Wattage question

[Collectors]

Hi, just picked up some reversing lights that were advertised like this, 12v x 48W LED Work Light Bar Flood Spot Lights. I am assuming 48/12 = 4 amps. Yet when i put it via the ma on my volt meter in series its reading 322ma ???. Any idea's what i am missing.

 

[AndyPRK]

Use the 10A socket and 10A knob on your meter

 

[Collectors]

Use the 10A socket and 10A knob on your meter

Yep! the same 0.321a

 

[AndyPRK]

maybe its the equivilant light output of a 48W

 

[fixitflav]

maybe its the equivilant light output of a 48W

That was my thought, but you'd think they would say it, for marketing reasons if nothing else.

 

[Collectors]

maybe its the equivilant light output of a 48W

I think your right. I just went outside with a small 12v lipo battery & its not to bad. & the Chinese do exaggerate things.

 

[EFLImpudence]

maybe its the equivilant light output of a 48W

 

[ericmark]

Says 16 x 3030SMD LED chips, and they are rated up to 1 watt each, so max should be 16 watt not 48 watt. In the days of tungsten, the max power for a reversing light was 36 watt, I would assume now in lumen, equivalent to 48 watt is around 4 watt mark so around the 340 mA, so does seem equivalent to tungsten watts, which is just as well as a 48 watt reversing lamp would be far too bright.

I seem to remember reversing lights have to have a BS EN number to be used, but left motor trade in the 80's, so not up to date, but LED lights are only permitted if original equipment so unlikely permitted. Seems now "The total wattage of any one reversing lamp shall not exceed 24 watts" "not bearing an approval mark." but it's been a long time since I worked on motor vehicles.

 

[Collectors]

Says 16 x 3030SMD LED chips, and they are rated up to 1 watt each, so max should be 16 watt not 48 watt. In the days of tungsten, the max power for a reversing light was 36 watt, I would assume now in lumen, equivalent to 48 watt is around 4 watt mark so around the 340 mA, so does seem equivalent to tungsten watts, which is just as well as a 48 watt reversing lamp would be far too bright.

I seem to remember reversing lights have to have a BS EN number to be used, but left motor trade in the 80's, so not up to date, but LED lights are only permitted if original equipment so unlikely permitted. Seems now "The total wattage of any one reversing lamp shall not exceed 24 watts" "not bearing an approval mark." but it's been a long time since I worked on motor vehicles.

Thanks for that. There seems like there was a lot changes, with reversing lights being one. Here's a daft one. cars before 1990 may have or not reversing lights fitted & wont fail an mot if not working. But cars later than 1990 would fail. I think we also have to remember that cars are made for the whole world with lots of regs in all country's.

 

[ericmark]

I think the Scammell Scarab was one of the best inventions to allow motorised transport to replace the horse, it could get the trailer into the same space as the horse could put a trailer, however it had no brakes on the front wheel, only 2/3 rds of the wheels were braked, so unless it has never been scrapped, i.e. has the original registration, it can not travel on British public roads, so two identical vehicles, both built at the same time, but one was sent for scrap and log book surrendered, but never actually scrapped, but can't run on British roads, but the other was never scrapped, and log book never surrendered so it can run on British roads.

The law does not need to make sense.

 

[fixitflav]

I think the Scammell Scarab was one of the best inventions to allow motorised transport to replace the horse, it could get the trailer into the same space as the horse could put a trailer, however it had no brakes on the front wheel, only 2/3 rds of the wheels were braked, so unless it has never been scrapped, i.e. has the original registration, it can not travel on British public roads, so two identical vehicles, both built at the same time, but one was sent for scrap and log book surrendered, but never actually scrapped, but can't run on British roads, but the other was never scrapped, and log book never surrendered so it can run on British roads.

View attachment 365357 The law does not need to make sense.

Not really a problem in practice, I can't remember the last time I saw one of them. Didn't British Railways (as it was at the time) run a fleet of them?

 

[Collectors]

Not really a problem in practice, I can't remember the last time I saw one of them. Didn't British Railways (as it was at the time) run a fleet of them?

BR had them in all the main stations in London running up & down the platforms with flat bed trailers unloading goods that were normally in the last few carriages.