Easy activation of Range Extender

More evidence: If you ever do any coding on the car, in the US you have to to get HSOC and 8l (2.4gal) tank activated, in that selection, for the 8l tank, there is another option, I don't recall the exact number but it's something big like 25gal. If I were to code the car for that option and run the REx, yes, one could run the Rex empty of fuel and potentially damage the fuel pump. But you see, this is further proof that the computer determines the size of the fuel tank, not the actuall physical size of the tank. So you see, again, once the pump meters approximately 8l of fuel (7l in the US in coded) it will shut off the REx and tell you you are out of fuel.

Edit: for all we know it might be a 3gal tank, the physical size does not determine REx shut off. There is not a way to code for whatever the actual size is though.

The car COULD end up getting slower, depending on where and how you are driving as the REx only tries to bring the level back up to where it was once initially activated. So, if it were quite low when you shut it off to refuel, except for a very small buffer at the bottom end of charge, it won't try to rebuild it all that far. Once you reach a critical SOC and are exceeding the output of the REx (easily possible when climbing a grade or high speed with all accessories on full - high beams, high heat, stereo blasting, seat heaters on, rear windscreen heater on, etc.), you WILL experience it slowing down, maybe rather abruptly. But, if you watch what's going on and understand what is needed to do to prevent it, yes, you can continue on and just keep filling the tank. 34Hp is not a very large amount of power - changing it to watts doesn't make it magically better...use more than that, and it will either 'slow you down' or pull it from the battery. Best to keep the battery up, and if you do, you won't notice any degradation, no matter how long the trip.

The max output of the i3's electric motor is 170Hp, or nearly 127Kw...certainly, you don't use all of that on cruise, but could approach it during acceleration. 34Hp is only a little over 25Kw, so you could be trying to draw over 5x as much just from the engine, not counting everything else that is running at the time...IOW, you CAN use more than the REx can generate at any one point in time, but any deficiency then must either come from the batteries, or you WILL be limited, most readily apparent will be an immediate drop in forward motion! Working up to that, the car will warn you, and start to turn off non-essential things like cabin heat, etc., trying to preserve forward motion. That only happens when the battery SOC gets quite low.

I think I got down to 2% driving on the interstate (flat) with AC running, driving well above the posted speed limit, might have been 1% (slept since then), trying to see what "Turtle Mode" was all about, it warned me "Reduced Power May Occur" or something to that effect, but then I made it to my exit and the car charged back up to ~6% pretty quickly.

Accelerating with the SOC that low might have put you into that slow-down mode, or a long grade, or even going slightly faster. But, it does not occur unless you stress things. IMHO, as long as you know and understand the process, there should be no surprises. If you drive it like an ICE expecting full capabilities until it literally runs out of fuel, you'll be disappointed. I don't remember the exact thresholds, but at 2%, it probably had already put the climate control for the cabin had either turned down or off. IT does things in stages.

Hi Guys—

Question for you. I was trying to purchase the “DVD in Motion” upgrade to get the on-demand REX function, but was told by the company that it wouldn’t work on my i3 because I have “Business Navigation” rather than “Navigation Professional”.

I purchased the car used so I’m not familiar with the difference.

Has anyone encountered this before, and if so what is the process to address it?

Thanks

The Bimmercode APP or the more conventional programming methods will work, with the APP probably the easier way.

When I set my REX to hold SOC the range continues to drop, at least on the highway, at the same rate it drops without the REX. Is that supposed to happen?

Benagami said:

When I set my REX to hold SOC the range continues to drop, at least on the highway, at the same rate it drops without the REX. Is that supposed to happen?

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It sort of depends. Keep in mind that when the REx is first turned on, it goes through a warm-up period of about 10-minutes. During that time, it won't run at full power, so depending on your current power load, it could continue to lose charge. THen, keep in mind that it is a 34 (38? on newest?) Hp motor...depending on how fast you are going and the road (going uphill?) and accessory load, it still might not be able to keep up even once it is warmed up and at full power. On straight and level, about 70mph is about max where the REx can keep up.

So, maybe...would need more details on what was going on at the time and what was turned on.

jadnashuanh said:

Benagami said:

So, maybe...would need more details on what was going on at the time and what was turned on.

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I suspect it was not on long enough. I was driving from Providence to Fall River, about a 20 minute ride on the highway. I turned it on about half-way, so it was likely less than 10 minutes.