REx Distance

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bstoneaz79

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Jul 28, 2020
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2
Looking into purchasing an i3 REx, probably 2015-2017, maybe a 2018 if I can find a great deal.

That being said, distance is my concern. I'm in outside sales so it isn't just a home-office-home scenario, and charging during the day isn't ideal.

My initial research appears I can just fill up the fuel tank and continue to drive while the REx charges the batteries. However, I went and spoke with a sales person at BMW today and he claimed the range is going to be significantly less than stated due to the AZ heat (at least in the summers) and I'm only going to get another 12-15 miles of range from the REx. The way he made it sound I might only pull 50-75 miles between the batteries and REx and the REx won't just continue to charge as long as I stop for fuel.

So, couple questions:

1) Anyone here drive one in AZ? If so, how's your range in the summer?

2) Anyone here rely more on the REx to get the distance you need or am I asking for trouble? Likely looking at 75-100 miles/day on average, but some days could be 150-200 miles.

I'll step to a true hybrid if necessary, and I'm not interested in a Tesla (service centers are so backed up in AZ it's 3-4 week turnaround for repairs).

Thanks!
 
The original design premise for the i3 was as a city commuter car where the normal commuter rarely drives more than 30 - 40 miles a day. The REx option was put in place more to address the range-anxiety of the potential buyer than turn the i3 into a true hybrid. It's a 650 BMW scooter motor that powers an electric generator, put there as an occasional-use back-up power source.

I live in Texas, and think my i3 REx is great. Below 80 degrees, I get around 60 -70 miles on electric, depending on how 'aggressive' my driving is. Get into the 90 - 100 degree days, with the AC going strong, the electric range does drop significantly (the AC not only cools the cabin, it also cools the high voltage battery pack). Great car for me - I rarely drive more than 20 miles a day. Could you use it to drive 75 - 200 miles a day? Sure - in the full AZ heat, guessing 50 miles max electric a day (maybe less), then gas up every hour or so to run with the REx. Would I do it? No. As much as I like my i3, I'd be looking for either an EV with at least 200 miles range like the new Chevy Bolt (knowing on some days I'd still have to stop and charge for an hour or so over lunch), or a solid 'real' hybrid. And do you have the option of installing a level two charge station at home? With an EV and the miles you drive - a necessity. Trying to keep a high-mile EV 'fueled' using the current public charging infrastructure will be a study in frustration.

Can you write off your car as a business expense? If so, I'd be looking at something new, which will have the biggest battery, and a service warranty that will provide a free loaner when the car is in for service. With the slow car sales due to Covid-19, there are some great new car deals to be had - 70 month financing to keep payments reasonable, and very low interest rates. Otherwise, I'd be looking at a used Prius or similar.
 
bstoneaz79 said:
Looking into purchasing an i3 REx, probably 2015-2017, maybe a 2018 if I can find a great deal.
A 33 kWh battery pack with ~40% greater usable capacity was included in 2017 and 2018 i3's. For your use case, I would avoid a 2015 or 2016 i3. Some of their smaller capacity 22 kWh battery packs seem to degrade more rapidly than the 33 kWh version. A minor update occurred in 2018 which includes some nice changes.

We have a 2014 BEV and have no experience with the REx version. I have read that the REx engine gets ~30 mph in unfavorable conditions, so with ~2 gallons of gasoline capacity, I'd be very surprised if the REx would add only 12-15 miles of range in hot weather.
 
Thanks, MKH. Honestly I was expecting essentially the answer you gave after my trip yesterday and reading this forum more and more. Thanks for the advice on the Bolt, I've put that and the Volt on my short list.
 
Under ideal conditions, while using the REx, you'll likely get about 30-35 mpg, so maybe a maximum of 70-miles. As said, the REx drives a generator, the vehicle always runs all electric. When it's necessary for the REx to turn on (or before, if you enable it), it will still turn on/off under certain situations on its own, and the RPM will vary depending on the load. At the state of charge when it turns on is the maximum the REx will try to maintain.

IMHO, if you need more range than the normal battery capacity on a daily basis, an i3 is the wrong vehicle for you.

The newest ones have a much larger battery than the original, and if there are any local rebates, and if you aren't impacted by the AMT, the feds will give you a decent credit as well. At least with the federal credit, it only applies to new users. Combining all of the credits that may be available could dramatically lower your cost to just buy new, and then, you'd have the full warranty as well to take care of anything that may crop up.
 
2015 REx owner here. I typically get 70 miles off battery and 70-75 off REx (coded my tank to 2.4g). For your needs a 2017 would work fine. 2017 would get you 115mi off EV + 70 off REx. Your AZ heat might kill 20-30% of those figures.

