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I came across an excellent presentation on Lithium-ion battery technology as it relates to automotive applications. The presentation compares a number of different technologies including those used in the Fisker, Leaf, and Tesla automobiles. Anyway, if you’re a nerd like me I thought you might enjoy this presentation:
http://youtu.be/9qi03QawZEk
Another presentation explaining the future of batteries and comparing the pros and cons of different technologies can be found here:
http://www.youtube.com/watch?v=ISEzvNevyck&feature=youtu.be#t=10.361344
While yet another very interesting presentation which appears to be associated with A123 with a very impressive ending can be found here:
http://www.youtube.com/watch?v=NmG1p6EuF3s&feature=youtu.be&spfreload=1#t=10.478466
 

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Since you maybe have watched all 1:13 of the first video (I fell asleep after 10 minutes) ... can you boil it down? Being in AZ, will I be very happy about having bought a warranty?
 

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Since you maybe have watched all 1:13 of the first video (I fell asleep after 10 minutes) ... can you boil it down? Being in AZ, will I be very happy about having bought a warranty?
Isn't pretty much everything in Arizona boiling down right now? :D
 

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It's just "summer" here. I'll take a 120 degree summer day here over 0 degrees with a 25 knot wind from a central IL winter day ANY FREAKIN' TIME! Sunshine is much easier to shovel! :D

However, I do care about my Karma batteries! They've been pretty good over the 18 months I've had 'em! :)
 

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Discussion Starter · #5 ·
Since you maybe have watched all 1:13 of the first video (I fell asleep after 10 minutes) ... can you boil it down? Being in AZ, will I be very happy about having bought a warranty?
In a nutshell, the Tesla has better batteries than the Fisker and the Fisker has better batteries than the Leaf. Also, heat is the biggest enemy of Lithium batteries. That's why active cooling for the batteries can make a big difference on battery life. The Tesla and the Karma both have active cooling.
 

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There is actually a lot of on-going research for batteries that will hold charge for cars right now I think and it seems like the market for the whole thing is going to get a lot more competitive with the demand for alternative energy increasing across the world too. (I didn't watch the whole video either, sorry!)
 

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In a nutshell, the Tesla has better batteries than the Fisker and the Fisker has better batteries than the Leaf. Also, heat is the biggest enemy of Lithium batteries. That's why active cooling for the batteries can make a big difference on battery life. The Tesla and the Karma both have active cooling.
2011 and 2012 LMO Leaf batteries had the issues... Nissan made a change to the pack in 2012 which mitigated these issues in extremely hot climates (Arizona).

The new Leafs have actually moved to NMC cathode with the 30kwh/40kwh in the vans.. so this is no longer an issue.


Just recently A123 has moved into this space... essentially abandoning Iron Phosphate and using their existing inventory for 48v start/stop batteries.

http://www.a123systems.com/nmc.htm


The A123 pack in the Karma is quite antique as I do not think any OEM in North America uses this Iron Phosphate chemistry. I know a lot of hobbyists use this chem and it is quite popular (you really don't need much thermal management).

The Karma is also antique in that it does not actively heat the pack so you see huge issues such as voltage drop and a myriad of other issues (although there is a claim that the new Revero's EXT chemistry negates the need for active heating- not so with the Karma). The battery balancing algorithm also actually uses resistive bleeding which is very archiac (that is why it takes many hours even days to balance a pack and even then will not really be able to balance it). Saying that the A123 Karma pack is better than anything maybe a huge overstatement. :angel::) YMMV
 

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Today I took my first extended trip in temperate California weather with a KA-certified replacement pack. In Stealth with 15 miles to go and 17 miles of theoretical range, there was no sudden range drop off and I had 2 miles left when I pulled into the garage.

I didn't think it was possible . . . except perhaps with a tailwind under ideal test track driving conditions. Anyone else experiencing this?
 

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Today I took my first extended trip in temperate California weather with a KA-certified replacement pack. In Stealth with 15 miles to go and 17 miles of theoretical range, there was no sudden range drop off and I had 2 miles left when I pulled into the garage.

I didn't think it was possible . . . except perhaps with a tailwind under ideal test track driving conditions. Anyone else experiencing this?
I have gotten pretty close, but never hit the coveted 1:1 EV miles. The two major factors are speed and terrain.
 

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downhill from big bear i got 68 miles of ev range pretty nuts on the stock 2012 A123 pack. But then I ran EV mode the rest of the way home and got about 28mpg in <55 degree temps. So Cal peeps we should do a trip from OC to Big Bear and Back of a ski trip. Would be fun.. We are down.
 

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If I had to guess, it looks like Gen 2 Revero will be using these NMC A123 cells.

They look to have similar power density vs AMP20.

Would guess they are going with a 30-40kWh pack or thereabouts with the 2nd gen Revero.

The form factor is very close to that of AMP20. At 3.7v per cell vs 3.3v in AMP20 they could probably also reduce the number of cells by 15 or so.
 

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