Alternator relay - hotwired?

[Spetz]

Hi everyone,

I have a 2001 Mirage that I use for track duties.

It has had an engine swap from a Mitsubishi FTO MIVEC.

Today I noticed that it is missing the alternator relay, instead it has what seems like a home made hotwire kit to provide a "constantly on" status.

1. What does the alternator relay do? Does it turn on/off the charging or something?
2. There are 4 slots there (which I believe is what most relays have?) however only 2 slots have anything behind them. This is where it was hotwired. What controls the relay?
3. What is the issue with having this hotwired and always set to the "on" position?

 

[eljefino]

Is this wired up to the main 100 amp lug or one of the support (field) wires?

Perhaps the relay has its own internal wiring/ logic to cut in/ out at a particular voltage or set of conditions, sort of like a breaker.

 

[Linctex]

Originally Posted by Spetz

There are 4 slots there (which I believe is what most relays have?) however only 2 slots have anything behind them.


It is absolutely, 100% IMPOSSIBLE for any relay to do anything (functionally, other than to make a clicking sound) when only two terminals are present.

 

[andyd]

Thas not a relay son, thassa fuse

 

[bullwinkle]

Would think that's a bad idea-would likely cause overcharging and wasting engine power to drive the alternator full power all the time. What's the voltage when running at 2000 RPM? That'll tell you if it's regulating it some other way.

 

[Spetz]

Hi guys,

So after some researching, what was there was a diode.

And the "alternator relay" on the car is a diode relay.... and from what I gather it is in the normally closed position so basically acts like a diode.

I assume, and please correct me if I am wrong, but the purpose of this is that the alternator can charge the battery, but it cannot discharge it parasitically?

I have a genuine "alternator relay" with me, and it only has 3 posts, however only 2 are actually used (I checked this from the other car that I took it off of), so it's basically just a diode and not a diode relay (or acts like it at least).