Using thick soderwick to build packs?

steveo

steveo

100 kW
Joined
Oct 6, 2007
Messages
1,786
Location
Woodbridge, Ontario
This is how i currently configured everything for my 66v 20s 5p pack; but i may be upgrading to 45amp Anderson power poles....

Disadvantages (currently)
- I hate using this 12 guage wire i used, its no the silicone type so its harder to bend,
as well as this wire is only 12awg & not the 10awg i would prefer
-also deans connectors are generating a bit of heat

Solution I'm thinking of..
-I've purchased 6m of 10awg silicon wire!! to start & try out!
-Ive purchased 300 45amp anderson powerpoles 150 black 150 red with pins + tool

2isvcic.jpg


I'm looking to do the same type deal if i do more packs but i would like to use sodderwick to parallel the cells & then attach the 10awg & Anderson connectors at the end.. I have currently some .125" sodderwick in front of me .. Will this be sufficent say to carry 50-70amps+ or is this a bad idea? My intentions are to be able to cap the ends of the packs with the factory dewalt black side caseings ( the ones used for balancing only***)

thanks in advance

-steveo
 
Solderwick is pretty small in terms of AWG.

I'd recommend stripping the jacket off some coaxial cable and use the braid (you can flatten it nicely).
The really big coax, like RG-8 is close to 10-12 AWG.
 
thats not a bad idea ...

... i don't know is it really worth it to sacrifice & use improper wire..?

Maybe i have to do some diying to the plasic cases so i can still get the benefit as using them as cell holders ...... the only other option i would have is to build a battery tab welder !

hmm

steveo
 
We have a surplus electronics place here in Orlando and can get the braided copper in different sizes, including quite fat.

I have used it and it works well. I prefer it over wire.
 
Will this be sufficent to use?, anyone?

http://cgi.ebay.ca/Braided-Copper-5-16-x-25-ft_W0QQitemZ230239533920QQihZ013QQcategoryZ134305QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

-steveo
 
I have done it a few times, and like it quite a bit.... The stuff I have on hand now is Pro Wick- size 6 - (.193" wide, .02 thick.) . Very tightly twisted, its diameter comes out to slightly more than 13 ga.
(Which, with just a cursory check, seems to be the widest that Mouser has listed. )

Should be no problem at all with 15A or less, borderline at 20 A. IMHO

That stuff on eBay is listed as 5/16 wide, .07 thick.... I'm GUESSING that that would be around 10 ga equivalent or a little better, therefore safe with at least 30 A.

I'd say give it a shot.
 
Hey RLT

Thanks for the fyi,

I would of thought i could get 50amps min out of it without it heating up ... if your comparing to 10 guage, are you saying that we can not draw more then 30 amps with 10awg?.... my bike will most likely peak about 70say for spilt seconds .. and come down to just under 50amps.. i've like to have the most efficent setup i can.


-steveo
 
Nah, I've run a hundred amps / 3600 watts through 12 ga and 120A through 10 ga for a minute or so intermittantly, and about 30-45 amps / 1600 watts through 12 ga for an about hour with no noticeable heating problems.

(Your mileage may vary, your wiring system may burn up, but mine didn't..... although one of my battery packs did burn up... {but that's a different story, which will soon be told here at E-S.})

The first AWG chart I pulled up through google said that the official limit of 12 ga is 20A and 30A on 10 ga...... Those ratings were probably for 120V AC, but that wasn't made explicit....
I don't know if it was accurate; Let some of the smarter guys around here chime in on that.

I always sort of figure that ratings like that are under estimated by at least 50% for the CYA / lawyer evading aspect.
 
Lets see, I have an extension cord right here: ...16 ga... rated at 1625 watts /13A @ 125V AC... As I understand it, you are supposed to derate wires if they are carrying DC... But I don't know offhand (I should) by how much.

Too tired to look it up right now. I need a nap. Maybe try to figure it out later if one of the Electrical Geniuses around here can't quote it from of the top of his head.
 
Thanks RLT.. :D

I know at least have an idea of what I'm looking at now ..now if anyone out there can figure out the quest? you asked.. I'm in the dark for that..

-Steveo :mrgreen:
 

Hi stevo:

I don't think you'll be too happy with the results of running 50-70 amps through 10 guage wire on a sustained basis.

I tried running 4 ft wires (10 guage) from my charger to my bike and ran a constant 50 amps through them @ 4v. The wires heated up, and I resorted to running double wires instead. However, I do pull a max of 40 amps on my bike without any problem using 10 guage wire.

It is hard to find any "noodle" wire in 10 guage, but an electronics store near me had some very flexable copper wire in 10 guage, so maybe you can find it.

