ArdWrknTrk Posted July 6 Share Posted July 6 One more change I would suggest is that the yellow/white sense wire from the 3G should be connected to the starter solenoid on the battery lug. The distance that sense wire is from the battery could result in a decent change in voltage and a decent change in alternator output. Another thing is from what I remember reading is that if the sense wire is on the alternator side of the fuse, if that fuse goes, the alternator will still see voltage that changes via the regulator. On the battery side of the fuse if the fuse goes the alternator wont sense a change in voltage when the regulator commands it and will essentially shut down output from the alternator. Many people short cut this wire looping it right back to the battery lug at the alternator, while this is cleaner it doesn't take into account what the voltage actually is at or near the battery. I saw a diagram that went with a Remy alternator post that stated that with a sense wire fleet companies reported 50% reduction in battery charge time and a 30% reduction in battery warranty claim over alternators they had before without the sense wire. Remy also states the sense wire for vehicles that don't have them should be fused and mounted directly to the positive terminal or the nearest positive common junction. All the 1990s 3G wiring diagrams I looked up also showed this sense wire terminated close to the battery in a common junction lug no different than the 1G externally regulated sense wire was terminated close to the battery at the common junction lug on the starter solenoid. For mine I am personally leaning towards using a male spade on this sense wire on mine and plug it into the sense terminal on the OE fender mounted regulator this way I am reusing the OE sense wire and fusible link to the solenoid. I might change my mind however and just connect it directly to the solenoid with its own fuse, but I think it minimizes clutter on the battery lug at the solenoid to reuse that terminal. You seem to have this backwards. If the alternator can only 'sense' declining battery voltage (or just "normal" -not charging-) battery voltage below it's -usual- 14.35V set point, then it will keep raising output (both amps AND volts) until it sees that. I've seen voltages of 20 and alternators literally smoking because the sense wire failed. or, in your scenario, the fuse, holder, connection, did Think of it like this... What would happen if you put your house thermostat on the outside? The thermostat is divorced from the internal temperature and the AC or heater will continue to run full tilt but never be able to affect what the thermostat is actually "sensing" Almost the moment the megafuse is out of the circuit your battery is going to be headed towards its steady state of 12.6V, even without any loads placed on it. The alternator is going to go full field, and it won't have any battery to absorb the charge. That's a recipe for disaster. Link to comment Share on other sites More sharing options...
Rusty_S85 Posted July 7 Share Posted July 7 One more change I would suggest is that the yellow/white sense wire from the 3G should be connected to the starter solenoid on the battery lug. The distance that sense wire is from the battery could result in a decent change in voltage and a decent change in alternator output. Another thing is from what I remember reading is that if the sense wire is on the alternator side of the fuse, if that fuse goes, the alternator will still see voltage that changes via the regulator. On the battery side of the fuse if the fuse goes the alternator wont sense a change in voltage when the regulator commands it and will essentially shut down output from the alternator. Many people short cut this wire looping it right back to the battery lug at the alternator, while this is cleaner it doesn't take into account what the voltage actually is at or near the battery. I saw a diagram that went with a Remy alternator post that stated that with a sense wire fleet companies reported 50% reduction in battery charge time and a 30% reduction in battery warranty claim over alternators they had before without the sense wire. Remy also states the sense wire for vehicles that don't have them should be fused and mounted directly to the positive terminal or the nearest positive common junction. All the 1990s 3G wiring diagrams I looked up also showed this sense wire terminated close to the battery in a common junction lug no different than the 1G externally regulated sense wire was terminated close to the battery at the common junction lug on the starter solenoid. For mine I am personally leaning towards using a male spade on this sense wire on mine and plug it into the sense terminal on the OE fender mounted regulator this way I am reusing the OE sense wire and fusible link to the solenoid. I might change my mind however and just connect it directly to the solenoid with its own fuse, but I think it minimizes clutter on the battery lug at the solenoid to reuse that terminal. You seem to have this backwards. If the alternator can only 'sense' declining battery voltage (or just "normal" -not charging-) battery voltage below it's -usual- 14.35V set point, then it will keep raising output (both amps AND volts) until it sees that. I've seen voltages of 20 and alternators literally smoking because the sense wire failed. or, in your scenario, the fuse, holder, connection, did Think of it like this... What would happen if you put your house thermostat on the outside? The thermostat is divorced from the internal temperature and the AC or heater will continue to run full tilt but never be able to affect what the thermostat is actually "sensing" Almost the moment the megafuse is out of the circuit your battery is going to be headed towards its steady state of 12.6V, even without any loads placed on it. The alternator is going to go full field, and it won't have any battery to absorb the charge. That's a recipe for disaster. And yet all manufacturers state to put the sense wire as close to the battery positive terminal as possible. It was done this way when our trucks were new and it was still done with the 3G in the 1990s. The charge wire is fused between the battery and the alternator and the sense wire is going to be between the battery and the fuse for the charge wire Just like our trucks the sense wire hooks to the solenoid from the regulator and the charge wire has a fusible link in line and it connects to the same battery lug on the starter solenoid. If this charge wire fusible link fails the same situation you speak of would be there, the sense wire is reading battery voltage with the charge wire not providing voltage/amperage to the battery circuit. Even if the battery voltage dropped to 12.6v the alternator will only ramp up output to the voltage set point which on mine is under 14.5v, outside of a regulator failure the alternator would never put out more than 14.5 volts Link to comment Share on other sites More sharing options...
