World first for Cedric Lynch!

General BVS related area
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retepsnikrep
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Postby retepsnikrep » Thu Jun 18, 2009 2:46 pm

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


Care to enlighten us please. :wink:
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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Jeremy
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Postby Jeremy » Thu Jun 18, 2009 4:13 pm

I gather that getting a good price direct from Kokam is a bit "challenging", based on some of the other stories I've heard. Kokam seem to have a well-established set of retailers, who often re-badge the cells and sell them in large numbers, so they don't seem too interested in dealing directly with people.

A few of the RC Lipo packs that are now available are looking quite promising though. Several people on the Endless Sphere forum seem to have been using these under fairly extreme conditions yet are still getting pretty good results.

Those prices I quoted were for the cheapest eBay packs I could find, because I was specifically looking for a low max discharge current pack. I'm guessing that, if used gently, even the really cheap packs will perform fairly well. The weight and volume advantage for the packs I looked at was substantial, hence my interest.

If anyone else is interested, the LiFePO4 pack I looked at was one of Li Pings (I already have a 36V 10Ah pack from him and it's excellent). The Lipo packs were from an eBay seller called CyberPort888 and the NiMH packs were from The Component Shop.

I'm not pretending that these are in anyway suitable for a high discharge application, they were just well-matched to the needs of a project I'm working on at the moment.

Jeremy

MalcolmB
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Postby MalcolmB » Thu Jun 18, 2009 7:35 pm

PHEV wrote:Cedric only managed to fit around 10KW/h on the bike for the race. Steve


Damn, that must have been cutting things close. At an average speed of 87 mph my back of an envelope sums say you need 20kW. The race lasted just under half an hour, so there couldn't have been much left in the tank.

What was the final pack configuration Steve? I've been reading 21s3p elsewhere, so was it 21s2p? That would only be 78V, which seems a bit low.

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PHEV
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Postby PHEV » Sat Jun 20, 2009 9:58 am

I'm unsure what configuration he used in the end, when Cedric came down to me he was still planning to use all the cells, but that would make sense Malc.
He told me he had geared the bike down so as to limit power needed for a WOT run. Gearing was very important on this race, I think Cedric was one of the few to get it right!

As to price of Kokams, I was quoted £16,000 for an 11KW/h pack.
*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.
www.jozztek.com

granada203028
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Postby granada203028 » Sun Jun 21, 2009 9:03 am

I paid approx £4000 for the 7.5KWh standard type Lipo pack on my H100. 200 x 10Ah cells from www.batteryspace.com. These are rated at 2C max discharge so in theory could be high rate enough for a 1/2 hour race. They sell some bigger cells but the 10Ah had the best Ah/£.

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PHEV
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Location: Peacehaven/Brighton

Postby PHEV » Mon Jun 22, 2009 10:37 am

I reckon Cedric was drawing around 600A batteryside peak, so 2C cells won't cut it on a race, unless its significantly longer that 40miles:P
*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.
www.jozztek.com


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