Thinking about a BMW i3

[Clem2k3]

So, since I've started commuting 65 miles a day in my MX5, the amount of money I pour into a car that does 32MPG (on a very good day) has become painfully clear. Mix in the odd trip from London to Bristol and I am approaching £300 a month ...

So whilst dribbling along the M3 through the roadworks the other day I thought to myself "I wonder if I could get an i3 (new bigger battery one) for that petrol money" and the answer is, close enough that a bit of man maths can see me through the financial barrier ...

Naturally I plan to maintain a petrol car for longer journeys but I was wondering if any i3 owners could give me a sanity check on whether its a practical idea for me. The commute should be easily managable, I'll be able to charge it at home and at work so I shouldnt struggle with this at all. However I live in London and my family is all in Somerset so I'd like to be able to make trips to Somerset and Bristol in the i3 to make the most of the running cost savings. So two journeys I'd like to make are:

Farnborough -- (100 miles) -- > Bristol -- (115 miles) --> London in one night for a gig. I would leave work in Farnborough fully charged in this idea. As I understand it, the fast chargers (from Ecotricity at least) for the i3 are rarer and Chievely is the only one on this trip. I would need to add about 40 minutes of charging total to make it. So in my mind I would go to Chievely and stop for 20 - 30 minutes charging at the DC charger there, then get the rest of the charging on the way home. I dont mind the waits, I can get food/coffee during these.

London/Farnborough -- (130ish miles) --> Somerset. Overnight charging from mains and returning the next day. Now this one I am a bit more dubious on. This is taking us to the edge of a single run range and the route I would usually take (M3/A303) does not have any chargers so lets assume I go the M4 route and charge at Chievely again. This brings the single stint range down to 81 miles and I probably wouldnt need to wait a full 40 minutes for a fully charge on this one.

So are those two journey plans practical? Have any owners got any thoughts on this. I guess the obvious ways my plans could get de-railed are things like chargers not working, charger in use and range not meeting expectations (because of weather for example). Do i3 (or any electric car) owners find these things happen a lot?

I'll probably come up with more questions but I'd appreciate any thoughts owners have ...

[Clem2k3]

RossP said:

Hi! i3s are great (I am on my second).

Are you considering a REx model or battery only?

Lots of info here - http://bmwi3owners.uk

Looking at the battery only one, I dont think BMW got the REx version right ... doesnt seem to add much range and cannot run the car on its own ... leaving you still with range anxiety ... Plus I like the purity, I am an electrical engineer (actually working in the area at the moment) and I think the pure electric is the way forward for a good chunk of driving. Will check out that site

[Clem2k3]

jkh112 said:

I did something similar a few years back. Leased an outlander phev which can do my commute on battery and it cost the same as the savings from not using my 911 daily.
I cannot comment on the i3, but can say that from experience you would be brave to rely upon the ecotricity chargers working at any one particular stop. I have pften found them out of order or damaged which is not an issue if you can make it to the next service station, but it sounds like this would not be possible for you.
Maybe an i3 rex is the answer, or use the i3 for the commute and the mx5 for the long runs - after all if you don't then why keep the mazda?

This is exactly the sort of experience I wanted to hear about ... I could make it to the next stop in this case but the fast DC charger is only at Chievely on their map. It would still be a viable option for me to just use the i3 for the commute but if I can save myself £40 on gigs in Bristol that would make me much happier and make the cost easier to swallow ... man maths is a delicate web of lies to oneself at the best of times ...

[Clem2k3]

AW10 said:

Both the Membury and Leigh Delamere services on the M4 are listed as having 43kW i3-compatible chargers.

On ecotricity's site it lists the CCS as only at Chievely. Lists Membury and Leigh as having "DC and AC fast charge" I couldnt find more detailed info. Do you have a better source?

EDIT: Ignore that ... I am being an idiot ... I see that Membury has CCS listed as well as the others. To regain face, I am going to claim that has changed since the other day when I looked, though this probably isnt true.

I guess this comes with a supplementary question. How do EV drivers find the charging points, what schemes work best and how much do people find they rack up in 1 off charging costs etc.

Edited by Clem2k3 on Thursday 27th October 12:53

Edited by Clem2k3 on Thursday 27th October 12:57

[Clem2k3]

RossP said:

Not sure I understand that statement. My first i3 was a BEV, and I now have a 94REx. REx adds unlimited range as you can just keep putting petrol in. It definitely can run the car on its own too. I agree on the purity idea but I wanted to do longer trips in the new i3 and the REx enables me to use the i3 more of the time. Definitely no range anxiety at all with the REx. Even if I am going a long way I just leave without necessarily looking for charging opportunities beforehand. In a BEV you need to plan.

I thought the REx gave you very limited performance (ie. max speed limit) when on petrol only due to being a tiny bike engine?

