Can REX be added aftermarket?

BMW i3 Forum

Help Support BMW i3 Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Manitou

Member
Joined
Sep 19, 2015
Messages
12
More of a hypothetical question, but let's be realistic too. Can it be done by a qualified mechanic? I.e. buy the scooter engine, installed properly, reflash the code.. I get the feeling I'm over simplifying it, but don't know.
 
There are a huge number of parts that are different between the BEV and the REx version of the i3 to include, front/rear springs, wheels(sometimes, depending on option - the REx has bigger rear wheels than the base BEV), gas tank, climate control system, front fender for the filler, the pressurization system for the gas tank with release mechanism, and maybe the whole rear chassis mounting assembly (not sure on this). IOW, you'd have to dismantle nearly the whole vehicle and buy a bunch of new parts, not counting the motor, muffler, and cooling system for it.
 
Manitou said:
More of a hypothetical question, but let's be realistic too. Can it be done by a qualified mechanic? I.e. buy the scooter engine, installed properly, reflash the code.. I get the feeling I'm over simplifying it, but don't know.

Probably cheaper to trade the bev in for a new rex.
 
Manitou said:
or carry a honda generator in the frunk

Actually that was discussed previously and you would only get about 6 miles of range per hour from a 2 kWh generator and i doubt it would fit in the frunk. Plus you could not drive while charging. Not practical.
 
It was more of a anti range anxiety thing. I'm tempted by a good deal on the BEV, but living about 20 miles from the city.. I worry that most trips to downtown would turn into required stops at the charging station too. Sure I *can* do that.. I just don't want to have to do that. I'm sure there will be enough times when I forget to plug it in the night before. Seems like too much of a head ache. Just over 100 miles a charge and I'd feel much better about a BEV.
 
I have been driving my REX from Westchester NY to Lower Manhattan every week day since 12/1/14. The round trip is 56 miles. I have NEVER, EVER needed the Range Extender for this trip. Temps as low as 4 degrees F and as high as 101. Yesterday my inbound trip took 2.5 hours but my range was fine because the vehicle is most efficient in stop and go (and this was mostly stopped). If I only commuted less than 60 miles every day, a BEV would do fine. Hope this helps.
 
I've never seen less than 60 miles for a charge in temperatures down to -10F. Once you get into the habit, it's second nature to plug the thing in when you get home (or at work, if you have an EVSE you can use there). If you set a departure time with preconditioning while attached to the EVSE, you may not notice as much cold weather battery degradation. The thing that eats up battery is lots of short trips where the car can reach ambient in between, meaning lots of heating or cooling sessions and not many miles driven. Note, the BEV (when optioned...may be standard in your market it is in the USA), has a heat pump which in milder temperatures is MUCH more efficient than the REx's resistance only heating. The BEV only uses resistance heating when the temperatures are really cold.
 
I'm not driving to an office and back. I'm driving to the city, running around errands, then back. The other day I calculated 68 miles. Too close for comfort.
 
mindmachine said:
Manitou said:
More of a hypothetical question, but let's be realistic too. Can it be done by a qualified mechanic? I.e. buy the scooter engine, installed properly, reflash the code.. I get the feeling I'm over simplifying it, but don't know.

Probably cheaper to trade the bev in for a new rex.
No probably about it.
 
TLDR

No

Trade your BEV for a REx, the depreciation cost alone will most likely be less than half of the theoretical cost to add it to a BEV, which again, just isn't possible. Or if you are leasing, find someone to assume your lease, then go lease a REx.
 
You'd have to remove the heat pump, rework the entire heating system, change the fender for the filler, add the filler, the tank, the fuel lines, the sensors, the engine, mufflers, engine mounts, the rear springs, add the radiator, the coolant lines, the water pump, and maybe the tires and wheels (they have different springs and bigger wheels/tires stock), update the software, change or at least add the harness and button for the REx activation, and the list goes on. It is not really a viable option unless you had a free donor car, the factory assembly manuals, lots of tools, and lots of time...You'd end up nearly stripping each car.
 
Hello,

Is it possible to enable charging while driving?

I have a 48v LifePO4 120ah battery bank that I use to charge my BMW i3 while car is in park. I use a pure sine wave inverter 40v-60v DC input to 240c AC 60hz output. The car lets me charge while in park or off but not while in motion. The batteries should be able to take a charge since the REX version charges while in motion. I would think all that is needed it to trick the J1772 charging port or onboard charger into thinking the parking break is on. If i can do it this way I will need to tether the charging cable out the window to the j1772 receptacle.

The other option is someone told me that they could add the code for a REX version and I might be able to wire it in similar to the 2 cycle engine in the REX version.
Please could someone tell me if this is possible?
 
Good luck, I don’t think anyone here can give you a definite yes or no. I can’t imagine driving down the road with your chargeport open and a cord going through the window won’t attract some odd attention, not to mention the wind noise from the window being cracked.

Best of luck!
 
Back to Manitou's predicament. If you have a 68 mile "commute" without benefit of charging, then you should probably start wit a min of 75% charge. I think your concern is having to start with a high state of charge. You "can" do it but it's not always convenient. So, you should get the REx.
 
Since the original post is from 10/08/2015 I hope he has already decided.

——

5.7 kWh x 4.0mi/kWh (also optimistic with additional weight and wind drag) = 22.8 additional miles.

Probably not worth the headache.
 
Back
Top