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Old Jun 14, 2002, 10:37 AM
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Chicago
Joined May 2002
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Building sub-c battery packs

What's the concensus on building sub-c battery packs, sticks or side-by-side? Any faq's out there?

It seems building sticks would be easier with the right tools (correct soldering iron tip, and a groved chunk of wood to line them up). Since sticks have less parts, there should be (theoretically) less resistance. Cheaper to build with less bars to buy.

OTOH, side-by-side has the advantage of being able to easily identify and replace a bad cell.

I have a couple DeWalt 12 cell packs purchased from Nicdlady.com and plan to use the cells to build a couple 10 or 12 cell packs as an experiment. I was thinking of getting a new tip for my Weller soldering gun and filing the sides of the tip flat so it'll heat two batteries at once (if I build them as sticks). Is there a preferred, lower resistance/stronger solder (silver perhaps)?

I have shrink wrap but it seems as if clear package tape, carefully applied would work. Or the new Saran Wrap style of stretchy plastic wrap would work fine too.
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Old Jun 14, 2002, 02:47 PM
Our Daddy and Heli Junkie
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Don't know if you tried the search yet, but there is lots of info on building packs out there. Try the Open and Science forums too.

Shrinkwrap is the best. It helps to hold the cells together better.

You can get a special tip for the weller 40 watt iron to make cells from Hobby Lobby. Just use regular solder.

Building packs does take a knack, so try with older cells a few times beefoore you hit the biig ones!
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Old Jun 14, 2002, 03:24 PM
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side by side is way easier, IMO. i glue the cells together with Goop, then solder strips of copper braid (aka solder wick) across the terminals. the copper braid is a great conductor, and is very easy to work with.
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Old Jun 14, 2002, 05:48 PM
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Side by side has good and bad tradeoffs, just like end to end.
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Old Jun 15, 2002, 01:15 AM
ElektroRC.com - MSH,LAHeli,YGE
Pewaukee, WI, USA
Joined Mar 2002
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I used to build my RC car packs. Now I build both my 8 cell flat packs for the Piccolos and the standard pack for the Hornet. But for my "big" (12 cell Logo) packs, I use the MEC solderless tubes. They cost 20 / pack (sub-c) but work awesome and thats a 1 time cost. For that price, I could never see messing with soldering these types of inline packs... (Thats just IMHO though )

If they were side-by-side though, I'd build them myself, those are easy...

Does your application (heli) take side-by-side or inline packs?
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Old Jun 15, 2002, 10:35 PM
DLG Addict
Peachtree City, GA
Joined Nov 2001
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Where can you find the MEC tubes?

Thanks,

Eric
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Old Jun 16, 2002, 12:33 AM
ElektroRC.com - MSH,LAHeli,YGE
Pewaukee, WI, USA
Joined Mar 2002
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http://www.modelelectronicscorp.com/spt.html

I saw their advertisement on this board. I posted a question about them, got lots of positive comments. I can see why...
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Old Jun 17, 2002, 11:25 AM
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Chicago
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I saw the Power Tubes before, but it seemed I should just buy completed packs if it's going to cost $20 to put the individual cells together. IMHO

Last night I soldered tubes together with my Weller gun. It was very easy, once I got the hang of it. All I did was file the sides of the gun's tip to put some flat spots on it for better heat transfer. I prepared each cell, sand/flux/solder puddle, then lined them up on a grooved piece of wood clamped to the workbench. I put clear package tape on each completed stick (to insulate them from the other stick), wrapped rubber electrical tape on the ends after connecting the two sticks and wires, and covered the whole thing with clear heatshrink. I'll bet it took a lot less time than side-by-side would have taken.

Now what remains to be seen is what the DeWalt battery packs actually have in them. The cells are unmarked, except for small letters "Japan FB", and they weigh 52g. The first cycle they took just over 1800 mah, which should improve with further cycling.

In the DeWalt packs they were assembled with cardboard sleeves covering them, which I discarded in favor of clear package tape. The finished pack, with clear heatshrink over clear package tape over shiny, unmarked cells looks very cool. And the individual cells only cost $2.08/each.
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