Charging upgrade

[jessemthompson]

Today I upgraded the charging system in my 72 C10. I have an LS swap in it. Before I did the work today, I was reading just under 13 volts in the cab with windshield wipers that were incredibly slow and caused almost a 2 volt drop in the system when operating. After the work, I’m sitting at 13.8 volts at idle and my wipers now operate at normal speeds without a voltage drop. Below is a diagram of what I did. I got this great info from mad electrical.

[VetteVet]

You must have a one-wire alternator from your drawing. Mad Electric don't like those because they don't sense voltage drops downstream in the circuit. Yours must be working alright.
I'm surprised you didn't check with us on the forum since we have been doing these conversions for years.

[CastIron]

That looks like you used some pretty good sized wiring there and kept it simple.
I have been thinking about upgrading my electrical setup as well. I converted to a 60 amp 10SI alternator years ago, but just used the stock wiring. I want to use larger wire from the alternator to the battery and use a fusible link. I just haven't done the research and looked at the wiring diagram to determine what to do. I am also going to install relays for the headlights and possibly switch my ammeter to a volt meter. I might just build a new harness myself using connectors out of a harness from my parts truck.

[jessemthompson]

No one wire charging system. The LS harness has the plug for the alternator, so I didn’t put it in my diagram. It’s working well though.

[davepl]

I did the same, just one big red wire coming out to my battery from the alternator and I let the LS3 harness operate the charging. Works as expected, and charges well. That was in my Camaro with no factory ammeter-style gauge or shunt (unless the idiot light still has one).

One thing I couldn't figure out was WHERE the LS3 harness does it's "voltage sense" read from. You'd think GM would give you a wire on the bulkhead harness that you'd run to your dash light or somewhere far downstream, but there isn't one that I know of.

[jessemthompson]

I like having the shunt on the firewall a lot. I want to install an amp in the truck and it will make like a lot easier hooking up to the shunt vs the battery

[VetteVet]

Originally Posted by jessemthompson

I like having the shunt on the firewall a lot. I want to install an amp in the truck and it will make like a lot easier hooking up to the shunt vs the battery

I don't like to correct a minor issue but in order to avoid confusion, the device you are calling a Shunt is just a simple junction. You will want to use a fusible link for the battery and alternator connections and fuse any loads that exit from the junction.

In our trucks the feed wire that goes to the firewall goes to a four way soldered junction and three of those wires feed the ignition switch the horn relay the fuse panel and the headlight switch. They are all unfused, for some reason the factory didn't find it necessary. the circuits from the fuse panel are fused but the headlights and the ignition are not run through fuses.

If you are intending to use the stock battery gauge, you will have to add two wires to your circuit. I assume you would like to use a voltmeter instead since it is much better indicator of the charging circuit. Also much easier to wire.


Here is a good example of a main junction, sometimes called a distribution block, to give you some ideas and show you that you aren't too far off with your design.

This one shows the battery installed at the rear of the frame but the connections are the same. It doesn't show the large battery cable to the starter solenoid so just assume it's there.





The two gauge cable from the battery is a good idea but it should have been run to the starter solenoid and then the 8 gauge wire from the junction would have been plenty good enough to keep it charged.

IMO the four gauge cable from the alternator is overkill for a 120 amp SI alternator. Again an 8 gauge would have been very adequate.


Here is another diagram with a distribution block that is way yonder better than the old stock wiring the factory gave us. Just keep in mind that what they gave us was quite good enough for the day.





That one also shows the two wires added for the battery gauge. They are the two with the 4 amp fuses in line for the gauge.

[jessemthompson]

Originally Posted by VetteVet

I don't like to correct a minor issue but in order to avoid confusion, the device you are calling a Shunt is just a simple junction. You will want to use a fusible link for the battery and alternator connections and fuse any loads that exit from the junction.

In our trucks the feed wire that goes to the firewall goes to a four way soldered junction and three of those wires feed the ignition switch the horn relay the fuse panel and the headlight switch. They are all unfused, for some reason the factory didn't find it necessary. the circuits from the fuse panel are fused but the headlights and the ignition are not run through fuses.

If you are intending to use the stock battery gauge, you will have to add two wires to your circuit. I assume you would like to use a voltmeter instead since it is much better indicator of the charging circuit. Also much easier to wire.


Here is a good example of a main junction, sometimes called a distribution block, to give you some ideas and show you that you aren't too far off with your design.

This one shows the battery installed at the rear of the frame but the connections are the same. It doesn't show the large battery cable to the starter solenoid so just assume it's there.


Attachment 1771909


The two gauge cable from the battery is a good idea but it should have been run to the starter solenoid and then the 8 gauge wire from the junction would have been plenty good enough to keep it charged.

IMO the four gauge cable from the alternator is overkill for a 120 amp SI alternator. Again an 8 gauge would have been very adequate.


Here is another diagram with a distribution block that is way yonder better than the old stock wiring the factory gave us. Just keep in mind that what they gave us was quite good enough for the day.


Attachment 1771930


That one also shows the two wires added for the battery gauge. They are the two with the 4 amp fuses in line for the gauge.

I have a fusible link in the charge wire to the battery. The 4 gauge wire may be a bit of overkill, but I could not find 8 gauge wire in town. So I figured 4 gauge wouldn’t hurt. As far as my volt gauge, I am using a Dakota digital dash. I didn’t include the starter in my diagram, but I am using 2 gauge wire to the starter and the wire from the junction to the battery is 10 gauge.

[CastIron]

VetteVet, I think you may saved me some time researching what I need to do to my truck. Thanks!