This is a wire resistance calculator:

http://www.stealth316.com/2-wire-resistance.htm

You can compare the area of a cross-section of the braided copper on ebay to figure out which size wire it corresponds to.

Also, copper is much more conductive than other metals. This means that there is lower resistance = lower heat on the wires.

I used this soldering iron:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=4328

It seems to be powerful enough to do batteries.

I don't agree with RLTs numbers for how much wires can handle. I'd estimate:

12 guage = 25 amps
10 guage = 40 amps dc
8 guage = 75 amps dc

My 10 guage wires were getting very warm at 50 amps.

My 2c
 
No arguments Eric..... My experience is minimal... I've only gotten two five minute test rides, one half hour test ride and one hour and a half hard 'shakeout' ride on my bike before I ruined one of my battery packs (due to doing at least two stupid things in a row, not because my wires were too thin.).

OK.. maybe a little argument: ;)
For short run lengths, say a couple of inches for feeder lines to a heavier main line, I think it would be OK to use that big braided eBay stuff.

The length of the wire run is not as as important as the thickness, but it is of some significance; so, if you are only running a couple of feet you can get away with thinner stuff.

Or maybe I'm not understanding what either of you guys are saying... Which is a possibility... (lets blame it on the Nyquil- I've got a cold or something)

Hey, I just found this handy dandy calculator:
http://beta.circuitwizard.bluesea.com/
It only goes up to 32V but at least it will give a ballpark figure....Maybe it will help.

I'm still looking for a solid rule for derating for DC, since most of the info I can find is for household AC current

Now that I think about it, part o the reason I had better luck with my 12 ga wires not getting hot is that they were kind of sort of 'heatsunk' because they were glued and zip tied to metal, including a pretty large area aluminum sheet and tube for most of the length of the longest run, and it was 40 degrees (F) outside.......
(edited:) Plus I'm using that really fine stranded monster audio cable, which is, according to what I have heard, capable of carrying more watts than regular Radio Shack / Checker Auto / Ace Hardware primary wire

I'll certainly agree that when it comes to wire in this application, the thicker the better for efficiency and safety.... Trying to balance that with what is easiest and neatest is the big trick.
 
I've seen automotive grounding straps of braided copper perhaps 1" wide by 3/16" thick. Auto supply store. We used to use heavy solder braid in the 60s to connect Nicads for electric glider competion and pulled 40-50 amps thru them. But the time limit was 30 seconds. Yeah, we go several flights out of a set of batts!
David
 
I draw 200 amp peaks and average 50-150 amps using 8 gauge monster battery wire and deans ultra connectors. I parallel the connector pins per polarity. The wiring and connectors are only a little warm after the 200 amp peaks (20-30) seconds. The magmotor is running far hotter. I know this is not recomended in the books, its worked for years now.
 
I'm glad Steveo started this topic. I was planning to use 1/8" desolder wick for battery interconnects, but maybe not now.

Wish I could purchase just three foot of the eBay braided copper. That's all I need, not 25 feet.

I've done research and learned: the current handling of wire depends upon how much heating you allow.

If you insist the wire to stay cool-to-touch with low I²R losses, then you obviously use large gauge wire.

If you allow the wire to warm to touch, but not melt & burn the insulation and short-circuit adjacent wires, the amps can go up or the wire can be thinner. PVC vinyl insulation works up to about 100°C; boiling water temperature.

If you use high-temperature insulation like PTFE teflon, you can get by with even more amps or thinner wire. PTFE teflon insulation withstands 200°C; fish-stick baking temperatures.

Teflon wire insulation is thinner than vinyl insulation, since teflon can withstand higher voltages than vinyl. The copper strands in teflon wire are silver-plated to make soldering easier. Most lead-tin solder melts at 180 to 190°C, which is less than the insulation melting temp. If the strands were solder-coated, the stranded wire would become solid the first time it got hot then cooled down.

BMC/Puma hubmotors and Xlyte 20A controllers use small-AWG teflon-insulate wire for the power leads. You can prove it by laying a piece against the hot-end of a soldering iron; the insulation won't melt and burn like vinyl. The motors & controllers exploit the thin, slippery, high-temp insulation for routing through thin axles and out small controller openings.

I replace these wires to lower heating losses, but save every scrap I can, because teflon wire is expensive (search "teflon wire" on eBay) and useful for it's thin size and high temp capability.

Teflon insulated wire can be purchased through retail at: http://www.powerwerx.com/wire-cable/
Scroll down until you see the "PTFE High Temperature Stranded Wire" link.

