Nissan Frontier Forum banner

1 - 20 of 25 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter #1
So I have a 2012 nissan frontier. I installed a AGM battery. I have a volt meter that runs in the dash and my voltage will drop from 14.2 to 13.1-13.2 Ive upgraded the grounds, and made sure everything is tight. Im not sure whats happening, Anyone have a clue??
 

·
Premium Member
Joined
·
5,973 Posts
Sounds normal to me...and is what I see when viewing this particular gauge through the OBD data port.
 

·
Registered
Joined
·
593 Posts
Normal for this vehicle. Will jump up to 14ish here and there but will generally settle down into low 13’s at idle or easy consistent driving.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #4
Normal for this vehicle. Will jump up to 14ish here and there but will generally settle down into low 13’s at idle or easy consistent driving.
If I were to add a second battery for audio. would this improve? Im worried that the alternator wont charge my batteries wnough. Or does the alternator not charge unless it needs the charge from heavy draw from the battery?
 

·
Registered
Joined
·
778 Posts
The voltage as-is is perfect. So adding a 2nd battery won't "improve" it, as there's nothing to improve. As you stated, the alternator will vary its output to keep the battery properly charged. A 2nd battery is great for very large loads such as a snowplow (nowadays they are electric; when I was growing up they were hydraulic fed by an engine-driven pump).
 

·
Registered
Joined
·
593 Posts
If I were to add a second battery for audio. would this improve? Im worried that the alternator wont charge my batteries wnough. Or does the alternator not charge unless it needs the charge from heavy draw from the battery?
As RedDR stated; adding a second battery won’t change the voltage, it will simply give you more amp hours and total watts to work with. The alternator is capable of providing a certain amount of amps at a certain voltage, which is what in turn equals wattage. If your audio system is going to use so much energy that it will outstrip the alternator then yes, adding a second battery would provide a buffer and extended run time. A second battery is usually most helpful for an item such a winch that draws a lot of power, but only for a short time, and then the alternator has time to charge up both batteries again.

so, to reiterate, assuming your vehicle is running and operating fine, the voltage reading you are getting is normal. It is what I get as well. What you need to do is compile your audio components and see how many amps they would be drawing at a time, and then go from there in regards to what you need to do (i.e. leave system alone, add a second battery, or install a higher capacity alternator).
 

·
Registered
Joined
·
2,286 Posts
What you are getting is normal. If you disable the amperage sensor that is a halo around the negative battery cable, the ECM will stop sending turn-off signals to the alternator and it will operate normally using its internal voltage regulator only.
As stated already by others, multiple batteries will only increase run-time or make up a temporary deficit for hi-load items like a winch, snowplow or massive audio system. I had a dual batt setup in my 83 Camaro with an Optima for the second battery ( back when Optima wasn't junk ), located in a custom box where the rear seat used to be ( along with the amps and a ventilation fan under one massive flat panel, doorjamb to doorjamb ) and they were slaved together when the engine was running, by a 150amp power solenoid and a 150amp in-line fuse. Worked great. Run the stereo as long as you wanted to, then start the engine off the main batt and recharge them both. Diesel trucks have multiple batteries for the same reason, to double, triple or quadruple the available starting / cranking amperage by sharing the load across multiple cells and cell groups. At -40F it takes quite a bit of juice to spin over an 18L engine. Oil's like molasses.
 

·
Registered
Joined
·
2,044 Posts
The voltage as-is is perfect.
"Typical" would be a better word than "perfect".

Nissan uses a goofy "POWER GENERATION VOLTAGE VARIABLE CONTROL SYSTEM" that periodically reduces the alternator output voltage, in the interest of improving fuel economy. (Less alternator output voltage means less mechanical drag on the engine, which means better fuel economy).

This is accomplished with a "Power Generation Command Signal" wire coming from the IPDM to the voltage regulator module inside the alternator. The signal on this wire instructs the voltage regulator to reduce the alternator's output voltage.

