dual alt questions

[95legwagon]

ok so i have a 95 subaru legacy wagon and the alt is rated at 85 amps but was bench tested to run 100 amps faithfully. now if i take the a/c out (which is run by a different belt by itself)

and make brackets to fit in either 1. a 250 amp alt or 2. another stock alt "rated" for 90 amps...... can i put 2 different amp alts on it or do they have to be the same? in other words can i put 2 like this:

1. 85 amp + 90 amps

2. 85 or 90 amp + 250 amp

is there any special way to wire these ( besides circuit breakers and such) would they fight each other and cause the weaker one to fail? or would they make me completely happy and work without a hitch?

anyone? any help appreciated greatly!

thanks

-jarrid

[Colin - STAPUFT]

I have been checking into this myself. I was looking to putting 2 of the same size and build in mine though.

The 3 schools of thought I have come across (assuming you simply parallel the wires from both alts together):

1) Don't do it ever ever, it will burn your car down and cause little children to cry.

2) Do it but run two different "systems" (one battery on one alt, one battery on the other alt)

3) Do it- it will be fine. Buuut-

no matter how alike 2 alts are, if they are both internally regulated, neither will be EXACTLY the same. Given a specific RPM, temperature, and load- one alt may put out charge at 14.0 volts. The other may put out charge at 14.1. This will cause the lower voltage alt to "see" the higher Voltage and therefore not work as hard- putting the majority of the work on the other alt.

The more I think about it, how could this really matter? Who cares if sometimes one is doing most of the work? With one alt it is the only one doing work anyway. If you put put enough of a load on the charging system, it will drop voltage enough to have the second fully kick in. I refuse to believe that 2 is worse than one.

lolz

[95legwagon]

me and you have the same thought about it then lol and i was having the idea of putting my stereo battery on 1 alt and let the car have its own alt so that i have like 100 amps of untouched power to play with..... not much but its better than 100 amps running the car and my amp.... heres another question..... so i want to make brackets to fit my 2nd alt into the space where the a/c compressor is now what size bar steel am i looking for? any suggestions? i was just going to go down to homer d. poe (lol) and buy some that was wide enough to accommodate the bolts i will be using. i just dont want to throw a belt from the brackets flexing at all.....ya know?

thanks

-jarrid-

[just1moreamp]

I use 1/4 plate when i made my dual alt bracket for my explorer. and i have my alts set up one to run the sub amps and the 2 runing the truck and hiend amps.

[95legwagon]

sounds like a nice setup lol i gotta take my a/c out to put in another alt though... there isnt any other room! im gunna have to use bar steel and some nuts and bots n lockwashers. its ran off its own belt and it mounts wierd unlike the stock alt. i have a 95 subaru legacy wagon if you look for engine pics of it youll see the space issue.