If you can plan your sales calls around some charging it’ll make it less stressful. I’m sure there’s some DCFC options for a quicker fill up.
 
If your normal day has you sitting in the vehicle with the a/c running while you do paperwork, your efficiency in AZ where it could be 115 in the shade, could be problematic on a typical EV...it's not just the miles you put on, it's the time the thing is functioning. Personally, I don't mind at all plugging in when I get home...takes only seconds, but would not be particularly happy having to stop and fill the gas tank daily. If you've really gotten your battery SOC down, and your sale was up a long hill, you also might end up crawling up at like 40-50 mph, as a 35 Hp kick from the REx's generator would make the vehicle about the equivalent of one of the early VW bugs...slow! I suppose you could keep a 10-gallon gas can at home and maybe get by with filling it once a week, and just fill up when you get home.

Note that the life of the battery is based somewhat on the number of charge/discharge cycles. So, if you discharge your battery nearly fully on a daily basis, along with the heat, your battery life may be impacted. One cycle is from 100-0-100%, and it's about equal to 10 charges from 90-100 and back. The larger your battery pack, over the same miles, the fewer charge cycles you'll accumulate, and the longer in time your battery pack should last. This all may become mute when SS battery tech gets here, but that's probably at least 4-5 years away. Toyota said recently, they expect 30-years life out of the SS battery they're hoping to get into the first cars in 2025, with only a 10% loss.
 
Bstone79az Wrote: "2) Anyone here rely more on the REx to get the distance you need or am I asking for trouble? Likely looking at 75-100 miles/day on average, but some days could be 150-200 miles."

I actually live in SO Cal and drive about 70 miles a day to work and back. When I fully charge my i3 (2017 w/Rex) I'm getting 108-118 miles per charge. What's kinda cool is you can get more miles out of charge if you drive a bit more conservative, like 125 - 130 miles using things like Eco Pro mode. If you add in the REX 70-80 miles you can easily get 200 plus miles. You can even "code your i3" for even better efficiency being able to turn on REX once you get your battery down to 75%. This way you can control your electricity use even more, and you can always stop to get some more fuel if you really needed to. To fill up an i3 with 2 gallons of gas (roughy) takes about 1 minute. I think you would be perfectly fine with a 2017 Rex i3. It will definitely serve you well !! :ugeek:
 
BL5 said:
2015 REx owner here. I typically get 70 miles off battery and 70-75 off REx (coded my tank to 2.4g). For your needs a 2017 would work fine. 2017 would get you 115mi off EV + 70 off REx. Your AZ heat might kill 20-30% of those figures.

If you can plan your sales calls around some charging it’ll make it less stressful. I’m sure there’s some DCFC options for a quicker fill up.

In warm conditions the battery actually provides more capacity then in cold conditions. Batteries are specified at around room temperature. (75) Depending on the chemistry you get up to 10% more when you got up to 100 Fahrenheit.

Tint the windows with ceramic infrared reflecting film and put a white wrap on the roof and the car does not need that much energy in the sun. Without any tint - year the i3 is a glasshouse.

Yes you need more power to cool, yet that is partial offset by the capacity gain.
I'm getting regular 130 miles out of my 2017 BEV in sunny and warm Florida and that's in Comfort mode. While in Ecopro I saw 148 miles at interstate speeds.
 
I agree with eXodus....ceramic tint the i3. I am on i3 number two and without tinting, the i3 is unbearable in the sun & heat! The difference when I tinted all side, rear and moonroof windows with high quality ceramic tinting made beyond a huge difference, and it makes the HVAC run so much more efficiently!

If you can get a 2017-2020 i3 Rex, I think the car can suit your needs perfectly! I live in an area of So. California that routinely sees months of 100-115F, and even when I have to drive on Rex, the A/C works perfectly and I easily do 75mph up somewhat steep freeway (highway) grades. In my 2019 i3S and now 2020 i3S, I have never noticed running on Rex feels slower or less powerful than when Rex is off (you will just hear the Rex when it is kicked on high gear; It sounds kind of like a lawnmower meets an old Porsche, LOL.
 
You'll get several advance warnings if your SOC gets low prior to the system starting to shut down functions to try to preserve power. The time you'll notice you can't keep charging up a long grade will be as the SOC gets into the low single digits. On the flat, the vehicle can hold charge up to about 75-mph, but the REx can't keep up if you throw in a grade, you've got the a/c or heat roaring, maybe the lights fully on, etc. The REx will only try to bring the charge up to either 6%, or the point where you manually activated it (requires coding in the USA). It will not try to raise the charge about 6% unless it was already higher, and you manually turned it on. WHen you shut the vehicle off, the SOC that it currently holds becomes the new maximum the REx will try to hold, so it won't recover more than to 6% on its own.
 
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