Technical Discussion Topics related to Technical Issues

electrical question

Old 07-19-2010, 06:54 AM
  #1  
ride it out
SuperSport
Thread Starter
 
nothing's Avatar
 
Join Date: Feb 2009
Location: NH
Posts: 745
nothing is on a distinguished road
electrical question

I have relocated my oil pressure and neutral indicator lights to just 2 LEDs.

I have temporarily removed the gauge cluster, so if you look at the schematic you can see that for those 2 indicators, they each have their own wire to trip on the indicator and share the same (BK/BR) power supply. I tested the voltage of that BK/BR wire and with the ignition on, +12V like I thought.

On the other end of each indicator light there is the two separate trip wires, BL/RD for oil pressure and LG/RD for neutral which each go to their own sensor which is a switch and I am guessing they are normally closed when in neutral and when there is no oil pressure, thus why the lights are on while not running with ignition power.

However here lies the problem. When I wire up just as explained above the "Meter/tail/Illum." 10A fuse for the BR/BK blows which also powers the tail/brake lights and horn. Since there is basically nothing else on this circuit except for the two indicators I am using and horn/tail, why is it blowing this fuse? Are the LEDs drawing too much power or something?


Schematic (for reference):
https://www.superhawkforum.com/galle...00F-wiring.jpg

nothing is offline  
Old 07-19-2010, 07:23 AM
  #2  
Out of my mind, back in 5
MotoGP
 
Tweety's Avatar
 
Join Date: Nov 2006
Location: Skurup, Sweden
Posts: 6,109
Tweety is on a distinguished road
Start with the basics... The LED is oriented the right way and you have the correct resistors on there to make it work with 12V right?

A LED drawn a lot less power than a bulb and no LED will ever work right of the bat with 12V, it's basicly a short then, so that could be why the fuse blows...
Tweety is offline  
Old 07-19-2010, 07:50 AM
  #3  
ride it out
SuperSport
Thread Starter
 
nothing's Avatar
 
Join Date: Feb 2009
Location: NH
Posts: 745
nothing is on a distinguished road
Originally Posted by Tweety View Post
Start with the basics... The LED is oriented the right way and you have the correct resistors on there to make it work with 12V right?

A LED drawn a lot less power than a bulb and no LED will ever work right of the bat with 12V, it's basicly a short then, so that could be why the fuse blows...
Ok that where I figured I needed to start. They're oriented the right way, yes. However unlike my LED tail, these didn't come with any resistors to limit the current draw. I know LEDs draw about 25mA and run off of ~2V, but I'm not 100% sure about those numbers for this exact application. Just going roughly, I need about a 10V drop across a resistor from the 12V battery that passes about 25mA to ONE LED, so 10/.025 = 400Ω. Think I should start there? And do you think it would be better for 400Ω for each LED or should I combine and go 10/(2 x.025) = 200Ω and use just 1 wire to supply them both? Thanks tweety
nothing is offline  
Old 07-19-2010, 09:05 AM
  #4  
Out of my mind, back in 5
MotoGP
 
Tweety's Avatar
 
Join Date: Nov 2006
Location: Skurup, Sweden
Posts: 6,109
Tweety is on a distinguished road
That's where to start yes...

Actually not too far off... Most small LED's draw between 10 and 30 mA, and 1.5-2V, so yeah your calculation is mostly right, a bit more margin might be a good thing though if you don't know for sure what spec they are...

Supplying the both from one resistor might prove fatal, since they will not always be turned on at the same time, so then the one turned on ends up getting to much and will probably stop working...

Also, since you have tried them with 12V it's more than possible that one or both of them are permanently fused now, making them into a wire/resistor, not a LED, so be prepared to replace them...
Tweety is offline  
Old 07-19-2010, 09:12 AM
  #5  
ride it out
SuperSport
Thread Starter
 
nothing's Avatar
 
Join Date: Feb 2009
Location: NH
Posts: 745
nothing is on a distinguished road
Yep, that could have happened hopefully not though. I have incandescent bulbs for the sockets that I removed, should have thought this out some more before I swapped them for LEDs. THanks for the help again Tweety.
nothing is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
jscobey
General Discussion
15
07-14-2013 08:44 PM
tbartley
Technical Discussion
3
07-29-2009 02:14 PM
Circuit_Burner
Technical Discussion
8
10-13-2008 09:59 PM
elijahawk
Technical Discussion
5
10-13-2007 03:56 PM
gambrjl
Technical Discussion
2
02-19-2007 03:22 AM


Thread Tools
Search this Thread
Quick Reply: electrical question


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.