Soon to be 2015 i3 REX owner low miles, purchase, BIMMER CODER?

[i3PDX]

HI Everyone

I am soon to be an owner of a 2015 i3 REX with 20" and Tera pkg.

I've been researching the reliability concerns but in addition trying to find out information on the dongle and BMW coder that allows you to unlock or program the EU Hold Charge feature, can anyone point me in the right direction?

1. Any suggestions or topic posts links

2. Will it void my warranty and is the update reversable?

3. Is there a recommended specific dongle or app for this?

4. What % of charge do you start activating this "Hold Charge Feature"

My only experience with the i3 REX is renting it for a few days on Turo which was enough to convince to purchase a used one for 20k as a replacement for my wife's Chevy Spark EV (Very fun car but didn't want to pay 11k at closed end lease, I will miss it)

Thank you

 

[TheMK]

It doesn't exactly void the warranty, and reversing the coding options is extremely easy. Coding, is kind of like editing config files for the software, it doesn't actually change the software that's running.

4. What % of charge do you start activating this "Hold Charge Feature"

My "goal" is not to burn gasoline, so usually I drive until the REx automatically engages at 6.5-8%. If you plan on taking an extended road trip, this isn't a good idea as it leaves you with a fairly small battery buffer, which can be disastrous if some planning goes wrong. On my 350mi trip, I engaged the REx as soon as it will let me (75% SOC), in practice this means about 20-25 minutes into my trip. This gives me 75% of the battery as a buffer to work with, if I need to climb hills, get to the next gas station after the tank ran dry, whatever. From that point out it's stopping every hour or so to put another 2.3 gallons into the tank, getting a snack or restroom break if necessary. Do note that the REx may or may not provide enough power output to completely power the car, so a trip that started out at 75% when you started the REx may have had several fuel stops and a battery that is sitting closer to 60%. We drove at least the speed limit which is 80MPH most of the way, and while the car is comfortable at that speed, you will be eating away at your battery buffer at that speed.

The other case is if I'm taking a medium range trip with a mix of highway and city driving, I try to use the REx on the highway instead of in the city. I also know that if I'm going to have to use REx power to get home, and I haven't climbed the hill (read mountain) to get to my house yet, I will set hold state of charge to 15%, so that way I can climb the hill without entering reduced power mode.

 

[alohart]

3. Is there a recommended specific dongle or app for this?

BimmerCode is the smartphone app. iOS and Android versions are available. The app is a free download but operates in demo mode only (i.e.. no coding changes can be applied) until it is licensed. The iOS license fee was ~$27 when I paid it. It seems that the Android license fee might be a bit more.

BimmerCode recommends specific OBD dongles because the response of some of these cheap Chinese devices is too slow to work correctly with BimmerCode. Both WiFi and Bluetooth dongles are supported by BimmerCode. However, iOS supports only Bluetooth 4.0 and later (many OBD dongles use earlier Bluetooth versions), so I bought a WiFi version. Amazon sells the dongles that are needed. I bought the Vgate iCar 2 OBD-WiFi dongle to avoid potential Bluetooth incompatibility with my iPhone. I paid ~$20 for this dongle. The Vgate iCar 3 dongle works as well but does not include the unnecessary on-off switch of the iCar 2. Just buy the least expensive recommended dongle.

Search this forum for "BimmerCode" to learn much more.

 

[jfran2]

Check YouTube for coding instructions; there are some good posts. Also, once you get the coding done, you'll be able to program the "Hold State Of Charge" function to one of the 8 buttons on your dash to make turning on the Rex really easy. Like TheMK, I usually like to use the Rex on the highway and save my electricity for in-town driving. Coding really unlocks the car's potential!

 

[i3PDX]

It doesn't exactly void the warranty, and reversing the coding options is extremely easy. Coding, is kind of like editing config files for the software, it doesn't actually change the software that's running.

4. What % of charge do you start activating this "Hold Charge Feature"

My "goal" is not to burn gasoline, so usually I drive until the REx automatically engages at 6.5-8%. If you plan on taking an extended road trip, this isn't a good idea as it leaves you with a fairly small battery buffer, which can be disastrous if some planning goes wrong. On my 350mi trip, I engaged the REx as soon as it will let me (75% SOC), in practice this means about 20-25 minutes into my trip. This gives me 75% of the battery as a buffer to work with, if I need to climb hills, get to the next gas station after the tank ran dry, whatever. From that point out it's stopping every hour or so to put another 2.3 gallons into the tank, getting a snack or restroom break if necessary. Do note that the REx may or may not provide enough power output to completely power the car, so a trip that started out at 75% when you started the REx may have had several fuel stops and a battery that is sitting closer to 60%. We drove at least the speed limit which is 80MPH most of the way, and while the car is comfortable at that speed, you will be eating away at your battery buffer at that speed.

