Battery Building ?

[neweuser]

Anyone have a site where i can check out how to build a good 16 cell pack?

[Tom F]

I wrote something for another RC Site. Hopefully this will be of some help:

It's not perfect, but hopefully it'll get you started...

Edit:

Darn. the pictures didn't work.

Never mind then =(

[coolhandcountry]

It is really no different than 6 cell packs but you adding 2 more. You need to figure out the configuration before you begin. If you have a gmaxx you can do them flat. Or other chassis that can do this as well.

Just make two 8 cell packs with a series connector going between them, then you can have a bit more versatility.

[neweuser]

Anyone have somepics? Or a how to do link? I can do straight packs no prob, but when it gets into making a custom pack my worry is current flow i guess...thanks! I'm running a stock chasis right now....

[Tom F]

I wrote this for another forum. I've re-uploaded the pics.

It's a bit wordy but i tried to be thorough with it. Like i said, it's not perfect, but you should hopefully get a rough idea of what to do lol

Finally, I got round to finishing my guide.

What you will need:
- Connectors (I will be using Deans)
- Wire (use silicone sleeved wire - nice and bendy. Deans make nice wire. I think thats what i'm using. You can pick up a real of 12 or 14ga Silicone wire from an electronics place for this purpose)
- 7 Battery bars (for a 6 cell pack)
- Cells (i'm using six GP3300s)
- Solder (use high silver, expensive solder. It makes a better join and flows better - Deans racing solder is good, and easy to find at your LHS)
- Tape, or ideally a jig
- A 60+ Watt solderring iron - you can try with less but it won't work very well so i dont recommend it - a cheap iron will work, but it might be worth looking at a variable solder station if you do a lot of work with electrics.
- I strongly recommend a multimeter for checking connections (and just about anything else). It's a great thing for anyone who runs electrics to have.

I bought a kit of stuff off ebay.

http://img518.imageshack.us/my.php?i...scf00164vt.jpg

(You can click on any of the pictures for a bigger version)

There are cells, wire, and battery bars in there.

I also got Deans connectors off Tower.

Step 1:

The first thing to do is to roughen the end of your cells. You can use a knife, screwdriver, sandpaper, or whatever to do this. This is done because it gives the solder something to stick to, which gives better contact and a mechanically stronger joint.

When you've finished them all (both ends of the cell), it should look like this:

http://img522.imageshack.us/my.php?i...scf00175se.jpg

After you have done this, it is a good idea to shrink wrap the cells

Step 2:

The next thing to do, is to get your connectors made up. Solder them up as it says on the instructions on one end (making sure you get the polarity right - we don't want a burned ESC here ). On the other end of the wire, strip off about 8mm of the insulation.

http://img522.imageshack.us/my.php?i...scf00232cm.jpg

Twist the bare end, tin the wire ('Tinning' is when you get solder on the surface, before you make the connection), and solder it to the battery bar. When solderring to anything, it's very important to get everything hot. Otherwise, you get a blob of solder sitting on the surface, and a very poor connection. Remember that the solder flows better the hotter it is, so it will tend to flow to the heat.

Having solderred the bar and wire together, you should end up with something that looks like this:

http://img501.imageshack.us/my.php?i...scf00241to.jpg

(And of course a black one for the negative side of your pack)

Step 3:

If you are building with a jig, you can miss this step.

If, however, like me you are too cheap to buy a jig, then this is the ghetto way to do it.

First, lay your cells out in a nice straight line, in alternating orientations.

http://img501.imageshack.us/my.php?i...scf00215nf.jpg

[It's important to lay them out like that (if you want a 6 cell, 7.2 Volt pack), otherwise it's not going o work.

http://img504.imageshack.us/my.php?i...gram8pa9rb.gif

(Thanks to Chris for the graphic)

In the end, thats the layout that it will be. (If you cant understand my stupid diagram, i'll clarify it)]

When you have got your cells right next to each other in a line, you can tape them together. Not a lot to this really - just make sure they are straight and all flush with one another.

