Wiring/control for dual alternator setup in patrol

I want to add a 200a alternator to my engine specifically for boost charge when winching. The existing alternator is 120a. Is there a recommended way to set this up? Is it possible to isolate the alternator when its not in use - either electrically or perhaps with a 12v clutch? The setup is for a chev 6.5 conversion and I am sourcing (trying) brackets for the alternator now. The winch battery is a 1300cca 200a/hr carcas size battery, so it can take the charge rate.

Why even bother isolating it?
If the Battery is charged the Alternator load is next to zero so won't affect fuel economy or engine torque.

OK, good point.

Mechanical: Remove the belt, put it on only when you need it,
Electrical: Alternator will unload when the battery is charged or open the field winding, some losses in belt & bearings.
Graham

Is this for a competition truck? It's a lot of mucking around for a "normal" 4WD. One 200 amp alternator would be more than enough for most purposes.

The alternator won't "load" without initial input voltage to the exciter windings.
It won't drain the battery if it's not running due to the polarity of the rectifier diodes.
Simply run a circuit from the ignition power, through a switch (call it ALT 2, or something), through a warning light globe IN SERIES to the the alternator exciter terminal.

When you turn on the Alt2 switch, the 2nd alternator will power up and put current into the battery, if it isn't charging the warning globe will light up. If you turn off the Alt2 switch it just sits quietly until needed.
Bear in mind you can also use a 200amp alternator for stick welding.

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Originally Posted by Arfa Brayne

The alternator won't "load" without initial input voltage to the exciter windings.
It won't drain the battery if it's not running due to the polarity of the rectifier diodes.
Simply run a circuit from the ignition power, through a switch (call it ALT 2, or something), through a warning light globe IN SERIES to the the alternator exciter terminal.

When you turn on the Alt2 switch, the 2nd alternator will power up and put current into the battery, if it isn't charging the warning globe will light up. If you turn off the Alt2 switch it just sits quietly until needed.
Bear in mind you can also use a 200amp alternator for stick welding.

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Arfa, thanks for the response, and yes I think this is the way I will go. The other suggestions have filled in the picture also, so thank you. The vehicle is not a competition rig, its a toy and i have too much time on my hands and looking to provide a solution that specifically meets my needs. My patrol is fitted with a 15000lb hydraulic winch on the front and warn 15000 electric on the rear. The original pump drive for the hydraulic was a belt drive and the belt was slipped on and off when required - took a couple of minutes, Since then, and with an engine swap I have now gotten the hyd pump driven off a PTO on the gearbox.

The rear winch was used recently and the 100a alternator didn't have a chance to keep up with the load, so with a 100amp alternator and integrated vac pump, I decided to use a 200amp alternator I had kicking around to top up the supply. I will let you know how it works out after the vehicle returns from WA. I am trying to source a dual alternator bracket in advance but think its going to be safer to just wait until I know exactly what I have to work with. Phil.

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Originally Posted by Arfa Brayne

Bear in mind you can also use a 200amp alternator for stick welding.

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Have you done that mate?
I'm pretty excited about this possibility, 'cos i tend to carry extra cranking battery or two for this purpose.
Can you please post bit more information about it?
Thanx

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Originally Posted by dom14

Have you done that mate?
I'm pretty excited about this possibility, 'cos i tend to carry extra cranking battery or two for this purpose.
Can you please post bit more information about it?
Thanx

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200 a is rediculous..
Most welding is done at 50-90 with 2.5 rods.

But apart from that..
If the winch is struggling is it supply sorce or the cable size?

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Originally Posted by bigguwesty

200 a is rediculous..
Most welding is done at 50-90 with 2.5 rods.

But apart from that..
If the winch is struggling is it supply sorce or the cable size?

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Cable size is fine, 70mm2 from memory and good connections. Its a simple case of 100amp supply to battery and 400amp drain by winch, so the battery volts drop and - you know the rest. Matching the in - to - out better is my aim.

