RC10Talk - The Net's Largest Vintage R/C Community

I made my first purchase of Li-Po packs two weeks ago and was surprised by the wire gauge used. They were Turnigy 2S 30C 5000MAh and have 8ga wire. I wondered if others used Deans with this size wire and did post the question on RC Universe and received a couple of answers that were basically "learn how to solder better". That isn't the problem, I have been soldering electronics for 28 years and have more soldering irons and related tools then most people own screwdrivers. That aside, I have come up with what I feel is a reliable way that is safer than two 8ga wires on a electrical bomb 1mm apart.

I used Pin Terminals of the 10-12 gauge size because they are available from McMaster-Carr and cost $2.33 for 10pcs. The pin is .120" diameter and I feel they have the current capacity. I spread them out to fit the 8ga wire. There are ones available for 8ga wire but are 1.95 for two and take several days to arrive. Those are available here : http://www.halfpricecaraudio.com/Stinger-SPT5158-Chrome-10-8-Gauge-Input-to-2.5mm-Speaker-Pin-Terminal-1-Red-and-1-Black-SPT5158.htm



These are the Pin Terminals, before & after I spread them open


Strip the wire 3/16"


Carefully slid the terminal on without feathering the strands


Squeeze close with pliers


Crimp with good crimpers, not the crappy ones that squeeze it


Solder, I used my 150 watt Hexacon iron. Heats the terminal to melt the solder in 2 seconds for no heat transfer to the battery. Slid shrink tubing on after it cools. Also clean any flux residue.


Then I used my 45 watt iron to solder to the Deans connector


Slid Shrink tubing over


Finished connector

Looks good, nice clean solder job...but aren't you losing any advantage of the gold contacts of the Deans by having the current go through a bunch of extra solder and whatever material those 1/8" speaker connectors are made out of?

I'm no electrician by any means but it'd be interesting if you measured resistance of both soldering methods.

The connector I used are Tinned Copper and are industrial-use connectors, the stereo ones are there as an option. They are crimped and soldered as per Military Specs, resistance loss is unmeasurable with any equipment available to the public. I use Deans connector because of their size and easy of use not because I'm drawing 150amps with a loss of .00001 volts (I don't really know or care about the voltage drop, the point is the drop is miniscule).

the resistance of battery connectors used to somewhat matter back when you could barely make a 4 minute race without dumping. we don't have those problems with todays packs.

My reasoning wasn't along the lines of ekeing an extra 30 seconds out of a 4-minute motor, it was actually based on how heat is created as a result of increased resistance. A year ago, I had no idea what Deans connectors were. Back in the 80's, people were just beginning to upgrade from Tamiya connectors to those orange gold-plated ones. With today's high-output "electrical bomb" batteries, those inefficient, inadequate, low-diameter Tamiya connectors would fry right off.

High-performance RC enthusiasts moved to large-guage, high-current-capacity wiring and connectors for this reason moreso than to get a longer run-time.

Maybe heat output at the solder joints would be an easier way of measuring this resistance than voltage drop.

It may not look quite as nice, but soldering the + lead to the OUTSIDE side of the positive terminal on the connector will give you a lot more distance/room between the + and - terminals. Solder the - terminal first, with say a popsicle stick between the + and - terminals to keep the gap free and clear, then flip it on it's side and do the + terminal.

That's how I do them, anyways.

That's not a bad idea at all, I have to say.... especially if you have to use the wire that comes with a particular battery.

HWS_Losi makes a good point about putting the positive on the outside.... but I just can't bring myself to do it!!!!

One point I have..... in the pics above, where you show the quality of your solder job (and it does look a quality job), you must have balls of steel to hold the two live terminals of the battery that close together..... I would have had a fireworks show right there..... lol....

Alex

I've been soldering the + on the "outside" for ages too

Curious to see the resistance of the terminals vs. that of an equivalent length of wire itself...

Not sure about whether it's the pic, but your solder joint looks really dull??? I understand you're a master solderer, but still it looks, mmh, not fully right...

Paul

nah, the soldering looks fine.

the gold plating is really to lower the contact resistance, while providing a surface that does not readily oxidize, between the connector mates. on the other side of the connector where it's soldered, you would not be losing much voltage at ALL.

this is a good idea, and I have done similar type things in the past.

I don't know why they feel the need to put 8 gauge wire on these packs. 10AWG is more than adequate, and I would even say 12AWG would not be a problem in most cases.

Lonestar wrote:I've been soldering the + on the "outside" for ages too

Same here, I didn't really see any point to soldering it on the inside, where it's that much easier to accidentally short out.

Lonestar wrote:I've been soldering the + on the "outside" for ages too

Curious to see the resistance of the terminals vs. that of an equivalent length of wire itself...

Not sure about whether it's the pic, but your solder joint looks really dull??? I understand you're a master solderer, but still it looks, mmh, not fully right...

Paul

same here, i've always done it that way. 6 gauge would fit, probably something bigger too.

my friend just picked up some turnigy 5000mah 25c 2s packs. wtf is up with the wire.... I wonder if they had some lawsuit against them having something to do with skimpy wire at one time so they decided to use something I might power a decent amp with...