This is what your pack should look like when you are finished.

http://img516.imageshack.us/my.php?i...scf00220lt.jpg

In all honesty, this is a waste of time. Save yourself some time and heartache and buy a jig. The Deans one has been very highly recommended

Step 4:

Tin your battery bars. To do this, get them hot enough to touch solder directly onto them ,and it will melt. Here is a tinned bar next to a normal one.

http://img516.imageshack.us/my.php?i...scf00259ou.jpg

Step 5:

Get solderring. You will need to make sure you get the bar up to temperature, otherwise you wont get a good connection. Also dont burn yourself and drop your solderring iron on your pack like i did - it's unprofessional.

First, solder up the five bars between the cells, as in the little diagram above. Look for the little positive (+) and negative (-) signs on the cells.

http://img518.imageshack.us/my.php?i...scf00192iy.jpg

Solder from the + end of one cell to the - end of the next, leaving one end on each of the two cells on the end of the pack unsolderred, one should be negative, the other positive.

Step 6:

You can attach your connector lead now, ensuring it's in the correct polarity, with the black lead going to the - end of your pack, and the red lead going to the + end.

http://img518.imageshack.us/my.php?i...scf00843eb.jpg

Step 7:

You should have created something which looks like this:

http://img518.imageshack.us/my.php?i...scf00839jy.jpg

Check it fits, get out there, and of course Beat your truck.

http://img524.imageshack.us/my.php?i...scf00867ox.jpg

Stuff to remember:

- Double check everything before you solder. It only takes a few second to check, but if you hook something up wrong, there is a very real chance you will burn something.

- Stuff will be hot after you take the iron away - don't burn yourself

- Msand pointed out that you can use a hot-melt glue gun to stick the cells together. I didn't bother, because i don't have a hot-melt gun, though this could be a worthwhile thing to do, especially if the pack isn't well supported. Chris suggested using Shoo Goo, which would work to the same effect.

- If a joint doesn't feel mechanically strong, then the chances are that it wont be very good electrically. If it moves, do it again.

- Chris raised a point which i completely missed. If you run a graphite chassis, remember that graphite will conduct electricity!. For this reason, it is worth spending some extra time making sure everything is properly insulated, and not going to sort out your new battery pack.

- Apparently there will be a guide in the Feb '06 issue of RC Driver too - that will probably be better written.

It doesn't work!

- If your pack doesn't work, go through and check everything is the right way round, and all the joints are strong. Make sure you have the battery bars going between the correct terminals, your connectors are on properly, and have been solderred up with positive and negative the right way round.

Any Questions?

If you have any other questions...post here

You will need to use more cells and more battery bars, but the basic procedure is the same.

[Mike.L]

thanks tom f that will help everyone in this fourm if they forget t.y!

[neweuser]

i tried to thank earlier but my system at work was down! sorry..thank you!

Hi, this is my first attempt building a battery pack. When i tried it yesterday, my battery bars keep dropping off. I read in Tom F's post that making the surfaces of the battery rough will help. And heating up a surface will also help to get a stronger soldered connection..but heating a battery cell is not advisable correct? What is the proper procedure for soldering the bars to the battery cell?:032:

[neweuser]

Well, technically yes, but you do need to apply enough heat to make the connection. Just don't hold the iron on it for minutes at a time.

[glassdoctor]

If you don't have a good iron it just won't work. Doesn't need to be expensive but it needs to be working right... and a fat tip helps a lot too. Those red weller 40w and 80w irons you see at HomeDepot, etc... are great for building packs. The 40w is only like $12-15.

[neweuser]

Here is the one I use. REALLY cheap, and works great on all applications for RC.
http://www2.towerhobbies.com/cgi-bin...&I=LXPR36&P=ML

[jollyjumper]

sorry to hijack, but since you are talking about soldering i tought why not ask now instead of making a tread bout it.
what type of solder is needed for R/C applications?

[glassdoctor]

Any basic electrical solder... 60/40... and you want rosin core. The stuff with a bit of silver is good too, just more $$.

Never use an acid core for sure. ;)

[jollyjumper]

ok, thanks.