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All Forums >> Radios, Batteries, Clubhouse and more >> Batteries & Chargers >> A123Racing Support >> Large packs... Check this out!!!
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Large packs... Check this out!!! - 5/26/2008 3:59:37 PM   
simplecj



Posts: 276
Joined: 2/10/2008
From: Cedar City, UT, USA
Status: offline 		I recently finished my design project. We were designing battery packs for an electric motorcycle!



Teammates Heather and Stan prepping batteries.



~1200 A123 Lithium Iron Phosphate cells, used/tested; cost ~$6000.



Battery module - 13.2V - 18.4 Ahr - about 600 max amps continuous! That's incredible power in a small package. Would cost you over $600
For our motorcycle we will have 32 of these modules all in series! That's 422v nominal!


We're hoping that this pack will help set record speeds!

       Post #: 1

RE: Large packs... Check this out!!! - 5/28/2008 1:35:22 AM   
dick Hanson



Posts: 10069
Joined: 12/12/2001
From: slc, UT, USA
Status: offline 		Where are you guys going to run the bike?
Drag strip? I can't think of any place in Cedar City which has room -unles yo u take the highway north, when no Highway Patrol is watching.
I am running A123 in my electric powered models - now going to setup a ZDZ1300 motor with a HV 45 CC controller - a measly 30 volts -(I am almost ashamed to mention this piddling voltage )-

< Message edited by dick Hanson -- 5/28/2008 1:37:46 AM >

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(in reply to simplecj)
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RE: Large packs... Check this out!!! - 5/28/2008 3:56:46 AM   
simplecj



Posts: 276
Joined: 2/10/2008
From: Cedar City, UT, USA
Status: offline 		I haven't heard from the guy who's building the bike, but I believe he's shooting for a run in the electric speed competition in June at Mirage (???) Salt Flats in California in June or a Bonneville comp in August. Hoping to break 200 mph!

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       Post #: 3

RE: Large packs... Check this out!!! - 5/28/2008 4:43:19 AM   
dick Hanson



Posts: 10069
Joined: 12/12/2001
From: slc, UT, USA
Status: offline 		Mirage - dry lakes old speed site from long ago
Wish him luck

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RE: Large packs... Check this out!!! - 5/29/2008 5:58:34 PM   
BocaBen


 

Posts: 162
Joined: 4/12/2002
From: Boca Raton, FL, USA
Status: offline 		$5 per cell when you buy 1,200, not bad!
I like seeing them in the plastic bag. I treat mine like explosives, trying to avoid shorts by individually wrapping them. Any explosion so far?
What kind of charger will you use to charge the 32 modules?

Good luck, keep us updated please!

(in reply to dick Hanson)
       Post #: 5

RE: Large packs... Check this out!!! - 5/29/2008 6:42:38 PM   
simplecj



Posts: 276
Joined: 2/10/2008
From: Cedar City, UT, USA
Status: offline
quote:

ORIGINAL: BocaBen
$5 per cell when you buy 1,200, not bad!
I like seeing them in the plastic bag. I treat mine like explosives, trying to avoid shorts by individually wrapping them. Any explosion so far?
What kind of charger will you use to charge the 32 modules?
Good luck, keep us updated please!


We got the cells used, they were in questionable condition when we got them for $5 each. We had them tested in California in their original configurations, then brought them back and spent HOURS and HOURS going through all of them snapping off the tabs and grinding the surfaces flat.

These cells are completely stable and have metal casing to protect from minor impacts. They are far from explosive! We actually did completely short a cell out when we were dismantling the original packs, the only thing that happened was that the cell got really hot and the voltage went to zero. They are designed to short out internally instead of exploding if that was even possible. This chemistry DOES NOT allow explosive reactions, that's why they are so great for electric vehicles! Who would want to sit ontop of a huge pack of regular LiPo batteries when they could ride safe with LiFe's??