[Clem2k3]

AW10 said:

I'm not an i3 owner - my experience is limited to having driven a friend's 64Ah REx some 110 miles a fortnight ago.

As I understand it the REx function operates in two modes:

normal - the car acts as a BEV until battery level gets very low and then the REx kicks in. In this mode you may find yourself in situations where you're asking for more power than the REx can provide and the car simply won't do what you're asking. For example, going up a motorway slope at 80mph with the AC on - the car will max out at a lower speed. The REx' output is less than the car is capable of demanding from the battery.

maintain charge mode - in this mode the REx operates almost continuously and you have full BEV performance until the battery is almost exhausted and the petrol tank runs dry. The REx will shut off below a certain speed (perhaps 10 mph) and switch back on automatically. You can see the battery level drop much more slowly or even rise if the load you're putting on the car is low. What you can't do is simply run the REx while stationary to charge the battery.

Others will be able to describe all this more accurately.

I would offer that if you're going to do a long drive that can't be done on BEV alone you might want to switch the REx on at some point to have full performance and to avoid being fully dependent on a fast charger. But REx miles are generally more costly than BEV miles, depending upon your charging costs.

Edited by AW10 on Thursday 27th October 15:44

Thats exactly how I understand it too, but the REx motor is 25kW (Compared to 125kW for the motor). This says to me that when you run out of battery juice you only have a 25kW (33bhp) car at very best. Some of that power is lost in the conversion to electric power to drive the motor. I would be interested to know how slow a 25kW i3 is, I suspect it is very slow and not something I would want to drive on a motorway. Given that to get to this state (dead battery) youve gone some 290km from home, there seems to me a good chance that you are on a motorway when this happens. Basically I suspect that I dont want to run on REx only power so the only useful function of the REx to me is the extension of the range, which is about 50km according to Wiki. Its a useful feature, but it does not take the car to infinitely extensible range as the car is not that usable on petrol power alone.

This is what I mean when I say I think that BMW got the scaling wrong for the REx. For me I think a REx should be able to drive at motorway speeds without difficulty on petrol power alone. I suspect a 25kW motor cannot do that for an i3.

However, I think they got the range, performance and vehicle size balancing act just right on the BEV version.

Edited by Clem2k3 on Thursday 27th October 16:37

[Clem2k3]

AW10 said:

Hmm, I thought REx extended the range by about 80 miles? Have a read of https://speakev.com/threads/whats-your-94ah-i3-bev...

Oops you are correct. I took my numbers from the wiki: https://en.wikipedia.org/wiki/BMW_i3. But instead of comparing REx to BEV I compared 94Ah REx to 60Ah REx by accident.

Even so, it just becomes a longer range battery car. In my opinion it shouldnt be thought of as a constantly extendable range vehicle. Once the battery is gone, its gone. So your range is 180mi on a REx. Not 180mi plus 80mi per refill.

I dont mean to be overly anti the REx, I just dont think its for me.

[Clem2k3]

Yes the "Hold state of charge" mode is what gets you the 180 mile range. Nothing more, nothing less. Its not any different from having a bigger battery. After those 180 miles are up, I cant just top up the petrol and keep moving because then I am driving a 33bhp car down a motorway. I dont think this is especially dangerous, but it is unpleasant. I know this ... I also drive a 998 mini.

For example the 220 mile round trip I was suggesting for a gig all done in 1 night using a REx I would be able to make it down in 1 and would still have to stop on the way home to charge, lets say for at least 20 minutes. In the BEV this trip would need 1 stop in each direction most likely. For the trip to Somerset I could make it in one without a stop with the REx whereas the BEV would probably need a short stop to be safe. Its definitely getting me further, but not really enough to make me want it.

The REx is clearly a longer ranged vehicle but I dont feel this design materially changes the experience enough to warrant the extra cost (in fuel and in initial purchase), the extra weight noise and (I've heard) the unpleasant warming of the back seat. I dont think it really removes range anxiety completely, just pushes it further down the road (boom boom) and thats exactly its job. It will still require planning and forethought for journeys in a REx and thats something I am fine with, but to me it doesnt really change the equation enough to warrant it.

[Clem2k3]

AW10 said:

I think you can drive it as a constantly extendable range vehicle if you wish - just switch the REx on at the start and it will do its best to keep the battery charge level as high as possible. I suspect if you were doing a constant 90 mph on the motorway the battery would eventually go flat but that's hardly the environment the car was meant for. Stopping every 80 miles would get tedious and at effectively ~40 mpg on petrol the car is just OK in the economy stakes.

Edited by AW10 on Thursday 27th October 18:33

I didnt see this when I wrote my last reply. I see your point and I get the suggestion you are making but if you are stopping for petrol that often to eek out the range, surely its just as good to stop for a little longer and charge the battery and dont have a REx?

