World first for Cedric Lynch!

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James Hubbard
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World first for Cedric Lynch!

Postby James Hubbard » Sun Jun 14, 2009 10:01 am

Or should I say another world first.
Amazing result for Cedric Lynch at the Isle of Man TT. This is BIG EV news... Why is this not on our website yet?

http://www.youtube.com/watch?v=devfPUUWwjo


James

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Postby arsharpe » Sun Jun 14, 2009 12:42 pm

Hi James,

Thanks for the link. Excellent video and well done to Cedric.
I agree it would be a good idea if the web page contained upto date info.
Unfortunately, the internet is small and is in need of additional help. Would you like to help with this ?

Rob

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qdos
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Postby qdos » Mon Jun 15, 2009 8:00 am

Well done to Team Agni

When I had looked during practice they were well and truly ahead of the whole E field. If anyone knew how to do it Cedric did so no real surprise there I suppose. Well done Cedric ImageImageImageImageImageImage

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Postby booboo » Mon Jun 15, 2009 8:56 am

..as it says in the clip, "Cedric is the man" :D

Nice to see him getting some well deserved recognition .

I remember some of the comments in the bike press when the TTxGP was first announced. They were less than complimentary to begin with, but they slowly came round to being more supportive.

Hopefully the TTxGP will grow into a regular event and help create similar events at other venues.

On a different note, when viewing the clip did anyone else find it odd that you could hear background conversations while the bikes were at the start line.

Normally you only hear the loud revving of the bikes :lol:
London to Brighton on a Sinclair C5 - 6/5/07 - what a trip !
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Postby granada203028 » Tue Jun 16, 2009 9:26 pm

Yes well done Cedric and collegues.

Interestingly, according to the TTXGP team profile, he used a large 16KWh battery of 63 Kokam lithiumpolymer cells and not the LiFeBatt cells often suggested for this hi rate application. This suggests he used the SLPB 60460330H 70Ah hi power cell. This is about the size of an A3 piece of paper!

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Postby retepsnikrep » Wed Jun 17, 2009 4:53 am

Cedric = Top Man.

I can understand his use of the kokam cell, Li-Poly are a bit more flaky and need careful tending but they can really deliver the goods in terms of power/capacity to weight ratio.

16kwh capacity is a lot for a motorbike!!

Was it really that much or was it 16kw, the peak power it could deliver?
Regards Peter

Two MK1 Honda Insight's. One running 20ah A123 Lithium pack. One 8ah BetterBattery Nimh pack.
One HCH1 Civic Hybrid running 60ah A123 Lithium pack.

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Postby GregsGarage » Wed Jun 17, 2009 12:36 pm

Peter,

It's 16kWh. 63 cells at 70ah. That would give a pack voltage of around 233 volts nominal. Interesting find out what controller(s) he used and how the motors were wired to them. If it was one controller did he wire the motors in series or parallel, or both using a contactor. The motor was the exact same motor I had in my Fiat 126 which weighed around 750kg with driver. My Fiat could do 55mph on a 72 volt pack, he has 3x the voltage and 2 motors in the bike! :shock: That particular motor can handle 200 amps continuous and up to 400 amps for short time. I would assume he is using the high power version of the cells which are capable of 5C continuous and 10C peak, so the pack could potentially deliver 160kw peak power!. :shock: But his choice of kokams over Lifepo4 probably gave him the edge over teams who chose the later, the kokams just store more energy. Possibly the most impressive part of Cedrics win is that the bike they converted was only purchased in April of this year! :shock:

EDIT: I was assuming the pack was wired in series but it could have been wired for 21s3p giving a 77.7 volt 210ah pack. Probably a more likely configuration.
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Jeremy
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Postby Jeremy » Wed Jun 17, 2009 2:07 pm

For light weight and race performance I think it's hard to beat the Kokam cells, but I'm not at all sure I'd want to use them for an everyday transport vehicle.

The LiFePO4 cells have the edge when it comes to safety and cycle life, but neither of those would have been particular concerns for a bike that only needs to run a few times on a battery pack.

