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Battery or Alternator?

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seminoles2005

15+ Year Contributor
138
1
Nov 17, 2003
sfield, Kentucky
Recently installed a one wire self activated alternator which is suppose to be a 200 amp saturn alternator which has just the 4 gauge power wire attached to it and connects to my battery.

When the car idles I'm reading 13.8 volts which seem okay, if i turn my lights or fans on the volts drop to 12.7ish. If i have both on along with my external water pump for my intercooler it sits right at 12 volts. Even while driving down the road it will remain at 12 volts. If i cut all the accesories off it will raise back to 13.3-13.8 range.

I do have a kill switch for my alternator that will cut the connection to my battery in my trunk. When the switch is up to kill the alternators connection to my battery the alternator is putting out 15.3 volts with no connections to the car. When i connect the alternator back to the battery it falls to 13.8.

Will a battery have any affect to a cars idle or the way the volts will sit if its a bad battery? Even if the battery is going out and still has enough power to start the car will it give me any other problems besides trying to start my car later?

The alternator seems to be working but as soon as any load seems to be put on it the alternator just falls on its face. Its suppose to sense any heavy load and react by putting out more power but it doesnt seem to be doing this. The car also has an idle surge that will not go away.
 
bad wires/connections on the battery terminals or on the wiring harness in the engine bay/inside the vehicle?
 
When you turn on different things it causes a load on the alternator like it's suppose to do. Sounds to me that they are causing too much of a load due to incorrect wiring and/or connections.
 
Would a bad connection or wiring cause such a bad drain? Like what exactly is going on to cause it, is it grounding or something because i would think the wires would blow the fuse or cause some wires to burn and i would notice that.

Would a pulley too tightly bolted down to the alternator or a belt too tight cause similar problems of the cars power draining when a load is put on the car?
 
Double check connections to be sure they are tight, then get the battery and alternator tested to be sure those are not the issue. If those are good, then its a wiring issue somewhere along the line.

Does your car have a CEL? I would take it down to get check regardless because some don't show up through CEL's?
 
Using my home charger it keeps throwing a code when i try to charge my battery. It's saying fo3 error which is an open cell or internal cell damage to the battery and wont charge fully. But maybe its just so dead it keeps screwing up the charge but i dropped it off at advance last night and they told me that the battery is fine and just needs a charge so i left it with them to do an overnight charge.

Car has no CEL's either. When i got my alternator from the ebay store i bought from online i noticed that the pulley wheel is really firm. When i spin the wheel it seems to have a lot of resistance and stops almost as soon as i let it go but i can spin my old dsm alternator freely and it will make one or two full rotations when i spin the wheel. Not sure why but i thought it was suppose to spin freely and not have a lot of resistance.
 
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