[RSouthern]

Hi all, Looking for advice/experience...

My daughter is taking her 2018 i3Rex to college in a few months and will be driving it there. We live in San Jose and she's going to school in Los Angeles. About 400 miles door to door on Hwy 5. We've driven up and back to SF from SJ, leaning heavily on the REX so we have done the round trip without needing to charge mid-way, that was a mix of battery then REX keeping the SOC at 75% most of the time (driving at highway speeds). Those drives are ~160 miles round-trip. So my question is related to extended use of the REX. Is it ok and has anyone driven using the REX for long periods, refueling (gas) multiple times on one journey? I assume that since it's a scooter motor, running for 5-6 hours straight (stopping to fill up gas) is ok, but wanted to see if anyone has done this and if there are any precautions/catches. The reason to run the REX most of the way is so we can get up the grapevine with the battery and REX (I don't want to be at a minimal charge and only able to climb the hill slowly), which for those not familiar with the area, goes from sea level up to around 4000 ft, then back down into the LA basin at sea level. It's a pretty steep climb over a relatively short distance.

Thanks in advance for any guidance!

-Richard

[Coastali8]

We have a 2018 REx also and run the scooter motor on short trips up to Portland and back with a stop for our 2 gallons of fuel. I’ve never seen any published limitations on the run cycle for the little motor.
Like you… I assume with the engine being taken from a BMW scooter and the horsepower being derated from 59 down to 34 for the REx it should run forever without any issues.

Here is a great YouTube video explanation of the range extender use and limitations.

[-c-]

Originally Posted by RSouthern

Hi all, Looking for advice/experience...

My daughter is taking her 2018 i3Rex to college in a few months and will be driving it there. We live in San Jose and she's going to school in Los Angeles. About 400 miles door to door on Hwy 5. We've driven up and back to SF from SJ, leaning heavily on the REX so we have done the round trip without needing to charge mid-way, that was a mix of battery then REX keeping the SOC at 75% most of the time (driving at highway speeds). Those drives are ~160 miles round-trip. So my question is related to extended use of the REX. Is it ok and has anyone driven using the REX for long periods, refueling (gas) multiple times on one journey? I assume that since it's a scooter motor, running for 5-6 hours straight (stopping to fill up gas) is ok, but wanted to see if anyone has done this and if there are any precautions/catches. The reason to run the REX most of the way is so we can get up the grapevine with the battery and REX (I don't want to be at a minimal charge and only able to climb the hill slowly), which for those not familiar with the area, goes from sea level up to around 4000 ft, then back down into the LA basin at sea level. It's a pretty steep climb over a relatively short distance.

Thanks in advance for any guidance!

-Richard

I drive from Chicago to Michigan about 6 hrs total drive to the metro Detroit area once every other month.

No issues at all. Just stop
To fill up every so often which works well for my bathroom breaks lol.


Have 93k miles now
You'll be fine

[RSouthern]

well I can now answer my own question and provide some mileage and experience feedback.

We drove slightly over 400 miles, leaving San Jose at 6p and arriving in Manhattan Beach (Los Angeles area) about 7 hours later. We drove down HWY 101 instead of taking the more direct HWY 5, reason: I wanting to avoid the steep climb up the Grapevine with a potentially low battery state of charge and didn't want to stop to charge the battery if we could avoid it. We wanted to make the trip with only the initial full charge in the main battery (2018 i3 Rex) and use the range extender to make as mush of the journey as possible. We were taking my daughter down to college and I wanted to make sure she had enough charge to be able to get around town when we arrived. My wife followed us in an X7 with all my daughter's stuff for school but we didn't draft/hyper mile, the X7 was always behind. We had very little baggage in the i3, just myself and my daughter, our backpacks and some of her more fragile possessions.

Needless to say, we made it, no problem. I really like the i3 Rex, it's not a "road trip" car but can go long distances when needed and is perfect around town, but since you're on this forum, you already know that The cruise control made the trip a lot easier (when it's not looking into the setting sun) and we were not the slowest car on the road (although we were far from being the fastest!)

