Please help me build a discharger

[blownsi]

Hi,
I am looking to build a discharger that can discharge a pack at 30A, without using 15 taillights (too big). I run a 9T SG Kryptonite in my touring car normally, and occasionally a handwount 7T and I am looking for a discharger that can condition my packs for the kind of abuse they are given. I would like to build something relatively small with a digital voltmeter so I can watch for the cutoff. Any ideas? I was thinking of maybe a headlight or foglight from a car could draw that much current? I am sure a series of resistors could do it but I don't know where to begin. Anyone know the conversion for watts to amps? I have a spare headlight that is 12v 60w. Should I just buy the Deans kit which is 20A and hook my multimeter inline? I am not afraid to build a project as I have done it in the past. I am good at soldering but have no pro training in electronics, so I don't know how to do the calculations for my project.

Thanks for any help in advance

[jeepinator]

volts divided by resistance (ohms) equals current (amps)
7.2/X=20
X=7.2/20
X=.36

If you connect your pack to a .36 ohm load, the resistor will "use" 20 amps. Not many resistors will handle that kind of power (144 watts). That is why most folks use multiple light bulbs (resistors) in parallel.
Maybe someone else could chime in with the part number for the automotive light bulb that is commonly used. I have made one before, but it is long gone now and I cannot remember the bulb part number. It is a common one though.

[sixandeightstringer]

I'd say just get the Integy or Orion discharger - it will be more reliable, and probably less problematic and expensive. That is, unless you want to do it for the learning experience....

[blownsi]

The bulb mentioned earlier is a 1157 tail light.

Also, yes I was kinda building it as a learning experience. The part I enjoy most about r/c is building stuff. I am probably opposite of most. But running the car for a few minutes isn't the thrill. It's building battery packs, installing servos and assembling the kit that are the fun for me. That's the one thing I dislike about my 2.5 Maxx. I only get to have fun when I brake something lol.

[vols-std]

try this link
this (http://www.*******.com/pkg-how/000016/resistor_discharger.shtml)
or
this one (http://www.*******.com/pkg-how/000015/index.shtml)

Greetz Ben