Interesting regards the welding as I do have a 200a Uniwelder alternator here and have found it next to hopeless for welding, even on 1.6mm rods. It was sent back to Uniwelder in WA for assessment and they said its fine, however it burnt out the windings soon after, was repaired by an auto elc and has sat on the shelf ever since. i think it might have been operator error, but can't be sure as they are pretty straight forward to set up and other people swear by them. Anyway I moved to a 24V mig welder from the US for welding and that works fine.

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Originally Posted by PBBIZ2

Cable size is fine, 70mm2 from memory and good connections. Its a simple case of 100amp supply to battery and 400amp drain by winch, so the battery volts drop and - you know the rest. Matching the in - to - out better is my aim.

Interesting regards the welding as I do have a 200a Uniwelder alternator here and have found it next to hopeless for welding, even on 1.6mm rods. It was sent back to Uniwelder in WA for assessment and they said its fine, however it burnt out the windings soon after, was repaired by an auto elc and has sat on the shelf ever since. i think it might have been operator error, but can't be sure as they are pretty straight forward to set up and other people swear by them. Anyway I moved to a 24V mig welder from the US for welding and that works fine.

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Yea right. Definitely something wrong with it.
But yea 2.5 rods only need 70A for a good weld..
3.2 are around 100A.
We use cigweld 175 welders and I can run 4mm rods in it.. maxed but it welds nice

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Originally Posted by bigguwesty

200 a is rediculous..
Most welding is done at 50-90 with 2.5 rods.

But apart from that..
If the winch is struggling is it supply sorce or the cable size?

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Need a bit more than 12V at those amps, you reckon?
Just wondering, when we use batteries to weld in an emergency situation, we are basically
short circuiting them to the point of damaging the batteries, aren't we?
How do we avoid doing the same thing to a second alternator that is used for stick welding?

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Originally Posted by dom14

Need a bit more than 12V at those amps, you reckon?
Just wondering, when we use batteries to weld in an emergency situation, we are basically
short circuiting them to the point of damaging the batteries, aren't we?
How do we avoid doing the same thing to a second alternator that is used for stick welding?

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Tbh not sure of the voltage. I'll have a look at the specs.
But yea thats all welding is.
Don't do long welds and your batteries will survive.. only like 30-40mm at a time and let the batteries cool a bit..

I have tried the direct connection to battery welder method and found I needed at least 24V to maintain the arc, and 25v gave a bit too much spatter, however if you were really after deep peno welds in a single pass it would be good. i only tried with 2.5mm rods. I have heard this is really not a long term or sustainable proposition as the shorting does eventually damage the batteries, however i am guessing for an emerg repair it would have little impact.

The Uniwelder Alternator i have and didn't have much luke with looks like a standard 80A Hitachi Frame alternator, however it has 3 big plates of diodes on the back of it and requires a cooling horn to funnel the air over the windings and diodes. When it was tested by the autoelec it would barely generate a spark with the rods, at any speed, so i am still guessing as to what the problem was, even after it was rewound. The literature and experiences of others attest to them being really good devices and they have a 240V output as well.

The mig welder also seems to operate better on 24v as well. It can run on flux core of gas wire.

Typo, 36V not 25V

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Originally Posted by PBBIZ2

I have tried the direct connection to battery welder method and found I needed at least 24V to maintain the arc, and 25v gave a bit too much spatter, however if you were really after deep peno welds in a single pass it would be good. i only tried with 2.5mm rods. I have heard this is really not a long term or sustainable proposition as the shorting does eventually damage the batteries, however i am guessing for an emerg repair it would have little impact.

The Uniwelder Alternator i have and didn't have much luke with looks like a standard 80A Hitachi Frame alternator, however it has 3 big plates of diodes on the back of it and requires a cooling horn to funnel the air over the windings and diodes. When it was tested by the autoelec it would barely generate a spark with the rods, at any speed, so i am still guessing as to what the problem was, even after it was rewound. The literature and experiences of others attest to them being really good devices and they have a 240V output as well.

