... the average of the cells have 10 cycles and are now at 3.7V wich is a good storage voltage.
Doctorbass said:now let's jump from 2009 to 2011
A friend of mine that worked on 4 different solar car race project contacted me yeaterday with a great offer.
For the project of Eclipse 6 they used 28s1p Kokam 31Ah cells that costed around 170$ each. Now they are at eclipse 8 version for the next race in australia and will use the EIG cells
Specsheet: SLPB 78216216 (31Ah)
http://www.enstroj.si/images/stories/Tech_spec_SLPB78216216H_31Ah_A1.pdf
http://xnet.rrc.mb.ca/solarcar/down...]http://eclipse.etsmtl.ca/fr/voiturespecs.htm
They got them in 2005.
They offered me to buy them for 15$ each
These cells are lithium polymer 31Ah and 10C capable and 5C continuous.
you can see the cells here: ( they are down to the page and are green color) https://picasaweb.google.com/eclipse.ets/EclipseVIElectriqueElectricalCircuits#
https://picasaweb.google.com/eclipse.ets/EclipseVIElectriqueElectricalCircuits#5376014525091986642
Assuming that they could have lost like 20% of their capacity and a rise of let say 1.5 time their internal resistance.. that is still satisfying!.. I would say from 31Ah and 0.9miliohm to 25Ah and 1.3miliohm
Let say there is 24 good cells out of 28, that's 88.8V at 25Ah, around 2.2kWh for 360$
I should get them during june, i must go to montreal to get them.
Doc
you go back a bit, thanks for the info.I'm interested in seeing what I could do with a factory direct price, not through metric mind, and for an order in maybe the $20k range.
If we could get the pricing down to something like $80 per 40Ah cell, that would be a pretty good deal. $0.54/Whr.
The beauty of these cells is low Ri, which means much less of the pack's energy is being wasted thermally, as well as no practical restrictions on current draw for an E-bike. For packaging, it would be so slick to have a stack of 40Ah cells in each side of pannier bags. No dead space in between them like round cells, simple and low reistance pack construction with 1P tabbed cells, and
LiFePO4 (BMI 10Ah cell)
193whrs per L (round cell's have deadspace, so this figure in a pack would be much lower than when I calculated it for a single cell)
101whrs per Kg
Kokam 40Ah cell
347whrs per L (no dead space in a pack)
174whrs per kg
So, using this battery technology, in practice I think it's safe to say the pack would be less than half the volume of a pack made from BMI cells, and about 58% of the weight. It would also appear to be cheaper than BMI cells, even at full retail price for a single cell from a vendor who of course has mark-up.
The Kokam batteries still can't match my non-safey LiPo pack on my E-bike though
50kW capable goodness in a light compact little package
