i3S REX - What to look for?
Discussion
I've become aware that i3 prices have softened in the past few months so I've taken the plunge and put a deposit down on a BMW AUC i3S; 40k miles and £17k. Its my first foray into EV ownership; while most of my use will be local pottering I will need to undertake a longer journey of 150 - 200 miles every couple of weeks so I've opted for the REX.
The dealer now has it for me to look at and try: anything I need to worry about apart from the usual 5 year old car things? I've got 12v battery age, front spring gaiters, aircon and brakes on my list.
I can see I'll have to pay £500 VED for a few months, what a poorly conceived system.
It doesn't have HK, are there any well known routes to improving the quality of the ICE?
thanks
The dealer now has it for me to look at and try: anything I need to worry about apart from the usual 5 year old car things? I've got 12v battery age, front spring gaiters, aircon and brakes on my list.
I can see I'll have to pay £500 VED for a few months, what a poorly conceived system.
It doesn't have HK, are there any well known routes to improving the quality of the ICE?
thanks
I have a similar use pattern to the OP. Nearly all my charging will be at home, but I will need to charge 'away' every now and then.
I opted for a 120Ah I3S. I'm old and risk averse. I just couldn't reconcile the additional weight of the REX engine for 95% of my use, with the additional complexity and servicing requirements.
For me, the occasional charge away from home was well worth the additional electric range and less to go wrong. Interestingly enough, the I3 BMS is such that there's no recommendation to only charge to 80%, and when on a 50kWh DC charger the full charge rate is maintained, it doesn't take forever to get the last 20%.
I miss the storage spaces my old Subaru R specB wagon had, so I've put a Wokeby trunk extension to fit a bit of extra stuff where the REX motor would be.
Oh, and it's quicker than the 3.0 flat 6 scooby as well. I like the car a lot.
I opted for a 120Ah I3S. I'm old and risk averse. I just couldn't reconcile the additional weight of the REX engine for 95% of my use, with the additional complexity and servicing requirements.
For me, the occasional charge away from home was well worth the additional electric range and less to go wrong. Interestingly enough, the I3 BMS is such that there's no recommendation to only charge to 80%, and when on a 50kWh DC charger the full charge rate is maintained, it doesn't take forever to get the last 20%.
I miss the storage spaces my old Subaru R specB wagon had, so I've put a Wokeby trunk extension to fit a bit of extra stuff where the REX motor would be.
Oh, and it's quicker than the 3.0 flat 6 scooby as well. I like the car a lot.
I think you might be disappointed by the range. The I3S Rex has only a tiny bit more range than the 120AH BEV so at 200 miles you are going to have to stop once for either petrol or a charge (unless you are outside the UK where there is such a thing as the 120Ah Rex) . Its quite difficult to improve the sound system as the basic I3 system doesn't even have rear speakers (or the wiring) so its a relatively involved step to fit better speakers. I had a standard I3 and I didnt think the sound was too bad it the drivers seat but i made sure the next one had H&K.
As mentioned above I'd avoid the rex personally as adds almost 200KG of weight, blunting efficiency, performance and ride quality whilst adding complexity and a higher likelihood of an expensive failure.
The 120ah i3S BEV will do 130-150 in winter and 170-190 in summer on a longer run + add an additional 50 miles of range in 10-15 minutes at any 50kWh charger. .
The 120ah i3S BEV will do 130-150 in winter and 170-190 in summer on a longer run + add an additional 50 miles of range in 10-15 minutes at any 50kWh charger. .
The Rex makes a world of difference if youre doing long trips. On reasonable weather like today you'll probably see ~125 miles on battery alone and the 9L tank will run the generator for another ~90 miles and this will be 60-70mph speeds. When the 9L of fuel runs out, you simply fill it again and run the REX - it is "battery" powered all the time. When you're doing trips to east coast/cornwall where charging is hard work, this problem disappears.
Check the tyres as they arent cheap, BMW servicing is greedy pricing (servicing is every 2 years). Watch for the luxury car tax, that sours it a lot. It is complicated though and I probably wouldnt like one without a warranty, some people have zero problems, some have mega bills, but this is more prevelant in the older (pre s) ones. The extended warranty prices from BMW and 3rd parties suggest they expect to pay out, if its not under the extended BMW warranty now I dont think you can add it.
Stereo is poor without HK (esp in a car of this list price). It should have the Professional Nav/large screen, but I remember after 3 years there is a subscription for map updates.
