Has anyone reached 0% battery while the Rex was running.

[Mamaci3]

-3 degrees in Colorado going 65mph on the freeway. Battery reached 1% while Rex was running. Decided to slow down a bit so I wouldn’t find out what would happen if I hit 0%. Can it reach 0% and will the car shutdown?

 

[alohart]

-3 degrees in Colorado going 65mph on the freeway. Battery reached 1% while Rex was running. Decided to slow down a bit so I wouldn’t find out what would happen if I hit 0%. Can it reach 0% and will the car shutdown?

At 1%, I would think that a few top segments on the power meter on your instrument panel would have changed to gray indicating that full power was no longer available. Had you not slowed, the battery pack's charge level would have continued dropping causing more segments to become gray indicating a further reduction of power which would likely have not been enough to maintain 65 mph.

The charge level would not likely to have dropped to 0% because the reduced available power would have allowed the REx generator's power to be sufficient to prevent a further drop in the charge level.

 

[i3Houston]

Mine slowed down to 50ish mph at 2%, at that speed maybe rex can maintain 2% SOC maybe.

 

[CharonPDX]

I got down to 1% while my REx was out of gas a few months ago! Power max lowered itself (I was on side-streets, so lack of power wasn't a problem,) but I got to my destination at 1% remaining.

 

[theothertom]

Mine ran down to around 4% and the power dropped so that I could only go about 40 mph max. The Rex was able to charge it up to around 6% at which time full power returned.

 

[TheMK]

Yes it's possible to run it down to almost 0% with the REx running, though you won't be able to do that while doing any semblance of normal driving. To do that I put the car in "roller mode", and did some drifting and spinouts on snow/ice. No regen, and no ESC to limit the amount of power going to the motor from wheel spin, so you can have it floored as you spin around. This drains the batteries very quickly. Once you hit 0% (as shown on the driver display), then ALL of the power bars disappear, and pressing on the go pedal essentially puts the car in neutral. The REx was able to quickly regenerate battery percentage though.

 

[EVMan]

Avoid this situation, turn rex on early
Its hard on battery when below 5%

 

[RexMan]

What year i3 have ye ?

In the 1 year 4 months I have mine , a 2017 94 Ah Rex , I have never lost power. At 75 Mph for 100 Kms never lost power even at 4%.

Under load the battery drops and when load is reduced it charges a few % again and so on.

The real trick is turning the Rex on when at speed and the battery SOC is higher, if I know I'm not going to make it I turn it on at 50 or more % to ensure the battery level doesn't get too low, then on slower roads and in town I use battery only.

Only once have I had to drive with a low SOC,

Very impressed with the car no issues in 1 year 4 months and about 20,000 miles

Total mileage is about 31,000 Miles, Battery capacity 29.3 - 29.5 Kwh , at 6,000 miles it was 29.5 Kwh.

I've never seen battery beyond 37 Deg C, even after long blast at 75 Mph and 40 Min DC charge at 50 Kw and at that it cools down again pretty quick, where as in my 24 Kwh Leaf it used to rise even when stopped.

Also been 100% reliable. I think most issues people have had with the rrex are people who only used it for a very short time and hardly gave it a chance to warm up , any time I use it it's for min 20 mins.

 

[jadnashuanh]

The computer requires the engine to warm up (takes about 10-minutes) before it can provide full power. During that warm-up period, it is likely that your SOC will continue to drop if you were pushing it at all. Probably not very noticeable running around at lower speeds, though.

 

[RexMan]

Can U.S i3's now use the Rex above 6.5% ?

 

[alohart]

Can U.S i3's now use the Rex above 6.5% ?

Not without modifying a parameter that controls whether the driver can manually start the REx below a 75% charge level. This change can be performed using the BimmerCode smartphone app.