nowtta60
Posts: 182
Joined: Sun Aug 03, 2014 10:15 am
Location: Staffordshire, UK

Re: I think I hate my i3 Rex...

Wed Apr 15, 2015 4:35 pm

Now the weather has got above 15 degrees C, my range in EcoPro+ is showing just over 80 on battery plus just over 80 from the REX. Take off a little bit for the US tank size and "upto" 150 miles is certainly achievable. If you drive in Comfort with the heating on and do 75 on the motorway you'll find that reduced by at least 10 miles for each power source. So only 130ish.

Last Thursday I managed over 360 miles on a commute + long drive. Started with a full charge at home. Ran the battery down to 30% on my long 120 mile commute, switched on the REX. Got back home charged to 100% on a 7kW unit whilst getting packed, having dinner and snooze. Drove 80 miles (15 on REX to keep a bit of charge for faster sections. Got to a failed rapid, 5 more miles got a succuessful rapid charge at BMW mini plant in Oxford which is free :) Ate our KFC whilst we waited and was at 75% by the time we got going. The another 20 miles to stop for a full top up to 80%, but after taking my 1yr old daughter for a leg stretch got back to find it 93%. Then the final 80 miles to destination (with about 15 on REX) and trickled charged at mum and dads overnight. In my old ICE I'd have had sto stop at 290 miles for fuel. So really the only extra stop was 1 failed rapid and 1 at mini. IF I'd stuck to my original plan I'd have only made 1 rapid stop and refuelled at the same time as i stuck a 10 litre fuel can in the frunk. Save queueing again for fuel as it can be done whilst charging (if you ignore the potential dangers of 50kW going in one end and flammable liquid giving off gases at the other).

The key thing to learn - is you really need to get your REXs coded so you can enable the REX anytime you want. It makes it a totally different car and you can use it like an ICE. Run the battery down first to about 12.5%. Then use the REX till you get to a rapid. Add fuel, electrons and fill belly and thermal coffee cup and you are good for another 150 miles, and can either use another rapid - or splash the fuel from a jerry can. Or both. That's 300 miles with 1 stop. 450 with 2. That's not much of a compromise. If you want to go fast (70+mph) - switch on the REX at 50% and the SOC will keep dropping - so you are using fuel and battery, when you get fed up of the REX revving like mad as it's got 10% below the set point, turn it off and on again if it's above 12.5%. If not slow down to 65mph for 5 miles to let it catch up. Good idea if you aren't sure if the rapid you are aproaching will be working. That 12.5% will mean you get plenty of chance the see the charge dropping before you get anywhere near the slow down point. I've driven my REX US style once (letting in come on automatically) just to see what happens at high speed. Nothing. But then we don't have mountains and most roads you get stuck at under 70 due to traiffic. So the REX catches up eventually.

Fuel is everywhere. Carry a 20 meter/60 foot 15 amp extension lead to plug your portable EVSE into - and so is electricity.
i3 REX Ordered 06/08/14. Collected 27/01/15
Capparis White, 429s, Loft, Park Assist, Winter Pack, Professional Media, Drive Assist Plus, DC Prep, LED headlamps.
Essential energy reading for EV owners... http://www.withouthotair.com/

psquare
Posts: 497
Joined: Wed Oct 15, 2014 5:57 am
Location: i3 REx, 225xe Hybrid UK
Contact: Website

Re: I think I hate my i3 Rex...

Thu Apr 16, 2015 6:17 am

nowtta60 wrote:Now the weather has got above 15 degrees C, my range in EcoPro+ is showing just over 80 on battery plus just over 80 from the REX. Take off a little bit for the US tank size and "upto" 150 miles is certainly achievable. If you drive in Comfort with the heating on and do 75 on the motorway you'll find that reduced by at least 10 miles for each power source. So only 130ish.
I was thinking exactly the same.

nowtta60
Posts: 182
Joined: Sun Aug 03, 2014 10:15 am
Location: Staffordshire, UK

Re: I think I hate my i3 Rex...

Thu Apr 16, 2015 4:30 pm

Things are getting even better. Today...
Full charge with precon and full REX this morning.
96 on the REX and 84 on Battery.

Got to work after doing 43 miles and it said
70 on the REX and 22 on battery. Despite not using any fuel :(

Charge to 100% at work 43 miles back home and it said
105 on the REX 45 on battery.

