NEWBIE REX ACTIVATION QUESTION

[JOHNR75]

Hi i3 Fans. On Friday we will pick up our CPO 2015 REX with about 25k miles on it. We are picking it up at a dealer that is about 90 miles away and they will have it fully charged and the REX tank full (I hope). I have searched this forum and Youtube for an answer to my question of: the drive of 90 miles consisted of about 25 miles of normal two lane roads and the rest will be on the highway where a 55mph speed can be maintained, obviously there will be hills to climb. If the electric charge gets us say 65 miles and the REX kicks in how will we be allowed to proceed to maintain a rough 55mph speed or is this not possible. I have read and seen that the performance of the vehicle degrades so it can get you eventually to a charging station and I have also seen videos of people driving like normal with the REX humming along. Although I am a beginner I will try to go in the ECO+ mode unless I can be convinced Comfort Mode won't hurt mileage too bad. Thank you in advance for your tips and predictions and we are SO looking forward to driving the i3. It is replacing a 2006 Mini Cooper S as the Fun Car.

 

[StreetPanda]

I go 70+ mph on the Rex on flat pavement. If it's been coded to turn the Rex on manually, you can do so once the battery is down to about 70% and see how well the Rex keeps it charged. You'll get it home no matter what, though.

 

[jadnashuanh]

The only issue is if the battery SOC gets below about 4% and you're pushing things, like trying to haul ass, or climb a long grade...at some point, as the SOC keeps going down, eventually, the car will start shutting down system. But, as was said, on the level, the car can maintain the SOC at speeds up to about 70mph. At 55mph, the REx can hold the SOC until it runs out of gas unless you were trying to climb Pikes Peak or something similar.

 

[jfran2]

Congratulations! You're going to love the i3! As soon as you feel up to it, I'd recommend getting the Bimmercode app and an OBD unit, and coding it so you can use the REX whenever you want below 75% charge. It makes it a much more useful car. I take mine on the highway often, and usually use the REX at highway speeds so I can save my electricity for city use.

 

[RostHaus]

As I just got back from a 500mi road trip in mine.
My take: Hold SOC can last 100s on miles...
Speed is a very minor factor to point, but the aircon is the biggest.

For the first 225mi, i kept it in eco pro+, no air con, ACC set at speed limit(60-75mph)

I arrived at my first dc charge with 68% on battery.

On the way back it was a hot afternoon, I decided to go comfort mode and use an extra charging station. 190mi between chargers.

-Comfort mode, full aircon, ACC set 5mi above speed limit the whole way.

When I arrived home my charge went from 80% to 43% in 190mi.


As for fuel. It took just over 5 complete 2.2 gallon fill ups.

Edit: I forgot 1 variable, payload.
On the way down, 2 adults, zero cargo.
Way back, 2 adults and 450 lb in the cargo area with seats down.
While the payload may decrease my range a bit. I've found it less noticeable on previous trips, driven in eco pro modes.

 

[JOHNR75]

Hey Everyone, thanks for your encouraging words and once again we are so looking for ward to picking up the 2015 i3!!! I am now confident we will make it the 90 +/- miles home. I do plan to have the coding done to increase the useful full tank of gas for the REX and also have the ability to turn it on when desired. I did look around and a place that works on BMW's and the like in Amherst MA claims they do coding work so we will see what they say. I am not brave enough to try it myself, I would certainly mess something up.
Once again thank you for your replies and I will post a trip report as well as our impressions of driving our i3.

 

[alohart]

-Comfort mode, full aircon, ACC set 5mi above speed limit the whole way.

For those who prefer the Eco Pro power pedal mapping but want full climate control power, there's an iDrive setting that will allow this.

 

[JOHNR75]

So we made it home easily from our 90 plus mile trip to pick up the 2015 i3. The REX kicked on seamlessly and we "motored" home sort of the rest of the way. I couldn't figure out if the REX lowers its RPM's or shuts off at stop signs and lights. So far we are very happy with the purchase and it was well received when I drove it to work today by my co-workers. I appreciate everyone's inputs that gave us the confidence that we would make it home from the car pick up.
And now to check into Coding the REX to make use of the 2.5 gallon gas tank and gain manual control of when it can be turned on and off!!
Thanks again for your help!!

 

[jadnashuanh]

The REx is there to try to maintain your charge, not recharge the battery higher unless you've been stressing it (it's only a 34Hp engine). So, while stopped, your load goes way down, and sort of like on an ICE with the auto off, the REx will slow down or even stop when your load goes down. Lowering the RPM when slower also means it will be less obtrusive. It will only keep running if during the initial cycle, where it wants to fully warm up, or if the SOC is lower than when you called it into action. It does not try to charge the battery to a higher level than when it was turned on.

Yes, some hybrid EVs can recharge the battery to full, but the i3 isn't designed to do that. Being designed as a city car, running the engine while in the city is frowned upon in many places in Europe where EVs get charged less to enter the center of the city.