Edit to cover this too:

AW10 said:

If you engage the REx early it will run out of petrol long before you run out of battery so just refill the tank and carry on. It would appear you're assuming that it will run out of battery before it runs out of petrol - the US version has this flaw but not the RoW (Rest of the World) cars.

I am not planning on using it for super long journeys, anything longer than the ones I suggested in my first post and I'll use a petrol car. Ultimately the petrol puts into the battery less than than the motor takes out, so at some point the battery will run out. I have no idea really how far you can eek out the range of a REx this way but it is not indefinite and requires lots of stops. I think our difference of opinion on the REx comes from the fact I think the petrol will put in a lot less than the motor takes out, and you think itll put in a bit less than the motor takes out. BMW isnt telling anyone which is the case and it will depend a lot on driving style, weather conditions, traffic etc.

Edited by Clem2k3 on Thursday 27th October 19:42

Edited by Clem2k3 on Thursday 27th October 19:44

[Clem2k3]

AW10 said:

I think you need to get yourself a 24 hour test drive to satisfy yourself as to what happens. And then report back!

An extended test drive is part of my plan

Is 24 hours the most I can expect?

[Clem2k3]

RossP said:

But that isn't how you use the REx...

If I am doing a long journey, I engage the REx early in the journey not at the end. Unless you are hoofing it like a mad thing or travelling at 70+ then the REx can easily keep up. Remember it runs all the time, so sometimes you might be slightly in deficit on the battery but as soon as you slow down the REx keeps running and tops the battery up to where it was when you activated the REx. So it is absolutely possible to keep topping up the REx and you can go as far as you like! Deactivate the REx when you have enough battery to complete your journey - job done!

Surely then you are driving a petrol car that has an 80 mile tank and does 40mpg?

I don't think doing over 70 on the motorway is an unreasonable ask. I would be really interested to know what a constant 70 does to the battery range in rex mode.

[Clem2k3]

mids said:

riving at 70mph with the REx on does not reduce the battery range, it can happily keep up (even in the cold/wet) although you are getting close to the speed at which the SoC will start to slowly come down. I drive 190 miles regularly in mine limiting my max speed to 75mph and do it with a single top-up midway and always have over a third of a tank of petrol remaining when I arrive.

Next month it will be 3 years since the first i3 REx's were being delivered. The questions being asked in this thread have been discussed to death in intricate detail all over the place. An evening of googling will get you lots of info. Check the i3 facebook groups (US & UK), speakEV, mybmwi3.com, bmwi3.blogspot.com, and even in here.

To be fair the REx conversation is a bit of a sideline ... an interesting one though. I found it very hard to find any real answers to the question of what performance is left when the battery runs out, partly it seems because you can keep topping them up and partly because the running out issue is more common in America and Highway speeds are not Motorway speeds.

I came here to ask whether my planned trips were reasonable with a battery only i3. The answers were "probably a bit dodgy to rely on any single charger being available" and "there are more chargers on the M4 than I thought".

[Clem2k3]

TallTony said:

It’s a bit tricky to answer your specific questions as range does depend on so many factors – driving style, driving speed, outside temperature and so on. Ask on the BMW i3 UK facebook page, you will get exact answers on there.

Obviously you will be fine if you are able to use the motorway chargers, but in my experience you cannot rely on them. I have a REx so luckily I have rarely had to bother with them which is good. Of the 5 times in the last 22 months I have tried to use them only twice have I been successful. Either they were broken, already being used or being blocked by some inconsiderate tw@t in a normal car.

Yesterday morning I ticked over 25k miles, overall I love the car. I initially liked the idea of going pure electric as it actually felt ‘wrong’ to not fully embrace the principle, plus I knew the weight does slightly affect the performance. However for me it was definitely the best decision. I have had no concern about range anxiety, no planning to see if I could squeeze in a trip to a friend’s house etc, or wondering if the weather will be cold (as that does affect the range significantly).

I would guess that 98% of my mileage is electric, just the occasional very cold day when I am a few miles short of getting home plus the occasional long trip. I have done 250 miles in a day on several occasions, I have a similar approach to RossP except I usually drive on electricity until I have around 15 miles left for emergencies and then top up the petrol every 50-60 miles.

To answer one of your questions - if the REx car has zero electricity then it does actually work fine just a little slower and the acceleration is terrible. However I just build up to 60/70mph and then slow down to a stop on regenerative braking, that normally generates enough to sort the problem.

However if I was to look to replace it right now then I probably wouldn’t get another. The BMW 330e is much more appealing to me, the business lease costs are comparative or at least used to be.

Thats interesting (and a bit worrying) that you are not doing well at getting access to chargers. Also the info on a dead battery REx.

What sort of cold weather drop in range are you seeing? And how much do you suspect is down to the added heating requirement and how much due to less efficient battery/drive?