Joined: Sun Jan 18 2009, 09:54PM
Location: BRUNSWICK, GA
Posts: 120
i hear ya furious70... I understand the ability for the 3 wire to compensate for drain but in my instance i am probably going to rewire this old boat anyways, using larger gauge wire that should experience less of a drop. My thoughts are that if i use the distribution block and then route any devices through it then the alt will have to keep up, meaning that the devices will draw the alternator down enough so that it will compensate with more voltage. my thoughts are that as long as you have the right size wiring or even one step above like i like to do then the voltage drop should be minimal, I would think it would be more of a concern if the old nasty wiring was still in the car because you want to compensate for the resistance in all that old timey wiring. you could probably just use a fusible link from the distribution point to the battery that way you still dont overcharge the battery and if you run a 140 amp alternator like i plan to then it should well keep up with the accessories through the distribution block and then still charge that battery without overcharging it. the only bad part might be if the alternator does dies out then it will blow the link too but that might just be a good thing too.
I just see the three wire as a method of compensating for high resistance outdated devices. the one wire should be able to provide the correct output as long as a good wire is used to lessen the voltage drop. I mean if you use a 140 amp alt and put 8 or 10 gauge wire on it then under load it is going to experience a significant drop but if you provide it with a big enough wire like in your instance furious then it should have no problem providing the correct output.
I have read the mad thing but i dont know, from my understanding the above should be true. I mean i dont mind the revving up to start it, cuz i usually blip the throttle after starting the car to hear that pretty engine, I dont mind not being able to find the alternator because i would just by a self exciting regulator and leave it in the car because that usually is the problem, and it would just be much cleaner looking with the regulator and all that on the firewall.
The relays on amazon are a great deal and i am glad that was posted, and with my prime membership i can get them shipped in two days for free.. yaaay!!!
Joined: Thu Feb 12 2009, 02:56AM
Location: Portland OR
Posts: 690
I do believe that the way you describe the 1 wire setup you are using is the way I was going to set mine up! Glad to hear it is working for you. Let us know if you find any other issues. I am still unsure of where the best place to wire in a distribution block would be. Read what the MAD boys had to say. And it dosent say exactly where to connect it for our cars. Unless Im missing something. They say to connect it to the main buss, in the case of the vehicle they are using for demonstration, It is the horn relay. I do not believe this is the case on The VIP. Anyone know for sure? I have a lot of knowlege in the electrical field, Just not super familiar with component locations and layout on this car. Ive only laid eys on her twice since I bought her, Due to my condo not allowing cars to be worked on AT ALL!! So a friend is allowing me to use his place but its over an hour away and outdoors, Rain is my enemy at this time, But would like to have this all figured out before the next time I go out there as it costs a lot to go back and forth.
Joined: Tue Oct 11 2005, 01:33AM
Location: Calgary, Alberta
Posts: 5893
furious70 wrote ... My 1 wire doesn't have any of the problems MAD writes about, just to stir the pot some more I have tried my 2g charge wire both straight to the batt and where it is currently, on the starter relay. I see consistent readings....
If I read that as being a AWG 2 gauge wire being used as a jumper, then you are absolutely correct - no voltage drops. The reason why others have problems is they use AWG 10 or sometimes AWG 8 wire.
AWG 10 will handle about 55 Amps over short distances, but AWG 8 will handle 73 and your AWG will do 181 amps.
The only downside of AWG 2 is its diameter is 0.2576" and routing it can be tricky, plus its weight means it had better be very well supported otherwise vibration will cause it to fail.
Joined: Fri Dec 22 2006, 08:41PM
Location: Warrenton, Virginia
Posts: 1366
Wow, you guys!! I'm away from the board for a day and a half and look what happens !banana
I really appreciate everyone trying to help....just as long as we all keep our cool and respect each other. Not all of us have the knowledge or experience some of the members have. I guess we can ALL learn something from each other. I'm really fortunate to have all of you as a source of INformation and well as INspiration !drive
Joined: Tue Oct 11 2005, 01:33AM
Location: Calgary, Alberta
Posts: 5893
plymouth383 wrote ... so here is a question... say you want a nice sound system in the car... I wouldnt want to hook a big amp up to the starter relay would you? something that draws alot of current like that would worry me. also on the one wire deal. could you in theory install a distribution block for all the electronics and power inside the car, and hook the one wire charge up to one side of the block and then run another wire to the batt? or would you be back at square one... the reason i ask is because my c body is going to have quite a few electronics on board, I am going to have electric fans, electric water pump, big sound system, hid headlights, and god only knows what else. I am sure the little 60 amp wont keep up, so I wanted to put in a GM alternator, the 12si i think it is. anyways, what would be the best way to hook all this up. I am not afraid of relays and have no problems using them. I just want to know the best way to do this.
