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Discussion Starter #1
This may be a dumb question, but...

How many connections can I put at this one junction block, the one that is located behind the battery for the positive leads? I currently am looking at the two that are normally there (one from wire harness and other to battery terminal), plus one from my MSD unit, and one from each of my fans for my radiator...Is it possible to have too many connected there? This would be like 5 of them at the one location...I could probably cut it down to 4 if I tie the two from the fans together and then connect to the junction box...

Also, on a side note, or question...I a plastic clip that one wire goes through the clip and can be as long as needed, and the other wire is pushed into the clip and bottoms out...once the two wires are in place, you push a metal clip or wedge into the plastic piece and it makes a connection between the two wires, which basically ties the two wires at that point and then the one wire that goes through the clip is used instead of twisting three wires together. Is this acceptable or a good way of connecting three wires into one splice or is there a better method?
 

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you can group wires there, but be careful with overloading it, you don't want the main wire from the battery as the weakest link. so consider its size, in relation to what the total draw will be of all combined loads.
probably the best approach with multiple wires attached would be a terminal block in place of the post (or in addition too), using a #10 or #8 as the feed to it. you really dont want to stack a bunch of wires on that post (no more than 2 additional ones imo), because you increase resistance with each new wire, and increase a chance of smoking the terminal from heat due to resistance.
as for the wire splices you describe, throw them in the trash, please. all they do is add resistance and give a new point for corrosion, i hate them with a passion, they are ugly too, imo.
your best bet is a good crimped connection, using proper connectors. soldering and shrinkwrap adds additional strength/conductivity.
 

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Discussion Starter #3
Thank you for the reply...

The two hot wires from the radiator fans (there are two fans on the radiator) both have I think a 30 amp inline fuse on each wire. I am planning on connecting these to a single line and then go to the junction block, and then the other wire is from the MSD unit. This would put me down to two additional wires and the one has the fuses so I dont know if that will help with any of this.

As far as all my connections, I will use solder and heat shrink...
 

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As Sean said, don't go near the scotchlock connectors... everything gets soldered and heatshrinked.

Make sure anything you run to power is properly fused.

If you have a factory style ammeter, connecting anything to that junction block will throw the reading off.

Be aware that when the car is running, normal current flow will be from the alternator to the junction block to the draws. You don't want to overload that wire. May possibly consider running a second 10 guage wire from the horn relay to the junction block. As you add electrical accessory's, you might think about oversizing the red wire from the alternator, too.
 

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Discussion Starter #5
There is no factory ammeter, so I am good there.

As far as running a second 10 guage wire from the horn relay to the junction block how will that help with the wire from the alternator to the junction block wire? My basic electricity skill are at zero...I would think that the setup with a MSD box and fans for the radiator is common nowadays...I am wondering where or how others are doing this type of setup. I dont have to go to that junction box, but the wiring diagrams show that I need to go to the positive terminal on the battery...but maybe there is another location or way to do this all without going to the junction block?
 

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Discussion Starter #6
Okay, after talking with you guys and with American Auto Wire, I am now understanding a bit more. apparently the brown wire from the battery to the junction block will not carry the load of all these components. Therefore, if I go directly to the positive terminal on the battery, or to the starter wire from the battery cable, I should be good to go. I am thinking that since the MSD unit is on the passengers side firewall, running down to the starter is probably the easiest, and I am pretty sure the cable is long enough from the fans to make it there too. Does this sound like a good alternative than the junction block?
 

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Liveinaz said:
This may be a dumb question, but...

How many connections can I put at this one junction block, the one that is located behind the battery for the positive leads? I currently am looking at the two that are normally there (one from wire harness and other to battery terminal), plus one from my MSD unit, and one from each of my fans for my radiator...Is it possible to have too many connected there?
It depends on what kind of junction block you are using. The factory one doesn't allow for many connections, a aftermarket one will allow more.
Heres a couple


http://www.madelectrical.com/catalog/cn-1.shtml
 

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Keep in mind that all that power for the fans won't come from the battery. It will come from the alternator. So if the pig-tail from the battery (+) to the junction block seems undersized, it isn't going to carry the brunt of the load. In fact, current will most likely flow the other way - from the junction block to the battery as the alternator keeps it charged.

