Building lipos for the DYI guy... or gal.

[Chris_The_Battery_Man]

Ok, so since I haven't seen anyone post up any lipo building tech, and with the exception of the chinese, I have more lipo building and general experience than 99.9% of anyone out there, I thought I would take some pix of a simple pack I put together today and do a little write up on the basics. I have been building lipos since before all the major reputable lipo companies existed and back when we discovered Enerland(Yes, we were the FIRST place to carry their cells and make packs with them) whom is as of now the second best lipo cell manufacturer with Elite on top with the best lipos there are out there... second to NONE! This is how I build all of our Elite lipos that are not pre-made, and how I have been doing it for nearly 6 years.



I do not recommend this to the Novice of soldering. It takes a little experience an a steady hand. Lack of experience can result in damaged cells.


Tools needed:
-60watt + soldering iron with a hammer head tip or wedge tip. You just need a broad flat surface.
-Sponge to wipe old solder on
-60/40 rosin core solder(Or zink solder with aluminum flux for those primitive cells that still have no copper/nickel tab welded to the + side for soldering. Our Elite cells have been coming with copper tabs that are nickel plated for about a year and a half to handle the current. But some will just have nickel tabs)
-Lipo cells, tap plug, leads, tape, and shrink wrap.
-Scissors for trimming the tabs.
-Wire strippers
-A steady hand



I am making an Elite 1100mah 3S pack with Align tap and A deans plug. Pretty simple. Lets get started...




First I test my cells. Notice on the right tab of the cells there is a tab welded to a wider aluminum tab... Thats the positive tab. If you dont have a + mark, look for the tab thats aluminum at the base and has a different tab welded to it. All lipo positive tabs are aluminum. And the negative is either Nickel or copper with nickel plating. In the old days we used to have to spot weld on a nickel tab to the aluminum tab for soldering or use a special flux and solder to be able to connect the - to the +.



Notice the dual tabs on the - tab. Some factories do this with both tabs. They double them up. From my experience, the factories that do this have crappy cells. But this cell only has the dual tabs on the - side, and they're out of the Elite factory so they're definitely not junk. There are also alot of cells in larger sizes with opposed tabs. Basically one tab per end. Generally that is with about a 3000mah and larger cell. In the 2200mah and down, the tabs are on the same end of the cell.



Tabs trimmed to appropriate length



Because of the dual tabs I have to solder them together. They will perform very poorly if the dual tabs arent soldered together. Luckily, I have the ease of dipping the cell in a pool of flux, then the solder pot. But manually soldering them will work too.



Make sure to tin all the surfaces you are soldering together. Using solder to help transfer heat works best. So I will tin both sides of the negative tab and only the top of the + tab because I always solder the - tab on top. This also allows for a great surface to solder your wires for the balancing tap. Make sure you don't keep the iron on the tab for more than a milli-second or 2 because you can ruin the cells. I generally only have the iron on the cell for a portion of a second.




The 2 cells soldered together. Be careful to not short circuit the cells



And the 3rd soldered on



I prefer to use balsa wood on packs that have both tabs on the same end. Wedging the balsa between the tabs prevents them from touching in the event of a bad crash.



With Deans lead and Align balancing plug installed



And the final product. I try to do all the cells I can in all clear these days because of our "Nothing to hide" policy. There are alot of places that cover the whole pack in black or fibertape and you can't see the tabs or anything inside if something goes wrong. This way the customer can see everything thats going on inside... No secrets here.

[run2jeepn]

Where can you buy just the Cells?

[racerrandy]

I know max amps list single cells but I am guessing Chris will sell them single too.


Randy

[JeremyH]

Awesome! Thanks for the info!

[Chris_The_Battery_Man]

Originally Posted by run2jeepn

Where can you buy just the Cells?

Im not sure. I know that we can sell loose Elite cells. But usually for the money, its easier to just buy them built. I mainly posted this because we get guys from time to time on the phone that have their heart set on building their own packs... even if they're only saving like a buck.

[TheHeadHunter]

Great thread , very helpful , thanks Chris

[Chris_The_Battery_Man]

Someone requested a tap wiring diagrahm... Well heres my pre-school diagrahm. Hope it's helpfull...

[JohnRobHolmes]

Maxamps and Cheapbatterypacks are the only places I would recommend for getting Lipo cells loose, as they do have quality control here in the states. As Chris stated, normally you may save a buck or two- certainly not enough for the average american person to save time or money on a build. I actually lose money in the form of both material and time if they aren't built for me, and I would rather trust a professional company to do the work so that I am ready to rock as soon as the package is opened. Sure I can solder and build packs no problem, but it isn't my job to do it.

Great writup Chris.