CSA Posted July 7 Share Posted July 7 Jeff - You shouldn't combine what we discussed in the Rethinking The 3G Conversion Pages/Process thread and what's on the 3G Conversion page. The thread is, as its title says, a rethink of how to wire a 3G. The 3G Conversion page is old-think. The reason for the relay was because I wanted to know the actual battery voltage rather than the voltage in the cab - and those are two different things. So I wanted the voltmeter to be connected to the circuitry as close to the battery as is possible, and that required a relay to turn power off to the volt meter when the key was off. But the new-think is that people don't really care exactly what the voltage is, so tap into a source of switched power because then you won't need the relay. (After all, there are no numbers on the Rocketman voltmeters, so they cannot be terribly accurate.) Given that we decided to wire it as shown below, and the LG/R wire comes from the ignition switch and provides both power to the alternator to bootstrap it in but also to the voltmeter. In other words, no relay is needed. Sir, I just wanted to mention that the diagram doesn't show the fuse for the regulator to B+ wire. This is normally protected by a fuse link on the alternator side of the fuse. I have found no definitive information for the need; but, I have found it this way in EVTMs that I have used. '84 EVTM does not show regulator fuse link w/ammeter, does w/indicator. My '84, G1 100a alt large case, had ammeter and both links and the '89, G2 alt, harness that I used to fix the burnt fuse panel had ammeter and both links. ?? '99 Explorer EVTM (130a G3 alt) used fuses with a 30a for the regulator to B+ wire. 93 Mustang EVTM PwrDist 60-70a 2G The pic is just to illiterate what I found in the harness. As a 90~100A alternator was available on both the '92 Econoline with the 3G small case and on both E & F series with the 1G (large profile), I would recommend using the specified fuse links and wiring. Hope this is helpful, if not, please, let me know. V/R Chris A Link to comment Share on other sites More sharing options...
CSA Posted July 7 Share Posted July 7 I'll say it differently. I don't remember how the W/Bk that is shown in the middle of the plug on the right is terminated on the cable I sent you, but I think it goes to the plug you circled. If so then your W/Bk wire to the choke heater goes there, and I assumed you had a matching connector. No? I have my choke heater wire spliced into the white/black wire. Has worked with Ford and with Holley chokes. Inline 20ga fuse link needed before choke. V/R Chris A. Link to comment Share on other sites More sharing options...
Gary Lewis Posted July 8 Share Posted July 8 Sir, I just wanted to mention that the diagram doesn't show the fuse for the regulator to B+ wire. I'm not sure I understand what you are saying. The B+ wire is the Bk/O wire which is the output of the alternator and we do show a fuse for that. What am I missing? Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted July 9 Share Posted July 9 One more change I would suggest is that the yellow/white sense wire from the 3G should be connected to the starter solenoid on the battery lug. The distance that sense wire is from the battery could result in a decent change in voltage and a decent change in alternator output. Another thing is from what I remember reading is that if the sense wire is on the alternator side of the fuse, if that fuse goes, the alternator will still see voltage that changes via the regulator. On the battery side of the fuse if the fuse goes the alternator wont sense a change in voltage when the regulator commands it and will essentially shut down output from the alternator. Many people short cut this wire looping it right back to the battery lug at the alternator, while this is cleaner it doesn't take into account what the voltage actually is at or near the battery. I saw a diagram that went with a Remy alternator post that stated that with a sense wire fleet companies reported 50% reduction in battery charge time and a 30% reduction in battery warranty claim over alternators they had before without the sense wire. Remy also states the sense wire for vehicles that don't have them should be fused and mounted directly to the positive terminal or the nearest positive common junction. All the 1990s 3G wiring diagrams I looked up also showed this sense wire terminated close to the battery in a common junction lug no different than the 1G externally regulated sense wire was terminated close to the battery at the common junction lug on the starter solenoid. For mine I am personally leaning towards using a male spade on this sense wire on mine and plug it into the sense terminal on the OE fender mounted regulator this way I am reusing the OE sense wire and fusible link to the solenoid. I might change my mind however and just connect it directly to the solenoid with its own fuse, but I think it minimizes clutter on the battery lug at the solenoid to reuse that terminal. You seem to have this backwards. If the alternator can only 'sense' declining battery voltage (or just "normal" -not charging-) battery voltage below it's -usual- 14.35V set point, then it will keep raising output (both amps AND volts) until