lighting electrical problem

Hey I'm new to this forum so I'm saying what's up! I have a 98 tacoma 4x4 5 speed reg cab. My electrical problem is that when I first got my truck I tried to put 4 off road lights on the front bumper. Well once I got them all hooked up and working I noticed that when I turn them on my fuel gauge drops to empty and when I turn the lights off it comes back up to full again. I'm guessing that I just don't have enough power and the fuel gauge is the first thing that gives up guessing that I just don't have enough power and the fuel gauge is the first thing that gives up power so the system can power the engine. So I thought adding another battery would solve the problem. This weekend I got another battery , put them together and I still have the same problem. So I was wondering if anyone has had this problem and if anyone has some advice it would be greatly appricated. problem. This weekend I got another battery , put them together and I still have the same problem. So I was wondering if anyone has had this problem and if anyone has some advice it problem. So I was wondering if anyone has had this problem and if anyone has some advice it would be greatly appricated.

P.s. I have the 2.7L

 

The lights are hooked directly to the battery through a relay right?

 

No just to the battery directly through the switch

 

You should wire the switch to a relay, then to the battery directly there should also be a fuseable link in there somewhere.

 

Sorry about the post I'm doing everything through my phone and it got all jacked up

 

So it should go from the lights to the switch to a replay to a fuse to the battery right? Also what kind of replay? What size? What size fuse?