Light bulb ratings

• Ponders

  24 Sep 05, 12:28

  ok... who here understand what the ratings mean for lightbulbs.
  
  e.g.
  
  60/55w = 135/125w
  
  does this mean that this bulb only draw a electric current equal to 60/55w but the light output is that of as if the bulb is a 135/125w??
  
  so it is different from,
  
  80/80w = 165/155w
  
  this would mean it requires a current of 80/80w and have a light output equal to a 165/155w bulb?
  
  from what i understand if i use a 60/55w = 135/125w bulb it will not spoil my circuits as most car circuits can tolerate 60/55w.
  
  but if i use 80/80w bulbs, i would need to change the relays. am i right??
  
  for the einsteins who is going to correct me on the SI units i used for currents... please refrain from doing so. I know current use ampere and watts is unit for power. i'm just lazy to do the calculations.
• hdbanger

  26 Sep 05, 10:40

  Originally posted by Ponders:

  does this mean that this bulb only draw a electric current equal to 60/55w but the light output is that of as if the bulb is a 135/125w??
  
  from what i understand if i use a 60/55w = 135/125w bulb it will not spoil my circuits as most car circuits can tolerate 60/55w.
  
  but if i use 80/80w bulbs, i would need to change the relays. am i right??

  for first para, you're pretty much right.
  
  all vehicles' manuals will specify what wattage their headlights are using. you'd know what type of bulbs you need to buy (eg H4, H3 etc) as well.
  
  if you use a bulb with higher wattage, the bulb socket can melt away with time.
  
  not sure if a relay will solve the problem. but i think it's safer to stay within the specified wattage. the socket stays in a piece, and the bulb functions proper.
  
  hope it helps.
• Ponders

  26 Sep 05, 16:17

  thanks!!!
  
  so i can safely install my PIAAs.