# EV battery state of the art



## Siwastaja (Aug 1, 2012)

aCoupe said:


> Is there a good Lithium Ion alternative out there now, for a reasonable price?


No. Li-ion is state of the art now and for foreseeable future.

However there are many different sorts of "li-ion". This is different from the earlier chemistries. NiCd was NiCd and NiMH was NiMH but li-ion comes in many more varieties.


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## aCoupe (Sep 11, 2013)

Thanks for the quick reply. Which supplier for Li-ion would you recommend? That seems like a fairly proven technology.


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## rwaudio (May 22, 2008)

aCoupe said:


> Thanks for the quick reply. Which supplier for Li-ion would you recommend? That seems like a fairly proven technology.


LiFePO4 is the chemistry of choice for non racing applications.
CALB and Sinopoly would be the leaders, but there are other brands as well.


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## Siwastaja (Aug 1, 2012)

Most DIY folks use the prismatic LiFePO4 cells from large Chinese manufacturers such as Winston, Sinopoly, CALB, GBS etc.

This particular chemistry has some extra safety leeway, especially in overcharging, and increased cycle and calendar life which increases the value, but the downside is the reduced energy density compared to other li-ion varieties. The energy density is actually about half of the state-of-the-art li-ion.


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## Roy Von Rogers (Mar 21, 2009)

Look here to get an idea whats available.....

http://store.evtv.me/products.php?cat=10

http://www.lithium-car-battery.biz/Lithium-Batteries--Prismatic_c_1.html

Be aware in your climate that you will need to insulate and use a heating system for those cells, when you have very low temps.

The size (ah) will depend on your weight and distance desired, figure that 10% of your weight will be the watt hour per mile used, its a good rule of thumb.

A 2500lb vehicle will use 250wh per mile, as an example.


Roy


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## Sunking (Aug 10, 2009)

aCoupe said:


> I live in Bend, OR (3500ft elevation). I had an EV a few years back with Lead Acid batteries. As most of you could guess it worked great during the summer and then...


Hate to tell you if you think Lead acid has problems in cold weather, you are really going to dislike lithium as they even more sensitive to cold. 

Lead acid that delivers 100% of capacity at 80 degrees will only deliver 50% at 0 degrees. Lithium at 0 degrees only deliver 20% and the internal resistance goes way up to the point they can become useless because they cannot deliver high current needed for acceleration. Just like when you go out on a cold morning to crank a gas engine, it cranks real slooooooooooooow. Lithium would be slower. Just ask a Leaf owner who lives in cold climates.


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## Roy Von Rogers (Mar 21, 2009)

Sunking said:


> Hate to tell you if you think Lead acid has problems in cold weather, you are really going to dislike lithium as they even more sensitive to cold.
> 
> Lead acid that delivers 100% of capacity at 80 degrees will only deliver 50% at 0 degrees. Lithium at 0 degrees only deliver 20% and the internal resistance goes way up to the point they can become useless because they cannot deliver high current needed for acceleration. Just like when you go out on a cold morning to crank a gas engine, it cranks real slooooooooooooow. Lithium would be slower. Just ask a Leaf owner who lives in cold climates.


I think you need to look at graphs of the SE and CA cells, its no way close to what you state.

http://media3.ev-tv.me/cellcare.pdf

Roy


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## Sunking (Aug 10, 2009)

Roy Von Rogers said:


> I think you need to look at graphs of the SE and CA cells, its no way close to what you state.
> 
> http://media3.ev-tv.me/cellcare.pdf


Thanks Roy but one thing I have learned in 35 years of engineering is to never trust manufacture data, especially Chi-Com manufactures. If that were true then CALB has done something no other manufactures can do including A123 Systems. Lithium cold weather performance is well documented by 3rd party testing agencies, and I tend to trust them more than a manufacture claim. At least they were partially honest in saying cold weather performance will be very sluggish due to much higher internal resistance. With that said CALB is contradicting their own specs. If a battery Ri triples in cold weather; What happens to capacity? Not Amp Hours, Watt Hours...


