A few weeks ago, a man named ’Don
Parsons of Denver, Colorado’ took his BMW i3 REx on a 128 mile road trip from his house
to Loveland Pass (Continental Divide, Colorado). He admittedly stopped at a
pizza shop whilst on his journey to recharge on electricity at their Charge-point EVSE where his i3 REx accepted 8.9kWh’s of
juice to help with the rest of the climb up the mountain. The car
showed 18 miles remaining at the top of Loveland Pass, and he nearly made the
trip entirely on electricity when 62 miles later the range extender kicked on
and he was only 2 miles from his home.
The trip summary:
-64 miles each way
-8,960 feet of climbing, 2329 Feet of descending on way out
-2329 feet of climbing, 8,960 feet of descending on way back
His next challenge was to
take his i3 REx up to the summit of Mt Evans which is the highest elevation paved road in the US. The trip would take him
over 14,000 feet above sea level and would most certainly push the range
extender beyond its limit. This was not the kind of road trip BMW envisioned
people taking the car on when they designed the REx, but nonetheless they have
to expect some people like Don would do just that.
After his trip up Mt Evens, Don wrote about his day! Want to
hear what he had to say? Keep reading…
“I've had my BMW i3 REx for
almost two months now and haven’t really used or tested the REx engine.
Before today, I’d driven about 1750 miles total with only about 10 miles using
the engine. I decided to drive from my house in Denver to the top of Mt.
Evans and return without stopping for gas or topping off the charge.
Using the REx engine in the mountains can be tough because the output of the small
engine can’t really put out enough power to go both highway speeds and climb
uphill. However, the road to the top of Mt. Evans is pretty narrow, has
steep drop-off's, no guardrails and a lot of cyclists sharing the road so you
really don’t want to go much faster than 35 mph. For this reason, I
thought the small engine could hopefully handle the climb.
For
those that don’t know, Mt. Evans is the highest paved road in North America
with an elevation of 14,130 feet above sea level! I live in Denver which
is at 5,280 feet above sea level. It’s 63.5 miles from my house to the
top Mt. Evans. With some up and down hill climbing, the total ascent is
12,446 feet and the total descent is 3,686 getting to the summit.
I set the car into Eco Pro+ and
set out on city streets of Denver, then I-70 west up the mountains to Idaho
Springs. Mt. Evans highway winds its way south from Idaho Springs to the
Mt. Evans summit in 28 miles. When I originally entered the destination
into the navigation system, the guess-o-meter said 61 miles of range. I
tried to keep the cruise control set to about 5 miles over the speed limit.
I was
surprised to find that the Rex engine didn't turn on until about 52 miles into the drive (about 10 miles from the summit) with a total trip average mi/kWh of
2.8 when the REx kicked on. However, about 1 minute after the REx turned
on I got a Brake error message that ended up making the brake pedal feel stiff
and pretty much unusable. Fortunately, I was still heading uphill and the
regen seemed to be working normally.
I could hear the engine speed
up during the straight parts of the switchbacks and as I slowed down for the
sharp curves, the engine almost immediately slowed down as well. I never
really wanted to travel faster than 35 mph so I didn't notice any performance
hit until near the summit. On the last few switchbacks, I put my foot to
the floor and couldn't get the car to travel faster than 26 mph. At close
to 14,000 feet of elevation, the engine was probably severely limited from its
usual output at sea-level. I've heard people say that an ICE reduces
power output by 5% for each 1,000 feet of elevation. In any event no
other cars were travelling any faster than 25 or 30 mph so I didn't feel unsafe.
I
finally made it to the top at 14,130 feet! The temperature had gone from
68 degrees in Denver to 35 degrees and quite windy. This road usually
shuts down for the winter sometime in September so they will be expecting snow
to start accumulating up there pretty soon!
As I
was getting ready to head down, I was worried about whether I would have any
use of the brakes since I had turned off the car and walked around the summit
for about 5 minutes hoping the error would reset but it didn’t and I still had
a stiff brake pedal. Since it was 35 degrees up there, I was pretty cold
and didn’t feel like waiting any longer so I thought I would start to head down
and see how well the regen worked to keep the car in control. You can
imagine how happy I was to have such a high regen rate because I felt like I
was in complete control all the way back home.
During the descent from the
summit down to Idaho Springs I was excited to see that the regen had built up a
full 25% of the battery SOC and the guess-o-meter said as high as 28 miles of
range on the battery. I drove home significantly on battery but the REx
kicked in a few times where there was some climbing. It also stayed on
once I got out of the mountains but I was easily able to maintain 75 mph on the
highway leading east back into the city.
Some stats
on the whole trip. I travelled 127.6 miles and averaged 4.9 mi/kWh and average speed was a total of 39.6 mph. I used a little over a quarter of
the rex tank which I think is pretty minimal for travelling almost 130
miles! As you can see from the picture, the brake error was still in place
when I arrived home. However, after being on my EVSE for a little over an
hour, everything was cleared out and a quick trip to grab lunch showed that
everything was back to normal.
I
should point out that I haven’t gotten any software updates yet as I haven’t
been able to set aside the time. Until this trip, the only error I’ve
seen from the car is the Check Engine Light, which remains
illuminated. There is a software update that will eliminate this waiting
for me at my dealer, so I guess it’s time to get the car into the shop for
the updates. Hopefully the brake error is related to the 12v battery
issues that others have discussed and will also be fixed with the latest
software version I’ll be getting.
When I
thought about getting the i3 Rex, I figured that I would use the battery over
95% of my driving miles. So far, it seems like I’m using the battery over 97%
of my miles. That said, I’m still happy to have the Rex as it completely takes
away any range anxiety when I’m travelling in the flats of the front range of
Colorado.
What
about the mountains? I was concerned about using the i3 REx in the mountains
and still believe that having a REx hold mode similar to the European version
of the i3 or the Chevy Volt would make this an even more enjoyable car in
Colorado. That said, a couple CCS fast chargers placed strategically off I-70
would go a long way to helping the issue. Locations in Idaho Springs,
Silverthorne (where the 8 Tesla Superchargers are located) Copper Mountain, and
Vail would be ideal spots to get a quick top-off and be truly useful in the
mountains. I’ve also kept my 335xi for long distance ski trips since it has all
wheel drive and is still a great car. However, even without the fast chargers I
was able to make it to the summit and home without a problem.
I’m
very happy with the the i3. The performance, handling, smoothness, and
quietness all contribute to a great experience. Like others have said, it’s
hard to go back to a regular internal combustion engine after experiencing
electric!”
By Millie Davis
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