Ford Ranger Forum - Forums for Ford Ranger enthusiasts!

Go Back   Ford Ranger Forum - Forums for Ford Ranger enthusiasts! > >
Forgot Password? Join Us!

Welcome to Ford Ranger Forum

Reply
 
Thread Tools Search this Thread

  #1  
Old 05-13-2011, 06:50 AM
SpitfireEMT SpitfireEMT is offline
Muddy, as usual
 
Join Date: Oct 2009
Posts: 386
Send a message via MSN to SpitfireEMT
Default Double check my math?

Okay, so I am in the process of finishing my front light bar, and I decided to run the numbers before I install my new lights.
(all numbers rounded to the nearest tenth for ease of calculation)
R1 (Hella 500ff1) = 0.6 Ohm
R2 (Hella 500ff2) = 0.6 Ohm
R3 (Hella 700ff1) = 0.7 Ohm
R3 (Hella 700ff2) = 0.7 Ohm
^ This all stand to reason, seeing as they are the same light bulb, ideally, pulling the same amperage.

Then:
Rt= 1/((1/0.6)+(1/0.6)+(1/0.7)+(1/0.7)
Rt=0.1615 Ohms
Rt=0.162 Ohms

Then:
Et=12
Rt=0.162
It=x
E/R=I
12/0.162=74.074

It=74.074A @12v

Et(running)=14.4
Rt=0.162
It=x
E/R=I
14.4/0.162=88.88

It=88.88(rep) A @ 14.4v

That is a lot of amperage to yank off of a stock alternator.
Need an upgrade much?
__________________
2000 XLT 4x4, 4dr ext cab, 4.0L OHV, 4.10 LSD
265/75/16 Goodyear Duratracs
Mountaineer seats, Expo OHC
2003 EDGE front clip conversion
133rwhp/192rwtq-->6-28-11

1969 Mercury Cougar
351W, FMX, 3:1 open diff in a Ford 9"
Undergoing restoration
Reply With Quote
  #2  
Old 05-13-2011, 09:41 AM
Pietato Pietato is offline
Ford Motor Company
 
Join Date: Feb 2011
Posts: 266
Default Re: Double check my math?

your resistance is going go change with heat aka turning them on

http://en.wikipedia.org/wiki/Incande...haracteristics
__________________
2004 4.0L extended cab FX4 Level II 5r55e

1998 3.0L extended cab XLT 2wd 4r44e

Last edited by Pietato; 05-13-2011 at 09:47 AM.
Reply With Quote
  #3  
Old 05-13-2011, 12:05 PM
SpitfireEMT SpitfireEMT is offline
Muddy, as usual
 
Join Date: Oct 2009
Posts: 386
Send a message via MSN to SpitfireEMT
Default Re: Double check my math?

Okay, so Im gonna have to bust out the old 12V PSU and start taking more measurements
__________________
2000 XLT 4x4, 4dr ext cab, 4.0L OHV, 4.10 LSD
265/75/16 Goodyear Duratracs
Mountaineer seats, Expo OHC
2003 EDGE front clip conversion
133rwhp/192rwtq-->6-28-11

1969 Mercury Cougar
351W, FMX, 3:1 open diff in a Ford 9"
Undergoing restoration
Reply With Quote
  #4  
Old 05-13-2011, 12:14 PM
Pietato Pietato is offline
Ford Motor Company
 
Join Date: Feb 2011
Posts: 266
Default Re: Double check my math?

I'm assuming you used a multimeter for all your previous data it should have something to measure current i would just use that and avoid all the calculations for simplicities sake
__________________
2004 4.0L extended cab FX4 Level II 5r55e

1998 3.0L extended cab XLT 2wd 4r44e
Reply With Quote
  #5  
Old 05-13-2011, 01:15 PM
SpitfireEMT SpitfireEMT is offline
Muddy, as usual
 
Join Date: Oct 2009
Posts: 386
Send a message via MSN to SpitfireEMT
Default Re: Double check my math?

My meter is rated at 20A in 30 sec bursts. I've got a clamp I use for current. I wanted to do the math before I hooked it up and overdrew on the system.
__________________
2000 XLT 4x4, 4dr ext cab, 4.0L OHV, 4.10 LSD
265/75/16 Goodyear Duratracs
Mountaineer seats, Expo OHC
2003 EDGE front clip conversion
133rwhp/192rwtq-->6-28-11

1969 Mercury Cougar
351W, FMX, 3:1 open diff in a Ford 9"
Undergoing restoration
Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Double Din in an 02? joldtown Audio / Video 21 01-27-2012 01:19 AM
Double Din... Is in! HoustonM Audio / Video 11 01-26-2012 08:37 AM
My double lift so far 4evermodding Vehicle Snapshots 31 03-29-2011 12:02 AM
Check Fuel Cap/Check Engine Light Texas001 3.0 Vulcan Tech 9 12-31-2010 11:03 AM
double plug 2.3? Booze1983 4-Cylinder Tech 3 08-07-2009 08:32 PM