The Alternator Bible!
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TECH Junkie
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Joined: Jul 2005
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From: Port Neches, TX
The Alternator Bible! As found on another great forum (Pirate 4x4): Alternator Bible
The above link is started at voltage sensing, as it seems that's what most people are asking about. There's good info if you scroll above and below too.
The above link is started at voltage sensing, as it seems that's what most people are asking about. There's good info if you scroll above and below too.
Most of those pirate 4x4 articles are pretty good. I like how he flat says to never hook the alternator straight to the battery.
That guy has issues with wire size though. 10 gauge wire for voltage sensing? Oh, and nuclear power doesn't come from our sun so he got that part wrong.
I like the explanations of remote sensing, battery charging as well as overall wiring tips in the site below. doesn't bounce around as much the 4x4 article but then doesn't have as much info about specific connectors.
http://www.madelectrical.com/electri...hreewire.shtml
That guy has issues with wire size though. 10 gauge wire for voltage sensing? Oh, and nuclear power doesn't come from our sun so he got that part wrong.
I like the explanations of remote sensing, battery charging as well as overall wiring tips in the site below. doesn't bounce around as much the 4x4 article but then doesn't have as much info about specific connectors.
http://www.madelectrical.com/electri...hreewire.shtml
It's ALL about wire size....in that vein, how can you NOT hook the battery straight to the alternator? They are ALWAYS connected directly.....through wire.....
Now if they could just explain how to get an alternator light to work properly when that circuit isn't used to excite the alternator (as on most LS swaps), they'd really have something!
Now if they could just explain how to get an alternator light to work properly when that circuit isn't used to excite the alternator (as on most LS swaps), they'd really have something!
http://www.madelectrical.com/electri...evymain1.shtml
As I said before - it's ALL about wire size. And the battery is directly connected to the alternator - always. By the way - opinions, even amongst the "experts", vary regarding the small charging wire counsel that some espouse. If you have a large, higher compression engine that gets started/stopped a lot (short in town trips) - you may come to wish you had installed a larger charging wire. It's simply not a one-size-fits-all.
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Verdad Gallardo I read the offerings of both the mad site and the pirate4x4 site when I was setting up mine. And I opened them back up when they were linked in this thread to be sure it was the same stuff. Everything I'm posting is consistent with their tech articles -- makes me wonder if you comprehended what you read? 
Ah - selective comprehension, as I expected. I enjoy the car tremendously.
We're all here (I hope) to learn and help someone else. Just because you read it at someone else's site doesn't mean it's the end-all. And the sites are clear -- they directly connect the battery to the alternator (it's all wired together). They simply suggest that a smaller gauge wire for connecting the battery can help prevent over-charging under certain circumstances. But neither site addresses the variety of different operating conditions that people encounter with their vehicles, and their are situations where a smaller charging wire is helpful, as well as situations where a larger charging wire is helpful. It's not a one-size fits all -- and I believe both sites generally point people in that direction.
We're all here (I hope) to learn and help someone else. Just because you read it at someone else's site doesn't mean it's the end-all. And the sites are clear -- they directly connect the battery to the alternator (it's all wired together). They simply suggest that a smaller gauge wire for connecting the battery can help prevent over-charging under certain circumstances. But neither site addresses the variety of different operating conditions that people encounter with their vehicles, and their are situations where a smaller charging wire is helpful, as well as situations where a larger charging wire is helpful. It's not a one-size fits all -- and I believe both sites generally point people in that direction.
I know this is an year old thread but I would like to have clarification. I have a P L I S alternator with just two wires hooked up. The L is a red wire and the I is a brown wire. I called the harness provider about voltage drop when I turn the fan and A/C on. I asked about the "S" terminal and he said not to hook it up because it would burn up the alternator. Now I have conflicting info. Should I hook up the "S" terminal or not?
My understanding is that the "S" terminal gets hooked to 12V+ somewhere on your system where you want to "S"ense the voltage -- the regulator will use that signal to alter output so that it maintains the voltage set point at the location you're sensing the voltage.
Thanks guys, always hate to have two authorities (harness provider and Alternator Bible) have conflicting into. I'll see if I can insert a wire into the "S" terminal of the alternator plug and run it inside to my main power terminal lug that I use to distribute power rather than have a bunch of wires coming off the solenoid. After I get that done I'll do some road test and report back on my findings. Might help others that can't decide.
Well, the wire has been in for several weeks and only about 150 miles but nothing has burned up...yet! I notice a little higher reading on the voltmeter when fans and A/C are on. I've taken the sensor wire off the terminal that supplies battery power to the fuse box. Any changes and Ill repost.