This post was written by Tom Moloughney, who drives Mini E #250. Tom has opted to keep his Mini E for another year. As you know, we've returned our electric Mini, so we've asked Tom to check in with us from time to time. He is quickly approaching 40,000 miles on the odometer. Here is his latest update. -- Donna DeRosa, Managing Editor
This summer has officially been confirmed as the hottest in recorded history in New Jersey. Not only has the kitchen staff at my restaurant been suffering through the extraordinary heat day after day, but so have the 5,088 lithium ion battery cells that are in my Mini E.
Last summer was mild and I never really had to deal with extremely hot days that would tax the Mini E's primitive thermal management system. This is the biggest flaw of the car by far. This is where it is evident the car is a prototype and not meant for production. The battery pack is very dense and sort of like three large blocks on top of each other. The only way to cool or heat it is a small fan that blows cabin air across it. On 100-degree days when you are driving at highway speeds, all you can do is watch the battery temperature gauge go up and up until the warning icons appear. There is no way to cool it down even if you have the A/C up full blast to get as much cool air in the cabin and ultimately across the modules.
More story and pictures after the jump...
At 106 degrees (battery temperature) I start to get frequent audible warnings with the temperature icon blinking. A few degrees hotter and the reduced power icon appears, meaning the car will not provide full power to the motor and the regenerative braking will be less aggressive since charging the batteries heats them up even more. The reduced power is barely noticeable unless you really punch the accelerator so it really doesn't affect normal driving.
At 116 degrees the regen completely disengages and you have to be prepared to use the brakes to slow the car. This might sound strange to some of you because using the brakes is what people do to slow down, right? Not with the Mini E. Since it normally has very aggressive regenerative braking you learn to drive with only the right pedal. I only use the brakes in emergency situations now, so having the regen disengage feels really strange as the car coasts like a normal car does when you ease off the accelerator. This is not possible when the regen is activated under normal conditions.
Another issue is that when the batteries are over 110 degrees, the car doesn't want to charge. On a few of the really hot days, after driving a while at highway speeds and then plugging in, the car waited until the battery temperature lowered a bit before it would charge. Then, by charging the temperature rises again, causing it to temporarily stop. This was only a problem when I charged during the day at work as the car is parked outside in direct sunlight and it was difficult to cool off. When I got home after dark and parked in the garage, I never had a problem. Every morning the car was fully charged and ready to go. I do suspect it may have taken longer than the usual 4 hours to charge when it was hot, but since I was sleeping and had 8 or 9 hours to spare, it didn't matter.
As for range, I have only noticed a difference in temperatures over 90 degrees. It's not nearly as profound as in cold weather with the heater on. I have observed a 10% to 15% reduction on these really hot days with constant use of the air conditioner. Other than these issues, the car has been running fine and I haven't needed any service visits since I hit a pothole in February and damaged the front end. I am approaching 40,000 miles now and recently did a blog post on reaching that milestone.
I continue to use the car as my daily driving commuter and for errands during the day. These heat-related issues never prevented me from using it. I just had to slow down a bit and try not to overtax the cells on the extremely hot days. Before everyone starts drawing conclusions about how EVs can't deal with the heat, remember this is a test car, not a production EV. BMW would never sell a car with this thermal conditioning flaw. The temperature management system is much more primitive than anything you'll see in any production car. Even the Nissan Leaf that has a similar passive thermal management system is much better designed to heat and cool the batteries, plus you can condition them while plugged into the grid, something that the Mini E cannot do and I really wish it could. Other EVs like the Chevy Volt, Tesla, Ford Focus EV and future BMW EVs will all have an active thermal management system that will practically alleviate all weather-related range issues as it will condition the batteries to keep them at optimum operating temperatures regardless of the ambient temperature.
I still have never run out of charge and don't yet need to see a shrink to get over the terrible condition of range anxiety that is rumored to affect all electric car drivers. Although I did have a dream once about it, so maybe it is beginning to infiltrate my psyche. I did, however, recently complete a 130.1-mile trip on a single charge, my personal best so far.
Mini E #250 @ 39,555 miles
hybris says:
08:32 PM, 09/16/10
Wouldn't putting a tarp over the car help somewhat with the charging issue?
slickersdrip says:
08:42 PM, 09/16/10
Considering that the sincere idiot isn't around here anymore, perhaps put some cash towards Tom as a part time editor? Love these updates, thanks for keeping the car and all of us apprise of how it's going.
tomm250 says:
09:05 PM, 09/16/10
Hybris: I don't think that would work because it wouldn't allow fresh air into the cabin. When it's parked in direct sunlight on 100 degree days the best thing to do is open the windows to allow as much air into the cabin as possible as the fans blow air from the cabin into the battery module compartment. It really wasn't a problem, I just had never seen the car refuse to charge before so I thought it was worth noting. On these days it took about 6 hours to fully charge when it usually takes about 3.
acbayard says:
09:16 PM, 09/16/10
A tarp with an aluminium surfacing will help lower the green house effect. Unfortunately, when it is 110 out, you're not going to get much convection cooling with flowing air alone.
anthonylam66 says:
09:31 PM, 09/16/10
Nice post. I'm with slickersdrip, how about a monthly update from Tom? With all the electric cars on the horizon, it would be nice to get more long term info on the MINI-E, especially with the winter coming. He's at 40,000 miles now, how are the batteries holding up? Any degradation yet?
Make it happen Donna!
firstwagon says:
09:34 PM, 09/16/10
Interesting. I always thought the biggest problem with electric cars would be the cold. Never really thought about the heat being an issue.
I'd be curious to have one here in Vancouver. The temp rarely goes above 80 F so it might do well here.