There is no reason to use the horn relay as a connection point. In fact, things that can handle a slightly higher voltage are best connected close to the battery. There is no need to have the fans, or headlights regulated. The higher the voltage, the better. There are more details to this than what I have provided here. Send me an email if you want me to explain further.

The starter is a good bonding point. The only down side is making sure your high amperage feeds can't possibly contact a hot header and short out. The terminal block behind the battery can handle several connections. Just make sure the connection point is clean and dope it up with dielectric grease to ward off corrosion. Most of the current will flow through the stack of ring terminals and not the bolt of the terminal block. So long as you have enough thread engaged and the block is not stressed by having too many heavy wires connected to it, you should be fine.

I like those aftermarket terminal blocks that greg posted. Those are similar to the ones found on 70's era Chevy trucks (and other models). Also for high current loads fusable links and thermal breakers are an acceptable alternative to fuses. Just be sure that any fusable links are hanging free in the event they do burn through. You don't want a hot link to catch something on fire or melt through to the insulation on ajacent wires.
 

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dnult said:
There is no reason to use the horn relay as a connection point. In fact, things that can handle a slightly higher voltage are best connected close to the battery.
Really depends on where the alternator is wired to. If using the factory setup, the horn relay is the best place since is is the closest place to where the alternator output is, if the alternator is wired to the battery, then this would be the best place. The idea is, where ever one plans on connecting all the add on accessries, you want to be as close as possible to the alternator output.




dnult said:
Just be sure that any fusable links are hanging free in the event they do burn through. You don't want a hot link to catch something on fire or melt through to the insulation on ajacent wires.
Good point, fusible links don't do much good if they are bunched up with other wires to short out against.
 

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Discussion Starter #10
That is a good diagram...

I got an American Auto Wire harness that is setup for the internal voltage regulator on the alternator...I am not sure with this setup if the alternator output is now closer to the horn relay or if this principle applies with this setup...I would assume that it would then be best NOT to go from the starter to a terminal block, but instead hook up from the positive terminal on the battery? I ask this because the length of the cable from the battery to the starter is even further away from the alternator...

I guess I am just not sure which is the best way to go with this...

I did find the terminal block from made electrical shown above for $2.45 at the chevy dealer locally. I went to about 10 different stores today looking for this part. The GM number, in case anyone is looking for this part is 10098794.
 

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I wish madelectrical had a more complete schematic for their "remote voltage sensing" tech sheet. I plan to use remote sensing with my CS130 alternator so that high current, unregulated voltage is available near the battery and that everything else comes from the regulated horn relay. Here is how I plan to do it. This probably won't work well for factory amp guage configurations though.

1. Connect a decent sized wire (8 guage) from the battery junction block to the horn relay.
2. Connect the remote sensing wire from the CS130 to the horn relay.
3. Connect the charge wire from the alternator to the battery junction block.
4. Connect high current loads without the need for regulated voltage to the battery junction block (i.e. fans, head lights).
5. Connect all vehicle power feeds to the horn relay (standard configuration - ignition, lights, etc.)

What I expect this will do for me is keep my vechicle power well regulated, while allowing the battery voltage to go slightly above the regulated voltage setting even under high current loads (wipers on, heater on, marker lamps on, etc.) This will also feed high current loads (headlights, fans) directly from the junction block through short lengths of wire using fusable links.
 

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Dave, all the electrical power is by design well regulated. The system voltage is maintained at ~14 volts, measured at whatever point the regulator voltage sense wire is connected. At least in theory, the wiring from the battery to the alternator, fusebox, and horn relay should never drop more than a few millivolts, and therefore would be considered the same point electrically.

The standard hookup for connecting an internal regulated alternator in a first gen is to jumper the firstgens factory regulator connector from pin 1 to pin 3. Doing this connects the sensing wire to the main splice.

Unless other loads are connected to the pass side junction block, the wire from the main splice to the junction block will only ever see battery charge current, rarely more than 30 amps, usually much less and the standard size wire is adequate. That wire should be upsized if additional high current loads are connected to the junction block.

I don't think it's nesessary or desired to connect the (drivers side mounted) alternator output to anywhere other than the main splice or the horn relay. I might connect it to the junction block on a 69 just to shorten the overall wire lengths. If I did that, I'd leave the voltage sense wire at the horn relay.
 
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