Motorcycle LifePo starter batteries

[72guy]

Howdy from a noob who needs some professional help. :wink:

I'm building a custom motorcycle. I need a small, lightweight, powerful battery. I came across this video ( http://www.youtube.com/watch?v=lyYBh4ec05c ) with custom bike builder Matt Hotch using a LifePo battery to turn over a large displacement/high compression engine.

The battery company is TekBattery.com ( http://www.tekbattery.com/battery_prices.html ). The battery Matt used in his demo was the model 4s6pm that sells for $999. The company also sells flat/flexible battery packs for custom applications.

My question. Is this pricing inline with other companies or is this a case of one company trying to make a killing off of an uninformed group of buyers? Any alternative companies that you can suggest that might have better prices?

regards

 

[dogman dan]

Maybe a bit high, but given the duty they are intended for maybe not. The batteries many of us use on the ebikes are much cheaper, but the cheap ones cannot repeatedly put out so many amps in a burst like a car battery needs to. The more expensive types can do that, and cost more. I'm not sure what a similar amount of A123 cells from tool batteries would cost, but I think it could be done for less than a thou. I would think a 12v 20 ah headway cell pack would do it too, at a price of not more than $50 a cell, 8 of em would cost about $200. You would also have to build a box for it, and come up with at least a low voltage cutoff to protect the cells from overdischarge. I would think a more reasonable price for such a battery would be not over 3-500 bucks, but again, the quality of the cells themselves can make them much more expensive. Racing stuff is always crazy expensive, so it may just be priced at what the market will bear.

 

[72guy]

dogman,
Thanks for the info. After more reading, I'm not sure of the battery technology used in these battery packs? TekBattery uses the terms LifePo, Lithium Ion Polymer phosphate, A123 Litium polymer, LifePo polymer, and Lithium ion nanophosphate. I'm making the assumption that they're only selling the battery pack with one technology. What is the proper/correct name for this battery type?

Regards

 

[flip_normal]

The total capacity for the 4s6pm battery is 13.8Ah divided by 6 (six cells per parallel group) gives 2.3Ah per cell which is the same as the A123 26650 nano phosphate battery, so it's probably 24 of those inside. They're rated for 70A continuous and 120A for 10 secs per cell, so for this 6p pack the cells are capable of 420A continious and 720A for a 10 sec burst. You can get them on ebay for about 180usd includung shipping.

Bundles of info here on how to keep these batts healthy.

 

[72guy]

flip,
Just got an email from the manufacturer. "The batteries are assembled from A123 cells that are LiFePo4 chemistry". They say it's the best and the safest.
Regards

 

[GGoodrum]

Yes, these are definitely a123 cells, and it looks like they are using the little shunt boards used on the Killacycle for charge management.

A grand for a 4s6p a123-based pack is definitely steep. It is pretty easy to get a DeWalt DC9360 tool pack, which contains 10 cells, for about a $100 on ebay. That's about $10 a cell. Even buying loose cells in the developer kits a123 sells, at about $18 a cell would still only be about half what these guys are charging.

-- Gary