REX/Battery issues and resolution

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I3Canadian

New member
Joined
Feb 27, 2017
Messages
4
I don't know if others have had REX issues like I have on my 2014 i3 but I thought it might help someone to share the story.

Symptoms
- Failure of REX to transition from start-up RPM to full RPM, thus not enough energy going into the battery to sustain highway speeds
- When battery was depleted and parked, returning to the car to leave I would find the SoC at 0.0% and forced to wait for the REX to charge the battery to 1.5% minimum before I could get the car to move.
- These symptoms were initially intermittent and then became consistant with every drive in the fall of 2016.

Fix
The car was at the dealer from early November until Dec. 27, 2016
- There were multiple items replaced: Defective cell module #1; Replaced SME control unit; Replaced all eight CSC modules
After picking up the car and driving it three times the RPM issue returned and it went back to the delaer from Jan. 9-17, 2017.
- The technician performed a "REME" procedure which is the removal of the temperature sensor from the REX, running the REX for up to three hours with the sensor removed (to eliminate the possibility of moisture).

The car has worked perfectly since.

Summary
I believe the issue was rooted in a few things:
1. Failure of battery cell #1 which the car did not identify as a fault. As a result, the SoC was actually less than what appeared on the instrumentation.
2. Possible bad control modules which did not correctly identify the battery fault
3. Moisture in the REX temperature sensor which is designed to signal the REX that it is safe for the engine to move from startup RPM to high RPM when needed. If that sensor doesn't work correctly the REX will not adavance the RPM in a timely manner or at all.

I hope my learning experience may be of value to some other i3 drivers.

Alan
 
See stuff like this is what scares me about buying one of these cars.

Highly technical problems that even the dealer can't figure out very easily.

I'm someone who likes to keep my cars for a decade or more. Imagine 10 years down the road. Finding someone to trouble shoot these cars will be impossible, killing any resale value and rendering them into 2200lb paperweights.

Anyone else worry about this stuff?
 
slipnslider said:
See stuff like this is what scares me about buying one of these cars.
. . .
Anyone else worry about this stuff?
Me, no but I'm an engineer.

It has been my impression that every car has a significant gap between what the owner sees and the engineers design with a large population of "helpers" whose sole goal is to separate the owners from the engineers.

Bob Wilson
 
slipnslider said:
See stuff like this is what scares me about buying one of these cars.

Highly technical problems that even the dealer can't figure out very easily.

I'm someone who likes to keep my cars for a decade or more. Imagine 10 years down the road. Finding someone to trouble shoot these cars will be impossible, killing any resale value and rendering them into 2200lb paperweights.

Anyone else worry about this stuff?
We bought our 2014 i3 BEV and avoided the REx model to reduce the complexity that frequently leads to lower reliability. We were able to do this because we didn't need the REx's additional range unlike some people. We tend to keep our cars more than 15 years which we'd like to do with our i3 as well.

I don't worry about a dealer or mechanic being unable to diagnose and repair problems in the future because they are learning about a very new and different type of car and will continue to learn as time passes. The percentage of EV's on the road will continue to grow giving mechanics more experience with them. The i3's battery pack seems to be holding up well with only slight deterioration over time and number of charge/recharge cycles, so I don't expect to have to replace ours. But if it deteriorates enough that its reduced range affects our lives, I expect replacements to be reasonably priced just like the replacement battery packs for our 2000 Honda Insight have become.

I worry more about an i3 being a BMW which automatically means that parts and service are more expensive than for a Toyota, Honda, or other less expensive and typically more reliable Asian brand. For us, one very expensive repair could turn our i3 into a 2,634 lb. paperweight (I wish it weighed only 2,200 lb.).
 
I'm an owner (not lessee) of a 2014 REX. Half of my service visits have been related to the REX and half to the Battery cooling system--total of about 60 days out of 2 1/2 years of ownership. If you are looking for a "keeper", don't buy a REX! I've racked up some $10K in warranty repairs, so far. I'm really worried about keeping it past the warranty.
 
ted99 said:
I'm an owner (not lessee) of a 2014 REX. Half of my service visits have been related to the REX and half to the Battery cooling system--total of about 60 days out of 2 1/2 years of ownership. If you are looking for a "keeper", don't buy a REX! I've racked up some $10K in warranty repairs, so far. I'm really worried about keeping it past the warranty.
How many miles?

Did you have a broken motor mount bolt replaced?

Bob Wilson
 
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