it sees that. I've seen voltages of 20 and alternators literally smoking because the sense wire failed. or, in your scenario, the fuse, holder, connection, did Think of it like this... What would happen if you put your house thermostat on the outside? The thermostat is divorced from the internal temperature and the AC or heater will continue to run full tilt but never be able to affect what the thermostat is actually "sensing" Almost the moment the megafuse is out of the circuit your battery is going to be headed towards its steady state of 12.6V, even without any loads placed on it. The alternator is going to go full field, and it won't have any battery to absorb the charge. That's a recipe for disaster. And yet all manufacturers state to put the sense wire as close to the battery positive terminal as possible. It was done this way when our trucks were new and it was still done with the 3G in the 1990s. The charge wire is fused between the battery and the alternator and the sense wire is going to be between the battery and the fuse for the charge wire Just like our trucks the sense wire hooks to the solenoid from the regulator and the charge wire has a fusible link in line and it connects to the same battery lug on the starter solenoid. If this charge wire fusible link fails the same situation you speak of would be there, the sense wire is reading battery voltage with the charge wire not providing voltage/amperage to the battery circuit. Even if the battery voltage dropped to 12.6v the alternator will only ramp up output to the voltage set point which on mine is under 14.5v, outside of a regulator failure the alternator would never put out more than 14.5 volts Your alternator is reading the battery -ON THE OTHER SIDE OF A BLOWN FUSE- The battery is going to immediately drop towards 12.6 from where it WAS charging. The damn alternator is going to crank itself up to max (just like "ground here to test") and stay there, charging into an open circuit. The windings and diode board have to try and dissipate that heat. It's appalling that our schools fail to teach even the most rudimentary maths and science, but maybe I need to reset my horizons in a day and age where everyone gets a participation trophy. Link to comment Share on other sites More sharing options...
BigBrother-84 Posted July 18 Author Share Posted July 18 Your alternator is reading the battery -ON THE OTHER SIDE OF A BLOWN FUSE- The battery is going to immediately drop towards 12.6 from where it WAS charging. The damn alternator is going to crank itself up to max (just like "ground here to test") and stay there, charging into an open circuit. The windings and diode board have to try and dissipate that heat. It's appalling that our schools fail to teach even the most rudimentary maths and science, but maybe I need to reset my horizons in a day and age where everyone gets a participation trophy. Hooray! I finally got all the main puzzle pieces! 1- Cluster Amp meter converted to Volt meter 2- Plug’n Play harness (thanks to Gary!) 3- 130A 3G alternator 4- 2.5 seconds LRC Voltage Regulator Will proceed to the swap somewhere during my summer vacations (which begin next weekend). But first I will have to rebuild the C-610 connector (that was cancelled and jumped somewhere in Big Bro’s past life). Thanks (again!) to Gary, I have a good shape part to install. I will document the whole process with picts and comments. I’ll certainly need your advices as the project will go on! See you! Link to comment Share on other sites More sharing options...
Gary Lewis Posted July 18 Share Posted July 18 Hooray! I finally got all the main puzzle pieces! 1- Cluster Amp meter converted to Volt meter 2- Plug’n Play harness (thanks to Gary!) 3- 130A 3G alternator 4- 2.5 seconds LRC Voltage Regulator Will proceed to the swap somewhere during my summer vacations (which begin next weekend). But first I will have to rebuild the C-610 connector (that was cancelled and jumped somewhere in Big Bro’s past life). Thanks (again!) to Gary, I have a good shape part to install. I will document the whole process with picts and comments. I’ll certainly need your advices as the project will go on! See you! Yippee!!!! Glad you have all the pieces. I'm along for the ride, although my grandtwins arrive tomorrow and I'll be playing with a French truck for the next week. So if you need me you have my cell and can text me. Good luck!!!! Link to comment Share on other sites More sharing options...
85lebaront2 Posted July 18 Share Posted July 18 Yippee!!!! Glad you have all the pieces. I'm along for the ride, although my grandtwins arrive tomorrow and I'll be playing with a French truck for the next week. So if you need me you have my cell and can text me. Good luck!!!! Gee, Gary, maybe he's the one you should be asking about French trucks. I imagine I will be getting question on stovebolts from you and Ian. Link to comment Share on other sites More sharing options...
BigBrother-84 Posted July 18 Author Share Posted July 18 Gee, Gary, maybe he's the one you should be asking about French trucks. I imagine I will be getting question on stovebolts from you and Ian. Link to comment Share on other sites More sharing options...
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