I've hit the search wall... SBC cs144 alt. upgrade (1 Viewer)

[Elfman]

I've spent the the bulk of my afternoon searching, maybe I'm just bad at it, but I think I've narrowed down my situation to 2 questions.
My rig is a 69 FJ40 Gen 1 SBC converted to an e fan recently. The 12SI alternator (63A) can't keep up after a few months of operation, it's literally crying for mercy. So I believe what I need is the CS144 alternator 170A ish. I should be able to clock it and mount it just fine with my current brackets and serpentine belt set up ( I think).

question 1: My puny charging wire runs in to the factory harness near the clutch drivers side. Then pops back out PS and drops down to the starter solenoid. Is it picking something up in the dash that would be factory (ammeter)? No charging/idiot light in the dash. Can I bypass this with a larger wire and go straight to batt or solenoid?
Question 2: Is there or do I need some kind of adaptor for 12SI plug to CS144 connector? Since there is no idiot light, does someone here on mud (like @Coolerman ) make such an adaptor with a resistor?
Help and experience always appreciated.

 

[Pin_Head]

Yes you can wire the alternator directly to the battery, but it is good practice to use a fusible link to protect the wiring. You will lose the functionality of the amp meter, so it might be a good idea to use a volt meter or idiot light. I would just get the cs144 plug and splice it in.

 

[76 PTO]

I too have a 350 with a electric fan. I have the whole setup from a 92 truck, serpentine belt and brackets. I opted for the larger amp alt. I by passed all the cruiser wiring and used a dedicated thick wire to battery.
A one wire alt needs a wire from the ignition too excite it. You will need a resistor in line or you will blow the internal regulator. Ask me how I know. You can look up online what that value is. I guess the idiot light acted like the resistor in the stock application.

 

[offrd63]

There is a lot of good info here. It's a lot of reading.http://www.madelectrical.com/electrical-tech.shtml

 

[middlecalf]

Yes you can wire the alternator directly to the battery, but it is good practice to use a fusible link to protect the wiring. You will lose the functionality of the amp meter, so it might be a good idea to use a volt meter or idiot light. I would just get the cs144 plug and splice it in.

Ok, this is good stuff. But I’m not sure how the fusible link stops the functionality of the ammeter.

 

[Pin_Head]

It doesn’t. Wiring the alternator output directly to the battery does.

 

[Elfman]

Yes you can wire the alternator directly to the battery, but it is good practice to use a fusible link to protect the wiring. You will lose the functionality of the amp meter, so it might be a good idea to use a volt meter or idiot light. I would just get the cs144 plug and splice it in.

I think I understand that going straight to the solenoid bypasses the ammeterCan the ampmeter handle the juice of a larger alt. and beefier wire? After viewing @Coolerman website wiring schematic (thank you sir) it seems likely that the current charging wire hooks into the factory harness and indeed passes through the ammeter. I'm working hard to maintain an operational factory gauge cluster.
Though my speedo woes are pushing me to the brink of a Dakota Digital. Anyone know if that can handle a larger alt.?

 

[Elfman]

There is a lot of good info here. It's a lot of reading.http://www.madelectrical.com/electrical-tech.shtml

Whoa! This looks like it could be very helpful. Thanks for the link. I've got more reading to do.

 

[Elfman]

A high current wire has to go into the cab no matter what so there is always some danger. That is why these wires must have a fusible link. With the older cruiser amp meter, the difference is that there are two high current wires entering the cab; one from the battery and one from the alternator. After about '78, Toyota moved the shunt outside the cab, using the fusible link as a shunt for the meter. Both of the meter wires are fused, to protect the meter in case the link burns out.

One trick for using the OEM meter with high output alternators is to double the internal meter shunts and run new, larger wires. Two shunts doubles the capacity so that the original 30-0-30 meter will now indicate 60-0-60.

QSL, 73s

Found this in another thread ,can you expand on this?

 

[nogo]

There is a lot of good info here. It's a lot of reading. MadElectrical.com - Electrical Tech

Fixed it.

 

[Pin_Head]

Found this in another thread ,can you expand on this?

High current amp meters typically have what is known as a shunt. They can either be built into the meter or external to the meter. The meter is typically made with fine wire that can’t handle high current without burning out, so a low resistance resistor (wire) is added in parallel with the meter so that 1000 times more current flows through the shunt than the meter. If you double the shunt, then 2000 times the current will flow through the shunt. If you triple the shunt, then 3000 times more current, etc.

To change the capacity of your meter, you need to find the size and length or wire to add to the shunt and make the meter read full deflection at higher current. You would put another high capacity amp test meter in series with the FJ40 meter and then run different size wires across the two terminals until the recalibrated meter reads what ever amp value you want at full deflection.

 

[Elfman]

High current amp meters typically have what is known as a shunt. They can either be built into the meter or external to the meter. The meter is typically made with fine wire that can’t handle high current without burning out, so a low resistance resistor (wire) is added in parallel with the meter so that 1000 times more current flows through the shunt than the meter. If you double the shunt, then 2000 times the current will flow through the shunt. If you triple the shunt, then 3000 times more current, etc.

To change the capacity of your meter, you need to find the size and length or wire to add to the shunt and make the meter read full deflection at higher current. You would put another high capacity amp test meter in series with the FJ40 meter and then run different size wires across the two terminals until the recalibrated meter reads what ever amp value you want at full deflection.

Ugh! My head! OK so do I do both of the things; add external 200A shunt (4 AWG) to the firewall on engine bay side then run smaller (12-10 AWG) wire to the ammeter and inside the ammeter increase the size of wire in the internal shunt?

 

[Pin_Head]

No. You can either add an external shunt between the battery and the chassis and alternator and get a new external shunt meter to match or you can increase the intrernal shunt size to increase its capacity and keep the OEM amp meter.

Or you could just run the alternator B+ output wire directly to the battery + (with a fusible link in series) and run a volt meter or an idiot light. Obviously the last option is the easiest.

 

[Elfman]

No. You can either add an external shunt between the battery and the chassis and alternator and get a new external shunt meter to match or you can increase the intrernal shunt size to increase its capacity and keep the OEM amp meter.

Or you could just run the alternator B+ output wire directly to the battery + (with a fusible link in series) and run a volt meter or an idiot light. Obviously the last option is the easiest.

thanks for your help with this. Think I'll take the easier option for now. I'd be pretty nervous to start running the larger wires and extra juice into the cab. Just curious, would the ammeter work between the key ignition and fuse block just to give it something to do. Any thoughts?
Feel like I'm pestering you at this point.

 

[Pin_Head]

The ammeter is a two way meter for current flow in and out between the battery on one side and the cruiser and the alternator on the other side of the meter. (The starter motor is not involved directly in this). When everything is good and happy, the battery is fully charged on one side and the alternator is supplying all the current for the cruiser on the other side, so there is no flow in or out of the battery and the ammeter reads zero.

If you attach the alternator directly to the battery, the ammeter only reads the current out of the battery that is used by the cruiser. This isn’t very informative as to what the alternator is putting out or the charge status of the battery. You want to know if the alternator is working and if the battery if fully or partially charged.