Big 3 and AD244 Alternator Upgrade
12-28-2015, 11:45 AM
#61
Thread revival.
I have a question for those in the know....
The OE charge wire coming off the alternator on all my GM vehicles is a small(er) fusible link wire. Same thing on my 96 Mustang...its actually 2 fusible links for redundancy. The GM alternators are 145a and the Stang 130a. Why are we putting oversized wires when the factory doesn't seem to feel its needed?
I have a question for those in the know....
The OE charge wire coming off the alternator on all my GM vehicles is a small(er) fusible link wire. Same thing on my 96 Mustang...its actually 2 fusible links for redundancy. The GM alternators are 145a and the Stang 130a. Why are we putting oversized wires when the factory doesn't seem to feel its needed?
The short answer is that running heavier-gauge wiring reduces voltage drop. In DC systems, power equals voltage times current (P=VI) and voltage equals current times resistance (V=IR). The more power your equipment dissipates, the more current it demands, and the greater the voltage drop between the source and the load becomes. This is a simplistic answer (EEs will know what I'm saying), because the lower voltage actually affects the current demand in negative ways.
Anyway, most people run into undervoltage problems after they add or replace audio or fuel system equipment since the OEM wiring was already marginal for the OEM system. Because of this, any additional current demand times the (relatively) high OEM wiring resistance usually results in low voltage (per spec) at the load.
Although people knock GM for their quality, they're masters at understanding how customers use their cars and where they can reduce design margin. The result (when GM gets it right) is a product that meets customer expectations at minimum cost or maximum profit. It just makes it harder on modders because we slam into those design limitations all the time.
Last edited by FuzzyLog1c; 12-28-2015 at 11:58 AM.
12-28-2015, 02:57 PM
#62
I wouldn't have resurrected this thread to discuss voltage drop, but now that the deed is done...
The short answer is that running heavier-gauge wiring reduces voltage drop. In DC systems, power equals voltage times current (P=VI) and voltage equals current times resistance (V=IR). The more power your equipment dissipates, the more current it demands, and the greater the voltage drop between the source and the load becomes. This is a simplistic answer (EEs will know what I'm saying), because the lower voltage actually affects the current demand in negative ways.
Anyway, most people run into undervoltage problems after they add or replace audio or fuel system equipment since the OEM wiring was already marginal for the OEM system. Because of this, any additional current demand times the (relatively) high OEM wiring resistance usually results in low voltage (per spec) at the load.
Although people knock GM for their quality, they're masters at understanding how customers use their cars and where they can reduce design margin. The result (when GM gets it right) is a product that meets customer expectations at minimum cost or maximum profit. It just makes it harder on modders because we slam into those design limitations all the time.
The short answer is that running heavier-gauge wiring reduces voltage drop. In DC systems, power equals voltage times current (P=VI) and voltage equals current times resistance (V=IR). The more power your equipment dissipates, the more current it demands, and the greater the voltage drop between the source and the load becomes. This is a simplistic answer (EEs will know what I'm saying), because the lower voltage actually affects the current demand in negative ways.
Anyway, most people run into undervoltage problems after they add or replace audio or fuel system equipment since the OEM wiring was already marginal for the OEM system. Because of this, any additional current demand times the (relatively) high OEM wiring resistance usually results in low voltage (per spec) at the load.
Although people knock GM for their quality, they're masters at understanding how customers use their cars and where they can reduce design margin. The result (when GM gets it right) is a product that meets customer expectations at minimum cost or maximum profit. It just makes it harder on modders because we slam into those design limitations all the time.
PS - great thread. Just upgraded my alternator to the ad244 from the ad230 (similar to the cs130d) for my LS/Mustang swap. I was running out of amps at WOT with the ad230 and now the ad244 is in place and solved the issue. But....I'm using the Mustang's charge wire which again, is 2 fusible links -probably 12g. I added another charge wire after doing all this reading. I guess I can install a real heavy charge wire and see if the WOT voltage changes via the data logger.
12-28-2015, 05:17 PM
#63
First 12 gauge is rated for 41 amps in a chassis wiring application. So that gets us much further along than your 20A estimate. Now think about wire length and duty cycle. How long is the 12 gauge run? Not long if 12 gauge so the voltage drop is minimal. Now consider how long is that 145A alt actually putting out 145A? Not long in most applications. Now if you are running a lot of electrical extras then yes the current draw is higher for longer periods of time. For most us the the big three is a waste. For bass heads or guys using light bars for hunting or running winches it starts to make sense very fast.
I have been into car audio for a while. One time after driving down the interstate for about an hour listening to the stereo very loudly I pulled over and smelled something burning. The charge wire from the alt to the battery was on fire. Not fun. Since then if I put in a new stereo I replace the charge wire.
