How to turn REx off?

BMW i3 Forum

Help Support BMW i3 Forum:

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

Tomasz

Well-known member
Joined
Nov 18, 2014
Messages
175
I've tried search and failed, so my apologies if it was already discussed here.

The problem at hand - I was driving on the highway today and knowing that I won't reach the destination on battery alone I have turned on hold mode around 20% of battery and let it sit there. But the last 5 miles of my trip is a city driving, and it was showing more than that available so I figured I'm going to turn off the REx and get to my destination quietly. So I went to the REx menu and tried to click on Hold mode to turn it off, but nothing happened. The REx stayed engaged to the very end of my trip.

Is there any trick I need to do to turn it off?
 
If battery charge is below 6.5%, the REX motor will remain on. No option otherwise. You can see the battery state of charge from the REX hold menu.

I regularly experience this slight "issue". I will often get within 1 mile of home and the REX will turn on as I hit 6.5%. I could easily make it home in just .5% but hey ho, that's what the REX is for.
 
Tomasz said:
I've tried search and failed, so my apologies if it was already discussed here.

The problem at hand - I was driving on the highway today and knowing that I won't reach the destination on battery alone I wave turned on hold mode around 20% of battery and let it sit there. But the last 5 miles of my trip is a city driving, and it was showing more than that available so I figured I'm going to turn off the REx and get to my destination quietly. So I went to the REx menu and tried to click on Hold mode to turn it off, but nothing happened. The REx stayed engaged to the very end of my trip.

Is there any trick I need to do to turn it off?

"I wave turned on hold mode around 20% of battery and let it sit there" Not sure I fully understand the "wave" or "let it sit there" but I assume you checked the box in the Rex hold screen to turn on the Rex, all you have to do is uncheck the same box on that screen and tap the controller? Not sure if that is what you tried. Plus as someone else said you have to be above the auto Rex turn on point of 6% but based on what I think you said your SOC should have been around 20% yet when you tried turning the Rex off.
 
mindmachine said:
"I wave turned on hold mode around 20% of battery and let it sit there" Not sure I fully understand the "wave" or "let it sit there" but I assume you checked the box in the Rex hold screen to turn on the Rex, all you have to do is uncheck the same box on that screen and tap the controller? Not sure if that is what you tried. Plus as someone else said you have to be above the auto Rex turn on point of 6% but based on what I think you said your SOC should have been around 20% yet when you tried turning the Rex off.
I meant "I have" above and yes, I have checked the box to turn on the Rex around 20% of charge. Then I tried to uncheck it by selecting it again and tapping the controller. At that time SOC was slightly lower then when I have turned it on (18% maybe).
 
elptex said:
If battery charge is below 6.5%, the REX motor will remain on. No option otherwise. You can see the battery state of charge from the REX hold menu.
It wasn't. I turned the REx on at 20% and I wanted to turn it off with about 18%. Nowhere near being empty. That's why it surprised me that I was unable to do so.
 
All you do is press the iDrive wheel down when you have the option selected. Alternately you can assign it to the shortcut buttons (1 - 8) by getting to the hold option menu and then press-hold the button you want to assign. By pressing that button it will toggle the REX on/off.
 
elptex said:
All you do is press the iDrive wheel down when you have the option selected. Alternately you can assign it to the shortcut buttons (1 - 8) by getting to the hold option menu and then press-hold the button you want to assign. By pressing that button it will toggle the REX on/off.
Except it didn't.

It turned it on when it was off, but several tries to turn it off failed.
 
elptex said:
Maybe an issue then. Call your dealer? Have them hook it up and pull any fault codes that might have come up.
That's the problem - can't really call the dealership and say 'hey, I've coded my BMW but it doesn't work as I thought it should. Would you mind fixing it for me?'
 
Perhaps ask this on the Facebook page as well? I wouldn't go to BMW unless all else fails. They could easily void your warranty saying that your coding has affect the engine since it's not designed to be on for a long period...... blah blah...
 
Dee123 said:
Perhaps ask this on the Facebook page as well? I wouldn't go to BMW unless all else fails. They could easily void your warranty saying that your coding has affect the engine since it's not designed to be on for a long period...... blah blah...

