A123 LiFePO4 Group Buy

General Discussion
1

Would anyone be interested in having a group buy for A123 25650 cells for $7 per cell plus shipping?

If you are, enter your order here: http://goo.gl/forms/VCZ4oOOWLx03OimD2 (You can edit your details after)

They are usually $12 per cell but with the group buy of 100, they will only be $7 plus shipping.

Spec sheet: http://goo.gl/ikxejT

These are the same cells that Boosted uses and they make for a pretty nice battery pack in a 12s1p configuration. Small but still powerful. The voltage discharge/sag is also more stable. The recharge cycles are around 1000 which is more than double that of regular Lithium Ion cells. Here’s a nice build for example: http://www.electric-skateboard.builders/t/a2esk8-mini-cruiser-30-carbon-fiber-deck-single-carvon-v2-hub-motor-12s1p-lifepo4-vesc/5543/12

Status: Gauging Interest

3 Likes
2

How many cells do you need to make 12s? 12?

3

Do you have nore info about the specs of the batteries ? voltage ? capacity ? weight ?

4

Yeah. 12s means 12 cells end to end (“series”, thus the “s”). The 1p means 1 row of them. In 12s2p, 2p means 12 sets of 2 cells next to each other (24 total cells). 12s3p would be 12 sets of 3 cells next to each other (36 total) and so on

5

Spec sheet: http://goo.gl/OHQ35u

6

I assume you mean how many cells to get to a regular lithium ion 12s voltage.

Nominal voltage for each cell is 3.2 so around 13-14 cells. That would make for an easy battery pack build however.

7

Is there a problem if you live in australia

8

Yeah I think… Shipping batteries via air is annoying. Usually via ground is allowed domestically within the USA. I should be able to sort things out for small quantities of batteries. I’ll update you if I can or not.

9

Here is a nice pack made with these cells :

1 Like
10

@Pantologist Did you ever go ahead with the group by? I’m surprise there wasn’t more interest considering these cells are good for 1000+ cycles and allow for 70A continuous discharge.

11

From what I have heard A123 is no longer an American company but now asian. Co-accidentally:

12

Nope. I think one person filled out the sheet.

That one person was me.

Yeah I used a pack of these. Great cells. I am going to make another pack soon. I am trying to design a 3D printable design so that you can spot weld the cells together and have a safe battery housing to fit them in. It would prevent short circuits and would be it more user friendly and tidy.

Here’s a glimpse of a few designs

Batteru.PNG975Ă—699 155 KB
Capture.PNG1194Ă—842 392 KB

:frowning:

2 Likes
13

Yeah they were bought out by some large Chinese company. I don’t think manufacturing facilities changed…

I doubt it is an issue with the batteries alone since it was bought out a few years ago. I’m guessing there is an issue with the BMS or there is a manufacturing defect or error in assembling the battery packs.

14

Yeah I hope (and think) its a software issue in their BMS.

15

They are using a 50v charger now… if the BMS does not cut off the voltage at 43.2v, they will be overcharging cells… after awhile that will lead to damage.

16

That’s a bummer! Those enclosure designs are super nicely done.

At the moment I’m deciding whether to go 12S1P A123 26650 or 10S2P 18650 (30A discharge capable cells). The latter will give more range but the 12S1P setup is so nice and compact. The 10S2P setup will be bigger and require more soldering, assembling etc.

Have you ever considered using 18650s instead of 26650s? What swayed your decision to go the 26650 route?

EDIT: What is the real-world range of your 12S1P 26650 pack?

Cheers

17

Curious on that as well. I am really interested in buildings similar pack.

18

Boosted uses 12S1P A123s, so Boosted specs should apply. I got about 5-7 miles with my Boosted before I returned it and went DIY.

1 Like
19

The A123 cells are safer but heavier. That’s the trade off. They also have great continuous discharge ratings so voltage sag is minimal.

I got around 5 miles. I’m pretty fat at 180lb.

1 Like
20

@Pantologist think we could gauge interest on another group buy for these i already know someone who could be interested in another 12 for a 12s2p and the same goes for me so that is already 24 cells! Thanks!