I have been into car audio for a while. One time after driving down the interstate for about an hour listening to the stereo very loudly I pulled over and smelled something burning. The charge wire from the alt to the battery was on fire. Not fun. Since then if I put in a new stereo I replace the charge wire.
12-28-2015, 07:28 PM
#64
First 12 gauge is rated for 41 amps in a chassis wiring application. So that gets us much further along than your 20A estimate. Now think about wire length and duty cycle. How long is the 12 gauge run? Not long if 12 gauge so the voltage drop is minimal. Now consider how long is that 145A alt actually putting out 145A? Not long in most applications. Now if you are running a lot of electrical extras then yes the current draw is higher for longer periods of time. For most us the the big three is a waste. For bass heads or guys using light bars for hunting or running winches it starts to make sense very fast.
I have been into car audio for a while. One time after driving down the interstate for about an hour listening to the stereo very loudly I pulled over and smelled something burning. The charge wire from the alt to the battery was on fire. Not fun. Since then if I put in a new stereo I replace the charge wire.
I have been into car audio for a while. One time after driving down the interstate for about an hour listening to the stereo very loudly I pulled over and smelled something burning. The charge wire from the alt to the battery was on fire. Not fun. Since then if I put in a new stereo I replace the charge wire.
12-29-2015, 08:16 AM
#65
First 12 gauge is rated for 41 amps in a chassis wiring application. So that gets us much further along than your 20A estimate. Now think about wire length and duty cycle. How long is the 12 gauge run? Not long if 12 gauge so the voltage drop is minimal. Now consider how long is that 145A alt actually putting out 145A? Not long in most applications. Now if you are running a lot of electrical extras then yes the current draw is higher for longer periods of time. For most us the the big three is a waste. For bass heads or guys using light bars for hunting or running winches it starts to make sense very fast.
I have been into car audio for a while. One time after driving down the interstate for about an hour listening to the stereo very loudly I pulled over and smelled something burning. The charge wire from the alt to the battery was on fire. Not fun. Since then if I put in a new stereo I replace the charge wire.
I have been into car audio for a while. One time after driving down the interstate for about an hour listening to the stereo very loudly I pulled over and smelled something burning. The charge wire from the alt to the battery was on fire. Not fun. Since then if I put in a new stereo I replace the charge wire.
Good info - thanks! Actually, that ~12g charge wire is probably only about 8" and its in the open air which probably gets you a little more rating still. In my case like the OP, I have a forced induction car. Only major items are a single OE cooling fan, meth inj system, duel fuel pumps (23a rating). I do think the low impedance injectors and ignition coils draw significant amperage at wot also. But, max wot time would be maybe a quarter mile so you talking 10-11 secs max really.
What brought me to this thread was my AD230 105 amp alt not keeping up at
WOT. Found it hard to believe I was pulling more than that at WOT considering no stereos, technology package etc. This old crusty 145a alternator seems to have cured the issue. Perhaps the fusible links also have a higher current rating for their size?
12-29-2015, 10:31 AM
#67
Typically over 6000 engine rpm it would go from 14v right to battery voltage and come back to 14 V when I let off the throttle. I thought at first I was overspeeding the alternator, I put a bigger pulley on And it didn't help anything.
The AD244 so far with the fusible links has kept voltage to 14v to 6600+ rpms, so I'm happy about that.
The DR44 alt is the newer AD244 but has a 2 pin connector. Some of them are rated at 160 amps, and you can get a late model used low-mile take off for 50-75.00 shipped to your home. Just need to install a 4 pin connector and your in business. I probably take this route when this 120k mile unit konks out.
The AD244 so far with the fusible links has kept voltage to 14v to 6600+ rpms, so I'm happy about that.
The DR44 alt is the newer AD244 but has a 2 pin connector. Some of them are rated at 160 amps, and you can get a late model used low-mile take off for 50-75.00 shipped to your home. Just need to install a 4 pin connector and your in business. I probably take this route when this 120k mile unit konks out.
12-29-2015, 12:35 PM
#69
Just to close the loop on this thread, I would not recommend an AD244 in the CTS-V. It doesn't fit without bracket mods. I eventually replaced it with a 240A Mechman S-series alternator, paired with their AVBM II adjustable voltage regulator. Expensive ($580), but you can see where the money went. I don't have a signal analyzer at home to show you the advantages on my car, but the benefit of 12-pulse vs. 6-pulse rectification is well-documented.
Last edited by FuzzyLog1c; 12-29-2015 at 12:50 PM.
05-31-2020, 09:28 AM
#75
I also added 2 sets of grounds 000 gauge. Try it out and I bet your voltage issues go away, or reduce significantly.
-Byron