Check the tyres as they arent cheap, BMW servicing is greedy pricing (servicing is every 2 years). Watch for the luxury car tax, that sours it a lot. It is complicated though and I probably wouldnt like one without a warranty, some people have zero problems, some have mega bills, but this is more prevelant in the older (pre s) ones. The extended warranty prices from BMW and 3rd parties suggest they expect to pay out, if its not under the extended BMW warranty now I dont think you can add it.
Stereo is poor without HK (esp in a car of this list price). It should have the Professional Nav/large screen, but I remember after 3 years there is a subscription for map updates.
The advantage of the REX is that you can fully use the battery. With a BEV I won't go below 30% battery when i am out as i never know that the next charger or the one after that or the one after that will actually be available. That means my 120Ah car has a useable range equal a 94Ah REX battery except for when I am returning home to a certainty of charging. The disadvantage of the REX is that the breakdown rate is significantly higher, although many of these break downs are due to lack of use. People buy the comfort blanket but never use it so the REX gets left there for months on end and fails due to being full of cobwebs when called upon. The moral is if you get a REX you do need to use the REX motor regularly
The Rex runs a maintenance cycle every 6 weeks if you don't use it, it won't be inactive for months at a time. Although it won't run if your battery is full. Also the Rex adds something like 120kg, not 200kg.
Sounds like you've identified the main issues, try and negotiate with the dealer to get those things done if they need doing. They're great cars, have fun!
Sounds like you've identified the main issues, try and negotiate with the dealer to get those things done if they need doing. They're great cars, have fun!
SWoll said:
As mentioned above I'd avoid the rex personally as adds almost 200KG of weight, blunting efficiency, performance and ride quality whilst adding complexity and a higher likelihood of an expensive failure.
I don't know the sales stats, but the majority of early i3's for sale are the REX models so you don't get much of a choice.Thanks for the comments and advice. I’m due to try it tomorrow; the non S Rex I tried had an unpleasant nodding sensation, I’ll be interested to see if this is better.
I also run an Audi A2: if the A2 had been continually improved over 20 years I’d still be driving one: as it is the i3 is about as close as I can get for a replacement.
I also run an Audi A2: if the A2 had been continually improved over 20 years I’d still be driving one: as it is the i3 is about as close as I can get for a replacement.
shoestring7 said:
Thanks for the comments and advice. I’m due to try it tomorrow; the non S Rex I tried had an unpleasant nodding sensation, I’ll be interested to see if this is better.
I also run an Audi A2: if the A2 had been continually improved over 20 years I’d still be driving one: as it is the i3 is about as close as I can get for a replacement.
If the battery is under ~75% SOC you should be able to start the REX manually through the menu, probably worth trying on a test drive. S models are more planted that the normal versions.I also run an Audi A2: if the A2 had been continually improved over 20 years I’d still be driving one: as it is the i3 is about as close as I can get for a replacement.
Jakg said:
SWoll said:
As mentioned above I'd avoid the rex personally as adds almost 200KG of weight, blunting efficiency, performance and ride quality whilst adding complexity and a higher likelihood of an expensive failure.
I don't know the sales stats, but the majority of early i3's for sale are the REX models so you don't get much of a choice.https://www.autotrader.co.uk/car-details/202212132...
OP, if you haven't found it already the tesla-info.com website has a comprehensive directory of current cars for sales
https://tesla-info.com/bmw/bmw-inventory.php?sale=...
https://tesla-info.com/bmw/bmw-inventory.php?sale=...
Paul Drawmer said:
and when on a 50kWh DC charger the full charge rate is maintained, it doesn't take forever to get the last 20%.
That isn’t what is indicated here - https://support.fastned.nl/hc/en-gb/articles/20478...SWoll said:
Jakg said:
SWoll said:
As mentioned above I'd avoid the rex personally as adds almost 200KG of weight, blunting efficiency, performance and ride quality whilst adding complexity and a higher likelihood of an expensive failure.
I don't know the sales stats, but the majority of early i3's for sale are the REX models so you don't get much of a choice.https://www.autotrader.co.uk/car-details/202212132...
After a test drive I'm going ahead. The ride was firmer than the non-S, but the nodding was much better controlled. Not much else to report, I just drove quietly around the lanes in no great hurry playing with the single pedal watching the electric range go up...
Dealer is currently sorting out refurbishing the diamond cut wheels(
), a MoT, and some stone chips. My biggest problem so far is trying to find a sparks to fit an external wall plug.
