Help! Questions about proper voltage, alternator, etc.
#1
10-02-2016, 08:46 AM
Help! Questions about proper voltage, alternator, etc.
Can anyone tell me if the below voltage readings are where they should be? Here's some background info - I replaced the old stock alternator with a TAD 190amp unit from Nations Starters & Alternators. I installed an upgraded 2 gauge wire between the alternator and battery, in addition to leaving the stock wiring. I didn't want to rip apart the existing harnesses. I monitor my voltage in the truck using an Edge CTS. I always keep the batteries connected to a trickle charger when parked at home. I have 2 new Optima red top batteries.
With the old alternator my voltage would would quickly drop down to low 13's while driving, often times getting into the 12's or even high 11's. So I expected to see a near constant 14 when putting on a new, high amp alternator.
With the new alternator I'm seeing this:
From the time I start the truck after disconnecting from the trickle charger(fully charged batteries):
First 0-60 seconds 12.2-12.4 volts.
Next 1-5 minutes 14.1-14.4 volts.
Next 30-45 minutes of drive time 13.3-13.7 volts. (no high electrical loads, just usual lights, etc.)
Is this acceptable or should I be seeing a constant 14+ volts now that I have a new alternator? I feel like the volts should never be dropping into the low 13's with a new 190 amp alternator and lower gauge wire.
With the old alternator my voltage would would quickly drop down to low 13's while driving, often times getting into the 12's or even high 11's. So I expected to see a near constant 14 when putting on a new, high amp alternator.
With the new alternator I'm seeing this:
From the time I start the truck after disconnecting from the trickle charger(fully charged batteries):
First 0-60 seconds 12.2-12.4 volts.
Next 1-5 minutes 14.1-14.4 volts.
Next 30-45 minutes of drive time 13.3-13.7 volts. (no high electrical loads, just usual lights, etc.)
Is this acceptable or should I be seeing a constant 14+ volts now that I have a new alternator? I feel like the volts should never be dropping into the low 13's with a new 190 amp alternator and lower gauge wire.
#3
10-02-2016, 11:24 AM
From the Ford Manual:
With the system functioning normally, the generator output current is determined by the voltage of the A circuit. This A circuit voltage (battery sense circuit) is compared to a set voltage internal to the regulator, and the regulator controls the generator field current to maintain correct generator output.
The set voltage will vary with temperature and is typically higher in cold temperatures than in warm temperatures. This allows for better battery recharge in the winter and reduces the chance of overcharging in the summer.
Ford’s service manual specs that the voltage is acceptable at the passenger positive terminal at 13.0 to 15.0 volts. And each subsequent leg of electrical connections can have an individual drop of 0.5v.
Most service advisories give wide latitude, be it from the vehicle manufacturers or field service industry.
Ford’s real spec as well as recommended by SAE is 13.8v to 14.2v at the first positive terminal. SAE recommendations for voltage drop depends on the current flowed through the circuit, but 0.2v is a good maximum guide. Temperature compensation was endorsed by SAE and that is what all the vehicle manufacturers follow and the why of 14.2v cold and 13.8v as the under hood and batteries warms up.
Aftermarket suppliers, both the small specialty shops or the majors (Bosch, Leece-Neville) can do as they wish, both in set points as well as temperature compensation. I typically see 14.4v to 13.8v off the alternator with my L-N 230a. Some aftermarket regulators may have a high temperature compensation of 13.6v. So it’s important to be mindful of where the under hood temperatures may be.
How you are reading voltage also has an impact on the values. Off the initial connection to the alternator, off the vehicle harness with some voltage drop at each connection, or off the OBD output in which the PCM reports some voltages in 0.5v increments. An alternator output of 13.8v may have a value of 13.49v in the harness while the OBD port shows 13.0v due to the reporting increments. If the harness voltage is varying 13.45v to 13.55v, the OBD display can show a variation (jumping) of 13.0v to 13.5v causing undue stress for the person monitoring it, not only to the swings but also to the lower value that in reality is not there.
And now that I'm back to this thread with another post, yeah I could have said those voltages are fine.
With the system functioning normally, the generator output current is determined by the voltage of the A circuit. This A circuit voltage (battery sense circuit) is compared to a set voltage internal to the regulator, and the regulator controls the generator field current to maintain correct generator output.
The set voltage will vary with temperature and is typically higher in cold temperatures than in warm temperatures. This allows for better battery recharge in the winter and reduces the chance of overcharging in the summer.
Ford’s service manual specs that the voltage is acceptable at the passenger positive terminal at 13.0 to 15.0 volts. And each subsequent leg of electrical connections can have an individual drop of 0.5v.
Most service advisories give wide latitude, be it from the vehicle manufacturers or field service industry.
Ford’s real spec as well as recommended by SAE is 13.8v to 14.2v at the first positive terminal. SAE recommendations for voltage drop depends on the current flowed through the circuit, but 0.2v is a good maximum guide. Temperature compensation was endorsed by SAE and that is what all the vehicle manufacturers follow and the why of 14.2v cold and 13.8v as the under hood and batteries warms up.
Aftermarket suppliers, both the small specialty shops or the majors (Bosch, Leece-Neville) can do as they wish, both in set points as well as temperature compensation. I typically see 14.4v to 13.8v off the alternator with my L-N 230a. Some aftermarket regulators may have a high temperature compensation of 13.6v. So it’s important to be mindful of where the under hood temperatures may be.