Two things you need to deal with, voltage drops and current draw.
Voltage drop is easy to deal with, oversize your conductors such that at your expected load levels, the conductor resistance effect is negligible. Over sized conductors are typically called buses. So if you use a 1 wire alternator, you know the regulated voltage is sensed at the battery terminal. You could therefore connect, as one docker has done, a "big honking" AWG 2 wire between the alternator and the start relay. Because the wire is so large, the voltage measured anywhere along the length will be regulated. You now have a power bus, but have created new problems.
Remember all the previous discussion about the need to have resistance in the battery charge wire that runs from your source of regulated voltage to the battery. In essence the wire must be of moderate gauge and long enough to induce a voltage drop over its length when the current load is high. Why? A dead or low battery will take all the current you can throw at it - but if you give it to much too fast, the battery over heats and boils off some of the water. Using a current induced voltage drop across the charge wire to control charge rate is a neat, idiot proof way to stop people from boiling their batteries dry. When was the last time you checked your battery? Bet your wife or gf don't even know it contains water.
The typical Mopar charge wire starts at the master splice on the alternator side of the ammeter, passes through the ammeter, the bulkhead connector, to the start relay and finally to the battery via the fusible link. Or about 7 to 8 feet of AWG 10 wire and a fusible link.
Our AWG 2 bus bar just eliminated everything but the fusible link. Note also, Leaburn's ammeter bipass chops about half the AWG 10 charge wire out of the circuit. All of these "fixes" result in some degree of excess battery charging rate.
The second problem our bus creates is where and how to connect the "toys".
The solution to these problems is to add a bus contact block. Bolt it to the firewall in a handy place. Attach it to the battery terminal of the alternator with a "big honking" wire so that the bus control block becomes "regulated". Connect a 7 to 8 foot length of AWG 10 wire from the bus block to the starter relay. Now you've got a nice long correctly sized battery charge wire protected by a fusible link.
The big honking wire from the alternator to the bus is protected, but obviously. If you short it out, two things happen, the total output of the alternator flashes to ground and battery shorts to ground and blows the fusible link. The bus voltage drops to zero which means no spark so the engine stops. I can tell you from personal experience, this chain of events happens instantly.
In my case the battery line from the alternator was touching the exhaust manifold. I had just got up to speed in busy traffic when the insulation melted through and pow - dead car! After I taped the melted insulation and replaced the fusible link every thing was fine.
Even though I started this description with a 1 wire alternator, it makes no difference if its a three wire type since the "big honking" wire makes both systems equivalent.
To protect individual toys, connect them to your new power bus with fusible links/fuses/breakers.
To control high current devices like headlights, amps, use relays to reduce switching loads.
If you have fans, big horns etc. add a second bus point on the rad support to simplify your wiring.
Just make sure the "big honking" wires are mechanically well supported and protected. "Big honking" wire is stiff and vibration will cause metal fatigue very quickly so buy lots of cable clips.
Joined: Thu Feb 12 2009, 02:56AM
Location: Portland OR
Posts: 690
Fury440 wrote ...
plymouth383 wrote ... so here is a question... say you want a nice sound system in the car... I wouldnt want to hook a big amp up to the starter relay would you? something that draws alot of current like that would worry me. also on the one wire deal. could you in theory install a distribution block for all the electronics and power inside the car, and hook the one wire charge up to one side of the block and then run another wire to the batt? or would you be back at square one... the reason i ask is because my c body is going to have quite a few electronics on board, I am going to have electric fans, electric water pump, big sound system, hid headlights, and god only knows what else. I am sure the little 60 amp wont keep up, so I wanted to put in a GM alternator, the 12si i think it is. anyways, what would be the best way to hook all this up. I am not afraid of relays and have no problems using them. I just want to know the best way to do this.
Two things you need to deal with, voltage drops and current draw.
Voltage drop is easy to deal with, oversize your conductors such that at your expected load levels, the conductor resistance effect is negligible. Over sized conductors are typically called buses. So if you use a 1 wire alternator, you know the regulated voltage is sensed at the battery terminal. You could therefore connect, as one docker has done, a "big honking" AWG 2 wire between the alternator and the start relay. Because the wire is so large, the voltage measured anywhere along the length will be regulated. You now have a power bus, but have created new problems.
Remember all the previous discussion about the need to have resistance in the battery charge wire that runs from your source of regulated voltage to the battery. In essence the wire must be of moderate gauge and long enough to induce a voltage drop over its length when the current load is high. Why? A dead or low battery will take all the current you can throw at it - but if you give it to much too fast, the battery over heats and boils off some of the water. Using a current induced voltage drop across the charge wire to control charge rate is a neat, idiot proof way to stop people from boiling their batteries dry. When was the last time you checked your battery? Bet your wife or gf don't even know it contains water.
