Gary Lewis Posted February 4, 2022 Share Posted February 4, 2022 Thanks Gary, I am going to disconnect the ammeter and send it off to be converted to a voltmeter. That should take care of that. Safety first!! No. Taking the ammeter out of the circuit does nothing for the shunt. If you leave the alternator charging the battery through the shunt you have a very real chance of melting the shunt, if not causing a fire. Let me say it this way: The shunt is not capable of carrying the full output of your new alternator. You must take the output of the alternator to the battery and not through the shunt. I encourage you to read the writeup on the Ammeter & Voltmeter tab on the page at Documentation/Electrical/3G Alternator Conversion. Link to comment Share on other sites More sharing options...
Rusty_S85 Posted February 4, 2022 Share Posted February 4, 2022 Thanks Gary, I am going to disconnect the ammeter and send it off to be converted to a voltmeter. That should take care of that. Safety first!! Two choices, can take and cut the shunt out and replace with a heavier gauge wire or you can do like I will be doing and take the OE charge wire and double it up with a larger gauge charge wire to a fuse that way the shunt will not be able to pass all the voltage with the doubled up wire. I dont believe you can leave the OE charge wire off and run a new charge wire in its place if you can do this and everything function properly then I would recommend this route and tape up the terminal ends. Link to comment Share on other sites More sharing options...
Gsmblue Posted February 4, 2022 Author Share Posted February 4, 2022 Two choices, can take and cut the shunt out and replace with a heavier gauge wire or you can do like I will be doing and take the OE charge wire and double it up with a larger gauge charge wire to a fuse that way the shunt will not be able to pass all the voltage with the doubled up wire. I dont believe you can leave the OE charge wire off and run a new charge wire in its place if you can do this and everything function properly then I would recommend this route and tape up the terminal ends. Understood. I will be running a new wire from the new alternator to the battery side of the starter relay. I will ensure the shunt and the old wiring is deleted as necessary and when I get a new voltmeter I will wire accordingly. If I have any doubts, I know where to come! Link to comment Share on other sites More sharing options...
Machspeed Posted February 4, 2022 Share Posted February 4, 2022 Understood. I will be running a new wire from the new alternator to the battery side of the starter relay. I will ensure the shunt and the old wiring is deleted as necessary and when I get a new voltmeter I will wire accordingly. If I have any doubts, I know where to come! I was very cautious when I did this on my truck last year, but then I don't consider myself real savvy in the electrical department. You're probably a lot less challenged than me there, but you might want to look over the following thread. As I stated above, Gary and Jim nursed me through this mod and I got exactly what I wanted and am very pleased in it. https://forum.garysgaragemahal.com/Help-On-3G-Page-tp86569.html Link to comment Share on other sites More sharing options...
Gary Lewis Posted February 4, 2022 Share Posted February 4, 2022 Understood. I will be running a new wire from the new alternator to the battery side of the starter relay. I will ensure the shunt and the old wiring is deleted as necessary and when I get a new voltmeter I will wire accordingly. Well, that will work. BUT, you won't have left the old wiring intact so you can put a 1G in place of the Powermaster when it fails. If you really want the ability to put a 1G in place of the Powermaster when you are on a trip, which I think is an excellent idea, then you don't want to remove the old wiring. The shunt isn't a problem if you don't try to put more than, ~70A through it. So I would put a 175A fuse on the fender liner some place and run a #4 or #6 wire to it from the battery side of the starter relay, and run the same size wire from the other side of the fuse to the 1-wire alternator. Tape up the other wires for the 1G alternator so they can't short out, and you are done. Your ammeter will only show discharge as it is now only seeing the load going to the cab from the battery/alternator. But that won't hurt anything. Then when you get the voltmeter from Rocketman you'll need to add a relay under the hood so the voltmeter isn't on all the time and draining the battery. And you'll have to cut one wire and take it to the relay. But it is simple stuff and you'll still have the original 1G wiring for when the Powermaster fails you in Timbuktu. Link to comment Share on other sites More sharing options...