Couple of comments from an ex-i3 Rex owner.
Consider how the Rex works. Its good, but it is designed to retain a state of charge or to extend your overall range, not to do both. I know this sounds pretty obvious, but say you want to do a 300 mile trip - yes, you can charge and fill up and head out, but if you are going 60+ MPH, the Rex will not really charge the battery. It will mostly keep the battery charged, but if you are going motorway speeds, your charge percent will drop, albeit slowly. Additionally, if you run low on fuel, yes you can just fill up, but again, if you are going quickly, battery charge will drop. It will absolutely depend on the trip, conditions and how you drive, but what a lot of owners do with a Rex is to start off with full charge and fuel. When the battery gets to 75%, turn on the Rex to keep it around this and burn through the fuel. Top up as much as possible, but as long as your destination has a charger, you are good - so working out total range and filling points is the key. Its not a hybrid - you cant just fill and go and expect it to be all good.
Secondly, the Rex is impacted by the weight of the engine and it does introduce some pitching backwards and forwards. Its not that bad, but compared with a non-Rex, it is there. Overall though its a small inconvenience for a lot more flexibility. Maintenance is higher, but the little 2 cylinder engine doesnt need a lot of servicing and it was costing me around $100 extra a year in maintenance, so it really comes down to your driving requirements.
Finally, I think a few others have mentioned - make sure it has the bigger screen (its relatively easy to replace, but post 2017/2018, BMW changed providers and they are more expensive to replace). HK is good and the standard system is OK. You can upgrade the speakers, which is a small but worthwhile upgrade if needed:
https://www.bavsound.com/pages/bavsound-explained
Others have mentioned the tires too - yeah, keep on the look out for these. They are still manufactured but its one, maybe two brands, so your choice is low. Dont expect to rock up to a tire place and get them replaced. You will most likely need to pre-order first. Just keep that in mind.
Oh, and if you havent, get a L2 charger installed. Makes it much more usable. L1 charging is slow, even with the smaller battery so L2 makes a big difference. But, since the battery is smaller, it really doesnt take that long to charge anyway. DC fast charging is pretty good, but remember this is slightly older tech, so dont expect the same speeds as modern EV's.
And you can check the battery status too - instructions here and it will give you the kappa value. Should give you some information on how the battery pack is doing and how much overall charge it has lost. i3's seem to be pretty solid in this regard and only the very earliest ones had issues. Anything post 2016 should be good.
https://www.youtube.com/watch?v=dIP_lThJYWE
Consider how the Rex works. Its good, but it is designed to retain a state of charge or to extend your overall range, not to do both. I know this sounds pretty obvious, but say you want to do a 300 mile trip - yes, you can charge and fill up and head out, but if you are going 60+ MPH, the Rex will not really charge the battery. It will mostly keep the battery charged, but if you are going motorway speeds, your charge percent will drop, albeit slowly. Additionally, if you run low on fuel, yes you can just fill up, but again, if you are going quickly, battery charge will drop. It will absolutely depend on the trip, conditions and how you drive, but what a lot of owners do with a Rex is to start off with full charge and fuel. When the battery gets to 75%, turn on the Rex to keep it around this and burn through the fuel. Top up as much as possible, but as long as your destination has a charger, you are good - so working out total range and filling points is the key. Its not a hybrid - you cant just fill and go and expect it to be all good.
Secondly, the Rex is impacted by the weight of the engine and it does introduce some pitching backwards and forwards. Its not that bad, but compared with a non-Rex, it is there. Overall though its a small inconvenience for a lot more flexibility. Maintenance is higher, but the little 2 cylinder engine doesnt need a lot of servicing and it was costing me around $100 extra a year in maintenance, so it really comes down to your driving requirements.
Finally, I think a few others have mentioned - make sure it has the bigger screen (its relatively easy to replace, but post 2017/2018, BMW changed providers and they are more expensive to replace). HK is good and the standard system is OK. You can upgrade the speakers, which is a small but worthwhile upgrade if needed:
https://www.bavsound.com/pages/bavsound-explained
Others have mentioned the tires too - yeah, keep on the look out for these. They are still manufactured but its one, maybe two brands, so your choice is low. Dont expect to rock up to a tire place and get them replaced. You will most likely need to pre-order first. Just keep that in mind.
Oh, and if you havent, get a L2 charger installed. Makes it much more usable. L1 charging is slow, even with the smaller battery so L2 makes a big difference. But, since the battery is smaller, it really doesnt take that long to charge anyway. DC fast charging is pretty good, but remember this is slightly older tech, so dont expect the same speeds as modern EV's.
