View Full Version : Adding a relay to my tower lights
08-30-2010, 07:07 PM
Hey guys, my tower lights (roswell 4 lights) will only stay on for about 3-4 minutes then kick out.. i'm sure it's because the guy just wired them in without a relay and the switch can't handle it... my question is what should i get for a relay... i know less than zip about electrical stuff other than to not stick a butter knife in the plug in!!!!! lol:p
08-30-2010, 08:28 PM
Get an automotive foglight relay and look up the schematic on the internet. You can use the existing switch to control the relay unless the switch is failing.
08-30-2010, 11:13 PM
Fortunately the Roswell lights are not that bright and do not pull as much current as some other lights (Zire for example). But DC lights wiring is potentially dangerous and pulls serious constant current as compared to stereos and other accessories. Here are the guidelines we go by. A 14 gauge 2-conductor tower harness is limited to three 5-amp lamps. Four lamps is stretching it. A 30-amp relay is rated for intermittent use so we only run at one-third of the relay's rating considering its continuous DC usage. At 5-amps per lamp, that's two lights per a 30-amp relay and three lights per a 40-amp relay. Four lamps is stretching it. We never run the relay supply to the helm buss. Instead we wire a fused 8-gauge power and ground directly to the battery. We always solder and heatshrink the connections since crimped connections generate resistance and heat. Here is the acid test. Bypass the tower and run your wire and connections externally. If the wire only gets mildly warm you are okay. If the wire and especially the connections get hot then you are taking an unacceptable risk. Its not uncommon for an undersized DC light circuit to get hot enough that you can't keep your hand on it. And people often have this condition on the inside of their tower without realizing it.
08-31-2010, 02:03 PM
thanks for the information David....I'll hook them up externally and check it out and go from there...
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