You can bet the lightbar will not actually be 700 watts, typically they will run anywhere between 50% and 70% of their claimed wattage. In lab conditions they may get the full 100%, but this is rarely true in the real world. My 400 watt bar (40x10watt crees) only drew 269watts when I tested it. Still ridiculously bright though.
PeeBee (2nd February 2017)
How is the LED bar actually 'current limited? Is it by some controller board or by the supply fuse size/ I was going to have a dig around and see if I could understand this and the light output rating point. There is a similar issue with solar panels in that they are all lab rated at 1000w/m2 density yet there isn't a place on the earth with this light density and max in Australia from memory is 650w/m2 in a small couple of pockets. I think the solar panel ratings could be for satellite ratings in space?Originally Posted by Turtle_au
Did you establish this output from current draw?
I found a pretty good article on the www.wranglertiforum.com site. Quote below. Light output governed by current, controlled by led controller, so output is independent of voltage as long as its within the operating range of the lightbar.
"Do not get the idea that if you apply more voltage that the LEDs should give off more light. The amount of light an LED gives off is determined by current, not voltage. The current at each LED is maintained within a narrow range by a device known as an LED Driver."
It sounds like you are taking a punt with this product. Even at 70% of the max wattage claimed, you would still need 40 + amps. If you have already ordered or got the unit, I suggest you hook it to which ever voltage you will run, and check the current draw. A friendly auto elec might test it for you.
Last edited by mudnut; 2nd February 2017 at 02:10 PM.
My advice is: not to follow my advice.
Typically the LED drivers will be in the main lightbar behind each LED. My single row lightbars on my old Pajero use a separate digital LED controller. I am guessing this is to save space in the single row bars ? Pretty sure the box just supplies constant voltage. I measured the current draw via a Victron BMV-702 battery monitor with a Negative shunt on the Aux battery. I connected these bars up to the Aux for testing purposes quite a while ago.
Funny you mention 40amps as that's what the supplied fuse is. I have taken on board what stevec has sad also, so will see what the sparkies have on site and do a check at 13V.
thanks guys, appreciate the input.
I borrowed a high quality clamp meter with DC function and checked the current draw at 12V DC . 9.0 amps, which equates to 108W in my world. I have fired off a message to the ebay seller requesting either an exchange unit or clarification on what is going on - will advise. Luckily i have not mounted it yet - looks reasonable quality though.
Sort of reminds me of audio systems ratings - peak music power, max power or rms power.
100x7w leds (700w) if driven to their limit.
Output limited to avoid overheating when mounted so closely together in a sealed enclosure.
If they did run at full rating, the amount of heat generated would melt any plastic nearby...ie grille
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Still you can ignore all the readings, install the unit and actually see how effective the light is. You may be surprised at how well it works. And running below rating helps reliability.
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