Outer Limits 4x4 Board

Hey guys i'd like to add another alternator as i have a spare one sitting around.

i want to connect it in parallel to my original alt i have two batteries that are the same that are also connected in parallel
the need for all this power is for my comp truck running 40amp thermo fans, 8 spot lights, winch, compressor etc so the amps add up

so is it as easy as using the same wires for excitor and bat but run a new cable for the output?

itws pretty much what i did but mine only has 2 wires coming out the back , one for the battery and one for ignition / dash light

I have heard of the two alt and 2 batt systems can give trouble if all the units aren't in exactly equal in output/voltage. ie if one alt is not putting out exactly the same as the other AND they are connected together one can somehow adversly effect the other.

I have no personal knowledge of this but have heard of it happening. Wouldn't it be better to split yr electrical system into 2 distinct seperate parts, so if you have a major failure you are only half down....

Bosch recomend that the two alternators be as similar ( well - identical is best ) as possible when doing this. However its not inherently risky.

The alternator ( well actually the regulator... ) with the lowest cut in voltage will start charging first then if the system voltage continues to drop then the second alternator will starts to assist. In reality its a regulator matching issue.

The reason for the "simialr" recomendation is to get the two cut in points as close as possible to provide good output voltage regulation chatacteristics under load, you don't want the sytem to have to drop its voltage too much to get the other alternator to start working.

There's a BOSCH techinal paper that covers this but it actually says pretty much what I've said.