The typical Mopar charge wire starts at the master splice on the alternator side of the ammeter, passes through the ammeter, the bulkhead connector, to the start relay and finally to the battery via the fusible link. Or about 7 to 8 feet of AWG 10 wire and a fusible link.
Our AWG 2 bus bar just eliminated everything but the fusible link. Note also, Leaburn's ammeter bipass chops about half the AWG 10 charge wire out of the circuit. All of these "fixes" result in some degree of excess battery charging rate.
The second problem our bus creates is where and how to connect the "toys".
The solution to these problems is to add a bus contact block. Bolt it to the firewall in a handy place. Attach it to the battery terminal of the alternator with a "big honking" wire so that the bus control block becomes "regulated". Connect a 7 to 8 foot length of AWG 10 wire from the bus block to the starter relay. Now you've got a nice long correctly sized battery charge wire protected by a fusible link.
The big honking wire from the alternator to the bus is protected, but obviously. If you short it out, two things happen, the total output of the alternator flashes to ground and battery shorts to ground and blows the fusible link. The bus voltage drops to zero which means no spark so the engine stops. I can tell you from personal experience, this chain of events happens instantly.
In my case the battery line from the alternator was touching the exhaust manifold. I had just got up to speed in busy traffic when the insulation melted through and pow - dead car! After I taped the melted insulation and replaced the fusible link every thing was fine.
Even though I started this description with a 1 wire alternator, it makes no difference if its a three wire type since the "big honking" wire makes both systems equivalent.
To protect individual toys, connect them to your new power bus with fusible links/fuses/breakers.
To control high current devices like headlights, amps, use relays to reduce switching loads.
If you have fans, big horns etc. add a second bus point on the rad support to simplify your wiring.
Just make sure the "big honking" wires are mechanically well supported and protected. "Big honking" wire is stiff and vibration will cause metal fatigue very quickly so buy lots of cable clips.
Ok if im using a 3 wire setup for the alternator and wire it as you suggest, which makes very good sense by the way, Im going to assume I would wire my sensing wire to the buss as well instead of the main splice. If I do this and then run a large gauge cable thru the firewall to another dist block for my interior accessories and power the main splice from that distribution block. If I do it that way with a high output alternator Im thinking that I should be set up for anything I could possibly decide to do to the car in the future. What cha think? !drive
Joined: Sun Jan 18 2009, 09:54PM
Location: BRUNSWICK, GA
Posts: 120
hey fury440 youd be surprised at what the gf knows, she is pretty knowledgable when it comes to cars. I understand the potential to overheat the battery that is why I mentioned the fusible link. I thought that would be the best way to wire it up and apparently im on the right track...
and the battery gets checked at every oil change, dont feel like burnin up with the car.
hey VIP I think that would work best, because most of the interior stuff or under dash things dont draw that much current, just the headlights, a/c, and whatever accessories that you add. I think that particular method would probably run the accessories best.
Joined: Thu May 01 2008, 11:15AM
Location: Chicago,IL
Posts: 2868
I think 4g would have been a better choice for me, you're right, the 2g is hard to deal with. I run it up on the motor and across the firewall in the OEM clips. As I understand it, my circuit to charge the batt. should be close to the same as the amp bypass kit as you said Bill, so I was not concerned about cooking the batt. There's not much of a voltage drop in the OEM charge wire from the starter relay to the batt however.
wrote ... The solution to these problems is to add a bus contact block. Bolt it to the firewall in a handy place. Attach it to the battery terminal of the alternator with a "big honking" wire so that the bus control block becomes "regulated". Connect a 7 to 8 foot length of AWG 10 wire from the bus block to the starter relay. Now you've got a nice long correctly sized battery charge wire protected by a fusible link
Bill, you're saying do this so that the new toys all get the juice they need but then the OEM stuff sees approx. the same voltage at the starter relay as it would have originally?
I really wish I would have spent a day probing around my car with my multimeter before I did the conversion to better understand how the OEM setup worked/failed. <span class='smallblacktext'>[ Edited Fri Feb 27 2009, 07:50AM ]</span>
Joined: Thu May 01 2008, 11:15AM
Location: Chicago,IL
Posts: 2868
one other wrinkle in my setup: I also hooked up the OEM batt wire to the alt such that the stock accessories are still being fed by that. I did that when I was first troubleshooting the system and was seeing low voltage. This was before I found that the pulley is a touch too big and I need 800rpm to get the alt to meet min. charge requirements. Bill, should I remove that wire now?