Wire size for high output alternator?
01-11-2005, 12:00 PM
#1
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Wire size for high output alternator?
I got me a high-output 1-wire alternator for Xmas. According to the tag on it, it puts out 60A @ 3000 RPM and 95A @ 6000 RPM.
I've got my battery in the trunk of my car.
What size wire do I need to run from the alternator to the cut-off switch? The docs that came with the alternator say 8 gauge, but I'm assuming that's for a battery that's mounted under the hood, not in the back.
I've got my battery in the trunk of my car.
What size wire do I need to run from the alternator to the cut-off switch? The docs that came with the alternator say 8 gauge, but I'm assuming that's for a battery that's mounted under the hood, not in the back.
01-11-2005, 12:06 PM
#2
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Here's another question that kinda goes along with that.
The RPM is the alternator speed, not the engine speed, based on a stock pulley (3:1). I've got a 30% underdrive pulley on my crank.
So... If the alternator is rated at 60A @ 3000 RPM (alternator speed), the engine speed is 1000 RPM. With the 30% underdrive, that's 1300 RPM, I think?
With that thinking, this alternator will put out full amperage at 2600 engine RPM? (rated at 95A @ 6000 alternator RPM, divided by 3 = 2000, plus 30% = 2600)? Is that right?
The RPM is the alternator speed, not the engine speed, based on a stock pulley (3:1). I've got a 30% underdrive pulley on my crank.
So... If the alternator is rated at 60A @ 3000 RPM (alternator speed), the engine speed is 1000 RPM. With the 30% underdrive, that's 1300 RPM, I think?
With that thinking, this alternator will put out full amperage at 2600 engine RPM? (rated at 95A @ 6000 alternator RPM, divided by 3 = 2000, plus 30% = 2600)? Is that right?
01-11-2005, 02:12 PM
#3
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Join Date: Aug 2004
Location: Long Island, NY
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I'm using 1/0 welding cable from
http://www.weldingsupply.com/cgi-bin...F:OR:terms::PA
I bought the swedge on tool for the cable lugs, should come out nice once I get to it.
http://www.weldingsupply.com/cgi-bin...F:OR:terms::PA
I bought the swedge on tool for the cable lugs, should come out nice once I get to it.
01-11-2005, 02:18 PM
#4
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Originally Posted by 82GT
I'm using 1/0 welding cable from
http://www.weldingsupply.com/cgi-bin...F:OR:terms::PA
I bought the swedge on tool for the cable lugs, should come out nice once I get to it.
http://www.weldingsupply.com/cgi-bin...F:OR:terms::PA
I bought the swedge on tool for the cable lugs, should come out nice once I get to it.
01-11-2005, 03:04 PM
#10
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Join Date: Aug 2004
Location: Long Island, NY
Posts: 278
Welding Cable By The Foot
Industry standard class K neoprene insulated welding cable. Made from 30-gauge soft-drawn copper strands for superior flexibility. Properties: 600v, -40 deg C. to +90 deg C., heavy duty/all purpose.
Industry standard class K neoprene insulated welding cable. Made from 30-gauge soft-drawn copper strands for superior flexibility. Properties: 600v, -40 deg C. to +90 deg C., heavy duty/all purpose.
01-12-2005, 12:05 PM
#11
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Join Date: Jan 2005
Location: Ellington, CT
Posts: 2
I used an 8 gauge wire to my battery in the trunk and have not had a problem in 4 years. I run an 75 amp one wire.
You have to connect the alternator to the battery side of the switch or directly to the positive side of the battery.
If not the car will not shut down if the switch is turned off.
You have to connect the alternator to the battery side of the switch or directly to the positive side of the battery.
If not the car will not shut down if the switch is turned off.
01-12-2005, 12:07 PM
#12
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Originally Posted by bdyj
I used an 8 gauge wire to my battery in the trunk and have not had a problem in 4 years. I run an 75 amp one wire.
You have to connect the alternator to the battery side of the switch or directly to the positive side of the battery.
If not the car will not shut down if the switch is turned off.
You have to connect the alternator to the battery side of the switch or directly to the positive side of the battery.
If not the car will not shut down if the switch is turned off.
01-12-2005, 04:23 PM
#13
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Join Date: Jul 2004
Location: Vernon, New Jersey
Posts: 278
Mike, what you could do is (if you already have 1 8ga wire) is to run a second 8ga. New math; 8+8=4ga equivalent. On long runs, the bigger gauge the better. If the wire heats up, you loose efficency.
01-17-2005, 08:20 AM
#15
Senior Member
Join Date: Sep 2004
Posts: 194
Originally Posted by Smink
I've got a Delco 3-wire 100 amp with internal regulator.
Direct wire to the positive post in the trunk is TEN GAUGE.
Do some checking, 10 gauge is all you need.
Direct wire to the positive post in the trunk is TEN GAUGE.
Do some checking, 10 gauge is all you need.
02-11-2005, 04:57 PM
#16
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I picked up some 4 awg wire for this, finally..
Scored 25' on eBay for a good deal:
http://cgi.ebay.com/ebaymotors/ws/eB...tem=4524436227
I also picked up some gold-plated terminals:
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=5749463599
So I guess my wire search is over!
Scored 25' on eBay for a good deal:
http://cgi.ebay.com/ebaymotors/ws/eB...tem=4524436227
I also picked up some gold-plated terminals:
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=5749463599
So I guess my wire search is over!
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