source for A123 LifePo4.

[armstrongracer]

Hi all, I'm a newbie here, so first post.
I have 2 projects on the go. The first is a self designed and built electric-assist cargo bike. Early days on that and will be putting a call in when I'm looking at motors power packs and controllers.

The second is to convert my motorcycle into a stripped down retro styled cafe racer. To complete the look I want, the existing lead-acid battery has to be junked. Too big, too heavy and difficult to package. I plan to build my own out of A123 LifePo4's. The power pack needs to be 12v/14ah but the important bit is 230cca. It's a high comp tuned motor, they (Triumphs) need to spin up hard before firing because of a tendency to backfire and blow the sprang clutch if starting is tardy. I think that 8 off in 26650 size will do the job. The question is where to source them from? When I use Google I get dodgy looking aliexpress sites in China which I don't trust. I'm informed that certain countries have restrictions regarding the shipping of batteries, I'm located in europe so I don't know if this applies. Also, I want to be able to keep the pack charged from the onboard alternator. To do that I would need a suitable circuit board to balance and control over/under charging. Can anyone recommend a system that will work with 2 parallel banks of 4xcells in series?

Thanks in advance.

 

[riba2233]

If you are from europe:

https://www.akkuteile.de/a123-anr26650m1ba-2500mah-3-3v/a-100702/

http://eu.nkon.nl/a123-systems-anr26650m1b-a-grade-3-3v-a-grade.html

http://www.tme.eu/en/details/accu-anr26650m1b/akumulatori/a123-systems/anr26650m1b/

 

[wb9k]

If you're in the US:

http://www.stortronics.com/inventory.html

 

[999zip999]

Location will help for advice.

 

[riba2233]

Location will help for advice.

He wrote it:

I'm located in europe so I don't know if this applies.

 

[armstrongracer]

Thanks for your replies. Any recommendations on a circuit to control charging from the alternator. Balancing I plan to do offline with a separate balance charger unless the control board can do both.

 

[Hillhater]

Hmm ?....do you actually know you will pull 200+ amps ?
Whilst those cells can certainly deliver 120 amps burst (240A in a pair), they won't do it without dropping significant voltage. It looks like your 8 cell pack could be down to 8-9 volts at that output, which would slow the cranking speed noticeably .
http://lygte-info.dk/review/batteries2012/A123%2026650%202500mAh%20(Green)%20UK.html
Oh, and a 8 cell, 4s, 2p pack of those would only be 5 Ahr !
For 12v, 14Ahr you would need 4s, 6p, ....IE, 24 cells.

 

[armstrongracer]

Strange, I've seen lots of Chinese sellers doing motorcycle batteries based on 4x2 A123 battery packs like this:

https://m.youtube.com/watch?v=HecT7T00AlA

If that can start a big V-twin like a Harley, it will crank mine just fine. If they can be got at reasonable cost a pack built around flat cells would be a better option from a packaging point of view. I have the capability to design and build a suitable casing and bus bar system.

P.s. The cca figure I've quoted applies to normal lead acid batteries it may not be applicable to LifePo4's.

 

[Hillhater]

P.s. The cca figure I've quoted applies to normal lead acid batteries it may not be applicable to LifePo4's.

This is why you should find out what is actually needed, rather than what is used else ware.
It's not hard to get an amp figure whilst cranking the starter, then use that with the cell data to decide how many cells are needed (in parallel).
That will then dictate your Ahr capacity also.
RC LiPo pouch cells can provide more amps than lifepo4 , if you really want to keep the size small,"..but are not as durable as the "can" type cells