BMW i3
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TomMoloughney
Well-known member
Parker said:
Yes, it's quite possible. By cutting the weight so dramatically with the extensive use of carbon, they were able to reduce the size of the battery which is the most expensive component in an electric car. For example, the MINI-E had a 35kWh battery pack. Then the ActiveE had a 32kWh pack. The i3's battery is only 22kWh's and will supposedly have about the same range as the MINI-E and ActiveE.
However if the base MSRP is that low, expect it to be void of many of the goodies most of us expect in a BMW. Premium sound, upgraded electronics package and the tire/wheel upgrade will likely add $5,000+ to the base MSRP. Then add the range extender if you want it and a fully loaded i3 will probably be $10,000 more than the base MSRP.
TomMoloughney said:
We're very used to adding £5-10K worth of extras to our German cars (the UK is not called "Treasure Island" by car manufacturers for no reason!) ..... so it will be useful if the base car starts off at a sensible price. Fingers crossed.
TomMoloughney
Well-known member
Parker said:
It is mostly the weight, but I'm sure the other refinements are helping to make it more efficient also. The i3 uses the same batteries as I have in my ActiveE, but the ActiveE weighs 4,000lbs. The i3 weighs 2,756lbs, 31% less than the ActiveE. The battery pack is also 31% smaller(32kWh vs 22kWh) so it really comes down to how much weight it's pushing around. Aerodynamics play a role at highway speeds, but at low speeds it's all about the weight. I suspect the i3 will be exceptionally efficient (miles per kWH) under 50mph because of it's low weight, but at the speed increases it's tall, boxy shape won't have the best drag coefficient so at highway speeds the range is going to taper off significantly. Time will tell.
"The i3's battery is only 22kWh's "
So I'm thinking the 35hp Rex ICE would probably be able to supply 22KWh's?
I don't know why but I had in my head there was a big miss-match between Battery output and Rex output .....but there isn't is there?
Which means pretty much no degradation in performance when in Rex mode ...... have I got that right? ....or am I missing something.
So I'm thinking the 35hp Rex ICE would probably be able to supply 22KWh's?
I don't know why but I had in my head there was a big miss-match between Battery output and Rex output .....but there isn't is there?
Which means pretty much no degradation in performance when in Rex mode ...... have I got that right? ....or am I missing something.
TomMoloughney
Well-known member
Parker said:
Yes you're missing something there
The REx motor will probably put out about 25 to 30 kW's, not kWh's. So the REx would have to run at maximum power for an hour(which it isn't designed to do) to produce 25 to 30 kWh's of electricity. Under normal highway driving the i3 may only need 10kW to continue driving along, but driving up steep inclines or if you want to drive fast(like a BMW should be driven!) it may require a constant draw of close to 30kW's to maintain its course. I agree it's a bit confusing, but think of kW's(kilowatts) as the rate the electric is supplied or used and kWh's(kilowatt hours) as the stored volume the car has. I could probably offer a better explanation but I'm in a rush now getting the BBQ prepared for my Independence Day festivities! I bet you could get a cleaner explanation of the difference from Wikipedia. If not let me know and I'll offer another reply when I have more time
By the way if you are interested I did an Independence Day blog post(and it's not about our Independence from Britain!): http://activeemobility.blogspot.com/2013/07/independence-plug-into-sun.html
Thanks for taking the time to explain to us Newbies these new concepts.......and especially on your special day.
Happy Independence Day.
I enjoyed your Blog entry ..... whilst I'm not allowed to put PV solar arrays on my house (it was built in the 1750's)* - my Fathers house does have an PV array so I look forward to visiting him and "refuelling" on Sunshine.
Have a great day.
* I use an Electricity supplier that gets high % of their Electricity from the London Array (Wind Farm) ...... unfortunately "I'm Driving on Wind" doesn't have the same ring to it!
Happy Independence Day.
I enjoyed your Blog entry ..... whilst I'm not allowed to put PV solar arrays on my house (it was built in the 1750's)* - my Fathers house does have an PV array so I look forward to visiting him and "refuelling" on Sunshine.
Have a great day.
* I use an Electricity supplier that gets high % of their Electricity from the London Array (Wind Farm) ...... unfortunately "I'm Driving on Wind" doesn't have the same ring to it!
Have been thinking about getting. 10 Sunpower 345w x series solar panels to help charge my i3. Not sure if that will be enough? Guess in winter in England it won't be
Did you see the latest photos today?
http://www.autoexpress.co.uk/bmw/i3/64846/bmw-i3-spy-shots
Did you see the latest photos today?
http://www.autoexpress.co.uk/bmw/i3/64846/bmw-i3-spy-shots
gaz26 said:
The photos are great aren't they (I wasn't going to go for another silver car but it does look good in Silver)..... I know I biased but I do think the i3 has what it takes to break peoples perceptions of EV's (as long as the price is right!)
Regarding PV's I think unless you are very lucky you will struggle to power your i3 purely from sunlight in the UK however as they say .... every little helps. .... and I know that the feeling of Energy Security you get with home generation is worth its weight in gold.
Yes not sure how I convert Kwh to miles available. My solar quote shows I could generate 3000 kwh per annum. Lower in winter higher in summer. I recall reading you should be able to drive 4 miles per kwh? So my panels would give me 12000 miles? I'm retired so the car can be at home during the day to charge?? I'm sure it's not that simple but maybe Tom can help!
