Voltage?
10-24-2004, 10:02 PM
#1
Guest
Posts: n/a
Voltage?
How much voltage should an alternator put out?
I measured the voltage on the line from the battery going to the master disconnect. With the engine off but the power on, I got 12.5 volts with a brand new battery. With the engine running, no accessories on, I got 12.8 volts. With the electric water pump and electric fan going, I got 12.8 volts. Both of those checks were with the engine at idle, about 800 RPM.
The alternator is supposed to put out 60 amps, and there's an 8 gauge line that runs from the alternator directly to the master disconnect.
Is this good or bad? I'm assuming that as long as it's at least 12 volts, it's good.
(edit)
I'm just thinking that the alternator (it's a Mopar, modified for 1-wire operation) has a regulator on it that doesn't turn on until 900 RPM. I probably should check it at about 12-1500 RPM.
I measured the voltage on the line from the battery going to the master disconnect. With the engine off but the power on, I got 12.5 volts with a brand new battery. With the engine running, no accessories on, I got 12.8 volts. With the electric water pump and electric fan going, I got 12.8 volts. Both of those checks were with the engine at idle, about 800 RPM.
The alternator is supposed to put out 60 amps, and there's an 8 gauge line that runs from the alternator directly to the master disconnect.
Is this good or bad? I'm assuming that as long as it's at least 12 volts, it's good.
(edit)
I'm just thinking that the alternator (it's a Mopar, modified for 1-wire operation) has a regulator on it that doesn't turn on until 900 RPM. I probably should check it at about 12-1500 RPM.
10-25-2004, 04:02 AM
#3
Administrator
Join Date: Aug 2004
Location: Hopewell Jct., NY
Posts: 501
Re: Voltage?
Originally Posted by BBLM23
Originally Posted by mikelbeck
How much voltage should an alternator put out?
I probably should check it at about 12-1500 RPM.
I probably should check it at about 12-1500 RPM.
10-25-2004, 09:30 AM
#5
Senior Member
Join Date: Jul 2004
Location: Vernon, New Jersey
Posts: 278
At idle you should have 14-14.5 volts at the battery. Even though the alternator is rated at 60amps, it's probably putting out much less. Check the Amp output at the alternator. 8ga wire is fine, I only run 10ga without a problem and don't use a relay to the battery in the trunk.
If you need to upgrade the alternator, Summit offers the Powermaster 120amp which is great. Their catalog wrongly lists it as 75amps at $160, but I ordered one and it came with a tag certifing it as 120amps. It listed in the Mopar section.
If you need to upgrade the alternator, Summit offers the Powermaster 120amp which is great. Their catalog wrongly lists it as 75amps at $160, but I ordered one and it came with a tag certifing it as 120amps. It listed in the Mopar section.
10-25-2004, 09:51 AM
#6
Senior Member
Join Date: Sep 2004
Posts: 194
Re: Voltage?
Originally Posted by mikelbeck
Originally Posted by BBLM23
Originally Posted by mikelbeck
How much voltage should an alternator put out?
I probably should check it at about 12-1500 RPM.
I probably should check it at about 12-1500 RPM.
10-25-2004, 09:51 AM
#7
Guest
Posts: n/a
Originally Posted by sickt7cuda
At idle you should have 14-14.5 volts at the battery. Even though the alternator is rated at 60amps, it's probably putting out much less. Check the Amp output at the alternator. 8ga wire is fine, I only run 10ga without a problem and don't use a relay to the battery in the trunk.
If you need to upgrade the alternator, Summit offers the Powermaster 120amp which is great. Their catalog wrongly lists it as 75amps at $160, but I ordered one and it came with a tag certifing it as 120amps. It listed in the Mopar section.
If you need to upgrade the alternator, Summit offers the Powermaster 120amp which is great. Their catalog wrongly lists it as 75amps at $160, but I ordered one and it came with a tag certifing it as 120amps. It listed in the Mopar section.
I was looking at the Tuff Stuff 1-wire alternator. Does Powermaster have a 1-wire version?
You're using a 10 gauge wire with a 120 amp alternator?
10-25-2004, 09:54 AM
#8
Senior Member
Join Date: Sep 2004
Posts: 194
Re: Voltage?
Originally Posted by Mopower71
Originally Posted by BBLM23
Originally Posted by mikelbeck
How much voltage should an alternator put out?
I probably should check it at about 12-1500 RPM.
I probably should check it at about 12-1500 RPM.
10-25-2004, 11:42 AM
#9
Senior Member
Join Date: Jul 2004
Location: Vernon, New Jersey
Posts: 278
Yes, Powermaster does have a 1 wire version in Chrysler trim.
And I am using 10ga with a 120amp alternator. Haven't had any roblems so far. With the 1 wire there is no need for an external voltage regulator cause it's built into the alternator. I should note that I have an underdrive pully on the alternator.
And I am using 10ga with a 120amp alternator. Haven't had any roblems so far. With the 1 wire there is no need for an external voltage regulator cause it's built into the alternator. I should note that I have an underdrive pully on the alternator.
10-25-2004, 11:44 AM
#10
Guest
Posts: n/a
Originally Posted by sickt7cuda
Yes, Powermaster does have a 1 wire version in Chrysler trim.
And I am using 10ga with a 120amp alternator. Haven't had any roblems so far. With the 1 wire there is no need for an external voltage regulator cause it's built into the alternator. I should note that I have an underdrive pully on the alternator.
And I am using 10ga with a 120amp alternator. Haven't had any roblems so far. With the 1 wire there is no need for an external voltage regulator cause it's built into the alternator. I should note that I have an underdrive pully on the alternator.
Oh... I just remembered that I have an underdrive pulley on the crank, I'll probably have to rev it up higher to get the alternator going.
11-01-2004, 10:54 PM
#14
Guest
Posts: n/a
Originally Posted by Mopower71
Originally Posted by mikelbeck
Originally Posted by sickt7cuda
Roger that. REV IT UP !!!!!
11-03-2004, 12:27 PM
#15
Guest
Posts: n/a
I started up the motor, checked the output at the alternator. A little over 13 volts at idle. When I rev it up to around 2000 RPM, it's almost 14 volts. At the battery, it was almost 13 volts at idle, so I'm losing a little bit on that long wire from the alternator to the master switch. I wasn't able to rev it up and check the voltage back at the battery, I was working by myself.
The volt meter it getting it's power from the starter relay via a 10 or 12 gauge wire. That's getting it's power from the starter, via an 8 gauge wire. Could this be why the volt meter is showing a lower voltage than what's actual winding up at the battery? What should the volt meter be connected to?
The volt meter it getting it's power from the starter relay via a 10 or 12 gauge wire. That's getting it's power from the starter, via an 8 gauge wire. Could this be why the volt meter is showing a lower voltage than what's actual winding up at the battery? What should the volt meter be connected to?
11-03-2004, 12:50 PM
#16
Super Moderator
Join Date: Jul 2004
Location: Moonachie, NJ
Posts: 886
Thread
Thread Starter
Forum
Replies
Last Post
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)