The mig welder also seems to operate better on 24v as well. It can run on flux core of gas wire.

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Can you post a picture of your 24V gas/gasless mig welder, please mate?

If I understood correctly, you still have that high amp(200A?) Uniwelder brand alternator, but it can't be used for welding. In other words it doesn't either generate enough voltage or amps to generate a spark?!

Thanx

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Originally Posted by bigguwesty

Tbh not sure of the voltage. I'll have a look at the specs.
But yea thats all welding is.
Don't do long welds and your batteries will survive.. only like 30-40mm at a time and let the batteries cool a bit..

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Yeah, I tend to use secondhand crankers that are still in good condition. I keep a couple of those el cheapos to use in an emergency situation. With the matching welding rod, you can do an acceptable quality weld in an emergency.

I will start by saying my welding skills are pretty much nonexistent, I blame this on a career in electronics where sparks are bad & are to avoided.
I remember reading about using the 2x batteries & seem to recall that the electrode lead was best if quite long & was coiled to give it some inductance. The added resistance & the inductance limits the current & helps maintain the arc.
Also how to remember which way around for the leads, the 2x houses of parliament
SENate: Standard Electrode Negative
REPresentative: Reverse, Electrode Positive.
Graham

Just a quick note with using a switch to isolate the exciter circuit, depending on the wiring inside the alternator and nearly 70% of alternators once you give it some rpm they can excite them selves leaving the switch you put in useless.

Check out Readywelder.com. I am yet to read how to post photos - bit lazy.

The Uniwelder I have is now just the 200a alternator. the control box went to heaven a long time ago and I was unable to get the support for repairs out of the guys in WA - we are talking circa 1998 . The alternator itself was used /installed as a 200a supply 100% duty factor unit to support the electric winch. In all the time I had it it was never used for winching, so cannot attest to its ability to generate 200a or not. When it did die and was put in for repairs with the autoelec he cast all sorts of doubts about its capacity, showing me a 200a truck alternator and that was a big unit - this is the size of a typical hitachi but about 3" longer due to the diode packs.I seem to recall it was also slow off the mark voltage wise, meaning it had to be spinning at 2000rpm engine speed to get to 13V, below that barely a pulse out of it. The alternator was designed to run at 11,000 - 13000rpm for welding, which it never did either when I had it as I burnt out a couple of vee belts trying to get it to that speed - very small pulley on the alternator and not much driving circumference. The alternator is in the garage somewhere - having a clean up now and might come across it - if i do, and if I can work out the photo attachment process i will put a couple of shots up of it.

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Originally Posted by PBBIZ2

Check out Readywelder.com. I am yet to read how to post photos - bit lazy.

The Uniwelder I have is now just the 200a alternator. the control box went to heaven a long time ago and I was unable to get the support for repairs out of the guys in WA - we are talking circa 1998 . The alternator itself was used /installed as a 200a supply 100% duty factor unit to support the electric winch. In all the time I had it it was never used for winching, so cannot attest to its ability to generate 200a or not. When it did die and was put in for repairs with the autoelec he cast all sorts of doubts about its capacity, showing me a 200a truck alternator and that was a big unit - this is the size of a typical hitachi but about 3" longer due to the diode packs.I seem to recall it was also slow off the mark voltage wise, meaning it had to be spinning at 2000rpm engine speed to get to 13V, below that barely a pulse out of it. The alternator was designed to run at 11,000 - 13000rpm for welding, which it never did either when I had it as I burnt out a couple of vee belts trying to get it to that speed - very small pulley on the alternator and not much driving circumference. The alternator is in the garage somewhere - having a clean up now and might come across it - if i do, and if I can work out the photo attachment process i will put a couple of shots up of it.

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If you can do it the way most guys do it these days with a smart phone and post it using the forum app, that would be enough.
Cheers. :)

P.S.
How did you manage to get the rpm anywhere near 10000??!!
Even with a smaller pulley it would be a tough call I reckon, with the fourbies we drive these days.
I'm guessing you were using a different vehicle?

