Alternator install vs key switch

[Mark Maulden]

I'm installing a balmar series 7 80a alternator with a requisite external regulator. The field current can be as much as ~9 amps. I'm going to have to pick reg power right from key switch as no other wiring is big enough to handle the current. The regulator is from Mark Grasser and this is an older volvo panel. Question is do these key start switches handle 9a in the "on" position? And when full fielded, there might be problems with other instrumentation due to volt drop.....I might have to install a relay.......

 

[Ken Cross]

9 amps on the field seems like it should work off a key switch. It may depend on what other loads are going through that same switch. Usually the starter solenoid and any instruments (fuel gauge, Tachometer, water and oil temp???) The field current should only be that high on max charge conditions.

Some switches have current ratings marked on them, or a part number so you can look it up. I always try to error on the conservative side.
Ken

 

[Prime Time]

Double check to see if the alternator is self exciting.

 

[Maine Sail]

I'm installing a balmar series 7 80a alternator with a requisite external regulator. The field current can be as much as ~9 amps. I'm going to have to pick reg power right from key switch as no other wiring is big enough to handle the current. The regulator is from Mark Grasser and this is an older volvo panel. Question is do these key start switches handle 9a in the "on" position? And when full fielded, there might be problems with other instrumentation due to volt drop.....I might have to install a relay.......

Regulator B+/red should go to battery or alt B+ and regulator turn on (yellow for Grasser reg) should go to ignition....

Both v-sense wires (neg and pos) MUST go direct to the battery terminals....

 

[Mark Maulden]

Understand that. Question is will the key switch handle 9a in the "on" position? When the alt is full field. That's where I hooked it up so well see. Do key switches typically this much current? The engineer in me is asking.....

 

[Maine Sail]

Understand that. Question is will the key switch handle 9a in the "on" position? When the alt is full field. That's where I hooked it up so well see. Do key switches typically this much current? The engineer in me is asking.....

Mark,

The yellow wire is switched not the red. Red should go to alt B+, battery, pos bus etc.. The yellow to ignition switch... Most ignition switches I know of are rated for 10A and they are already powering gauges and a fuel pump etc..

 

[Mark Maulden]

Maine,
You are correct as field is connected to white. But, Grasser's instruction sheet states yellow needs to be able to handle field current. Hence my reason for asking about key switch. As of now, it works!!

 

[Maine Sail]

Maine,
You are correct as field is connected to white. But, Grasser's instruction sheet states yellow needs to be able to handle field current. Hence my reason for asking about key switch. As of now, it works!!

Sorry Mark my info was flawed! I have two old regs in stock with different colored wires.. Yes the yellow on your Grasser carries field current. I would not expect you will see more than 7A on a 7 series... Balmar does this a tad differently in that the ignition wire carries no real current...