80m commute no charger at work; REX or no REX?

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Drdave

New member
Joined
Apr 30, 2020
Messages
4
Hello there, looking for some advice!

I drive 40 miles each way to work, 80 miles round trip. I am thinking that a 2017+ 94ah i3 may work well for me. No charger at work. Do you think I'll be fine even if driving in winter and 80mph on highway for almost all of the miles? Or do I need a 2019+? Or would REX solve the problem on cold days and I really need it?
 
It will be a stretch with the BEV in winter. You can get >30% range hit in winter. Besides the car would sit there for 8 hours in the cold. My wife's commute is 48 miles one way and in cold days she has to use the REX engine to make it there with pre-conditioned car (2014 REX with a bit of degraded battery). Luckily she has chargers at work.
 
Hmmm. Yeah, definitely knew the early generation batteries would not do it at all. Had thought the larger 94ah one might make it. 30% hit would make it impossible. Or, with the REX would have to fill up every day, which defeats the purpose. I'm not up for paying for a 2019, at least until the prices fall further. Thanks for your input. I do think I'll need more buffer than the 94ah will offer unfortunately, unless I am missing something, or unless I can figure out a way to at least get on a 110 charger at work, which I don't think is possible. There is a charger on the way home, but again, defeats the purpose (which would be conveniently getting to and from work without having to hit gas stations/chargers).
 
Lobby for your workplace (employer, or building management) to install a commercial charger or two. Many States have utility and State incentives for businesses to do so, and they aren't really that expensive.

https://evcharging.enelx.com/commercial-charging?utm_source=google&utm_medium=cpc&utm_campaign=GS_NB_BMM_B2B&gclid=Cj0KCQjw7qn1BRDqARIsAKMbHDaH2QF70OmK745OyN1Yo70u5eP92u0DgJFEW5L7igGi_AYscfg2jYIaAvvFEALw_wcB
 
What's a "cold day" to you? Whereabouts? Do you have access to a 120 volt receptacle at work to plug in to on colder days? 80 MPH is probably as much a factor as temps. It takes 7 minutes longer to drive 40 miles at 65 MPH if it was 100% freeway.
 
I have (whenever I start going back to the office) a ~70 mile round trip, almost all highway. I do have chargers at work, but no guarantee they will always be available. Big company, only 4 chargers, more and more people buying EVs... Anyway, after checking into this and asking basically the same question I concluded that I personally would not be comfortable without a REX. By my best calculation (just got it so this is all educated guess): If I fully charge every night, precondition before I leave, don't need to go more than a few miles outside the work commute doing errands or whatever, use echo Pro mode, keep highway speeds low and drive easy I should be able to make it without much wiggle room on the coldest of days. Pass. I bought a rex so I could drive normally, no stress, no hypermiling, no relying on the seat heater with a chilly cabin.
 
Nashville area. Hospital parking, no chargers, big lots and parking deck, but I don't think I will have any luck getting even a 110 plug to charge on. Yeah, I totally agree about there being very little point in driving faster than the 70mph speed limit, and generally I don't. I think you are being generous in estimating 7 minute time savings; there is almost always someone in front of you anyway, and many situations even on the highway don't allow for safely going faster, so you are never going to save many minutes. But, I know that if there's traffic on some of the way that slows me down, or I push the time, I will go faster, when I can, to try to avoid being even a minute late, and want to consider worst case. It is good you brought it up, though. I never speed at all on the way home. So, realistically, I won't face this worst case scenario much at all. And we have other cars, so I can just use another on a cold day.
 
It's all educated guessing of course, but it sounds like you'd be in pretty much the same situation as I am. Buy the REX for piece of mind and the rare occasion where you need to go farther than normal, but a typical day will be battery only, even in the cold.

edit: you mentioned another car for bad days... If I have to commute in ice or snow I'll be driving my Jeep. Nothing to do with battery life, all about rwd + questionable bad weather tires vs. full time 4wd + severe winter rated all terrains. Might be a different story if I decide to buy a set of winter wheels/tires for the i3.
 
Honestly, I think you're fine. Nashville gets down into the low 30s but if you're working a day shift, you'll be leaving home pre-conditioned without much penalty. And even a cold winter day in Nashville is still in the 40's. I don't think you have a problem. If the rare day comes when you need to stop for a 10 minute top-up on the way home, it sounds as if you have that covered.

I think it would be unusual for a parking structure to have no power outlets, unless they're locked or there's a prohibition. It's worth scouting the area. If there is any practical way to avoid a REX, I'd recommend it. If you need a REX, you need a REX, but your commute sounds reasonable and you're got a back-up. Even, worst case, you parked the i3 in January (or planned on a quick charge every day), the other 11 months out of the year you'd be sittin' purdy.
 