Whew! I hope this is useful information, and I wasn't too pedantic. :oops:
 
The problem isn't how much thermal heating you're willing to allow. It's about how much of your battery's power you'll allow to be lost before even making it to the controller. The relevant number isn't a wire's maximum current, but rather the Ohms you add to your battery's wiring resistance. This in turn will reduce the volage sag under load. Since you can't improve battery's internal resistance, or the motor's efficiency, or the controller's efficiency, better wiring is one place you can make (very small) improvements.

More to the practical matter, I've run 55A through 10awg noodle wire and 45amp Andersons for minutes continuously with zero detectable heating. I figure some stranded copper 10awg with the insulation cut off would be easiest. Get the "automotive hookup" stranded stuff; it's cheap, and the only 10awg RadioShack carries. Then take a razor and slice the length of the insulation. And of course, make sure your iron can provide enough heat to make a good solder with all that copper trying to dissipate the heat.

Again, I have to ask. Is that soldering gun at harbor freight real?! Really?! $10?! That's a quarter what I paid for my Weller 140/100w unit, and it's getting very cranky about what tips are used.
 
Yes lazerus its real. I have one in my garage.

I agree with lazarus that the heat is a bad indication that you're not using big enough wire. You don't want your wires to heat up.

Laz, where did you find 10ga noodle wire????? I looked everywhere. That would be a great find for all of us. Too many people are using 12ga becaause it the biggest available.

Also, you don't need to use as big of wire to connect the batteries together because the parallel connections don't handle the full amperage of the whole pack. The best way to connect batteries in parallel is the way RLT did it--spot-welding a piece of copper onto the tops/bottoms. You can ssee it in his build thread:

http://endless-sphere.com/forums/viewtopic.php?f=6&t=3836

Personally, I hope to move away from having to solder/weld batteries together in favor of connections like on the LifeBatts. They have threaded studss on each end, so you just bolt them together. This soldering/welding stuff is B.S.

 
Xyster pointed out the 10awg noodle wire last fall, from cheapbatterypacks.com. Since then, I ordered 30ft of the stuff (half red half black) and I'm almost out. It's very good stuff, and very very noodely. Check it out here: http://www.cheapbatterypacks.com/?sid=1074165&pgid=wire

And... I think I have to take a trip to my local harbor freight tomorrow!
 
lazarus2405 said:
That's a quarter what I paid for my Weller 140/100w unit, and it's getting very cranky about what tips are used.
Click to expand...

I paid ~14 dollars for my Weller 100/140 watt soldering gun but then again that was back in 1970 sumpthin...

It's been used and abused and after all those years it still works like a charm.I fashion # 10 or #8 (can't remember) copper non braided household into soldering tips,seems to work rather well.

Eric
 
I use the 10 AWG cheap copper stranded wire from RadioShack for all my battery connections. My batteries are 10s6p subpacks, in which I take six of the 10s tabbed DeWalt A123 packs and connect them in parallel using the 10AWG insulated wire. I then connect two or three of these in series. Large (75-amp) andersons are used for the output leads of each 10s6p pack because they have much lower resistance than the 13/30/45 connectors (each of which also have slightly different resistance despite the similar size/appearance).
 
My three wheeler at 72 volts would heat up the wires from controller to motor real warm ,almost to a to hot to hold on to. I replaced the wires from controller to motor with 10 gauge wire, got rid of those crappy little Black & Red connectors and bike runs so much better. Has lots more power on the bottom end and wires don't get hot any more, those little Anderson connectors that came with the 72 v ,40 amp controller are junk IMHO . they just don't seem to hold a tight enough connection .. My bike is super heavy but is so dependable now since the fix....I guess what I'm trying to say is wire size means more then you would think. Go extra if you can
 
lazarus2405 said:
Again, I have to ask. Is that soldering gun at harbor freight real?! Really?! $10?! That's a quarter what I paid for my Weller 140/100w unit, and it's getting very cranky about what tips are used.
Click to expand...

I found you have to crank down on the nuts that tighten the tip really hard. Over time the copper oxidizes and increases resistance there.
 
Just some more FYI:

I found this:
http://www.surplussales.com/antennas/Antennas-11.html

Lists the 1/2" X .075" as good for up to 85A
1/4" X .060 as good for 30 A
and 7/8 X .062 as good for 100A
 
Oh! Grounding braid? That's what that stuff is? I saw it at Orvac and wondered what it was for. It didn't look very useful as wire since it had no insulation.

Hey, that stuff would look really good on a carbon fiber shirt...

I swear, I'm doing it after I finish this ebike project. 8)
 
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