So recently I picked up a set of lightforce 140 lances to add to my front bumper in addition the the two 55w hid converted 170s already on there. I wired everything up with the two lights, a relay, and a cheap switch. I wanted to be able to turn the lights on regardless of the truck being on or not so all power is coming directly from the battery.
Here's the issue: whenever I turn the lights on the needle on my gas gauge drops to about the 1/4 tank mark. It doesn't matter if the tank is full, half full, it still drops. I have good grounds on the lights and the relay, and I didn't tap into any existing circuits, only the battery.
This doesn't happen with my other lightforces which are wired the same way. The only difference is the 170s are 55w apiece and the new lights are 75w apiece.
Any ideas on what's going wrong? Is my alternator just on it's last legs and can't keep up with the added draw? I'm pretty lost as far as what the problem could be..