I have a set of fishing lights that I made a few years ago and was woundering what size generator I will need to run them.

I have 8 hi beam headlights wired in series so I can run them off 110V AC. At 110V/8lights = 13.75 V per light.

I need to know the wattage draw so I can figure out how big a generator I need to run them without burning up the generator or lugging around too much generator.

The only thing that I will be running are the 8 lights.

what amprage are the 12 volt lights?
if we assume they are 15 amp a peice... 15*8=120.. thats alot of amps to be pulling....
you should find the specs for the lights. i have some big round lights i found from walmart that are fairly bright, they pull about 10 amps... 10*8=80

Voltage*amprage=watts so 80*120= 9600 watts....

You should find the specs on the bulbs.

The bulbs are GE H4651. I googled it and came up with a spec sheet that said at 12.8V they pull 50Watts.

I just want to make sure that 50W*8=400W.

Can this be right?

I was looking in the new Offroad Adventures mag and the 1000 watt generators that they highlighted looked good because of the small size.

To determine amps, all I need to do is put a multi meter across the terminals on one light and that should give me the amps on the whole load since they are wired in series?

I can turn a wrench, but this electrical stuff gets me so confused <img src="/forums/images/graemlins/shiner.gif" alt="" />
Thanks for the help

can that be right? V / W = Amps, therefore 12.8 v / 50 watts = 0.26 Amps?

I believe it's the other way round Fred, W/V=A I don't know how many watts the head lights are but, 9600w/110v=87.2 amps. Why not use one multivapor HID light? it would be much more efficient all the way around. <img src="/forums/images/graemlins/cheers.gif" alt="" />

I'm going to take this as my fault. I really shouldn't be postin at night when IÆm tired....
Series means the voltage is multiplied and the amperage the same per load, parallel means the voltage stays the same and amperage multiplied.

SOOO... if you rig lights in series, the required amperage is the same and but the voltage goes up. sooo.... 12.8*8 = 96 volts. W\V=A so each bulb is 4.1666666666666666 amps SO.... 4.1666*120=499.99999999

you can add/multiply powers like 50*8=500.... you just gotta remember to keep your other rules straight....

Running 8 bulbs on 120 will make them run a bit high (15v)... see if you can go out and get another bulb...

Sorry bout the confusion.

this may sound far too easy, but why not use regular floodlights? when run in series you'll be searching for the blown one by replacing each lamp, one at a time, and heaven forbid 2 go at the same time! 8) 100 watt floods run in paralell are gonna run you 800 watts, and that's the generator size you wanted.

That makes more sense! <img src="/forums/images/graemlins/cheers.gif" alt="" />

12V headlights are DC current and will not work on AC nomatter what the voltage you try to push through them. Just get some halogen drop lamps if you're running them off of a generator.

If you did somehow manage to get 120 Volts DC (10 batteries in series, not too economical IMO) the formula is I=V/R I being the amperage, V being the voltage, and R being the total resistance of all the lamps together.

I think you're mistaken, AC or DC the bulb has a Filament (usually tungsten alloy) in a partial vacuum. There are no diodes or rectifiers involved. At the right AC voltage a DC incandescent light will work. <img src="/forums/images/graemlins/cheers.gif" alt="" />