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Originally Posted by johno90

Just a quick note with using a switch to isolate the exciter circuit, depending on the wiring inside the alternator and nearly 70% of alternators once you give it some rpm they can excite them selves leaving the switch you put in useless.

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The replacement alternator(the amp upgrade) from a EF Falcon and modified for the RB30, couldn't self excite, if I recall correctly.
I guess I can test it again by disconnecting the exciter wire?!!

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Originally Posted by dom14

If you can do it the way most guys do it these days with a smart phone and post it using the forum app, that would be enough.
Cheers. :)

P.S.
How did you manage to get the rpm anywhere near 10000??!!
Even with a smaller pulley it would be a tough call I reckon, with the fourbies we drive these days.
I'm guessing you were using a different vehicle?

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Pulley on alternator is approx 2" pcd - really small. I had it on a Mercedes Benz 300d GWagen with the 5 cyl diesel engine. I dont recall what I achieved but enough to totally smoke the belts and stink out the house as well - got into trouble for that one.

I will wait for some help regards the app you mention - I not really into the phone stuff.

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Originally Posted by GeeYou8

I will start by saying my welding skills are pretty much nonexistent, I blame this on a career in electronics where sparks are bad & are to avoided.

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Career in electronics is "cooler" than welding though. :) You don't need to deal with "heat management" like the welding profession demands. :D

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I remember reading about using the 2x batteries & seem to recall that the electrode lead was best if quite long & was coiled to give it some inductance. The added resistance & the inductance limits the current & helps maintain the arc.

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Yeah, though i would have some trouble finding welding electrodes like that. Instead, I can use a long spiralled jumper lead that connects to the welding electrode. :). I guess, I might had been doing it unwittingly when I tried welding with batteries. :)

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Also how to remember which way around for the leads, the 2x houses of parliament
SENate: Standard Electrode Negative
REPresentative: Reverse, Electrode Positive.
Graham

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Thanx for the mnemonic mate. Now, I know how to remember. :)

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Originally Posted by PBBIZ2

Pulley on alternator is approx 2" pcd - really small. I had it on a Mercedes Benz 300d GWagen with the 5 cyl diesel engine. I dont recall what I achieved but enough to totally smoke the belts and stink out the house as well - got into trouble for that one.

I will wait for some help regards the app you mention - I not really into the phone stuff.

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cool, thanx.

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Originally Posted by dom14

Have you done that mate?
I'm pretty excited about this possibility, 'cos i tend to carry extra cranking battery or two for this purpose.
Can you please post bit more information about it?
Thanx

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This is a very old trick, going back to the early 1970's. There have been a raft of "welding alternators' and even prior to that I believe there were generator units set up for welding. I have personally used 3x different ones, but they were all 24v.
The amperage needs to be higher than a proper welder to help hold the arc, and they spatter a bit more too.
General consensus is not to weld for longer than 20 seconds in every 2 minutes to allow for cooling.
One was a 240 amp unit on an old 4 tonne International truck in the NT (almost as good as a proper welder)
One, on a Case tractor in VIC, and the 3rd was a bush welder cobbled together from 2x 24v alternators and a Briggs 12hp engine

The dedicated alternators have terminals on the back for welding leads and are massive bloody things. The bloke with the Inter would isolate the battery when welding to get a stable current and protect the batteries.

I keep 1.5mm rod in the toolbox (it's a bit hard to get, but not uncommon) which seems to work ok with 12v x 80a, but is much better with 2x batteries in series as 24v. Just use jumper leads for welding leads. Soot/smut up some sunnies with candle smut for welding glasses, or carry a welding mask glass in the toolbox.

