Added 12v alternator, what size relay to use?

[Smokinyoda]

I just added a 12v alternator to power my bed crane, lights, backup camera, etc and am in the process of wiring it all up. It is a 60 amp 1 wire alternator and I want to wire in a 24v relay to turn it off and on with the trucks master switch. Since its a 60 amp alternator I need a continuous duty 60 amp relay correct? Reason I ask is all the pictures Ive seen of other peoples setups most use the little black plastic bosch or hella type relays, and I cant find one in 24v that goes up to 60a. Only thing I have found in 60 amps is the big metal solenoid that looks like the ones used on older Fords, and for CUCV glow plugs.

So what do you electrical gurus out there recommend?

 

[dmetalmiki]

Texas industrial electric co have loads of things in the line of duty you are looking for. Have a chat with them.

 

[Smokinyoda]

Texas industrial electric co have loads of things in the line of duty you are looking for. Have a chat with them.

Thanks, but after looking at there website I think I may go a different route. They have a Cole Hersee 24144 24v 200 amp continuous solenoid that I could use between the grounds of both the 12v and 24v batteries (there grounded to same place on the frame). Wired to a key switch in the dash this will kill both systems, safety and security all in one!
[h=1][/h]

 

[M37M35]

My understanding of alternators is that if the load (battery) is disconnected while the engine is running (alt is turning), it causes a sudden voltage spike which can kill the alt and anything still hooked to it. I wouldn't put any kind of disconnect between the alt and battery.

Putting a switch or solenoid between the batteries and ground is fine as long as it is only switched with the engine off.

 

[59apache]

FMHO ...200AMP continious load is way to small for the 24V system...the starter will fry it.

 

[jpg]

This is my understanding also. The alternator voltage regulation circuitry depends on the fact that there is a battery on the other end of the wire. Without that battery, the voltage regulation circuitry will behave poorly, perhaps destroying itself and other things in the process.

My understanding of alternators is that if the load (battery) is disconnected while the engine is running (alt is turning), it causes a sudden voltage spike which can kill the alt and anything still hooked to it. I wouldn't put any kind of disconnect between the alt and battery.

Putting a switch or solenoid between the batteries and ground is fine as long as it is only switched with the engine off.

 

[jpg]

FMHO ...200AMP continious load is way to small for the 24V system...the starter will fry it.

It depends on where he puts it in the circuitry. If he puts it between the starter and the battery, it will certainly fail. I was assuming he would not put it there, but I'm not sure where he does intend to put it.

If he hopes to power things from an alternator without a battery, that will end badly.

I suggest the OP look at the Plan B Mod CUCV owners use. A 2-battery 24V bank is charged with a 24V alternator. A separate 12V alternator charges the 12V battery in that bank that that is grounded to the frame. 12V power for the vehicle comes from the + post on that battery, and from the alternator feeding it. This setup works great on my truck. I have a 200-amp 24V alternator and a 160-amp 12V alternator -- plenty of power for nearly any application.

 

[Jeepsinker]

If you use a 60 amp 24v relay, it should handle 30 amps 12v. Find a bigger relay. Or dont bother at all. If it is a true one wire alternator it should not need to be switched off on shutdown.

 

[jpg]

If it is a true one wire alternator it should not need to be switched off on shutdown.

Right. The biggest question here is why? What is the OP trying to accomplish? If we're guessing correctly, and he just wants ample 12V power, a variation of the Plan B mod is the ticket. Just add a 1-wire 12V alternator feeding the 12V battery that is connected to chassis ground, pull your 12V power from that battery, and have a beer. No solenoids required.

 

[VPed]

Right. The biggest question here is why? What is the OP trying to accomplish? If we're guessing correctly, and he just wants ample 12V power, a variation of the Plan B mod is the ticket. Just add a 1-wire 12V alternator feeding the 12V battery that is connected to chassis ground, pull your 12V power from that battery, and have a beer. No solenoids required.

Yep, that's the way I went. (except for the single beer part)

 

[welldigger]

He needs to put the relay into his fuse bank. Not in between the alternater and battery.

 

[59apache]

something like this ?
http://www.steelsoldiers.com/showth...ternator-12V&p=1327860&viewfull=1#post1327860

http://www.steelsoldiers.com/showth...ternator-12V&p=1327862&viewfull=1#post1327862

http://www.steelsoldiers.com/showth...ternator-12V&p=1392835&viewfull=1#post1392835