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Auxiliary Lights


LawnSite Platinum Member
I'd like to add some auxiliary lights to my utility vehicle. Currently it has (2) 37.5 watt headlights. The alternator is rated at 13 amps and has a 32-amp hour,295cca battery. How many watts can I safely add to the system?

Eric ELM

Husband, Father, Friend, Angel
Chicago, IL USA
In AC, a 120 Watt bulb pulls 1 amp. To figure this you divide Volts by Watts to get Amps, so if DC is the same, 12 Volts times 13 Amps should be 156 Watts. I run 6 big hallogen lights on my JD 430 in the winter with a blinking light, 3 head lights and two tail lights and have never had a problem. I don't remember what the Watts of the Lights are or the Amps of the Alternator, but I will try to look it up for you.


LawnSite Bronze Member
Watts = Amps x Volts in both AC & DC.

The reason why the WHOLE world isn't DC is because you can't change the voltage like AC.

Anyway, Eric's math is correct, you can safely have 150 or so watts without a problem. You do have SOME reserve with the battery, but you don't want to have extended periods of battery discharge.