dc power supply question

[steveng]

i am providing a dc circuit for 2 set of bar lights(cop cars), they light bars are rated at 20 amps dc 12volts
will one 30 amp dc 12 volt continous power supply handle this load?

each bar light has its own switch, and will be fused at 20 amps.

 

[StreamlineGT]

and then?

edit: nevermind

 

[480sparky]

Depends on what they actually draw, not the rating of the lights. If they draw their rated loads, then you have a 40amp draw on a 30amp supply. You'll end up letting all the smoke out.

 

[StreamlineGT]

I'm sure these are older light bars, not brand new off the shelf? Are they halogen rotators, strobe, LED? Any info will be helpful. Make and model would be best.

 

[steveng]

i will have to check to be sure but, i believe they are the older type ,
thanks for the replies

 

[StreamlineGT]

I would count the rotators, if there are rotators, and figure 55 watts per bulb. This is standard usually, unless a 100 watt, or a 2056 is used, rare though. 20amps sounds about right for a 4 lamp rotator bar, 18amps for the bulbs, 2 amps for the motor.

 

[LarryFine]

i am providing a dc circuit for 2 set of bar lights(cop cars), they light bars are rated at 20 amps dc 12volts

There's a difference between "provide a 20a circuit" and "this device uses 20a", so the answer depends on this.

Otherwise, can you get ahold of a DC ammeter?

 

[steveng]

There's a difference between "provide a 20a circuit" and "this device uses 20a", so the answer depends on this.

Otherwise, can you get ahold of a DC ammeter?

ok, larry, my power supply is a 12volt dc 30 amp continous.

my bar lights are rated @ 20amps 12vdc,

can i put 2 of the bar lights on this power supply?

i will have to get a dc ammeter

 

[LarryFine]

ok, larry, my power supply is a 12volt dc 30 amp continous.

my bar lights are rated @ 20amps 12vdc,

can i put 2 of the bar lights on this power supply?

Obviously, the math says no. The transistor temperature will tell you for sure.

 

[steveng]

thanks for the reply.
i thought so, so i ordered 2 power supplys
thanks

Obviously, the math says no. The transistor temperature will tell you for sure.