Good write up BTW.
super_ongoy says:
09:39 PM, 09/16/10
Montclair, NJ? Is that near or just below Upper Montclair? Logic would dictate that it would be but the world no longer operates based on logic (Mini E).
Anyway, I think I lost a testicle or two from laughing when I read, "I only use the brakes in emergency situations now." Plow through!
bodyshopboy says:
03:01 AM, 09/17/10
Add a Tesla to the Fleet? That would be interesting....
ms3fun says:
03:42 AM, 09/17/10
bodyshopboy says:
Add a Tesla to the Fleet? That would be interesting....
+1 on that idea
You guys could get the Model S when it comes out in 2012. Four door sedan with a 300 mile range and it's quicker then most cars IL has in their fleet.
That would make a great long term car for you guys.
What do you think Donna?
tomm250 says:
05:05 AM, 09/17/10
Firstwagon: Overheating the Li-ion batteries is the biggest problem. Continued exposure to high temperatures (over 150 degrees) can permanently degrade the battery. That's not so in the cold weather, when the only side effect is reduced range and that's temporary until the battery warms up.
Thermally conditioning the battery in EV's is crucial to the longevity of the battery, as well as offering a consistent range regardless of the outside temperature. As much as I have grown to love the MINI-E, as I wrote above, the lack of any real thermal management system is obvious when it's either hot or cold outside, and we get both extremes here in the Northeast.
I think it's possible than BMW may have purposely designed the car like this to fully expose the weaknesses so they could better understand the conditions that cause problems. Next summer when the MINI-E program is finished and I have to give it back, BMW is starting another testing program like this with an all electric BMW coupe. It's a 1 series with four seats and a trunk and is called the ActiveE. It has an active thermal management system that keeps the battery within a set temperature range regardless of the ambient temperature. I'm anxious to see how well it works and hopefully IL will let me report here how that car performs.
tomm250 says:
05:07 AM, 09/17/10
I meant 105 degrees in the above post, not 150 (gotta get comment editing here!)
bodyblue says:
06:40 AM, 09/17/10
Tom, Thanks for taking the time to tell us about your car. You will be attacked like the last time you blogged and I hope that does not stop you from sharing with us. The folks that attack even the concept of an electric car have other issues than what they talk about on here. I am not sure I would want an electric car but your experience has been really interesting.
ptcdawg says:
06:47 AM, 09/17/10
I like reading this type of info. Keep up the good work.
old_volvo says:
07:24 AM, 09/17/10
interesting post. Are the batteries really inside the car? I have recorded temperatures as high as 130 inside my car on sunny days, would that have a detrimental effect on the batteries?
tomm250 says:
07:52 AM, 09/17/10
Bodyblue:
You're welcome, thanks for commenting. I write guest posts for a few other websites and blogs also, so I'm used to being called an idiot or a wacko, liberal environmentalist. Funny thing is, I'm actually a moderate-right leaning republican and not an Al Gore disciple. Some seem to think the only people interested in electric cars are the people you see holding up global warming signs and protesting the war in Iraq. Energy independence isn't a republican or democratic thing, it's a national issue that effects us all for economic and security issues as well as environmental.
I'm a car guy like many others here. I've owned a twin turbo RX7, a Porsche boxster, and when I was 18 I put a nitrous oxide kit on my 86 Honda CRX-Si to give it almost 200hp under boost (the car weighed 1,800lbs) and used to love to see frustrated 5.0 mustang and IROC owners in my rear view mirror.
Electric drive IS fun. This car is nothing like driving a prius or any other econo-box. Plugging in takes about 5 seconds and the car charges while I'm working or sleeping so for me it really doesn't matter if it takes a few hours to fully charge. Even if you drive 2 hours a day you still have 22 hours that the car can potentially be charging.
Of course there are limitations, and if you only have one car a 100 mile BEV would probably be a poor choice, but there are many people that it would work perfectly for and save them a lot of money in fuel and maintenance, plus they wouldn't be sending their energy dollars outside the US. Coal isn't clean, but at least it's our coal and the money spent on it stays in our economy.
tomm250 says:
08:01 AM, 09/17/10
old_volvo: Yes they are. The MINI-E is a prototype, and will not be sold. BMW wanted to get the car on the road ASAP and the easiest way was to simply remove the back seat of a MINI Cooper and dump a 35kWh battery block behind the drivers seat. This configuration is bad for convenience (limited cargo space) as well as for thermal conditioning. Most all EV's that make it to market will have the batteries located below the drivers compartment and trunk/hatchback area so you won't even notice them.
Here's a link to an illustration of the MINI-E. Notice the huge black box in the rear of the car where the back seat would be, that's the batteries:
http://www.independent.co.uk/life-style/motoring/motoring-news/mini-and-mitsubishi-start-uk-electric-car-trials-1840347.html?action=Popup
minie183 says:
11:58 PM, 09/17/10
Tom,
Great post.
As a Mini-E driver #183 with 20,000 miles (Tom has officially lapped me) I find it fascinating that I also am a moderate Republican. I had assummed that most/all or my fellow drivers would be Democrats (nothing worng with that, half my family are Democrats)
I am hopeful that the electric vehicle and renewable energy, wind/solar/hydro/geothermal/bio will reach the point where it is the answer regardless of political affiliation.
As to the car. I love my Mini-E. when I was 16 I used to wash my cars by hand. The last car I washed by hand was a 90 twin turbo RX7, That was my second favorite car of all time (It only had two seats) I find myself washing #183 by hand,
Now that's the sign when a guy loves his car.
I am going to hate give this car back.
Keep writing Tom!
Cheers
Peder