making a a123 pack

[team_orr]

hi guys

for my new drum spinner i plan to run it off a123's...but iv never worked with them before...i have a rough understanding of building packs, but im sure theres some stuff i dont know, heres a link i found on how to build a a123 pack

[typhoon_driver]

Yup a very nice demonstration. To answer your questions,

- 100W+ soldering iron with a big flat surface, leave it to heat up for a good few minutes and allow it to reheat for a minute between cells
- I didn't bother with balancing wires, didn't need them
- I used a dapter with my nicad charger, do a search on google and you will find them but as I said this method won't balance the cells, merely trick your current charger into thinking its charging nicads.
- Ebay had a supplier selling them for a while. The cells were removed from battery packs and not all of the same voltage so a bit of balancing was required but nothing major.

If you are going to use a balancer then place one wire on the positive end of each cell, or on the bar and one on the negative of the whole pack.

[widow_twanky]

Here's a useful little document for it

http://media.hyperion.hk/dn/a123/packas ... ckassy.pdf

Andy

[typhoon_driver]

Just remembered, if you want a roboteers take on it all, check out the pages that John Reid put on the terrorhurtz webpages about pack assembly and testing.

[widow_twanky]

Just remembered, if you want a roboteers take on it all, check out the pages that John Reid put on the terrorhurtz webpages about pack assembly and testing.

Yep, they're very good too and here http://www.terrorhurtz.co.uk/a123/

Andy

[psycho_fling]

i can't see that link you posted jack???

I have built a couple of packs and have the following things to pass on

i would reccommend using balance wires and a balancer, remmebr the balance wires have to be all the same length

i would say glue your pack of 4 or whatever to gther first then solder much easier

big hot soldering iron

and ebay is the best place i would say (take cuation) the a123 cells seem to be green atm this is ok

couple of links

balancer ( you will need a hyperion charger to match can't find the one i use atm

http://www.rcdude.com/servlet/the-165/H ... Net/Detail


enjoy

[team_orr]

Hi. Those links are very nice thank you! Alex. I'm not sure why you can't see the link because it is defo there Iv checked out eBay and most of the cells seem to be those yellow ones... Would the cells from this work? http://wap.ebay.co.uk/Pages/ViewItem.as ... on&emvcc=0 or would I have to get them via a big name brand? Ta muchly

[widow_twanky]

we used these which are basically stripped down dewalt packs

http://cgi.ebay.co.uk/12-Pcs-A123-3-3v- ... 1c124cbe23

Or we did consider these pre-made packs:

http://cgi.ebay.co.uk/7S1P-A123-22-4V-N ... 255a7e125f

http://www.hobbyking.com/hobbyking/stor ... rentCat=85

Andy

[RogueTwoRobots]

For chargers, I'm looking at getting this model when I move to A123s:

http://www.giantcod.co.uk/dual-power-ch ... 04349.html

Mainly because it has a 240V mains plug so you don't require a separate power supply (not a fan of chargers that don't have mains plugs and require an external power source, just another piece of kit you have to buy/maintain/lug around)
As far as I am aware, it charges A123s (they're Li-Fe aren't they?) and has built-in balancing connections for up to six cells. Pretty low-cost too.