Converted 2520 wannabe 20amp alternator to a real 45amp

[glc24]

They come standard with a 20 amp

My 2009/2010 2520 comes standard with 40 amp alternator.
I was just wondering why it ever was a 20.

Greg

 

[2305JD]

My 2009/2010 2520 comes standard with 40 amp alternator.
I was just wondering why it ever was a 20.

Greg

Good question. Mine is a 2007 and it had a 20 amp. Half way through 2008 they switched to 40 amp...

Mario

 

[kennyd]

Maybe they felt guilty charging so much for the upgrade?

Yeah right...who knows

 

[Henri88]

My 2009/2010 2520 comes standard with 40 amp alternator.
I was just wondering why it ever was a 20.

Greg

Sorry guys, my mistake. Did not know that the 40 amp was now standard on the 2520. In the 2009 ''purchasing guide'' book, it shows the 2305,2320 and the 2520 with a standard 20 amp alternator. Is it possible that they automatically upgrade yours because you have added some option, such as extra lights. If not, it is a good thing, because there is not much extra option you can add with 20 amp. It is also possible that they did not upgrade there guide book.

 

[8934]

Are you using a car 40 amp alternator?

If so you may want to think twice. The design is slightly different, and they make their power at a higher RPM, so you dont really get 40 real amps since diesels are often used at low RPM.

 

[Henri88]

Are you using a car 40 amp alternator?

If so you may want to think twice. The design is slightly different, and they make their power at a higher RPM, so you dont really get 40 real amps since diesels are often used at low RPM.

I don't think that it would be a problem. It is true that a gas engine have a higher red line rpm, but they operate pretty much at the same rpm, (not talking about the tractor trailers) maybe a little more with gas engine, but not enough to make a difference. I could be wrong, but I don't think alternators have to turn at a high rpm to get their full amperage, compare to the old style generator which would not event charge at idle.

 

[glc24]

I could be wrong, but I don't think alternators have to turn at a high rpm to get their full amperage, compare to the old style generator which would not event charge at idle.

I've been told that also,that alternators aren't like the old generators,where the faster they spun,the more current they put out.

Greg

 

[orlo]

Alternators don't have permanent magnets like true 'generators' or magneto's. They have a field that's energized by energy put into it. (You need to put power into an alternator to get power out). The output is proportional to the field power so the more power put into the field of an alternator, the more power comes out. Typically there is a regulator circuit so that based on the output required the field varies. This is a big advantage of an alternator over a fixed/permanent magnet generator. With permanent magnets the torque required to turn a generator is constant. With an alternator the torque required to turn it is proportional to the field energy.

What this boils down to is that alternators are generally more efficient when not using full power. The voltage is proportional to the speed, the amps depend on the field energy I believe. Generally ANY alternator or generator is spec'ed to make the minimum voltage at the lowest anticipated engine speed.

Also, with any auto type engine the alternator/generator when belt driven doesn't necessarily run at the engine speed. It depends on the ratio of the drive (engine) diameter pulley to the accessory pulley. i.e. If my drive pully is 4" and my alternator pully is 4" the alternator will spin at the same RPM as the engine. If the drive pully is 4" and the alternator pully is 6" the alternator will turn at 2/3rds (66%) of the engine RPM. This point being regardless of the minimum operating RPM of the alternator/generator you can always match it to the engine by varying the pully. the exception would be if at max engine RPM you exceed the max safe RPM of the alternator in which case you'd risk mechanically damaging the alternator...

For a direct drive alternator like motorcycles the above isn't true.

 

[2305JD]

Are you using a car 40 amp alternator?

If so you may want to think twice. The design is slightly different, and they make their power at a higher RPM, so you dont really get 40 real amps since diesels are often used at low RPM.

No, I gave them the Nippondenso number off the new 2520 40 amp alternators and they found an alternator from a Toyota forklift and Kubota tractor that was the same.

I have been using it for a few weeks now with front and rear worklights, radio, heater, defrost fan, windshield wiper and have had no issues.

So far so good.

Thanks,

Mario

 

[jimdiesel1]

I came across this alternator, can you tell me which of the 2 terminals is the excitation terminal of the 2 which accept spade connectors?