The journey: we were able to go about 85-90 miles on the generator/Rex between fill-ups. I have the "enable range extender" programming enabled so the first 25% of the main battery was electric, then the rest of the driving was mostly on the Rex. I would turn off the Rex as the remaining mileage on the gas indicator approached 3-5 miles remaining. We were generally driving at the speed limit, 77mph on the speedometer was showing 70mph on GPS, not sure which was more accurate. Driving at this speed showed around 3.8m/kw on the average consumption gauge. I ran the car on the main battery from the point I turned off the Rex until we could find a Chevron gas station, which was anywhere between 5 and 10 miles from the Rex shutoff, so we continued to use power from the main battery throughout the drive - we couldn't have gone indefinitely. We arrived at our destination with about 40% main battery remaining and a full tank of gas.

Filling 2 gallons of gas is humorously quick, especially compared to the 20 gallons the X7 drank. One gas station showed we pumped 2.2 gallons (I'm certain that pump was miscalibrated to the station owners benefit), the rest showed we pumped between 1.7 and 2.0 gallons. It looks like using the Rex was getting us something around 45mpg at highway speeds.

We used air conditioning when we left at 6p since it was still hot but by 9p we turned that off to save power.

So yeah, that's a lot of words to basically say, no problems with longer distances using the Rex. The car is fine at highway speeds up to about 80mph but it's not designed for that, so don't expect a grand touring experience. The seats were comfortable and we never had range anxiety since we had the main battery as our "reserve". Road noise was mild at these speeds, but never intrusive. Wind noise wasn't an issue and when we were driving we never heard the Rex running, the only indication was the brighter white color of the fuel gauge (vs grayed out when on the main battery).

Overall, we love this car and are a little sad that it's now living with our daughter and not available for us to "borrow" like when she was at home. May be looking for another one in the not too distant future to offset the gas costs of our 2 v8 cars for around town driving. It's really too bad BMW discontinued the i3, it really feels like a "swiss army knife" type of car for short to medium length journeys.

[cncmastr]

I just picked up my Rex from KY and drove to ATL the same story as you over the weekend. It got old quick filling her up 7 times but I didn't want to drive with less than 30 miles of fuel in the tank.

[2mAn]

Right on, thanks for the update. I’m planning to do the opposite trip one of these, heading up to Central Cali (Turlock) from Inglewood. It’s about 300 miles door to door. I want to see if I can make it with one stop. I also have to go over the grapevine, so my plan is to make it over the hill and charge / refuel/ etc and then cruise the rest of the way.

I’ll report back if it’s something I can do in one stop.

[RSouthern]

definitely let us know! I'm curious how the climb from the Valencia area goes since my daughter will probably want to drive home during holidays. I feel like heading north over the grapevine is a milder climb than heading south, hence our avoiding it entirely and going 101 (which would have been more scenic if not done in the middle of the night!). Based on your profile it seems you have a 2017, so you have the same size pack as our 2018 (90Ah), do you have the coding to allow the ReX to be turned on manually? That was key to our success and strongly recommended if you don't have it enabled yet.

[RSouthern]

Originally Posted by 2mAn

Right on, thanks for the update. I’m planning to do the opposite trip one of these, heading up to Central Cali (Turlock) from Inglewood. It’s about 300 miles door to door. I want to see if I can make it with one stop. I also have to go over the grapevine, so my plan is to make it over the hill and charge / refuel/ etc and then cruise the rest of the way.

I’ll report back if it’s something I can do in one stop.

Inquiring minds want to know! My daughter is coming back up to SJ from LA this weekend and driving the 2018 i3Rex back going over the Grapevine. How did your journey go?

She will get a full charge in Santa Clarita and will have a full tank of gas and enable hold state of charge as soon as she can. Did you have any problems with the climb? Did you stop in Castac (38 miles from Santa Clarita but a 4000' climb). The rest of the drive is mostly downhill, so I'm not concerned about after Castac/Tejon since that will be like the drive down 101 at the beginning of semester, just lots of stops to fill the tank.

[RSouthern]

well I can now answer my own question and share with the community... We started with a 90% charge and a full gas tank in Santa Clarita (after a quick stop at Tommy's!) and had no problem driving north over the Grapevine on HWY 5. We used the battery until it got to 75% then turned on hold state of charge and used about 1/3 of the gas to get to the top of the hill. So driving 70ish mph (+/- 4 mph), it only used about 1/4 of the battery and 1/3 the gas. Keep in mind this was north bound, during the day in 70F weather, without using A/C. Rain, night, snow etc could have cut deeper into our energy reserves. We had pretty optimal conditions.

