MiguelsC2

I have Vintage Air and Spal fan on my '63. As suggested in previous threads, I rewired my a/c and Spal fan power wires from Vintages recommended battery connection, over to the horn relay.
Instead of a positive charging situation, it now takes a deep negative dive when the a/c and spal fan go on.

When not using the a/c system,the car charges fine. Needless to say,it's losing badly with the A/C-Spal fan on.To the point of draining the battery.

I am running the Powermaster 65 amp alternator.

Hooking it up the way Vintage Air suggested causes the needle to go about 25% + past 0 on the gauge face. Is this even an issue? I have returned the hookup to Vintage Airs suggested connection.
Any ideas?

Kensmith

I have a 100amp alternator and hooked up the electric fan and A/C to a 50amp circuit breaker I mounted near the alternator. I have 30amp fuses on the fan and a/c lines. The power now comes directly off the alternator to the breaker. That supplies only the A/C and Fan. My battery gauge now reads correctly.

MiguelsC2

How is your positive alternator wire hooked up? At the new breaker or from the back of the alternator.
I am wondering if a 140 amp alternator will cure the issue without any wiring changes?

Kensmith

Yep, run a second red wire from the alternator to the 50amp circuit breaker. I did this because I didn't want to change the original harness or send too much juice through the harness than intended.

wmf62

my .02... a higher potential amperage should have a larger wire, probably a 10 gauge all the way back to the battery.

if you are going to use a bus bar arrangement (which is what the horn relay is acting as), then run a dedicated additional wire from the alternator to the bus bar and draw your a/c stuff from that.
Bill

MiguelsC2

I dropped my unit by the local alternator shop. They are upping it to the 140 amp range. I am considering a larger gauge alt wire also. Some say you should and some say you don't need it. ??

wmf62

better safe than sorry... i suggest a 10 gauge wire.
Bill

MiguelsC2

Thanks Bill. I think you are right.

magicv8

Run an additional 10 ga wire between the alt and the horn relay, whether you have a 65 or a 140 amp alternator. The 10 ga harness wire on the alt gets too hot otherwise. After that, if the battery meter problem persists, clean the battery meter connections in the bulkhead plug.

MiguelsC2

Run both the harness 10ga and an extra 10ga wire at same time?
All bulkhead and gauge connections are fresh and clean.

wmf62

yes, i think he is saying to run an additional 10 gauge along with the orig wire. the horn relay is acting as a bus bar, splitting the current off to other places. i would go so far as to run an additional #10 parallel to the original, all the way back to the battery.

fwiw, doing the math, 2 #10s is a larger conductor than a single #8,

#8 0.128x3.14=0.40 conductive surface
#10 0.102x3.14=0.32 x2=0.64 total conductive surface

saves pulling the old wire out...

Bill

MiguelsC2

Thanks Bill. I am not much for electrical. I can get it done. But analysis is not one of my strong points.

magicv8

and you really can't just pull the old wire out, because the regulator reads the demand at the big splice in the harness where the power heads forward to the horn relay.

Kensmith

What does this mean? Sorry for the interruption!

because the regulator reads the demand at the big splice in the harness where the power heads forward to the horn relay

MiguelsC2

These thing are more complex than they seem. I have only a modest idea of what the splice is and what it does.

Kensmith

Mike, we seem to be kind of in the same boat here. I do have a NOS under hood wiring harness I purchased some time ago as I was going to have my mechanic re-wire the car before I had him install the Vintage Air. I might try and take a pic of it and maybe it will show the splice ??? Or just throw more confusion on the table? What do you think?

wmf62

Ken
toss it on the table, it's the only way to get an answer (or answers... )
Bill

magicv8

I didn't mean to confuse anyone. I just want to be clear that my advice is to add a 10 ga from the alt to the relay buss.

Trying to REPLACE the line in the factory harness with a larger wire may have unintended consequences - no disaster, but where the regulator senses the load on the harness is important. I know the added wire works because I did it to my car 10 years ago.

magicv8

Here's an article about the harness junction: http://www.madelectrical.com/electri...esensing.shtml

MiguelsC2

Keep it coming. Solutions are around the corner.