316155


As a result of this signal, in some cases, the output voltage from the alternator can drop down into the high-12's - which is not particularly useful for recharging the battery.

Here's how to defeat it:

316156


After this wire is cut, the voltage regulator inside the alternator operates like any other "normal" voltage regulator, producing "normal" battery charging voltages.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #9
"Typical" would be a better word than "perfect".

Nissan uses a goofy "POWER GENERATION VOLTAGE VARIABLE CONTROL SYSTEM" that periodically reduces the alternator output voltage, in the interest of improving fuel economy. (Less alternator output voltage means less mechanical drag on the engine, which means better fuel economy).

This is accomplished with a "Power Generation Command Signal" wire coming from the IPDM to the voltage regulator module inside the alternator. The signal on this wire instructs the voltage regulator to reduce the alternator's output voltage.

View attachment 316155

As a result of this signal, in some cases, the output voltage from the alternator can drop down into the high-12's - which is not particularly useful for recharging the battery.

Here's how to defeat it:

View attachment 316156

After this wire is cut, the voltage regulator inside the alternator operates like any other "normal" voltage regulator, producing "normal" battery charging voltages.
So cutting the wire will give me what I’m looking for, is there any long term issues cutting that wire? I’m going to install connectors to each end just in case I need to reconnect them.
 

·
Registered
Joined
·
2,044 Posts
There's no long-term issues with cutting the wire. The alternator works just like any normal alternator afterwards.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #14
How did this work out for you? I just purchased a Mechman 270a for my Frontier.
How did this work out for you? I just purchased a Mechman 270a for my Frontier.
So I haven't cut he PCM wire because I don't feel confrtable with that. I unplugged the plug right at the ground halo. Voltage without A/C sticks at 13.2-13.4 with the A/C off I stick around 13.9. So far I think I need the alternator to fix the low voltage. Let me know how you like that alternator! I may mechman or Brand X
 

·
Registered
Joined
·
2,044 Posts
The air conditioner compressor draws almost no current - So it shouldn't be affecting your battery voltage at all when it kicks on.

What is a "ground halo"?
 

·
Registered
Joined
·
370 Posts
If you install a super stereo, your alternator will do its job, if, your battery is in tip top shape, todays eletrical systems as mentioned already control the output of the alternator, but ONLY when there is no need, if you need anything for your system look into capacitors, and no battery is going to keep up with a stereo like I believe you are talking about if the truck isnt running and mayve even at idle,,, If anything you may need a higher output alternator and definitely a capacitor or capacitors.

Its got to be one hell of a system to overpower your alternator while the truck is running, anything over 13 volts at the battery is good, 14 or better output from alt is acceptable as well.
 

·
Registered
Joined
·
3,012 Posts
An AC compressor clutch can pull up to about 4amps. The blower motor also requires a little.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #18
If you install a super stereo, your alternator will do its job, if, your battery is in tip top shape, todays eletrical systems as mentioned already control the output of the alternator, but ONLY when there is no need, if you need anything for your system look into capacitors, and no battery is going to keep up with a stereo like I believe you are talking about if the truck isnt running and mayve even at idle,,, If anything you may need a higher output alternator and definitely a capacitor or capacitors.

Its got to be one hell of a system to overpower your alternator while the truck is running, anything over 13 volts at the battery is good, 14 or better output from alt is acceptable as well.

So Im atually doing well on electrical for the current Im drawing. High output is a givin for what Im doing. But its a slow go. Right now I have a 91Ah AGM intimadator, and upgraded grounds, and upgraded the power cable from the alternator. I have done a few car systems before, just nothing with the PCM. Power wise Im pretty good with what Im needing for the future
 

·
Registered
Joined
·
2,044 Posts
An AC compressor clutch can pull up to about 4amps. The blower motor also requires a little.
In the V6, the OEM alternator is rated to produce at least 82 amps at 1800 RPM - or 130 amps at 5000 RPM. In that context, 4 amps is insignificant.
 
  • Like
Reactions: Pacer6
1 - 20 of 25 Posts
Top