We did stop at the outlets at Tejon (bottom of the Grapevine) to recharge at a chargepoint, except the Chargepoint charge wasn't a Chargepoint, it was a Shell Energy station (located adjacent to a huge Tesla/SuperChargerand farm) and required we setup a new account and deposit a credit of a min of $10 to use the charger, which then proceeded to charge as slow as a level 1 charger, giving us about 3% charge over the course of an hour. Terrible. And the money is locked up with the account since it only used about $1.60 for the charge. But that's a rant for another day.

Luckily using the hold state of charge got us all the way home with 5 gas ups. Leaving us with 65ish% charge and a full tank of gas in San Jose. While it's not a road trip car, it was more than capable of driving the 300+ miles, through the central valley, at highway speeds (70-75 mph) with occasional use of AC and was ready to resume around town duties. I love this car!

[Johnny_Cakes]

Originally Posted by RSouthern

The journey: we were able to go about 85-90 miles on the generator/Rex between fill-ups. I have the "enable range extender" programming enabled so the first 25% of the main battery was electric, then the rest of the driving was mostly on the Rex. I would turn off the Rex as the remaining mileage on the gas indicator approached 3-5 miles remaining.

I'm a new i3 REX owner -- I've Google'd and read everything I could about REX strategies for long trips. Basically, turn on HSOC as soon as possible at 75%.

But let me see if I understand this correctly: Under some conditions, the REX cannot keep up with the outgoing demands of the battery. So the battery is depleting despite being charged by the REX.

So the strategy is to turn the REX on as soon as possible, to recharge the battery as much as possible as its depleting, thereby keeping as much charge in the battery as possible.

Is that about right?

And what happens when the battery gets to the point where the charge is completely used up and what is being supplied to the battery by the REX is all the current there is?

Thanks!

[RSouthern]

Late reply, but yes, that's essentially correct. I stopped to "top off" the charge and experienced the adventure that is otherwise knows as "charging at an electrify America public charger" (hit and miss), but yes, for long road trips where you don't plan to stop to charge, run the range extender starting at 75% SoC on the battery (assuming you have turned on that option via Bimmer-Code or other tool - for US customers, other countries may not need to enable hold state of charge).

Regarding what happens if you run the battery down to 0%, I don't know. I expect you'll be left having to run the range extender while standing still or at least moving at low speeds. I believe the car will slow to sub-highway speeds before then anyway so your situation would need to be very specific and intentional to get to 0% - and not paying attention to the car and what's happening on the dashboard. ReX gives you that option, which is why we got this car to be a transition for us to full BEV (I've since bought a Porsche Taycan and am now full BeV for my daily driver)

We were driving at CA HWY 5 speeds between SF and LA, that means slow lane at 85 +/- mph with occasional drops to 70 as we encountered traffic from the large trucks traveling slower. It was very hot outside (107F) so we also had the air conditioning going pretty strong, keeping the cabin cool. We also had 2 people in the car (driver and 1 passenger), so we didn't have optimal conditions for preserving the main battery state of charge, it was dropping by 1% every 25-35 miles when driving like that. Nothing to worry about though, 400 miles and we arrived with plenty of battery. The recharging stop was not necessary as I had indicated and we could have kept going (and had on previous drives taking 101 instead of 5). There are also plenty of places to stop and charge, Harris Ranch (bad EA chargers) is almost mid way, Cattleman City is about 30 mins further south and had relatively good charging by comparison (and shade!) But we could have stopped at other charging vendors (EVGo and others) - we had choices.

[Erik-AA]

"Regarding what happens if you run the battery down to 0%, I don't know.."

What, you didn't do the experiment? I did it within the first week I had the car, I wanted to find out.

My 2018 i3s rex slows to about 65-70mph on the level when the SOC is very near zero. So it's not really good for the freeway but backroads are fine. Acceleration is reduced and a big climb might be problematic.

This makes complete sense as I have noticed that below about 70 the rex can hold state of charge constant, but if I cruise faster than that the SOC is slowly dropping. So that's the limit of how much power that little engine can make.