How you are reading voltage also has an impact on the values. Off the initial connection to the alternator, off the vehicle harness with some voltage drop at each connection, or off the OBD output in which the PCM reports some voltages in 0.5v increments. An alternator output of 13.8v may have a value of 13.49v in the harness while the OBD port shows 13.0v due to the reporting increments. If the harness voltage is varying 13.45v to 13.55v, the OBD display can show a variation (jumping) of 13.0v to 13.5v causing undue stress for the person monitoring it, not only to the swings but also to the lower value that in reality is not there.
And now that I'm back to this thread with another post, yeah I could have said those voltages are fine.
#4
10-02-2016, 05:46 PM
That's pretty much what I see and I just have the Factory 140A with overdrive pulley + second cable to pass battery and 2nd cable between batts. It is when I did those cable mods when I got the higher readings. Even when hot I will see a jump to the 14s here and there. The consistently highest Voltage reading PID for me is (in Torque) the Adapter Voltage and that usually is close to what the nifty cigar lighter voltage gauge reads that Jack turned us on to...
You are good
You are good
#5
10-04-2016, 08:18 AM
From the Ford Manual:
With the system functioning normally, the generator output current is determined by the voltage of the A circuit. This A circuit voltage (battery sense circuit) is compared to a set voltage internal to the regulator, and the regulator controls the generator field current to maintain correct generator output.
The set voltage will vary with temperature and is typically higher in cold temperatures than in warm temperatures. This allows for better battery recharge in the winter and reduces the chance of overcharging in the summer.
Ford’s service manual specs that the voltage is acceptable at the passenger positive terminal at 13.0 to 15.0 volts. And each subsequent leg of electrical connections can have an individual drop of 0.5v.
Most service advisories give wide latitude, be it from the vehicle manufacturers or field service industry.
Ford’s real spec as well as recommended by SAE is 13.8v to 14.2v at the first positive terminal. SAE recommendations for voltage drop depends on the current flowed through the circuit, but 0.2v is a good maximum guide. Temperature compensation was endorsed by SAE and that is what all the vehicle manufacturers follow and the why of 14.2v cold and 13.8v as the under hood and batteries warms up.
Aftermarket suppliers, both the small specialty shops or the majors (Bosch, Leece-Neville) can do as they wish, both in set points as well as temperature compensation. I typically see 14.4v to 13.8v off the alternator with my L-N 230a. Some aftermarket regulators may have a high temperature compensation of 13.6v. So it’s important to be mindful of where the under hood temperatures may be.
How you are reading voltage also has an impact on the values. Off the initial connection to the alternator, off the vehicle harness with some voltage drop at each connection, or off the OBD output in which the PCM reports some voltages in 0.5v increments. An alternator output of 13.8v may have a value of 13.49v in the harness while the OBD port shows 13.0v due to the reporting increments. If the harness voltage is varying 13.45v to 13.55v, the OBD display can show a variation (jumping) of 13.0v to 13.5v causing undue stress for the person monitoring it, not only to the swings but also to the lower value that in reality is not there.
And now that I'm back to this thread with another post, yeah I could have said those voltages are fine.
With the system functioning normally, the generator output current is determined by the voltage of the A circuit. This A circuit voltage (battery sense circuit) is compared to a set voltage internal to the regulator, and the regulator controls the generator field current to maintain correct generator output.
The set voltage will vary with temperature and is typically higher in cold temperatures than in warm temperatures. This allows for better battery recharge in the winter and reduces the chance of overcharging in the summer.
Ford’s service manual specs that the voltage is acceptable at the passenger positive terminal at 13.0 to 15.0 volts. And each subsequent leg of electrical connections can have an individual drop of 0.5v.
Most service advisories give wide latitude, be it from the vehicle manufacturers or field service industry.
Ford’s real spec as well as recommended by SAE is 13.8v to 14.2v at the first positive terminal. SAE recommendations for voltage drop depends on the current flowed through the circuit, but 0.2v is a good maximum guide. Temperature compensation was endorsed by SAE and that is what all the vehicle manufacturers follow and the why of 14.2v cold and 13.8v as the under hood and batteries warms up.
Aftermarket suppliers, both the small specialty shops or the majors (Bosch, Leece-Neville) can do as they wish, both in set points as well as temperature compensation. I typically see 14.4v to 13.8v off the alternator with my L-N 230a. Some aftermarket regulators may have a high temperature compensation of 13.6v. So it’s important to be mindful of where the under hood temperatures may be.
How you are reading voltage also has an impact on the values. Off the initial connection to the alternator, off the vehicle harness with some voltage drop at each connection, or off the OBD output in which the PCM reports some voltages in 0.5v increments. An alternator output of 13.8v may have a value of 13.49v in the harness while the OBD port shows 13.0v due to the reporting increments. If the harness voltage is varying 13.45v to 13.55v, the OBD display can show a variation (jumping) of 13.0v to 13.5v causing undue stress for the person monitoring it, not only to the swings but also to the lower value that in reality is not there.
And now that I'm back to this thread with another post, yeah I could have said those voltages are fine.
#6
10-04-2016, 08:23 AM
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