Alternator current

[ramdough]

I am confused...... and I did search.... but did not find what I was looking for.

With the 100A, 200A, and 400A alternators...... what voltage does the alternator deliver the rated amperage?

For example, do you get 100A on the 24v or 12v output or both or 50/50?

I am just trying to understand this. Are there actually three different alternator options to pick from or am I confused there as well?

Thanks


Sent from my iPhone using Tapatalk

 

[DiverDarrell]

Think it's 50/50.

 

[ramdough]

Would that mean that the 200A one is 100/100?

I have heard of a 400A one. Is that a rare one? I have heard more about a 200A kit and I have heard of a 200/400A kit, but I know nothing about it.


Sent from my iPhone using Tapatalk

 

[coachgeo]

past comments in here has said body of 400 amp is said to be too long to fit. If recall right it runs into the Turbo Housing. As to AMPs split or not.... good question.... curious on this myself.

 

[Suprman]

The 100a rating is at 28/14 volts and is split between the two voltages. Niehoff does not specify a percentage split with these alternators as they do with some others. In theory it should be able to put out a bit more current under normal conditions though. The rating given is under the worst operating conditions. First gen trucks had a 200a upgrade option. The manuals do not show any other intended options. A1 trucks can have a 260/140a alt. You would probably have to do some bracketing modification but it should physically fit. Harder to find part though.

 

[coachgeo]

ahhhhhhhh... so in reality we only have available potentially 50amps on each leg of 12 and 24 volts. Good to know

 

[Suprman]

Not exactly

 

[gimpyrobb]

As seen in this thread, they do not just put out one amperage.

http://www.steelsoldiers.com/showth...asurements-of-Stock-60A-Alternator&highlight=

 

[coachgeo]

As seen in this thread, they do not just put out one amperage.

http://www.steelsoldiers.com/showth...asurements-of-Stock-60A-Alternator&highlight=

Thanks, This fits comment earlier of alternator amperage is rated when under a set standard of "adverse conditions"

Not exactly

So if one had an alternator in use under same conditions in which it's labeled rating was done at...... do you think its output is meant to weigh one leg more heavily than the other? If so which one? The 12 or 24? (example: 70amp 24v potential / 30amp 12v potential) or do you think it automatically weighs the side that has the most need? Thus it could be that example or the opposite if the demand calls for it.

 

[Suprman]

50 amps at 28 volts is 1400 watts where as 50 amps at 14 volts is only 700 watts. I dont know exactly how the alternator outputs are taken. It is under rated to begin with as pretty much anything military electrical is. You would have to set up a dual load test of sort to get an actual max output rating and vary the two loads across the two voltages and see what happens. For most truck owners this alternator puts out plenty of power. Unless you are running a special application like high power radio gear you wont need more.

 

[ramdough]

The 100a rating is at 28/14 volts and is split between the two voltages. Niehoff does not specify a percentage split with these alternators as they do with some others. In theory it should be able to put out a bit more current under normal conditions though. The rating given is under the worst operating conditions. First gen trucks had a 200a upgrade option. The manuals do not show any other intended options. A1 trucks can have a 260/140a alt. You would probably have to do some bracketing modification but it should physically fit. Harder to find part though.

So, are you saying the A1 trucks can fit a 400A alternator with only bracket mods?


Sent from my iPhone using Tapatalk

 

[Suprman]

You would have to find the correct alternator and bracketing that works for it. And a v belt pulley since the a1s are serpentine. And upgrade some power wiring with the higher current capacity. I did the 200a kit on my truck because I had the kit. The 100a would have been fine for me. Early on I had some charging issues until I figured out that the excite wiring is a common issue. If I knew then what I know now I would have stuck with the 100a. A few lights here and there don't pull that much power and I have 4 newer agm batteries that can easily absorb a quick high current draw.

 

[scottmandu]

Due to turbo placement the alternator can't be too long, and you can't move it further away from the engine as the cab/shock tower gets in the way. If you want more amps, go with the 200 amp upgrade or look at installing a secondary alternator somewhere, or a diesel powered 28vdc generator.

 

[coachgeo]

50 amps at 28 volts is 1400 watts where as 50 amps at 14 volts is only 700 watts. I dont know exactly how the alternator outputs are taken. It is under rated to begin with as pretty much anything military electrical is. You would have to set up a dual load test of sort to get an actual max output rating and vary the two loads across the two voltages and see what happens. For most truck owners this alternator puts out plenty of power. Unless you are running a special application like high power radio gear you wont need more.

Those considering a Cab 12v or 24v AC system will be in a "Special Application" environment. For them would be nice to know if it is a necessity to upgrade Alternator to 200amp model or if under non-adverse conditions the existing one will do them fine.

 

[Suprman]

I think you can get away with the 100a with a 24v AC system as long as you have good batts. Adding more stuff on top of the AC will require a larger alt.

 

[coachgeo]

I think you can get away with the 100a with a 24v AC system as long as you have good batts. Adding more stuff on top of the AC will require a larger alt.

As knowledgeable as you are in things electrical I trust your judgment on that. Just for Shiatz and Grins posted in the other thread linked in here to see if he is willing to link up with a MI based LMTV and run a test as you advised.


Was wondering also if it would be better to "just" for AC use, have ALT send power to a separate 24v power bank or even better a "Capacitors Bank" since it is not really long term storage of power needed in that bank since it's intended use is to be for a "traveling" AC system only. Granted that must be set to happen only once main Batteries bank is fully charged; which should not take long into the journey when that battery bank is good. Do you think at night with lights are on..... Esp. if one has switched to LED's already, combined with the temps being lower and one is not needing as much AC..... then you should still be good?

 

[scottmandu]

It's sketchy at best, many of those 24V A/C systems draw 80-90 amps, leaving 10-20 amps for ancillaries, and that's assuming your alternator/regulator is operating at peak performance. Does anyone know the amperage draw for the various systems? The fuel bowl heater and dehydrator heater are pretty amperage hungry.

 

[coachgeo]

...The fuel bowl heater and dehydrator heater are pretty amperage hungry.

is the Fuel bowl heater ambient temperature controlled? As in does it always come on or only when Ambient temperatures show it must come on to keep fuel from Gelling?

 

[coachgeo]

It's sketchy at best, many of those 24V A/C systems draw 80-90 amps, leaving 10-20 amps for ancillaries, and that's assuming your alternator/regulator is operating at peak performance. .....

Scott I think what Superman is saying that since in reality the alternator probably puts out a good bit more than the 100amp rating; thus it should be fine; except in adverse conditions. That is what the other linked thread seemed to point out as well. Hopefully, 74M35A2, who ran the previous test can shed more light with new testing on an LMTV if he is willing.