I33t
Posts: 883
Joined: Fri Dec 13, 2013 3:01 pm
Location: Australia

Re: Chevy Bolt begins production “in just a few short months

Tue Jan 26, 2016 2:54 pm

michaelbmw wrote:I really don't care if my next car gets 130 or 110 MPGe, I just want to be able to charge at home at night and get through my 100 mile daily drive without worries about cold weather, battery fade, errands, or access to workplace charging. The Bolt seems to offer this, and no 80 or even 100 mile class car does.

Even if the Bolt turns out to not quite equal the MPGe of the I3 Rex while in EV mode, there is no doubt it will be vastly better after the 72-mile mark when the Rex turns into a 39 MPG hybrid.


To be fair to the REX, if your trip is 100 miles and the rex cuts in at 72, you use it for 28 miles = 0.72 Gallons. Fossil Fuel consumption for your trip is way better than 39MPG, try about 140MPG.

I agree it is a better idea to have an EV that covers your daily commute distance without running out of range. If you look at the distribution of daily commute distances, the i3 covers the majority. Increasing range requires more cost, manufacturing, resources and weight.

Regen does put some of the energy back into the battery, but as efficient as the i3's regen is, you do not get it all back. It takes less energy to accelerate a lighter car to speed than a heavy one. The only time it makes no difference for a heavier car is when it is coasting or in regen. Other factors like aerodynamic resistance come into play when running at speed and it certainly looks like the Bolt isn't the leader there.
2014 BMW i3 BEV deposit placed 19th Dec 2013
Delivered in Melbourne 4/12/2014. Arrived locally 11/12/14, with 24km on the clock.

alohart
Posts: 1350
Joined: Sat Nov 01, 2014 7:36 pm
Location: Honolulu, HI

Re: Chevy Bolt begins production “in just a few short months

Tue Jan 26, 2016 3:34 pm

i3an wrote:Only time will tell, but don't dismiss the Bolt just because its engineering isn't as elegant as the i3, or that GM has a long and inglorious history of unrelenting mediocrity.

I'm dismissing the Bolt only for myself because elegant engineering and what's "underneath" are particularly important to me. I understand that most people don't care so much about these things, so the Bolt could be a fine choice for them. I wish it well.
Aloha,
Art

2014 BMW i3 Arravani Grey, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, JuiceBox EVSE

michaelbmw
Posts: 30
Joined: Thu Jan 15, 2015 1:32 pm

Re: Chevy Bolt begins production “in just a few short months

Tue Jan 26, 2016 3:35 pm

I33t wrote:
To be fair to the REX, if your trip is 100 miles and the rex cuts in at 72, you use it for 28 miles = 0.72 Gallons. Fossil Fuel consumption for your trip is way better than 39MPG, try about 140MPG.



That is the same reasoning that Chevy uses to try to claim that Volts are getting 250+ MPG. It ignores the electrical energy that is consumed and gives a number that imagines the entire distance was covered using only the gasoline energy.

Using your example of a Rex going 100 miles on a battery full of 18 kWh plus 0.72 gallons of gas, the total equivalent gasoline used is approximately...

18/0.85 = 21 kWh (assumes 85% charging efficiency...MPGe is calculated wall-to-wheels)

21 kWh/33.7 kWh per gallon = .62 gallons equivalent (EPA uses 1 gallon = 33.7 kWh)

0.62 + 0.72 = 1.34 gallons equivalent

Try about 100/1.34 = 75 MPGe....same as a Tesla model S or RAV4 EV. Any greater distance and the portly Model S would be more efficient than the Rex.

I33t
Posts: 883
Joined: Fri Dec 13, 2013 3:01 pm
Location: Australia

Re: Chevy Bolt begins production “in just a few short months

Tue Jan 26, 2016 6:08 pm

Those figures are just totally arbitrary michaelbmw. I understand the EPA's reasoning, but it does not apply to all cases, probably to very few.

That is the reason I applied the term "Fossil Fuel" I grant you that it all just depends on where your electricity comes from. If you charge from solar PV, then there is little to no FF in your electrical consumption. If you charge via a coal fired power plant then there is a lot more consumption.

In our case, the local power supply is one of the best in Australia, but it is still ~75% fossil fuel, mostly natural gas and a bit of coal for top up from interstate. We were not happy to increase our FF consumption so we installed more solar PV than we need so our i3 BEV runs on 100% renewables. If we had a rex with your driving distance, our MPG would be as previously said, 140MPG, same for anyone using 100% renewables.
2014 BMW i3 BEV deposit placed 19th Dec 2013
Delivered in Melbourne 4/12/2014. Arrived locally 11/12/14, with 24km on the clock.

archieb
Posts: 45
Joined: Tue Jan 20, 2015 10:00 am
Location: Wisconsin

Re: Chevy Bolt begins production “in just a few short months

Thu Jan 28, 2016 10:23 am

This discussion is one of the best I have seen lately, even if it has strayed off topic a bit. Information and references are excellent, and I have both learned and enjoyed it.

To add one more piece of information, Green Car Reports just added an updated story January 27th:

http://www.greencarreports.com/news/108 ... cs-updated

The i3 does have the highest MPGe rating at 124 and the Porsche Cayenne S E-hybrid the lowest at 47. With a one year average of 5.3 miles per kwh (5.7 until winter temps arrived) and a TOD cost of $0.055 per kwh, the i3 costs me about a penny a mile to operate. My one year anniversary is tomorrow so I drove 7,500 miles for $75.

I look forward to what will be available in 2018 when my i3 lease is completed. Unless some new technology is introduced I will continue to drive an BEV.

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