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Discussion Starter · #1 ·
What's up fellow jeepers. I recently installed a headlight wiring harness with relays running 100w/90w platinum white h4 bulbs and also installed some h3 xenon 55w bulbs into my fog lights:zap:

All this new wonderful stuff I put on is great, but it also causes a little problem. When I have both the headlights and fogs running with my heat on high, my volts will drop when I'm at an idle to the point I have to stay on the gas to keep her going. While running down the road its says she runs at 12v but only in this tri fecta of headlights,fogs and heater running together does this problem happen. I've got a few ideas but I like to see what you guys think first before I try to resolve this problem.
 

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I have kinda the same problem with my daylighters an even when they aren't on the stereo will drop my power to the point where my lights flicker when my sub hits an I have the same problem with my heater goin
 

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Alternator is not large enough to keep up, you may also need another larger capacity battery.
 

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I was lookin into dual batteries I just put a new 90amp napa alternator an it still doesn't crank out the power it needs
I was thinking you would need 100, but then it depends on how you use your system.

90 could be enough, just keep in mind that you would need to shut things down for a while; say when you are driving home from the trail, with your lights off so the battery can charge back up.
 

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Dont they make a 140 for jeeps? Green monster or some such?

2nd battery would fix ya up, as the alternator is carrying the load driving. The only time the 2nd battery would be pulled from (for lack of a more complex explination) would be at idle. While driving you should be able to recharge it. To confirm take a voltage reading with the engine revved to 1500 or so with all electronics on. You should read higher than nominal battery voltage. If not, you will need to power down to allow recharging, as camarozz said.
 

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Discussion Starter · #8 ·
Thanks for all the help guys. Its great having a place you can go and get advice. It looks like its time to start saving some money up:rofl: I looked at some bigger alternators yesterday and in comes the "Just Empty Every Pocket" theme. Looks like its going to be between 350 to 450 for my application. Nice and cheap, just the way I like it.:rolleyes: once again thanks guys.
 

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So when I check the voltage drain should I check it off the alternator or the battery ? An should I turn every light on I have along with the heater?
 

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Check your voltage at the battery. It's directly connected to the alternator anyway. Thru two 50A fuses if it's like my 94 YJ. There are many things that can cause voltage drop. Check all connections first. Clean with wire brush, sandpaper, or something similar. Tighten all connections. Measure with various amounts of load. Most likely, bigger battery, conductors, and high output alternator are what you need. Recommend starting with the cheapest item. Also, high amp lighting should be connected directly to the battery thru a relay so the power to the lights doesn't go thru the switch.
 
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