Gsmblue Posted February 4, 2022 Author Share Posted February 4, 2022 Understood. I will be running a new wire from the new alternator to the battery side of the starter relay. I will ensure the shunt and the old wiring is deleted as necessary and when I get a new voltmeter I will wire accordingly. Well, that will work. BUT, you won't have left the old wiring intact so you can put a 1G in place of the Powermaster when it fails. If you really want the ability to put a 1G in place of the Powermaster when you are on a trip, which I think is an excellent idea, then you don't want to remove the old wiring. The shunt isn't a problem if you don't try to put more than, ~70A through it. So I would put a 175A fuse on the fender liner some place and run a #4 or #6 wire to it from the battery side of the starter relay, and run the same size wire from the other side of the fuse to the 1-wire alternator. Tape up the other wires for the 1G alternator so they can't short out, and you are done. Your ammeter will only show discharge as it is now only seeing the load going to the cab from the battery/alternator. But that won't hurt anything. Then when you get the voltmeter from Rocketman you'll need to add a relay under the hood so the voltmeter isn't on all the time and draining the battery. And you'll have to cut one wire and take it to the relay. But it is simple stuff and you'll still have the original 1G wiring for when the Powermaster fails you in Timbuktu. As always, great advice! Thank you Gary :) Link to comment Share on other sites More sharing options...
Gary Lewis Posted February 4, 2022 Share Posted February 4, 2022 As always, great advice! Thank you Gary :) Just don't want you to hurt that beautiful truck! Link to comment Share on other sites More sharing options...
FuzzFace2 Posted February 4, 2022 Share Posted February 4, 2022 Just don't want you to hurt that beautiful truck! The only reason I would not run any 1 wire ALT is in the AMC world some that have run the 1 wire have ended up with dead batteries after driving. Because the 1 wire dose not get feed back from the battery it dose not know it needs charging and you keep pulling power out and not put anything back in. If you were to open up the wiring (on AMC's) the factory sensor wire for the regulator goes back into the harness and not to the battery just for that reason. The sensor wire on the 1 wires are done at the ALT inside IIRC How can it know the battery needs charging as it sees it is putting out volts just not enough! After seeing that on more than a few post I went with a GM type ALT with the regulator built in on my AMC but ran the sensor wire back into the harness to make sure the battery stays charged. Dave ---- Link to comment Share on other sites More sharing options...
Rusty_S85 Posted February 4, 2022 Share Posted February 4, 2022 Understood. I will be running a new wire from the new alternator to the battery side of the starter relay. I will ensure the shunt and the old wiring is deleted as necessary and when I get a new voltmeter I will wire accordingly. Well, that will work. BUT, you won't have left the old wiring intact so you can put a 1G in place of the Powermaster when it fails. If you really want the ability to put a 1G in place of the Powermaster when you are on a trip, which I think is an excellent idea, then you don't want to remove the old wiring. The shunt isn't a problem if you don't try to put more than, ~70A through it. So I would put a 175A fuse on the fender liner some place and run a #4 or #6 wire to it from the battery side of the starter relay, and run the same size wire from the other side of the fuse to the 1-wire alternator. Tape up the other wires for the 1G alternator so they can't short out, and you are done. Your ammeter will only show discharge as it is now only seeing the load going to the cab from the battery/alternator. But that won't hurt anything. Then when you get the voltmeter from Rocketman you'll need to add a relay under the hood so the voltmeter isn't on all the time and draining the battery. And you'll have to cut one wire and take it to the relay. But it is simple stuff and you'll still have the original 1G wiring for when the Powermaster fails you in Timbuktu. This is what I am going to be doing with the exception of I was thinking about doubling up the wires but I may just leave the 1G battery lug wire off and taped up since my ammeter doesnt swing either way. Link to comment Share on other sites More sharing options...
Rusty_S85 Posted February 4, 2022 Share Posted February 4, 2022 The only reason I would not run any 1 wire ALT is in the AMC world some that have run the 1 wire have ended up with dead batteries after driving. Because the 1 wire dose not get feed back from the battery it dose not know it needs charging and you keep pulling power out and not put anything back in. If you were to open up the wiring (on AMC's) the factory sensor wire for the regulator goes back into the harness and not to the battery just for that reason. The sensor wire on the 1 wires are done at the ALT inside IIRC How can it know the battery needs charging as it sees it is putting out volts just not enough! After seeing that on more than a few post I went with a GM type ALT with the regulator built in on my AMC but ran the sensor wire back into the harness to make sure the battery stays charged. Dave ---- I dont like 1 wire for that reason, I have started up many cars at work with 1 wire alternators and they never hit the self excite threshold so the engine is running on just the battery. Link to comment Share on other sites More sharing options...
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