Alternator replacement

[PTK]

I currently have the ALY-8420 60 amp alternator. When the time comes I'd like to go up in amps if possible. Plane power has the AL24-P70 which is 70 amp.  

Is this a drop in replacement without any other changes to the electrical system?  and are there any other options that go higher in amps? 90 or 100 amps?

 

[Guest]

System wire size is the general limiting factor.  

Clarence

[capthaak]

I concur. You can't run 100 amps through wire sized for 60. 70 might be okay, but 90-100 will cost you a lot more than the alternator alone.

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[larryb]

Why do you want to upgrade current? Modern radios and lighting take less.

[PTK]

On 4/3/2016 at 2:03 PM, larryb said:

Why do you want to upgrade current? Modern radios and lighting take less.

No particular reason really. Other than when the time comes to replace alternator why not go up in amps if i can. Not rewiring for it though!

[N201MKTurbo]

The only time the full power of the alternator is used is recharging the battery after starting the plane. Mine usually settles back to zero after 5 min. or so.

With everything running, the current draw of the plane is nowhere near 60 Amps.

I could make a good case for putting in a smaller alternator to save weight.

[PTK]

That's interesting. How much smaller and how much weight are we talking?

[cliffy]

As mentioned, the electrical system downstream from the alternator will have to be checked and/or reworked to allow the added current rating (wiring, CB, etc)

Also the question was asked- Why? Only real reason is added electronics that draw more current from the system. 

One should really do an electrical load analysis to see what the continuous amp draw of all the electrical components is (when running at the same time) and compare that to the output of the generator. 80% of the generator capacity for continuous draw is the "rule of thumb" . More than that and the electrical system needs to be upgraded. 

It really isn't as simple as a drop in replacement (in a certified airplane). It may be just a plain, unnecessary expense.  . 

[ArtVandelay]

My J has a 100 Amp alternator, probably put in when the dual wing mounted taxi,landing lights were added.