From the first word that the
North American version of the i3 REx would have restrictions not found on
its European counterpart, i3 enthusiasts and customers in the US and Canada
have wondered how well it would work under strenuous driving conditions.
In
fact, it is by far the topic I now get the most correspondence over. I have
probably received over 100 emails through this blog from followers that want to
know how well the range extender works and how capable it is. People want to
know things like what speed the car can maintain in charge sustaining mode and
for how many miles can the car maintain highway speeds on a certain percentage
upgrade, and so on.
I even have had people ask me
if I could conduct specific tests with my car to confirm it can do what they
need it to. The reason being is the 34hp REx engine can only deliver about
25kWs (although some reports say BMW upped it to 28kWs) of power. That is
plenty of power for nearly all normal driving needs, but not enough for
continued high speed or long upgrade driving. The problem then arises if you
continue to consume more energy than the REx can deliver.
The
root of the problem reverts back to BMW’s desire to have the i3 REx certified a
BEVx vehicle by the California Air Resource Board. This allows BMW to get the
most ZEV credits per vehicle, and also allows the i3 REx to qualify for other
perks, like sales tax exemption in New Jersey and Washington State. It also
allows the owner to get the full $2,500 California CVRP
rebate, unlike all other PHEVs which only get $1,500. However this came with a
cost. BMW had to restrict the REx use to comply with CARB’s BEVx
classification. The European i3 REx can be manually turned on any time the
state of charge is lower than 75%. This is called a Hold Mode and allows the
driver to hold a higher state of charge and keep a higher battery buffer which
they may need for continued strenuous driving conditions later in the journey.
The North American version has no Hold Mode, and the range extender only comes
on when the battery is reduced to a critically low 6.5%. For normal driving
that is fine, but when really pressed for continued periods, the car cannot
maintain full power.
This creates a problem
when the driver needs to drive for an extended period which demands an energy
draw of more than 25kWs. The meager 6.5% battery reserve can quickly deplete in
these conditions. When this happens, the car goes into a reduced power mode and
can only maintain a speed of about 40mph. To make matter eve worse, the driver
gets no warning and the car just slows down. This is not what you want
happening to you when you are on a highway and cars are whizzing by you at
70mph. This is a real issue, and compounded by the problem that most BMW client
advisers didn’t know how to communicate this to the customers and sold them the
cars without informing them how to properly operate the vehicle in REx mode.
I’ve had people contact me that were completely unaware of how the range
extender worked and said they were told by their client adviser that “the car
can do anything in range extender mode as it can in all electric mode, it just
doesn’t have quite as much power.” That isn’t true, and many early i3 REx
customers were disappointed when they found out they couldn’t drive up that
mountain to their summer home, for example. In fact, one the Born Electric guest bloggers here mentioned an instance where he went into reduced power mode with a
car full of friends.
All that said, I now have
over 10,000 miles on my i3 REx and not once have I ever gone into reduced power
mode, and I’ve actually tried to make it happen! The “problem” I’m having is
the highways are relatively flat here in New Jersey and the REx can basically
handle anything I give it. The times I have tried to make it happen the flow of
traffic wasn’t fast enough for me to maintain a speed of over 75mph for a long
enough period. 75 mph on relatively flat ground seems to be the upper limit the
REx can handle for continued driving. There is plenty of energy to go up and
down the hills I routinely drive over, and also to have short bursts of power
well past 80 mph for passing if needed in REx mode, so for me the car works
perfectly and I really don’t need a modification. However my friends in
California and other areas of the country that have long, steep inclines to
negotiate disagree, and want to see some kind of modification to allow the
range extender to turn on at a higher state of charge so the vehicle has a
larger electric buffer. In fact, there will soon be a two-part post here by an
i3 Rex owner in California that has been obsessing a bit over this very topic.
(well, I call it obsessing, he calls it studying – I’ll let you be the judge when
you read his post next week!)
So now that we
understand the problem, what is the solution. Should BMW simply give up the
value of the BEVx designation and allow the driver to initiate Hold Mode as the
European i3 REx owners can? That isn’t happening as far as I can tell. What I
do believe is going to happen? Well for starters there will be software updates
that include better indicators that the car may be headed to reduced power mode
if you don’t take action to alleviate it. Perhaps by slowing down 5-10 mph you
can completely avoid having a problem at all. I also expect there will be a
better state of charge display so the driver has more accurate display of how
much power they have left. I would also love if BMW could add a display that
would show the actual power draw you are using, so the driver can see if they
are drawing more energy than the REx is producing. That would be an awesome
tool for the driver to use in these situations and I do hope the BMW engineers
consider adding it.. However I’m saving the best for last. It is my belief that
BMW is working on an update that will indeed allow the range extender to turn
on much earlier than the 6.5% threshold if the car determines you will need the
extra power. This will work with the navigation system which accounts for
topography. Once a destination is entered, the car will determine how early the
REx will need to be turned on so it avoids reduced power while climbing an
upgrade at the end of the journey.
While this isn’t quite as good
as having the ability to manually turn on the range extender, it’s pretty
close. The bottom line is people just want to be able to get to their
destination without worry of a reduced power “slowdown” while driving on the highway.
If the modifications that BMW are working on do indeed work, I don’t think
anyone will complain. In fact, I’ve privately asked this very question to quite
a few current i3 REx owners and every one said as long as it works, and they
can use the car to drive up long, sustained inclines at highway speeds, then
they’ll be very happy. From what I understand the update could be available as
early as the first quarter of 2015 and will indeed be available as a software
update to existing i3 REx owners.Of course it would have been better if this
was available right from the launch, but at least BMW is working quickly (the
i3 has only been available for about five months in North America) to correct
the problem.
Written by Unknown
If you’re looking for motoring advice, tips, and exclusive information about Big Motoring World; this is the source!
.jpg)
0 comments:
Post a Comment