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Discussion Starter #1
Finally got around to hooking up my alternator right...I have a CS130 working great, never an issue that I seen 13v all the time. BUT, I had the voltage sensing wire looped right to the battery post on the back of the alternator.
NOW, today I finally got around to hooking up the wire to the horn relay for voltage sensing...all's great, 14v at the battery (in trunk) 14v at back of alternator, 14v at the horn relay....but now when the fan comes on (electric) it loads the motor and wants to stall :(


Should I go back to the way it was, or keep what it is now and fix it ? (and what's the fix :confused: )
 

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Where does your fan power connect to?

Don
 

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Other side of the horn relay.
I think that’s the issue. Try taking fan power from the battery or the battery cable on the starter. Make sure it’s properly fused.

Make sure the charging wire from the alternator is adequately sized for the amp rating of your alternator.

Don
 
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Discussion Starter #5
I think that’s the issue. Try taking fan power from the battery or the battery cable on the starter. Make sure it’s properly fused.

Make sure the charging wire from the alternator is adequately sized for the amp rating of your alternator.

Don
#8 wire from alt to battery in trunk
Starter cable is on a solenoid. so only hot during cranking


Where else would be a good spot :confused:
Don't want another wire to the trunk if I can help it.
 

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#8 wire from alt to battery in trunk
Starter cable is on a solenoid. so only hot during cranking


Where else would be a good spot :confused:
Don't want another wire to the trunk if I can help it.
Fans generally draw a lot of current. You could try running it to the alternator output post but the correct solution is to run it back to the battery with a large gauge wire imho.

This is one of the reasons I am not a fan of these solenoids that kill starter power. You don’t have a nice low resistance connection to the battery in the engine bay.

Don
 

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Discussion Starter #7
I'll have another look around. Maybe I was being lazy and went to the closest post ? :eek:
 

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If I am following you correctly the only place that has a hope in heck of working is connecting the fans to the power post on the alternator. All the other wiring in your car is too light gauge to supply your fans. I suspect your fans had low voltage in your previous arrangement.

Single or dual fans? Do you know the current rating of the fan?

Don
 

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Discussion Starter #9
Twin 10's or 12's ? Can't remember. Unsure of amp draw.(40A maybe ?)
Using a Craig Davies fan controller....1 fan comes on at a set temp with the other a few seconds later to prevent power surge.

I can say in this configuration, fans, water pump, and fuel pump all sound stronger....which is a good thing.

As for the power to the horn relay/bus bar....been using this as a reference.

 

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You should be able to connect your fans to the junction block as shown in that schematic. Your fuel pump and water pump should also be connected there.

Don
 

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Discussion Starter #11
Basically using the horn relay as the junction block.... I guess.

Trouble wrapping my head around why it would/wouldn't matter where the block is.
 

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Basically using the horn relay as the junction block.... I guess.

Trouble wrapping my head around why it would/wouldn't matter where the block is.
Because you don’t want all that extra current flowing through the presumably smaller gauge wire connecting the junction block to the horn relay. The high current will cause a voltage drop across that small gauge wire which in turn causes the regulator to push the alternator output voltage higher to compensate for that voltage drop.

Should be 8 gauge or larger from alternator to junction block.

If you don’t have a junction block add one per your schematic.

Don
 

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Discussion Starter #14 (Edited)
OK, will try that and see what happens...electric isn't my strong suit. (can you tell :sad: )


While I'm waiting, just for giggles, I'm going to run a temp wire to the battery for sensing and see what it does.
 

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OK, will try that and see what happens...electric isn't my strong suit. (can you tell :sad: )


While I'm waiting, just for giggles, I'm going to run a temp wire to the battery for sensing and see what it does.
That will likely help but you will likely see a drop in fan speed etc.

Don’t know where you got that schematic but it’s a pretty good design.

Don
 
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