - constant slight slippage where the rubber hits the puddle. Even deflating the tires back down to factory specs makes no difference. Haven't driven the i3 in the rain yet — we are in the midst of a historic drought, after all — but I expect the same effect.
 
i3an said:
Rain, I suspect, is the main culprit in range loss during foul weather, more so than cold or humidity. Most ICE drivers won't notice it (because they're not looking out for it), but I have driven a Honda Insight, with hard narrow skinny tires, since the dawn of the century, and it absolutely struggles in the rain and fuel consumption rises steeply. I suspect what I call micro hydroplaning - constant slight slippage where the rubber hits the puddle. Even deflating the tires back down to factory specs makes no difference. Haven't driven the i3 in the rain yet — we are in the midst of a historic drought, after all — but I expect the same effect.

Well today, dull with little standing water. . Headlight on.. Ac on... heating on 19celcius.. wipers on auto cos it was raining light and on ecopro I had 80 mile range... so the only differing factor really was standing water... i suspect the drag is pretty significant.
 
Narrower tires with decent tread design is much less susceptible to hydroplaning than a wider tire - the vast majority of water moves to the sides, and when the sides are closer, it does it better. Now, throw in colder weather, and especially with performance tires, they get harder and will not perform as well as a tire designed for colder weather as will be clearly evident in comparison stopping and skid pad tests in the cold.

Water on the roadway means you are always slightly climbing a hill to get over the water buildup that you have to push away...that does take some energy.
 
i3an said:
Rain, I suspect, is the main culprit in range loss during foul weather, more so than cold or humidity. Most ICE drivers won't notice it (because they're not looking out for it), but I have driven a Honda Insight, with hard narrow skinny tires, since the dawn of the century, and it absolutely struggles in the rain and fuel consumption rises steeply. I suspect what I call micro hydroplaning - constant slight slippage where the rubber hits the puddle. Even deflating the tires back down to factory specs makes no difference. Haven't driven the i3 in the rain yet — we are in the midst of a historic drought, after all — but I expect the same effect.

Interesting thought, in that it is the exact opposite of what I have experience/concluded. We have come from a VW Passat with 225 wide tires and find that the i3 slices through water puddles like a knife. It is a drastic, day/night difference.

There is a spot on our daily commute that half of the time the road is covered in a couple inches of standing water. Because I have driven through it for years, it is my reference point.

Hit that puddle in our Passat and it is like pressing the brakes quite hard--the water resistance really kills forward momentum. I learned how much additional acceleration I had to give to overcome that slowing down and it is quite a lot. If I don't give more power, the car will slow from 40mph down to 25mph.

The i3 with its skinny tires is the exact opposite. I don't change the pressure I put on the accelerator at all and I go from 40mph to maybe 38mph. I'd venture to say it only dips to 39mph. The first time I drove the i3 through it, I did the usual increase of pressure on the accelerator that I was used to with the Passat and wound up increasing my speed to 45mph despite going through the water. Even my partner in the passenger seat could feel the difference and we were both enjoyably amused.
 
noakey said:
Hi all..

Just wanted to share my observations re my BEV... All driving below is done on ecopro.

My normal daily commute is a total of 60 miles, and I always return home with about 30 miles range left, indicating a total range of 90 miles on my charge. Its always been dry, light and no air-con, with cabin heating at 19celcius.

Today it was dull and raining and cold and steamy.. so the same commute now included headlights, wipers and air con. I returned home with 10 miles range remaining... or a range of 70 miles.

So the headlights, wipers and aircon in total consumed 20 miles of range over a 2 hour period...

Just saying...

A 20% drop in range in Fall vs Summer weather is worrisome.

What will happen on a winter day when it's -10C outside and there's snow to drive through?

In my range calc, which was posted here, I assumed a 25% drop in range (vs ideal conditions). That now looks unreasonably optimistic. Maybe more like 40-50% drop is more likely.
I don't think anyone on this forum has driven an i3 in these conditions...
 
Surge said:
noakey said:
Hi all..

Just wanted to share my observations re my BEV... All driving below is done on ecopro.

My normal daily commute is a total of 60 miles, and I always return home with about 30 miles range left, indicating a total range of 90 miles on my charge. Its always been dry, light and no air-con, with cabin heating at 19celcius.

Today it was dull and raining and cold and steamy.. so the same commute now included headlights, wipers and air con. I returned home with 10 miles range remaining... or a range of 70 miles.

So the headlights, wipers and aircon in total consumed 20 miles of range over a 2 hour period...

Just saying...

A 20% drop in range in Fall vs Summer weather is worrisome.

What will happen on a winter day when it's -10C outside and there's snow to drive through?

In my range calc, which was posted here, I assumed a 25% drop in range (vs ideal conditions). That now looks unreasonably optimistic. Maybe more like 40-50% drop is more likely.
I don't think anyone on this forum has driven an i3 in these conditions...

I seem to be at 80 miles range now... With the difference from the posting above being no rain. I still had ac and lights. So about 10% loss with lights and 5 degree celcius drop in temp. Will keep posting.
 
Hi Surge, guys,

my experience, so far, has led me to beleive that moist, coldish weather is at least as heavy on the battery (or maybe even heavier) as frosty weather. My guess ( ! ) is that with moist+cold the air drier (A/C) and heater have to work against each other to keep the cabin both defogged and warm, possibly consuming up to 10kW together (AFAIK, A/C = 4kW, standard heater = 6kW). Absolute moisture levels tend to be much lower when it starts dropping below zero, lessening the load on the drier.

Regards, Steven
 
Some of the difference will depend on whether you have the heat pump or not. In the USA, the heat pump is standard equipment. It's pretty efficient at making heat. Resistance heating is not, often by as much as a 3:1 ratio (and maybe more). If you can precondition the vehicle while still on the EVSE, that will make a significant difference. The sensors monitor the clarity of the view through the windshield, and will turn on the a/c when required to clear it. Pushing through snow, rain, or slush will take more energy than just running down a dry road. The i3, with its narrow tires takes a smaller hit on that verses something with wider tires on it, but it's still there. THere's a good reason why the BMW winter tire package is square (all the same size tires/wheels) verses the wider wheel/tire on some versions...it slices through the crud better, and takes a smaller hit for its softer tread compound than the less resilient all season stuff (and definitely softer than if you tried to use your summer performance tires when it gets cold!). Lots of shorter trips where the car cools off and has to be conditioned again will result in a hit on range verses a longer one where, once it is conditioned, it's easier to maintain than starting from ambient again.
 
Thanks. Well let's hope it's not more than a 20-30% drop in severe (-10C) snowy weather.

And the heat pump only comes with the BEV, not the REx.
 
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