Electrical: Alternator questionsl

[MPallock]

Gentlemen: I have just purchased a new alternator from Powermaster. It is 150amp unit. It is going in my 54 commander. It is 100amps at idle and 128 at cruise. I am running 2 push fans, electric fuel pump. It is a 1955 259 motor. 2 6 volt Optima batteries in series for starter. Trans is 700r4 with a 12 volt starter. Rest of the car is 6 volt. 2 questions is there someone who makes custom brackets for the alternator and can the wiring handle the current load?. The wiring is all new.
Thank you

Mark

[41 Frank]

It is recommended that you double up on the battery wiring from the alternator with that much alternator capacity. My painless wiring harness had that advice included. I had not done so and my battery wire showed signs of overheating with one electric fan and a 100 amp alternator, after I replaced the original 65 amp unit.

[64V-K7]

If you have a lot of new stuff going onboard, then create a separate, auxiliary, fused buss leaving the original in place. Emphasis on separate, where the only common aspect is they're both grounded to the frame. Feed both circuits from the same alternator BAT post, using a fusible link for the higher power circuit. Make a traceable schematic for your ease of access ( and the next owners)

[Treblig]

I'm running the headlights, heater blower, electric fans, stereo, speaker amps, and a few other items off a dedicated fuse box. The fuse box will be energized with two or three 40 amp relays (ign "on"). The ignition switch will activate the relays (which require less than an amp to energize). Once the amps put power to the new fuse box I can run most of the heavy amp accessories directly from the battery through the new fuse box bypassing all factory wiring. This should take the majority of the load off the original interior wiring.




The only things that will be pulling power through the ignition switch will be the starter circuit, dash lighting, interior lighting, stop/brake lights, gauges, etc.


Treblig

[JoeHall]

Dang. I thought 60-75 amp alternators were overkill to power the EFI, AC, aux heater, cruise control and halogen lights in my Studes. I used to run pusher fans, while living in the desert, too. Back then, 50 amp alternators were in vogue, and considered HD. With the, "more is better" trend in alternators, wonder where it will end. I noticed the 75 amp alternator tended to whine, so went back to a 60 when it wore out. Even with 50 amps, never any problems keeping the electrics powered up.

In order to run that kind of juice, I'd suggest consulting an auto electrician. Likely, the entire car will need to be rewired accordingly. That much juice, without changing the wiring, seems like putting a 427 in a VW bug, without any other mods.

[Mike Van Veghten]

All you have to do is check out the PowerMaster instructions for their recommendations for the alternator wire size... I'd run the alternator power wire straight to the batteries (or the battery post of the starter will also work). Also, as per the wiring requirements, if the batteries are in the trunk, go up one size for the wire. For a long run, and insulate (protect) it well.
Also, expect to hear some belt squealing every now and again with that much alternator and a "V"-belt.

As far as brackets...come-on...you're driving a Studebaker. Unless you just use the factory, later model brackets, home made should be on your list of things to do. I just bought the S.I. alternator bracketry for my 54. Works fine (bolts on under head bolts).

Mike

[garrilla]

I believe you have way too much alternator for your stock wiring. If the alternator ever has to put out the amps it's capable of it will melt your alternator wire and destroy your amp gauge. A 8ga. wire from the alternator isn't even rated for your alternators max output. The electrical load that you have doesn't need an alternator of that capacity.

[Treblig]

I believe you have way too much alternator for your stock wiring. If the alternator ever has to put out the amps it's capable of it will melt your alternator wire and destroy your amp gauge. A 8ga. wire from the alternator isn't even rated for your alternators max output. The electrical load that you have doesn't need an alternator of that capacity.

HEY, Garrilla!! How's it going???

Treblig

[garrilla]

HEY, Garrilla!! How's it going???

Treblig

Hey Gil, pretty good except it's still early March up here!

[RDWEAVER]

Gentlemen: I have just purchased a new alternator from Powermaster. It is 150amp unit. It is going in my 54 commander. It is 100amps at idle and 128 at cruise. I am running 2 push fans, electric fuel pump. It is a 1955 259 motor. 2 6 volt Optima batteries in series for starter. Trans is 700r4 with a 12 volt starter. Rest of the car is 6 volt. 2 questions is there someone who makes custom brackets for the alternator and can the wiring handle the current load?. The wiring is all new.
Thank you

Mark

I think the brackets are out there, I cant remember where I got mine at the moment but I know it was from a Stude vendor. Is the alternator a one wire or three wire unit? One wire units are easy but a poor choice for an automobile with a junction so far away from the charging source. Voltage drop comes into play and it is common to see our headlights operating at 10.5 volts. They are designed to operate at 14. There is a huge difference in the number of lumens in relation to voltage. Same thing happens with our heater/AC fans anything in the system is subject to this with the one wire alternator because it senses voltage at the alternator. The three wire units have a sensing wire that is required to go all of the way back to that junction. Use a fusible link, get rid of the shunt wound amp gauge and use a volt meter and read up on this before wiring. The factory harness is only good enough for the factory items, todays electrical systems are very much different than what was used 50 years ago. If you want to read up on this google MAD ELECTRICAL these people know what there talking about.

[MPallock]

Alternator question

I think the brackets are out there, I cant remember where I got mine at the moment but I know it was from a Stude vendor. Is the alternator a one wire or three wire unit? One wire units are easy but a poor choice for an automobile with a junction so far away from the charging source. Voltage drop comes into play and it is common to see our headlights operating at 10.5 volts. They are designed to operate at 14. There is a huge difference in the number of lumens in relation to voltage. Same thing happens with our heater/AC fans anything in the system is subject to this with the one wire alternator because it senses voltage at the alternator. The three wire units have a sensing wire that is required to go all of the way back to that junction. Use a fusible link, get rid of the shunt wound amp gauge and use a volt meter and read up on this before wiring. The factory harness is only good enough for the factory items, todays electrical systems are very much different than what was used 50 years ago. If you want to read up on this google MAD ELECTRICAL these people know what there talking about.

As I read my post I see I wasn't real clear. When I re did the wiring I split out the 12 volt and 6 volt systems into 2 separate fused blocks. Everything is fused. I am running heavy wire I believe it is #6 from the alternator directly to the battery. Everything seems to work fine and nothing shows signs of overheating yet . But with the power Gen putting out about 55 amps and with everything on including lights it was a struggle to keep the battery at full charge. It is a one wire unit.
At idle I was 14.2 volts with nothing on. With everything on there was about 2.5 voltage drop which meant a heavy current load. And according to the tech at Powermaster I should up the size of the alternator. Which ultimately I will.
My biggest issue was getting a bracket the will accommodate the GM alternator. I now have enough data to do that.
Thank you for all your input.

Mark

[garrilla]

As mentioned previously (http://madelectrical.com/) is the best site for automotive electrical. He explains why your 1 wire set-up is dropping voltage. 1 wire systems not really recommended for cars. There is a lot of reading and you will have a greater understanding of wiring if you get through it. Much better than some of the advice you find here. I spoke to the gentleman for over an hour and came away very impressed. He doesn't push his products, just knowledge. I have purchased his products and find them to be of the highest quality.

[E. Davis]

I have a one wire alternator that has performed flawlessly for thousands of miles. Of course I am not trying to run any modern sound systems, fans, added lights or any other misc. electricity greedy items. These old cars are just that...old cars...if we want all the modern advancements then maybe we should look for a more modern car. I personally like the simplicity of the original systems and drive them for that reason. Just my humble opinion.