Tuning Range Extender? 28kW -> 32,5kW?

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DisruptInnoLover

New member
Joined
Aug 14, 2015
Messages
1
Hi All,
Already a year driving the i3 in Europe and covered many km's.
Very happy with the car. My i3 has a REX with 28kW installed.

What I would like is to increase the charge capacity of the Rex.
At present it is ok for sustained driving of approx 125 km/hr on the highway.
If you go beyond this to say 130km/hr the Rex charging cannot keep up with
the discharge of the battery. (I assume a SOC of > 10%)

Many highways in Europe allow 130 km/hr. When I am on a long stretch I would
like to have some extra charging capability so that this speed can be maintained.

Does anyone here at the FORUM know of chiptuning companies who could get the REX some extra kW's?
 
I am a professional chiptuner, and as far as I know I have never heard of any available protocol, what is needed for reading and writing the ECU for the
i3. But that could be because of low demand for it. If you can located the ecu, and take a picture of the label on it and send it to me, I can do some investigation.

I guess the ecu look something like this:
edc17_immo_off.jpg
 
How would you go about increasing the charging capacity? Higher RPMs or higher output from the generator at stock max RPM, or both?

It would also be helpful to have a Charging Mode that would allow you to actually increase SOC when driving at lower speeds. If I was away from home overnight and was unable to plugin it would be nice to charge the battery a bit on the way home to allow electric running in town for the final miles. Doesn't the Volt do this from the factory?
 
The Volt has an 80-something HP motor that is designed to be fully capable of charging the battery, and moving it along (I think this year also gets a bigger motor). What do you want from a 34Hp motor? Running it harder would also mean more heat, and the system may not be capable of dealing with that. It would take some careful testing and engineering analysis to determine if it was possible to do safely, and considering the goal was to keep weight and noise down, they probably did not give the REx cooling system a huge amount of excess capacity nor provide noise suppression for the potentially louder and different frequency sounds it might make...not even thinking about longevity.

Not many cities have 130Km/hr speed limits, and the i3 can handle them for short distances. It is designed as a city car and commuting, not a long-distance tourer which would dictate different capabilities.
 
It would be nice to have maybe 25% more output in future revisions? But honestly I would think 30 KW is more than enough to maintain 130 kph on a flat road with no headwind.
 
It would be nice to code the REx to run at full output below 55mph to charge the battery instead of just maintaining SOC. There are lots of times where I am driving between 35 and 55 when the the REx could be roaring away without disturbing the public or me. It isn't THAT loud from the inside and since I am on a freeway or a multi lane street who really cares if it's a bit loud outside.
I realize that this is contrary to BMWs castrated view of the REx in NA, but it would be very useful for those who want to use their soon to be short range EV to the maximum.
 
WoodlandHills said:
It would be nice to code the REx to run at full output below 55mph to charge the battery instead of just maintaining SOC. There are lots of times where I am driving between 35 and 55 when the the REx could be roaring away without disturbing the public or me. It isn't THAT loud from the inside and since I am on a freeway or a multi lane street who really cares if it's a bit loud outside.
I realize that this is contrary to BMWs castrated view of the REx in NA, but it would be very useful for those who want to use their soon to be short range EV to the maximum.

+1 on charging
 
I believe that it was tuned up a bit to give more power in the newer models. At least this was the impression I got from Tom's Blog and from David Bricknell (the UK fellow who wrote the great i3 book).

Also, even though it would be desirable sometimes to have more REX power, keep in mind that you don't need to maintain the SOC for many long trips. I have found that if I start a long trip (i.e. I did one of about 700km one way) at 75% SOC then I can afford to let the SOC drop say 5% per hour which would still not deplete my battery by the end of the trip and then I can charge the car at my destination. I see many posts that seem to mislead people that the car's power and speed are limited on REX. This is not the case, it is only limited if you are trying to maintain the SOC but you don't always need to maintain the SOC. The important thing is to code the car so that you can engage the SOC at 75%.

...Roger
 
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