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Old 01-07-2019, 06:39 PM   #2
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Join Date: Jan 2002
Location: Liberty, & Garden City S.C. , U.S.
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Thumbs up Re: Dimming lights, altenator or battery?

Originally Posted by tino0217 View Post
I have a 71 c10 with a 350, i noticed when i bought it that the lights would get brighter when i accelerated. I replaced the altenator (70 amp) but still does it. I started using a 760 watt Schumacher power converter and i have it running thru the lighter to plug in some 110's. I installed a stereo system, 250 watt Kenwood with 500 watt speakers, nothing fancy. I took my home theater subwoofer which has a 110 plug in. After a couple of minutes of sitting idoling the coverter statts beeping saying low battery. I installed a 100 amp altenator last week and the lights are still dim til i accelerate and the converter goes about 5 to 10 minutes before it indicates low battery. I also have a battery kill switch. With all that said, it my battery? Battery is 700 cold cranking with 95 reserved capacity. Anyone have advice?
100 amp alternator pulling these kind of watts=
250 watts = 20.833333333amps
760 converter=63.333333333

I'd say your maxing out the alternator & battery pretty quickly.

Charge the battery up good and crank the truck up Have some one turn everything on and take a voltmeter and check the voltage of the battery with all of it running. Do this at idle and have them rev the motor and see what voltage you get anything less than 12.5 is not going to work.
1971 LWB Custom, 6.0LS & 4L80E, GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver
Seeing the USA in a 71

Upstate SC GM Truck Club
2013,14 and 2016 Hot Rod Pour Tour

Get out and drive the truck this summer and have some fun!
It sucks not being able to hear!

LWB trucks rule, if you don't think so measure your SWB!
After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.
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