Measuring amps/watts.

[Eric2.0]

I have a multimeter.

What is the best way to determine the amp draw/wattage of a light bar such as a Federal Vista?

I'm guessing measuring the current as the light is on.

 

[Jarred J.]

Ohm’s Law - Science4Fun

Ohm’s law is the fundamental law in the field of electricity. It was discovered by George Ohm, and named after him. Ohm’s law provides the relationship between current, voltage, and resistance. It states that, the voltage across any resistance is equal to current times the resistance. V = I*R...

science4fun.info

 

[shues]

Your multimeter is probably only capable of a maximum of 10 amps DC, and is probably fused at 11 amps. You could measure the amp draw of each component individually, if you're careful, and add them up. If you want an exact number for the entire bar at once, look for a clamp style ammeter that's capable of 100 amps DC or better.

 

[Eric2.0]

Ohm’s Law - Science4Fun

Ohm’s law is the fundamental law in the field of electricity. It was discovered by George Ohm, and named after him. Ohm’s law provides the relationship between current, voltage, and resistance. It states that, the voltage across any resistance is equal to current times the resistance. V = I*R...

science4fun.info

Your multimeter is probably only capable of a maximum of 10 amps DC, and is probably fused at 11 amps. You could measure the amp draw of each component individually, if you're careful, and add them up. If you want an exact number for the entire bar at once, look for a clamp style ammeter that's capable of 100 amps DC or better.

Good information, thanks.

 

[Jennifer Rose Towing]

Keep in mind the amp draw will be different between 12 and 14volts. If you are using a power supply, many are not designed to be run at peak amps for very long. IIRC in general 80% capacity is a good rule.

 

[Eric2.0]

Keep in mind the amp draw will be different between 12 and 14volts. If you are using a power supply, many are not designed to be run at peak amps for very long. IIRC in general 80% capacity is a good rule.

No power supply. I guess I'm coming off the battery, to my control head and then to the light bar, using a breaker for the main leads. I think that is the way to do it. If there is a better way I'm all ears.
My setup will be a Federal JetStrobe or Vista with some grill flashers and rear tailight strobes in the reverse lights. I'm setting my truck up for pushing race cars at our race track this summer....if we ever get to race due to the pandemic situation

 

[jmamrak]

I use an inductive DC amp clamp. Make sure if you use one that it’s DC compatible. Not all are. Mine is from amazon and converts amps to milivolts. @shues is correct. I use mine for many things including proper fusing, calling bad starters, and many more.