ALSO, when they are all loose cells, there's no way to short them out by themselves! Think about it, how would you complete the circuit with two loose cells and nothing else??

We grouped them in bags of 32 for each module we intended to build, it looks kinda getto, but it worked well and helped us know exactly how many modules we had cells for. We needed at least 32, we ended up with 35!

Then we took them all the way to Boulder Colorado to use a special spot welder to weld on the new interconnect materials.

The motor system has an integrated charging system, but we're not sure about the specifics because the manufacturer wouldn't ever get back to us about it. I had recommended finding a charger that could balance charge the whole pack by charging each individual 13.2v module (32 total balanced charges overall). We did find a couple heavy duty chargers that can handle this many cells, but again, the specifics on how that would work with balance charging is uncertian. Alot of big chargers only charge on two leads. At this point battery management is not extremely important because they will not be used over and over and over again, this is more of an experimental set. If it works, our client will be able to get the funding to buy more cells (probably new ones) and hopefully a proper battery management/charging system.

< Message edited by simplecj -- 5/29/2008 6:59:43 PM >

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       Post #: 6

RE: Large packs... Check this out!!! - 8/4/2008 11:58:49 AM   
warheadforever



Posts: 1824
Joined: 1/6/2008
From: Sunrise, FL, USA
Status: offline 		Well that is very neat! I can't wait to see the result.

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May you grass be green, and your tides be high forever.

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       Post #: 7

RE: Large packs... Check this out!!! - 8/4/2008 3:33:18 PM   
simplecj



Posts: 276
Joined: 2/10/2008
From: Cedar City, UT, USA
Status: offline 		I guess due to money problems the motorcycle was put on hold. The original motor/controller system that we were planning to use costs about $25,000 and it's on back order anyways. We had located a couple units that weren't being used but apparently we didn't get them.

SOOO, now the bike still isn't built, I don't think the battery housing has been built either, and now we're changing to a water-cooled AC induction motor from a different company.

I may very well be continuing with this project into my senior year, but who knows. Do I want to waste my time and have my efforts go no where because my client can't get his end of it pulled together?? I guess it's not his fault, there's a million things to consider and it all costs alot of money....

< Message edited by simplecj -- 8/4/2008 3:34:27 PM >

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       Post #: 8

RE: Large packs... Check this out!!! - 8/4/2008 3:38:17 PM   
warheadforever



Posts: 1824
Joined: 1/6/2008
From: Sunrise, FL, USA
Status: offline
quote:

ORIGINAL: simplecj
there's a million things to consider and it all costs alot of money....


I know what that is like.........

_____________________________

I have God, Guns, and southern pride!
May you grass be green, and your tides be high forever.

(in reply to simplecj)
       Post #: 9

RE: Large packs... Check this out!!! - 8/6/2008 10:53:43 AM   
kelvintwt


 

Posts: 2
Joined: 5/19/2007
From: , SINGAPORE
Status: offline 		how do u guys get them at just $5 each? i got mine at almost $30 bucks SGD..

< Message edited by kelvintwt -- 8/6/2008 10:54:17 AM >

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       Post #: 10

RE: Large packs... Check this out!!! - 8/6/2008 4:33:12 PM   
simplecj



Posts: 276
Joined: 2/10/2008
From: Cedar City, UT, USA
Status: offline 		Well, it's not like I was some dude just trying to get some cheap cells. My dept chair had some connections and purchased them from a hybrid vehicle company, they were some test packs for remote comm stations. One of my teammates actually drove all the way to Denver to pick them up cause you can't ship anything in that large of a configuration. We got them in like 12s16p arrangements.

ALSO, in case you didn't read.. they are USED cells that we received in very questionable condition. We had to have all of them tested before using them. And we bought over a thousand cells, that's why they only cost us about $5 each.

Even for new cells, $30 is a rip off. You should be able to find them for more like $15 to $20 new. ...and what is SGD??

(in reply to kelvintwt)
       Post #: 11

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