The key difference on the expected remaining range is that on the way to work the slow section comes first. Two miles of urban, 10 miles of B roads at 50-60mph, followed by 30 miles of 65-75mph motorway then a mile of urban road. coming the other way the slower section is last.

If you average that out - you can say on a 43 mile each way commute with 10 miles of 50-60, 30 miles of 65-75 motorway, and 3 miles of urban gives you :

70-105, 87.5 average on the REX
65-98 average 81.5 on the battery.

Note on the way in - I hadn't realised I only selected EP not EP+ so the A/C and heater were running!

So thats a true min / max range picture for spring weather in the UK! Bit of sun, but not exactly warm. LOL.

Both times I drove stuck to speed limits. On the way back I stuck at 67 instead of 70 on the motorway except when overtaking slower vehicles so as not to hold up the traffic.

I'm back to experimenting a lot as a new job means I nolonger use the REX so am finding out about electrical efficiency. I did find out - if you go to the REX screen so you can see the SOC, do a full throttle 0-60 run and you'll eat up 1% !
i3 REX Ordered 06/08/14. Collected 27/01/15
Capparis White, 429s, Loft, Park Assist, Winter Pack, Professional Media, Drive Assist Plus, DC Prep, LED headlamps.
Essential energy reading for EV owners... http://www.withouthotair.com/

MikeS
Posts: 713
Joined: Thu Jan 16, 2014 8:29 am
Location: Brighton UK

Re: I think I hate my i3 Rex...

Thu Apr 16, 2015 11:45 pm

With ref to your statement 'Got to work after doing 43 miles and it said 70 on the REX and 22 on battery. Despite not using any fuel :( “ - I have noticed the same thing. I assume, for example, that it the car thinks you are driving enthusiastically then the REX predicted range is adjusted accordingly as its not a direct petrol drive and depends on the electric motor. Therefore, REX predicted range depends on elec consumption.
BMW 3 Series 2005 - Aug 2014
BMW Z4 35i 2009 - Mar 2014
BMW X1 Mar 14
BMW i3 Sep 14

jadnashuanh
Posts: 4986
Joined: Thu May 22, 2014 2:07 pm
Location: Nashua, NH USA

Re: I think I hate my i3 Rex...

Fri Apr 17, 2015 1:22 pm

ANY range calculation depends on energy use...don't care if it is via electrons or hydrocarbons! The REx adjusts how fast it runs based on your energy requirements to maintain your current moving average style of driving.

The range estimates are based on the last 18-miles of your driving, so it is expected that you'd get a difference in distance to empty on a round-trip if you started slow on one leg, or ended slow on the other. The estimate will be more accurate if your entire trip were fairly consistent.
Jim DeBruycker
2011 535i x-drive GT, 2014 i3 BEV
Soon (hopefully!) A 2021 X5 45e will replace the above

Jeffj
Posts: 252
Joined: Mon Sep 15, 2014 12:32 pm
Location: Boulder, CO

Re: I think I hate my i3 Rex...

Fri Apr 17, 2015 4:09 pm

I think of it in the sense that the REx can produce XX kWh of charge from a given amount of fuel. It runs at varying speeds, so it doesn't always produce power at the same rate, but I bet the curve is relatively flat I don't know exactly what XX is, but I can estimate (using EPA numbers) that 38 MPG x 1.9 gallons is 72 miles, and using a conversion of 4 mi/kWh, that means the REx can produce 18 kWh from a single tank. How much range that actually means is obviously dependent on your driving conditions.

PluviaPlumbum
Posts: 152
Joined: Fri Oct 03, 2014 5:18 pm
Location: Lancashire UK

Re: I think I hate my i3 Rex...

Sat Apr 18, 2015 10:39 am

I am seeing similar numbers now that the heatwave has arrive in the UK :lol: @15c 80+ miles range for the Rex and 80+ Electric

The guess 'o meter definitely calculates REX range predictions based on your driving style. I suppose because it is within its own limitations/parameters merely a source of electrons, just like the battery pack.
Born Electric 3/3/15 i3Rex, Andesit, Neutronic, Park Assist, Pan Roof, 429 Turbine Alloys, Pro Nav, DC Prep, Sun Protection Glass
Audi A4 2.4 Cabrio, VW High UP
@30/10/16 Total 23638miles 22315/1323 95%electric/Rex 5% 124.61 L fuel 48.20 mpg (imp)

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