Glad you like em...that's what we like to hear :) :nod:

Direct Soldering your batteries
 

OK, here we go again. I try every once and a while to dispel this myth, but no matter what I do, this one won't die.

The resistance of 12AWG copper wire is about 0.0002 ohms per foot. 14AWG is about 0.0003 ohms. The resistance from the end of the wire to the end of the cell, thru the battery bar and it's 2 joints, is about 0.00025 ohms, mainly because only about 20% of the racers I see can solder properly, but that's a different story. A perfectly soldered hardwire connection will have about 0.0015-0.0002 ohms of resistance, end to end. About the same as an inch of 12AWG wire.

The resistance from a properly terminated Deans or Corally style connector is about 0.00002 ohms.Yes, they're both LOWER than an inch of 12AWG wire (0.000025 ohms).

Let's do some math.

At 20A (stock class here, with a fast track), tells us we'll get about 0.005V lost across the average (poorly soldered) direct wire method, the same as a foot of 12AWG wire. That's 5 thousandths of a volt. with 7.2V (give or take) coming out of your pack, it's 0.0694% of your total voltage. Seven hundreths of a single percent of your energy.

The loss in the connectors will be a lot lower, on the order of 0.0004V. Including solder joints. 0.0055% of your nominal pack voltage. Fifty five thousandths of one percent.

In engineering terms, it's nothing. it's less than your speed control. It's less than a Tamiya connector by several orders of magnitude. It's less than the bad solder joint the guy in the next pit just made while hardwiring his pack. It's absolutely lost when you take into account the inefficiency of your motor.

You'll lose more track position by driving badly or moving an inch and a half outside the perfect line than you will because of the loss of your connectors. If you can't solder, or use a foot and a half of wire in your car, it's your own fault. The only conceivable reason to hardwire your packs is so that in the event of a crash, you won't get disconnected. Funny thing, I'm a really bad driver from time to time, and the only time I had a pack get disconnected was when I lost a retainer clip and the pack came out of the car.

Regarding soldering, if the joing isn't shiny and smooth, like a little drop of polished silver, it's wrong. If it looks dull, its wrong. If it looks crystalized, it's wrong, If it's lumpy it's wrong. If you can't see yourself in it, it's wrong. If it's wrong, you're losing more voltage than you ever would with good connectors.

This applies to battery bars, ESC conenctions, motor connections, and every other place you put solder in your car. Think about it.

Oh, and when you solder batteries, if it takes more than 3 seconds to get the solder on the end of the cell to flow and the joint to be happy (battery bars, wire, anything) you need a bigger iron, because you're just killing your batteries. I use a 350W gun to make packs. It takes 2 seconds to solder a bar, and my cells are cool to the touch when I pull them out of the jig.

My $0.02.

-dave

Soldering vs Plugs
 

dpaton;

FINALLY someone to present the true FACTS of this argument in a clear readily understood manner. (I use Plugs)

Thank you!! :nod:

I agree.Its really personal preference and on a club level its even less of an issue.I personally hardwire.Been doing it for years.

Brand 'TP' Batteries
 

Guys;

Think about what 'dpaton' just posted.

With this being the case, how does Brand 'TP' Batteries claim TWICE the availible voltage at the ESC using Packs built with their special solder method? :rolleyes: Our Stock Motors should run like a 10T with twice the voltage. :lol:

Dave - once again your knowledge astounds me. You gave us a great explanation to this subject. Now in your soldering argument, do you solder per government standards and how would you learn this trade to better reduce the resistance within solder joints?

John

Dave is obviously right as far as the hard wire joints having more resistance because most of us solder "wrong" and that the resistance from a bad joint is greater than the plug. BUT, when you install a plug, insted of having only one bad solder joint from ESC to battery, you have three now. One from battery to wire, one from wire to plug, then your plug connection, then from plug to ESC. You end up with three times the bad joints, and three times the resistance. Right?

You guys should have seen how fast Tosolini's car was last night with the new batts :eek: I believe that they made the difference in him getting the TQ or not getting it, he TQ'd by .09 seconds :cool:

Was Brian there?

No, havent seen Brian there on a Tuesday in quite a while...

How does he like the cells. Does he like his new sponsorship? :)

dpaton,

You hit the nail right on the head! Good job. Still waiting for your stuff. :sneaky:

Dan

He shouldn't of ran the tires you glued for him in the Main. :lol::lol::lol::lol::lol::sneaky:

Dan

John,

Did you really have to ask?!? :lol: :sneaky:

btw, call me at the office please. Thanks

Dan

Man those tires were flawless, just werent scrubbed in...