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Originally Posted by Arfa Brayne

This is a very old trick, going back to the early 1970's. There have been a raft of "welding alternators' and even prior to that I believe there were generator units set up for welding. I have personally used 3x different ones, but they were all 24v.
The amperage needs to be higher than a proper welder to help hold the arc, and they spatter a bit more too.
General consensus is not to weld for longer than 20 seconds in every 2 minutes to allow for cooling.
One was a 240 amp unit on an old 4 tonne International truck in the NT (almost as good as a proper welder)
One, on a Case tractor in VIC, and the 3rd was a bush welder cobbled together from 2x 24v alternators and a Briggs 12hp engine

The dedicated alternators have terminals on the back for welding leads and are massive bloody things. The bloke with the Inter would isolate the battery when welding to get a stable current and protect the batteries.

I keep 1.5mm rod in the toolbox (it's a bit hard to get, but not uncommon) which seems to work ok with 12v x 80a, but is much better with 2x batteries in series as 24v. Just use jumper leads for welding leads. Soot/smut up some sunnies with candle smut for welding glasses, or carry a welding mask glass in the toolbox.

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Thanx mate.
I have a couple of welding goggles, both auto darkening. One, I bought off fleabay, the other I made using a fleabay bought AD lens glued onto a pair of safety goggles(and can fit onto a full head mask for overhead welding). The both are el cheapo solar powered ones.

Where do you get 1.5mm rods? I've never seen them before. I would love to get hold of them.
Fleabay has a listing of them.
http://www.ebay.com.au/itm/1-6mm-Sti...kAAOSwNRdX2dlX


Thanx

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Originally Posted by dom14

Can you post a picture of your 24V gas/gasless mig welder, please mate?

If I understood correctly, you still have that high amp(200A?) Uniwelder brand alternator, but it can't be used for welding. In other words it doesn't either generate enough voltage or amps to generate a spark?!

Thanx

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Photo of 24v gassless mig and also 200a uniwelder alternator and comparison to my other 200a alternator
Attachment 69114Attachment 69115Attachment 69116Attachment 69117Attachment 69118

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Originally Posted by PBBIZ2

Photo of 24v gassless mig and also 200a uniwelder alternator and comparison to my other 200a alternator
Attachment 69114Attachment 69115Attachment 69116Attachment 69117Attachment 69118

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Thanx mate.

The 200A alternator is a massive unit, by the looks of it.

Cheers

The Bosch/Lucas unit with the external rectifyer plate - the stator winding section looks like it is only about 18mm.
A 200amp alternator should be about 30mm thick, the one you have looks around a 40amp unit. Dunno if someone has pulled a swifty on you.
The rotor windings are fairly interchangeable up to a point and don't effect output much, but the size of the stator is where the power comes from.

Sorry, just looking for a photo online of what I'm trying to explain and all the Bosch alternators are either different casings or the stator is a similar width to yours - either I'm wrong or Bosch have changed the method of getting more amps. COmes from being a dinosaur mechanic.

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Originally Posted by Arfa Brayne

The Bosch/Lucas unit with the external rectifyer plate - the stator winding section looks like it is only about 18mm.
A 200amp alternator should be about 30mm thick, the one you have looks around a 40amp unit. Dunno if someone has pulled a swifty on you.
The rotor windings are fairly interchangeable up to a point and don't effect output much, but the size of the stator is where the power comes from.

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Rafa you are no doubt correct as I could never get it to perform yet the manufacturer swore black and blue it did what it claimed. Anyway it's probably going in the bin as its no use to me now.

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Originally Posted by PBBIZ2

Rafa you are no doubt correct as I could never get it to perform yet the manufacturer swore black and blue it did what it claimed. Anyway it's probably going in the bin as its no use to me now.

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Sorry Arfa but spell check scrambled the damn letters again

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Originally Posted by PBBIZ2

Rafa you are no doubt correct as I could never get it to perform yet the manufacturer swore black and blue it did what it claimed. Anyway it's probably going in the bin as its no use to me now.

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If you do decide to chuck it in the bin, do PM me mate. I'm happy to "help" you by taking it away from you. :D