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Lights Dimming

741 views 6 replies 6 participants last post by  badboycaraudio 
#1 ·
Well, in the past month or so I have been having some problems with a weak charge and the battery draining over the period of about a week. I went through it all and found some really poor wiring from the alternator to the batt. Once replaced the battery was showing about 14 volts across the terminal and it seems that everything is fine and fixed. However, when I'm at idle it doesn't seem like its charging properly. My headlights are dimmer at idle than if I rev the motor? I'm not sure if this is normal for YJ's or not. I know that I have the stock size alternator, but I thought it would be able to keep up with such a small load.


Thanks
 
#2 ·
My jeeps lights would only dim if I run something like my winch that draws a lot of power. Maybe your alternator isnt that great. I was thinking about getting a high performance alternator which would make it much easier on the jeep. You have an Optima right?? It was leaking?
 
#3 ·
My heep has been doing that for a while now, it is worse when its cold... but I first noticed one night after starting it up after a few seconds of running i rev'd the engine and noticed my lights get brighter.... I didnt really think anything of it as the lights are not dimming really low. Ive thought about looking into it but its never gotten worse my battery has yet to die even after sitting 2+ weeks..... sooo I figure, meh.... I'll worry about it when I need to
 
#5 ·
the optima isn't in it right now because of the problems I was having. I though it might have been a problem with the battery itself, but that turned out not to be true. I think the alternator in it right now is only a 70a so I think it is likely the weak link. I'm going to replace it with the 136a CS-144 when it dies.
 
#6 ·
The stock alternator doesn't put out a whole lot of amperage at low RPM. Some newer ones are designed to give full output across a broader RPM range. Also, the headlight load is increased by the resistance on the undersized factory wiring. Besides upgrading the alternator, it would help to run heavier gauge wire from the battery thru a fuse to some relays mounted up behind the headlights - use the original wiring to switch the primarys on the relays. I know I have seen a write up on this here..........
 
#7 ·
body grounds are also an issue ,the stock ones are pretty anemic ,if you should choose to redo the "big three" here's what you should do :

using 4 gauge wire go from the battery to the alternator,from the battery ground go to the firewall ,and last but not least from the engine to the same body ground point or battery ground.

with that you should see an increase in charging potential
please note that the more you pull from the positive post ( i,e amps,alarms,winches ,lighting ,etc,you should also add the same size from the battery ground to the body.

I have spent 11 years in car audio ,and this was one of the key lessons.
 
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