Thread: Second Alternator

it'll work and youd want to be looking at something like a 6 preferabley 9 horse power 12v winch motor

the hardest part will be cooling the motor and the electrics

Originally Posted by Blknight.aus

it'll work and youd want to be looking at something like a 6 preferabley 9 horse power 12v winch motor

the hardest part will be cooling the motor and the electrics

Was hoping you would reply Dave thanks

I might drop round a few Auto Electrical places this week and see what they have lying about

With the belt onto the alternator should I be looking at making the mount so it will be the AC belt that will run it or get a longer fan belt?

Didn't think about cooling, be nice if I could find something with an inbelt fan

When you say electrics do you mean wiring the alternator into the charging circuit?

With the 12V motor I'd be able to just wire it in like a winch wouldn't I?

Thanks mate

it'll wire up pretty much like a winch yes but then you have to worry about alternator excitation, remote excitation (in case the batteries are properly flat and wont do it for you) and if you retain the AC compressors clutch the fact that it wont hold up against much pressure in the delivery system once the battery voltage drops to about 10v.

the setup in fozzy (ask Redback for the VID which reminds me I still have to send steve my DVD's) is pretty much exactly what your after and thats running of a very primative 2 n70s wired in parallel charged by a 35a alternator.

If you were going to go that way unless you were planning on using the motor to drive the AC compressor Id forgo the second alternator and just put in a decent second battery and controller then wire it up winch style (obviously using a pressure switch to control the solenoids.)

Don't forget you'll need separate battery(s) with your second alternator.

Have you thought of making your second system 24 volt? half the currrent draw as 12 volts for the same power, a quarter of the cable power loss or you can use cheaper thinner cable for the same result.

Just a thought.

Deano

Originally Posted by Blknight.aus

it'll work and youd want to be looking at something like a 6 preferabley 9 horse power 12v winch motor

the hardest part will be cooling the motor and the electrics

Hi Dave

Just done a bit of maths here, correct me if I'm wrong but 9HP @ 746Watts = 1HP, say 750 to make it easier in my head makes 6750 watts or 6.75 Kw. From a 12 volt source 6750 divided by 12 or 563 Amps. Thats one hell of a big alternator.

My small shed compressor, which I use mainly for pumping up car tyres has a 2HP motor and works fine. Why such a big one here ?

Deano

over head.

a 6hp motor working against a 2hp load will work easier and run cooler and generally have a nicer life for it compared to having a 2hp motor working flat out.

It will also deal with some minor line loss and lower battery voltages.

I was thinking 9 Horse was a bit much

I am currently runnning 2 Century N70s

So from what I gathering I can't run two alternators in one circuit? I'll have to split the batteries?

As with the clutch on the compressor; I'll have a switch to turn the electric motor on and one to engage the clutch. So if the clutch isn't working for me then I'll weld it up

you can but you wind up with the problem of if the regulators aren't set to exactly the same output voltage then one alternator winds up doing 90+% of the work which kind of defeats the purpose of having 2 alternators in so far as your reason for having 2 alternators goes. Same deal if you have a dicey electrical connection anywhere between any of the batteries and alternators if its all one box'o'tricks.