Alternator Power Wire Upgrade
 

Hi everyone. I am having a minor issue with my charging system. I know this might be a dumb question, but here it goes. At night, when the car is in gear at idle with my LEDs, small electronics (GPS/Radar detector/radio), headlights, 2 sets (factory and aftermarket) of fog lights, and the A/C fan on max, the voltage drops to what it is when the car is off (around 12.5, but no battery light) and the lights dim, but then returns to normal (14) when I start rolling again, shift into P or N or turn off the A/C (It seems the fan uses the most power). This does not happen just when the car is started, but only after driving for a bit and I stop at a traffic light. The battery is brand new and is an Autocraft Gold (JUST replaced because my previous Bosch battery failed and left the truck useless with no power and me stranded at a gas station. I had to push the truck away from the gas pumps and call Advance (a mile away) to deliver a battery to me.). The alternator is only about a year and a half old and has a lifetime warranty (Advance Auto said there was a ripple and recommended replacement soon, which I did). This problem has been going on for a long time (even with the previous battery/alternator) with no other issues other than the reduced voltage. This isn't even that many amps because all of my gear doesn't draw that much. Not nearly as much as a decent audio setup with an amp, speakers and sub. I could even plug the in-car computer in and it wouldn't reduce it further.

I bought a 4 gauge 24" battery cable (labeled "Switch to Starter") from Walmart earlier and I already had a side terminal extension laying around. I was thinking: What if I replace the positive terminal bolt with the extension and connect a thicker cable directly between the alternator terminal and the battery? I checked the bolt sizes and clearances and I think it will fit perfectly if I do it right, the question is would it be beneficial to the charging system since there will be less resistance? I think the engine compartment heat is increasing the resistance of the 8gauge OEM cable and the high load is too much for it. Maybe it might be just enough to reduce the impact on the voltage? I was thinking of the "Big 3" upgrade, but I can't really do the other two. The Alternator to Battery is the most important one, right?

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It most certainly is beneficial. Like you said, there is less resistance so the electrical system will be more efficient. If you are going to upgrade, you said you have some 4 awg. And 4 awg is minimal if you are going to upgrade. Obviously the thicker the wire, the better.

Here is a whole article from the s10 forum about it: Clicky

Let me know how it turns out, I need to do this upgrade soon too.

Edit: Sorry lol, I didn't see the last part of your post as you mentioned the big 3 upgrade, you probably already have visited the s10 forum. My bad.

And why can't you upgrade the other wires too?

I think it will help alittle, but not much. You need to do all 3 to get any decent gain. If you only do one leg the other two will still have the higher resistance and you will still lose power to heat. It's not really worth it to just do one IMO.

I did it and it did help a little. I then let the engine warm up and turn everything on as I did last night and the improvement was surprising. It only went down one notch at idle and I could turn the A/C off and it would go back to 14. I don't know about in gear or actually on the road, but there is improvement. I am posting photos.

All of my cables are 1/0 welding cable, lol. The big 3 upgrade really helps

Great. I took a look at the battery ground and found that it goes to the frame (larger wire) and body (thinner wire) and I am considering upgrading it in the same manner as the alternator wire with a side terminal extension and 4 gauge wire or larger.

Why is the engine block to frame ground important? Why is it part of the big 3? I can't even find it in this crammed engine compartment.

Your ignition and, on some, the fuel injection requires a ground.

Current flows over the surface, not through the wire.

Thinking of it, I need to better ground mine, it gets a little week on the output - because of the recieving end, the ground!

UPDATE: It didn't really help that much. Still about the same and dimming the lights at stoplights. Just under 14 when moving. I found a longer 4 gauge battery cable at Walmart that can be used for the ground wire upgrade. Something to consider. Or maybe just a side post extension and use a separate wire so the original one is untouched in case something goes wrong.

Bigringtravis: 205k? How did you manage that? All original?

The engine ground on most all s-series is on the head to the firewall with a ground strap.

mDE huge difference when i did it too