The other case is if I'm taking a medium range trip with a mix of highway and city driving, I try to use the REx on the highway instead of in the city. I also know that if I'm going to have to use REx power to get home, and I haven't climbed the hill (read mountain) to get to my house yet, I will set hold state of charge to 15%, so that way I can climb the hill without entering reduced power mode.

Thank you for the tips, I am trying not to burn gasoline as well. I am intending to use this i3 only for 150 miles max trips and below.

Hopefully I can make a driving of 40-60 miles and hopefully can make it without REX being used in the winter time where it its -7C to 0C (18F to 32F) here in Portland Oregon.

Has anyone noted or measured if using the REX while driving does that degrade the battery packs faster? I assume faster battery degradation since the battery pack is charging while discharging energy for use at the same time.

 

[jadnashuanh]

Keep in mind that functionally, a lot of the output of the REx is going directly to drive the wheels. I'm not saying there's a direct, mechanical connection, but the power from the generator ends up going to the motor, and only any excess makes it back into the batteries to recharge them. The REx does adjust its output to the load, and whether it needs to try to pull the battery back to the turn-on point. So, when running the REx, the batteries are not seeing that power going into them directly unless the SOC is lower than when the REx was enabled.

 

[TheMK]

FYI the W20 manual is definitely an interesting read if you want to know more about how the REx works, from a technical standpoint. https://attachments.priuschat.com/attachment-files/2016/07/108943_12_W20-Engine.pdf
While it talks about engine mechanics, cooling system, and other various things, there's a whole chapter on "Operating strategy in the BMW I01 [i3]". Do note that some of the engine mechanics have changed in newer software versions, and the power output was increased.

 

[alohart]

Has anyone noted or measured if using the REX while driving does that degrade the battery packs faster? I assume faster battery degradation since the battery pack is charging while discharging energy for use at the same time.

Nope. That's not the way it works.

Consider a plumbing analogy in which the motor is connected to a T connector with the battery pack on one leg of the T and the REx generator on the other leg. The REx generator pipe includes a one-way valve that prevents water from flowing to the generator, but two-way flow is allowed into/out of the motor and the battery pack.

During regen, water flows from the motor to the battery pack but is blocked by the one-way valve from flowing to the generator. Nevertheless, water from the generator continues flowing to the battery pack in addition to water from the motor. Water flow from the motor or maybe the generator is reduced if the total water flow into the battery pack exceeds the maximum flow that the battery pack can accept without accelerating degradation.

When the motor is propelling the car, water flows to the motor. If the generator can meet the motor's needs, no water flows from the battery pack. However, if the generator cannot meet the motor's needs, water also flows from the battery pack.

At no time does water flow both into and out of the battery pack simultaneously. Also, the generator's water flow cannot exceed the water flow that the battery pack can accept (i.e., the battery pack doesn't experience excessive charging power, so degradation isn't accelerated).

 

[sipabit]

1. Download Bimmer Code.
2. Pay to use it. It's a high price for an app, but it's worth it for what you're trying to do.
3. Go on ebay and look for a wifi enabled OBD II reader.
4. When it arrives, it's pretty self explanatory. You'll find more detailed info in the forums here but one thing to note that I wasn't aware of is that you can't engage the use of the gas tank until you're down to 75% battery or less. So if you're sitting in your garage and wondering why it's not working, that's probably why. There's also a delay from when you engage it. I'd recommend assigning one of your preset "radio" buttons to engage the "battery hold" function.

You never heard this from me.

 

[alohart]

1. Download Bimmer Code.
2. Pay to use it. It's a high price for an app, but it's worth it for what you're trying to do.
3. Go on ebay and look for a wifi enabled OBD II reader.

Many OBD dongles respond too slowly to work with BimmerCode, so buying a random OBD dongle on eBay could result in BimmerCode not working. Also, some Bluetooth dongles are now supported. However, under iOS, only Bluetooth 4.0 or later are supported.

When I downloaded BimmerCode, OBD dongles that are known to work were listed in the app store or on the BimmerCode Website.

 

[sipabit]

Good advice. Maybe I just lucked out. I bought mine from Amazon actually and just went with the higher rated ones. I did pick one that was recommended by i3 owners. I forget the source but glad you brought up the specifics. Mine is called the "icar" by a company called Vgate.