And you can check the battery status too - instructions here and it will give you the kappa value. Should give you some information on how the battery pack is doing and how much overall charge it has lost. i3's seem to be pretty solid in this regard and only the very earliest ones had issues. Anything post 2016 should be good.
https://www.youtube.com/watch?v=dIP_lThJYWE
Might want to look at the media system as well.
Ours is a prefacelift 2017 I3 94Ah REX and it has the same professional nav as my 2014 5-series. Think it's called the NBT one and it's connected to internet through the 3G telecom network which is becoming obsolete. Supposedly it reverts to 2G-communication and should still be able to receive some remote commands, but will probably be too slow for traffic info and things like internet adress search.
I think the postfacelift cars (late 2017?) come with the NBT EVO system which works on 4G.
PS Personally I really dislike it for big motorway distances. The car has poor soundproofing, economy/range drops significantly over 60mph and in cold or windy weather. The steering rack is extremely short which makes for nervous driving at 70mph, especially if there is crosswind. It's a world apart from my 5-series but also of smaller cars like a 1-series or VW Golf...
Mind you it's perfectly doable but the only way I arrive as relaxed is by lowering my speed as it's just not feeling at home at 75mph. Maybe the S is a little better for this though.
Ours is a prefacelift 2017 I3 94Ah REX and it has the same professional nav as my 2014 5-series. Think it's called the NBT one and it's connected to internet through the 3G telecom network which is becoming obsolete. Supposedly it reverts to 2G-communication and should still be able to receive some remote commands, but will probably be too slow for traffic info and things like internet adress search.
I think the postfacelift cars (late 2017?) come with the NBT EVO system which works on 4G.
PS Personally I really dislike it for big motorway distances. The car has poor soundproofing, economy/range drops significantly over 60mph and in cold or windy weather. The steering rack is extremely short which makes for nervous driving at 70mph, especially if there is crosswind. It's a world apart from my 5-series but also of smaller cars like a 1-series or VW Golf...
Mind you it's perfectly doable but the only way I arrive as relaxed is by lowering my speed as it's just not feeling at home at 75mph. Maybe the S is a little better for this though.
Edited by HelldogBE on Monday 22 May 18:05
Good point on the side wind stuff - yes, they seem to be afflicted by this! Though if I remember correctly, the S model has a slightly wider track and revised shocks / springs that were supposed to make it a little better to drive (standard ones are not that bad to drive at all) and should help resolve some of the side wind stuff.
And on the headunit thing - being a BMW, they are really easy to code (Bimmercode for this) and update. The cross-over is 2017, but if you are careful, its easy to pick up an Apple Carplay / Android Auto supporting system, Its a little bit of a faff, since you have to get to the rear seats where the headunit controllers are and route the wiring around. Did this to our old one and had full screen CarPlay which was great. Not expensive either.
And on the headunit thing - being a BMW, they are really easy to code (Bimmercode for this) and update. The cross-over is 2017, but if you are careful, its easy to pick up an Apple Carplay / Android Auto supporting system, Its a little bit of a faff, since you have to get to the rear seats where the headunit controllers are and route the wiring around. Did this to our old one and had full screen CarPlay which was great. Not expensive either.
shoestring7 said:
I've become aware that i3 prices have softened in the past few months so I've taken the plunge and put a deposit down on a BMW AUC i3S; 40k miles and £17k. Its my first foray into EV ownership; while most of my use will be local pottering I will need to undertake a longer journey of 150 - 200 miles every couple of weeks so I've opted for the REX.
The dealer now has it for me to look at and try: anything I need to worry about apart from the usual 5 year old car things? I've got 12v battery age, front spring gaiters, aircon and brakes on my list.
I can see I'll have to pay £500 VED for a few months, what a poorly conceived system.
It doesn't have HK, are there any well known routes to improving the quality of the ICE?
thanks
VED will be £165 from 2025. You don’t pay the “expensive car” supplement. Only on new EVs from 2025.The dealer now has it for me to look at and try: anything I need to worry about apart from the usual 5 year old car things? I've got 12v battery age, front spring gaiters, aircon and brakes on my list.
I can see I'll have to pay £500 VED for a few months, what a poorly conceived system.
It doesn't have HK, are there any well known routes to improving the quality of the ICE?
thanks
Gassing Station | EV and Alternative Fuels | Top of Page | What's New | My Stuff