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## gunnarhs (Apr 24, 2012)

Sunking said:


> Thanks Roy but one thing I have learned in 35 years of engineering is to never trust manufacture data, especially Chi-Com manufactures. If that were true then CALB has done something no other manufactures can do including A123 Systems. Lithium cold weather performance is well documented by 3rd party testing agencies, and I tend to trust them more than a manufacture claim. At least they were partially honest in saying cold weather performance will be very sluggish due to much higher internal resistance. With that said CALB is contradicting their own specs. If a battery Ri triples in cold weather; What happens to capacity? Not Amp Hours, Watt Hours...


I can confirm your doubts.
We have had tests here in Iceland on a different variety of EV and their range is usually at least 50% less of what is stated in the OEM during winter time (around 0 degree Celsius in Reykjavik). It is partly due to lower performance of the batteries themselves (20-30%) , the other factor is increased use of (electric) heating during cold weather. The diy-cells which have performed best during cold weather are the Y-trium enhanced ones, (LIFeYPO4 from Thundersky f.example). The other things helping is using an additional Webasto gasoline-heating element


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## pm_dawn (Sep 14, 2009)

Sunking said:


> Thanks Roy but one thing I have learned in 35 years of engineering is to never trust manufacture data, especially Chi-Com manufactures. If that were true then CALB has done something no other manufactures can do including A123 Systems. Lithium cold weather performance is well documented by 3rd party testing agencies, and I tend to trust them more than a manufacture claim. At least they were partially honest in saying cold weather performance will be very sluggish due to much higher internal resistance. With that said CALB is contradicting their own specs. If a battery Ri triples in cold weather; What happens to capacity? Not Amp Hours, Watt Hours...


Don't you have any clue about the testing that EVTV has done.
Look it up on the archive page.
There they show all the old shows and what they feature.
There are shows with the testing of cold CA series cells. They state the complete number of ah aswell as wh that the cell under performs in the cold.

I have real winter and cold temp experience from 5 years of driving my car with Thunder Sky 160ah cells. The voltage drop is manageable. The cells heats up fairly fast in insulated bateryboxes. And then performs almost as in warm weather.
When it is really cold (-20 deg C) i get about 15 % shorter range.

Regards
/Per


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## Sunking (Aug 10, 2009)

gunnarhs said:


> I can confirm your doubts.


Not so much doubts, but contrary to what is known and documented. All batteries regardless of chemistry loose capacity and higher resistance as the temperatures drop. Some more than others. Lithium is well capacity losses are well documented and known. So when a manufacture claims 25% capacity loss that is known to be substantially higher raises Red Flags and doubles when it is a Chi-Com manufacture making such claims. 

It can be dealt with. For one keeping your EV in a heated space, or a plug in heater built into the batteries to keep them warm and charged. That is great for round trips, but if you commute to work or someplace where an EV is parked outside in the elements for a period of time might have a nasty surprise waiting for you on the trip home, especially if you need defrosters or heat and the source is electric heat. Sounds like a good solution might be some LPG for heat.

Of course keeping your vehicle plugged into a source of electricity to keep batteries warm kind of defeats the purpose of going electric. Its not perfect and still a long way from mainstream.


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## JRP3 (Mar 7, 2008)

Sunking said:


> Lead acid that delivers 100% of capacity at 80 degrees will only deliver 50% at 0 degrees. Lithium at 0 degrees only deliver 20% and the internal resistance goes way up to the point they can become useless because they cannot deliver high current needed for acceleration. Just like when you go out on a cold morning to crank a gas engine, it cranks real slooooooooooooow. Lithium would be slower. Just ask a Leaf owner who lives in cold climates.


I've never heard of any EV owner, including LEAF owners, get only 20% of rated range as you claim. And why the replies to a year old thread?


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