There's a really big weight advantage, and a significant volume advantage, in using the Kokam cells, which is probably why Cedric opted to use them. The higher peak discharge current was probably another good reason, as few LiFePO4 cells seem to be good at supplying high rates, certainly all the LiFePO4 pouch-type cells I've seen are barely able to do more than about 2 to 5C or so, it's only the cylindrical cells that seem to be able to deliver up in the 10 to 20C+ region.

I've been looking again at Lipo pouch cells recently, and it's clear that the prices have tumbled for RC type packs. Even the really cheap 15C packs seem to be gaining a resonable reputation for reliability, too, which means it might be worth looking again at ways to use them safely in small EVs. I compared the prices for Lipo, LiFePO4 and NiMH recently, for a low peak discharge rate 36V, 20Ah pack (for an electric canoe project). The results were quite a surprise:

£ per Wh:
LiPo £0.25
NiMH £0.48
LiFePO4 £0.72

Wh per kg:
LiPo 176.2
NiMH 66.6
LiFePO4 102.9

These prices were based on a quick Google and eBay search, so may not be the best, they were just the best I could find in half an hour or so. The prices include delivery.

Interesting to see that Lipo is around 1/3rd the price of LiFePO4 for this sort of pack. The weight advantage is also clear, particularly as the LiFePO4 pack is also pouch cells.

Jeremy

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Postby GregsGarage » Wed Jun 17, 2009 9:06 pm

Jeremy wrote:The LiFePO4 cells have the edge when it comes to safety and cycle life,

Jeremy, A while ago on the Thundersky group, Jukka Järvinen talked about cycle life of the Thundersky LCP and LFP cells. He reported that if you have a LCP battery pack of the same kg as a LFP pack and treated the LCP pack as a LFP pack, that is you only discharged the amount of energy that you could get from the LFP pack, the LCP pack the cycle life would be the same. The shallower discharge of the LCP pack increases its life. Kokam also documents this on their website. As far as safety, well I have managed to set a Lifepo4 pack alight! :evil:

I've been looking again at Lipo pouch cells recently, and it's clear that the prices have tumbled for RC type packs. Even the really cheap 15C packs seem to be gaining a resonable reputation for reliability, too, which means it might be worth looking again at ways to use them safely in small EVs. I compared the prices for Lipo, LiFePO4 and NiMH recently, for a low peak discharge rate 36V, 20Ah pack (for an electric canoe project). The results were quite a surprise:

£ per Wh:
LiPo £0.25
NiMH £0.48
LiFePO4 £0.72

These prices were based on a quick Google and eBay search, so may not be the best, they were just the best I could find in half an hour or so. The prices include delivery.

Interesting to see that Lipo is around 1/3rd the price of LiFePO4 for this sort of pack. The weight advantage is also clear, particularly as the LiFePO4 pack is also pouch cells.

Jeremy


Now that is a surprise! 20kwh pack for £5k! 8)
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Postby PHEV » Thu Jun 18, 2009 2:28 pm

Due to the unweildy size of these cells Cedric only managed to fit around 10KW/h on the bike for the race. I helped him make a couple of pannier style packs to carry the extra range, but it was decided it was too heavy and unweildy for the track.

The weight advantage wasnt so great on these cells, but the volume advantage was clear (over LifePo4), with 10KW/h sitting right under the tank and the upper part of the frame. Given cells of the right dimensions (perhaps several different sizes) I'd say 18KW/h could have been fitted using all the space I usually need to fit LifePo4 cells into..

From the quotes I recieved recently from Kokam, good quality Lipo is more expensive than decent LifePo4.

Congrantulations Agni, a fantastic result. Sorry I couldnt bring my bike so you had some serious competition!:P

Steve
*Mazda MX-5, 300KW peak, 300v 20KW/h lipo pack, Soliton 1000A controller. 1100KG.
*Ducati SS twin Agni 80HP peak.
*Aprilia RS motorcycle, 500A controller, Cedric's AgniMotor, 96v 6kw/h LiPo pack, 130kg, 90mph.
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