Building A123 Packs
 

Any suggestions...

I picked up three batteries... hence 30 cells...

I was thinking:

2 X 5s1p
2 X 3s2p or 4 x 3s1p
2 X 2s2p or 4 x 2s1p

That way I can run:
2s 2p or 4p (3p)
3s 2p or 4p (3p)
4s 2p
5s 2p
6s 2p
7s 2p
8s 2p
10s 2p

Just a touch nervous of making 2p packs and if they would get out of balance. Alternative is to make all of them 1p packs but then have to use lots of deans adapters to join them back up!

Any other suggestions welcome?

i just bought a 5s2p pack from cart on these forums and it came with this "blinky balanceR" he called it so im sure that will help alot to keep the packs balanced.

when i get the pack in i can take it apart and get some pics of if youd like.

Hi Arkt1k
I charge my 5S packs on a B6 charger with balancer (pretty cheap from UH). The packs always come up within 2mV of each other and parallelling them has caused no dramas so far. But I still measure before I join them up. I have not yet used one pack a lot then tried to charge it up to match the second one though....
Good luck- I love these cells as they seem safe and abuse-tolerant. I just wish I could buy some at decent prices downunder!

I just got 2 dewalt packs (20 cells) for $170 shipped, and they are new.
http://www.rcgroups.com/forums/showthread.php?t=794975
He only has 2 trader feedback, but he seems legit, read the post, he can do an ebay buy it now for $10 more.

Anyways, I was thinking about making a bunch of little 2 and 3 cell packs, and then a bunch of adapters to combine them. Like these:
http://www.helidirect.com/product_in...oducts_id=5387
http://www.helidirect.com/product_in...oducts_id=5389

Then I can make it a 5 cell, or 6 cell, or 2, 3, and 4 cells by using the connectors. In parallel or series, depending on what I want.

And as far as balancing them, I have an LBA10+ that can balance them, but they dont need balancing as much as lipo.
If you dont have a balancer, just do what Johnrobholmes said, charge them slow once in a while and they will balance them selves out.

@ ICUBoy. I'm in Australia too

This is just an idea at the moment and I wouldn't be doing it for a while but I'm after some dewalt packs and I'll probably end up getting them from ebay. Postage is steep though. If you want though I can but extra and send the others to you. It may not be worth it and we probably won't want extra packs at the same time but it's something to think about.

Update - I built the 5s1p packs without too many dramas... Phew!

Waiting on some supplies from Maxamps and my EOS5i to come back from BPP (they rae flashing it to work with A123) and then I'll do for the 2/3s packs...

Photo's up tomorrow

MTBikerTim this sounds good, and I'd be keen to work on this with you.
If you can pick up any that land downunder I can pre-pay you as required. I guess anything under USD100 shipped each would be pretty good (but let's aim for less!). Also I have a contact in Missouri who will on-ship for us at cost so we should keep a lookout...
Regards
David

If you find any deals I'll also ship to you for cost from nj...

Thanks Arct1k!

What kind of voltage drop is everyone getting? My 5S pack seems to drop below 15 fairly quickly.

I got my 2 packs from the rcgroups link above. pretty cheap.
I took them apart, both packs measure 30.3v each

now im going to solder them into a bunch of 2 & 3 cell packs, then use adapters to make any configuration I want.

click on this link to see the full dewalt pack in my new savage (I got 2fastSS4U's savage) I need a motor and ESC though, that got sold before I got it...
I put paper in there so i did not short anything out, but if anyone gets the FLM savage conversion, these packs should fit nicely:
http://www.korgon.com/ryder/RC/savage/a123%20flm.JPG

Can any body recommend what balancer style I should get.
I all ready have the adapters for Thunder power, and polyquest/hyperion for the LBA10 balancer and a 1210 hyperion charger.

I'm going to add balancer taps to my A123 cells. Is one better/easier then the other.

Is there a cheaper alternative like something from digikey?

Should I use the Thunder power leads:
http://www.cheapbatterypacks.com/mai...ectors&scat=TP

or the polyquest/hyperion leads (scroll to bottom)
http://www.cheapbatterypacks.com/mai...ctors&scat=HYP

I have been reading here:
http://www.slkelectronics.com/DeWalt/hints.htm

Those A123 cells in dewalt config do fit perfectly in your savage (i'm not as lucky as you could be. I do have to brake them apart in 2 5s1p packs). At your place i would solder some cables+connectors and shrink wrap them without braking them apart. And then aim for a 10s1p A123 setup -> MGM 9032 and Neu 1515/1Y (1100kv). Crazy power (up to 2.5KW) and cool running components. Running time and weight could be optimised with 8s lipo in the future. That's what instantly popped up my mind when i saw your dewalt style pack config fitting so nicely inside your savage.

Sorry can not help you with your balancing questions as i do not balance my A123 cells at all. I connect 2 packs in series and charge them with a hyperion 1210i as 10s1p with 5A (35min charging time). My oldest pack is at 70 cycles and still takes 2250mah after a run.

I bought a hyperion 0610i charger for my a123s and used this connector -

http://www.allerc.com/product_info.p...oducts_id=3169

The charger has a built in balancer and I routinely balance and charge every time.

Found this cool chart that shows you what battery uses what type of balancer tap:
http://www.rcaccessory.com/pdf/Batte...on%20Guide.pdf
After reading here, post 90:
http://www.rcgroups.com/forums/showt...=569164&page=6
I found the digi key part numbers to order my own stuff.

Now I can make balancer taps for any number of cells I want. With help from brianG's site:
http://www.scriptasylum.com/rc_speed/_lipo.html


And while I'm at it I can order some more caps for the Mamba Max Mod (Get 4 of these and wire them together and put them in line with your mamba max:
http://search.digikey.com/scripts/Dk...me=493-1866-ND