Soldering A123's.....

[Bunky F. Knuckle]

Hey guys!! Just a question here......... Anyone else out there besides me who is building their own batteries???? I'm starting the process of building packs for my 42% Dalton. Just wondering if you guys who are building packs, have issues with tinning the POSITIVE side on the A123's??? I am able to tin and solder a battery tab between the 2 NEGATIVES.

I'll be building 2 2S2P packs for Rx, and a 2S 2300 for ignition.

I'm using a Butane soldering iron, and it is HOT!!!!!

Positive ideas, only!!!

[bodywerks]

It is very important that you use a SUPER high wattage soldering iron. If you spend too much time with the iron on the cell you risk blowing the thermal vent.
Personally, I DO NOT remove the tabs that came welded onto the cells. I just used a cutoff wheel to separate the cells in pairs, leaving one series-joining tab in place per pack.
If you have either purchased cells without tabs, or have removed the tabs, you need, at the very minimum, a Weller 40 watt soldering station with a 1/4" tip. An 80w station would be better. And even though those soldering guns can claim 250+ watts, they really don't seem to be able to do the job so stay away from them.

[cjcyclesrc]

I use a 80watt station with a 3/8 chisel tip. My big honk'n 100+ watt gun wont even touch them. You have to have a tip with some thermal mass.

[MODE 1]

Yep agreed.......its the same for any bat use a big iron. Also when you solder the deans I split the wire in 2 so its soldered on each side of the plug tags.

[jsc]

Scuff up the cell ends with fine emory cloth or a small sanding drum in a dremel, just buff up the surface. I use a 40W Weller and a hammer head tip with it turned full blast. Flux and good solder and it flows like a dream without heating up the cells.

[dick hanson]

I clean (as noted) then use plain ol Radio Shack board solder and a good iron -works everytime.

[HuckinChikn]

i'm glad someone started this thread... I'm getting ready to buy some single cell A123s to assemble
packs for a brushless R/C Boat, and i wasnt sure the best way to solder the tabs.
My other concern was about the balance lead...
My A123Racing brand charger requires a 1 wire balance lead with the deans plug before the charge
will start, so where will the single balance wire attach to on the battery pack?

[dmcquinn]

Jared - on a two cell pack the balance lead goes like this:

black (pin 1) to the same place as the black power wire
Red (pin 3) to the same place as the red power wire
Pin 2 on the balance plug goes to the middle of the two cell pack.

I've been using A123 exclusively on my big planes for two years. BTW - I crashed my 42% Dalton last night. Engine quit when I was low 'n' slow. Can't explain it. Engine was perfect for the previous 180 flights. I suspect something clogged the carburetor or something.

[Bunky F. Knuckle]

	Quote: Originally Posted by bodywerks
	Personally, I DO NOT remove the tabs that came welded onto the cells.

There were NO tabs on these cells bro! Just a plain jane ole RAW 2300mAh 1S A123 cells!!!! I bought 10 of them. Just the cardboard wrapper!!

I have "scuffed" the + and - of the cell. I am using a HOT butane iron, and a regular soldering tip that come with it. It is a Weller. And solder is 60/40 Rosin Core. I typically never have any issues soldering cells, as I used to do this for a living back in '03-'05 !!!! I was the soldering guy at RadicalRC while I worked there. I built all their custom packs and large Poly/NiMH's/etc......

[cjcyclesrc]

	Quote: Originally Posted by Bunky F. Knuckle
	There were NO tabs on these cells bro! Just a plain jane ole RAW 2300mAh 1S A123 cells!!!! I bought 10 of them. Just the cardboard wrapper!! I have "scuffed" the + and - of the cell. I am using a HOT butane iron, and a regular soldering tip that come with it. It is a Weller. And solder is 60/40 Rosin Core. I typically never have any issues soldering cells, as I used to do this for a living back in '03-'05 !!!! I was the soldering guy at RadicalRC while I worked there. I built all their custom packs and large Poly/NiMH's/etc......

The positive button really seems to conduct the heat into the cell. It takes a lot of thermal mass in the tip to overcome it. The solder will try to just sit up on top and not flow. When you get enough heat to it the solder will flow right out. The negative side doesn't seem to take near as much heat to flow. With the 80 Watt Iron made for Stain Glass, I just tin the tip of the iron touch it to the cell and it flows as soon as you touch it. I scuff the cell with a scotchbrite pad, clean with alcohol, and apply rosin flux first.

[Olli-Matti]

This video by Hyperion might be helpfull:

YouTube - Broadcast Yourself.

[Kookaburra]

Notice in the video they are NOT using sandpaper to buff the ends. You will actually transfer resin from the sandpaper onto the surface. Use scotchbrite or just scrape with a sharp pocket knife.

[Neogenesis]

I had the same problem, used a 100 watt iron with a HUGE tip on it, was previously used to do stained glass work, and that finally had enough oomph to get the job done. I think the key to all of it was mentioned earlier, use a tip that can carry a large thermal load as those batts will suck the heat out of anything less.

Neo

[tony-amps]

Great thread guy's ! Excellent video also for those that want to learn about making their own A123 packs. I have been using and making my own for 2 years now and i swear by them.

Tony Fandino

[HuckinChikn]

DAVE NOOOO!!!! so sorry to hear, that really sucks! that was a beautiful plane too
Excellent video by the way, thanks!