I seriously doubt that that reason would fly since the EU UK version allows engaging the Rex just the same as in this case.
 
Tomasz said:
elptex said:
Maybe an issue then. Call your dealer? Have them hook it up and pull any fault codes that might have come up.
That's the problem - can't really call the dealership and say 'hey, I've coded my BMW but it doesn't work as I thought it should. Would you mind fixing it for me?'

I hear you me too. In the good old USA we aren't supposed to be able to turn on the Rex it did work for me but I don't know why it isn't working for you.
 
So I had another longer drive today and played with REx some more. About 3/4 of the tries did in fact turn it off, but there were still few unsuccessful ones. Me thinks there has to be some software algorithm looking at how the stars are aligned in regards to the moon to determine if the REx can be turned off at will.
 
Tomasz said:
So I had another longer drive today and played with REx some more. About 3/4 of the tries did in fact turn it off, but there were still few unsuccessful ones. Me thinks there has to be some software algorithm looking at how the stars are aligned in regards to the moon to determine if the REx can be turned off at will.

I don't have much experience, well actually hardly any, but could it be that the times when it does not shut off on command that it was working hard and needed to cool down first? Just guessing now.
 
mindmachine said:
I don't have much experience, well actually hardly any, but could it be that the times when it does not shut off on command that it was working hard and needed to cool down first? Just guessing now.
It may as well be, but if that is the case it should uncheck the box, and shut down later (exactly as it does when it starts). Or acknowledge my command in any other way, maybe display a comment "Turning Range Extender delayed due to system requirements" or something in that range. Otherwise it just confuses the driver.
 
They could easily void your warranty saying that your coding has affect the engine since it's not designed to be on for a long period.
They couldn't seriously assert that: here in Europe, the Rex is happy to run for over 90 miles while whizzing along the motorway at 70+ mph on the speedo!
I've programmed softkey 8 to toggle the Rex on/off without having to take my eyes off the road. Works a treat.
 
I doubt that a U.S. court would care or be permitted to care about what goes on "over there". Unless your car was sold with a European Warranty by mistake what goes on elsewhere is irrelevant. All that matters is if you and BMW are both in compliance with the terms of the US contract (warranty) when push comes to shove. Whether or not BMW would make a big deal about a customer taking control of the REx is another matter entirely, but I am sure they have the power to do so if they wish (or are forced by CARB). Remember that there is a not insignificant amount of money involved in Carbon Credits that could be at risk if CARB gets pissy. This is not like chipping a 3series or putting a loud exhaust on to an M: CARB does not have a $100M hammer with which to beat BMW over smog violations. Where to classify the REx was the subject of much negotiation and debate between BMW and CARB. Would they be forced to revisit their decision if large numbers of customers began to change their cars in ways that completely change the emissions profile?
 
WoodlandHills said:
I doubt that a U.S. court would care or be permitted to care about what goes on "over there". Unless your car was sold with a European Warranty by mistake what goes on elsewhere is irrelevant. All that matters is if you and BMW are both in compliance with the terms of the US contract (warranty) when push comes to shove. Whether or not BMW would make a big deal about a customer taking control of the REx is another matter entirely, but I am sure they have the power to do so if they wish (or are forced by CARB). Remember that there is a not insignificant amount of money involved in Carbon Credits that could be at risk if CARB gets pissy. This is not like chipping a 3series or putting a loud exhaust on to an M: CARB does not have a $100M hammer with which to beat BMW over smog violations. Where to classify the REx was the subject of much negotiation and debate between BMW and CARB. Would they be forced to revisit their decision if large numbers of customers began to change their cars in ways that completely change the emissions profile?

If CARB had anything to say re: how often or how long the Rex could be used it would be coded in the software. Right now nothing prevents me from driving 100% on REx, whether my car is coded or not. Adding fuel every 50 miles gets pretty old pretty fast, but again I can do it all day long if I wanted. The only difference between coded and non coded car would be the HV battery state of charge, and I bet it prefers to be charged a little more than between 3.9 and 6.5%
 
Back
Top