SOme of the dealers will let you do an extended test drive. Even if it ends up over a weekend, you could try your commute and see what happens the way you drive. On the highway, speed is a significant range hit. The drag goes up in a non-linear fashion, so double your speed is lots more than double the drag. Even small speed changes can make a difference. While you may not notice it when driving an ICE, climbing a grade at speed can overcome even the output of the REx, and your battery level could be dropping even when it's running at max.

If you can precondition by setting a departure time while connected to your EVSE, at least in one direction, you can minimize the degradation you get in range from the cold. WHen you do that, also have it condition the cabin so you start out comfortable and don't need to bring the cabin up. Note, the REx creates all cabin heat from the battery like a toaster. The BEV has a heat pump, which is lots more efficient. FWIW, when preconditioning the cabin and the batteries, I"ve seen my BEV drawing in the order of 20A, so the 120vac occasional use EVSE supplied would not leave with a full battery if you tried to run that.
 
How long are you planning to keep this vehicle? Once the battery degrades you won't have the same range. So you may want to consider REx if you are planning on keeping vehicle over long term.
 
Thanks everyone, very interesting input. I am keeping my eyes open for a deal on one. I'm inclined toward the BEV; but there is a REX available nearby that might work, so that may sway me. Either way this looks like a fun little car for trying out electric. I have said for a while I think I have bought my last ICE, though I will probably have the ones I have for a long time to come.
 
Drdave: I'm not sure why you are trying to avoid the REX option. It totally and completely removes the range anxiety problem for your commute. And gives you flexibility for using the i3 for longer trips as the need may arise. My 2014 i3/REX has the smallest battery but I'm not sure I could own an i3 even with the largest available battery pack without a REX. But obviously everyone has different needs and comfort levels. Standard disclaimers apply. Your mileage may vary. Objects in the mirror are closer than they appear.
 
I'm not sure I'd feel comfortable relying on a 94ah BEV for that commute year-round but I agree you could probably do the trip *most* of the time. Ultimately it probably depends how much you're willing to accommodate your car's needs/ how much you're willing to risk it on those days when it'll be close.

Starting with the EPA's numbers (114 mile range), you basically have a 30% buffer on an 80 mile commute. For battery degradation, consider that BMW warrants the battery to 70%, which means in a worst-case-scenario just shy of triggering the warranty, you're already short on range in ideal weather.

Now, hopefully your car would stay away from that level of degradation for a while, but in combination with the losses in efficiency from cold weather it could be tricky. At 10% battery degradation and a goal of arriving home with 8 miles of range (when the car's second warning comes on), you'd need to average 3.6mi/kwh which (from my experience) should be easy when it's above 50 degrees out but might be tricky below 40(F).

I think some questions for you to consider are:
Can you reliably leave home with a fully charged battery? (L1 isn't enough for this scenario)
How willing are you to use a different vehicle, if the range estimator says 79 miles when you leave in the morning?
How willing are you to hypermile if the range estimator says 39 miles when you leave to head home?
How willing are you to stop and charge if it says 30 when you leave to head home?
Do you ever go out to lunch at work, or want to take the car to go to dinner or other side-trips shortly after getting home?

All this is to say that the 94ah BEV can probably do it (most of the time). But the 94ah REX definitely can.
 
80 miles round trip with a 2017+ 94ah BEV will be fine. Back when we could go to workplace, I commuted 50 miles round trip a day and charged every other day. Easy to get ~120 miles per charge. Even in ~25F winter you can get well over 100 miles per charge.
 
One thing to consider about battery degradation...the more important thing is total percentage use in between charge cycles. From what I've read, ten recharges from 90-100% is the same 'wear' on the batteries as one charge from 0-100%. The closer you are to coming to depleting your battery on a daily basis, the more degradation you'll see. If you look at it that way, the bigger the battery, the less it would be discharged, the longer it would last even if you topped it off each day. Because the computer keeps a buffer on the actual battery capacity, it literally disconnects the acv when it's done, and that it can cool the batteries when required, those on the i3 tend to have quite good reliability. NOt all battery chemistries are created equal. The one chosen for the i3 seems to have fairly slow degradation characteristics. It's a big tradeoff...reliability, capacity, and discharge rate. You can tweak the chemistry to achieve any one of those characteristics to be better, but usually with a detrimental effect on at least one of the others. Batteries will continue to get better. We've been tweaking ICE engines for over a century...LiOn much less time.

Ultimately, a cheaper, quicker way to make hydrogen may beat out batteries. Using excess say solar energy during the day may make hydrogen production cheaper and still be clean. Give us maybe another 10-years and things will likely look quite different. A BEV may be an anachronism and ICE may be obsolete as our only tailpipe emission may be water (and oxygen during the making of the H2).
 
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