Removing Rex to use as back up generator for solar system

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shellhunter

Member
Joined
Jul 4, 2017
Messages
13
When I bought my i3 Rex I thought that if BMW came out with a more efficient battery I could remove the Rex Engine to use as a backup generator using the old battery in a solar system.
As it turns out I've only used the Rex twice since I purchased the car in 2014 .
I'd just as soon remove it now to lighten the car and save it for a future backup generator if I buy a new improved battery.
Has anyone else considered this option ?
 
I highly doubt it is feasible. Loading the BEV software in the car to allow it to run without REX could be possible, but starting the REX outside the car will be challenging.
 
Without commenting on the overall feasibility of the project, I think it would be fairly easy to start the REx once outside the car. After all, isn't it one of BMW's motorcycle engines ? Get a battery and a starter and you should be in business. Or maybe I'm naive :)
 
First of all, REX may have a different flywheel which may not work with a regular starter. Second, you will also need a motorcycle ECU, wiring harness and ignition lock (for the security chip in the key). All this might get your engine idling.
Now you need to control the engine RPM to get the required output form the generator. The hardware and software to do it will probably need to be custom designed.
 
Hi guys,

the REx has no starter motor. It is started from the HV battery using the generator as motor, like Jim said.

Regards, Steven
 
If it uses the generator to start it then could you do the same once the entire assembly is removed ?
 
CanisLupus said:
If it uses the generator to start it then could you do the same once the entire assembly is removed ?
Theoretically, yes. Trying to figure out the engine controls and the generator controls would likely be a little intimidating to make it all work. They are computer controlled, and you don't have the ability to code it, or a good way to reverse engineer it.

FWIW, a standalone generator would likely be as efficient and knowing how to interface it to your home is included in the installation manual...IOW, it's common knowledge. Given what the equipment in the i3 costs, a dedicated generator set would be cheaper.
 
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