Battery voltage above 15V?

[2021AreaFiftyOneOBX]

2.7 OBX has been showing battery voltage anywhere from 14.5 - 15.1V on my gauges the majority of the time. Seems excessive compared to normal ranges when searching for the answer (couldn’t find anything specific to the Bronco)

Is this a typical range for this battery/alternator?

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[fzracer484]

I might double check it by hand with a voltmeter to see if the digital guage reading is accurate. 15 is a bit on the high side though not completely outrageous so you're not going to cook anything quickly but it can kill a battery over time or worse create some electrical gremelins. If it is in fact charging high it's a simple alternator swap.

 

[MLRey]

Sounds a bit high, I would check with a real voltmeter to see if the reading is correct. If it is really 15 volts it could cause a problem with some batteries. Regular lead acid won't care much but the AGMs need lower voltage and can be damaged with high (> 14.8 ) voltage.

 

[Nolabel]

I actually noticed mine above 15 the other day but it dropped down to 13 after a few minutes so I didn't pay much attention otherwise.

 

[Bongo Fury]

https://www.autobatteries.com/en-us/battery-testing-and-maintenance/car-battery-voltage-and-testing

I'd double check with a multimeter to confirm.

 

[WuNgUn]

As long as it doesn't stay at 15+V all the time. You should see it varying depending on conditions.

 

[Murraydog11]

https://www.autobatteries.com/en-us/battery-testing-and-maintenance/car-battery-voltage-and-testing

I'd double check with a multi-meter to confirm.

This article states not to use a hand held multi-meter, but a true load (carbon pile) battery tester. A much more expensive and specialized piece of equipment. If you don't have one of those, take it to the dealer with your concerns.

 

[Bongo Fury]

This article states not to use a hand held multi-meter, but a true load (carbon pile) battery tester. A much more expensive and specialized piece of equipment. If you don't have one of those, take it to the dealer with your concerns.

The article did mention carbon pile testing as a means of testing battery under load conditions....so yes, but using a multimeter to test voltage charge would be my first check to see if my alternator was functioning properly.
A quick check a dealership would be the easiest option, I'd agree.

"this measurement should be 13.7 to 14.7 volts. If you don’t have a multimeter to tell you the voltage of your battery, you can do a test of your electrical system by starting the car and turning on the headlights."

 

[JohnnyBronco]

What is being displayed is not the actual battery voltage but the voltage of the entire electrical system at that particular point in time. Nominal and desired voltage of a 12v auto battery when not connected to vehicle is 13.6v. It takes charging at higher than 13.6 to keep it at 13.6 charging voltage (output of your alternator) of 15v is of no particular concern and in no way, in my experience, evidence of a problem at all.

LiFePO4 Battery Voltage Charts (12V, 24V & 48V) - Footprint Hero

Your vehicle shuts off at most stops, with all electrical functions still running from lights to music to communications. A system drop to a certain point and your vehicle won't restart when you take your foot off the brake. I have not checked the CCA of the batteries but certainly to provide the extra on demand starting that a first gen Bronco would never need they have to be more substantial than the battery in a Fiesta. More substantial battery requires higher capacity charging

 

[66Fan]

Battery voltage <> Alternator output

It's fine.

 

[flip]

Charging System

The PCM controlled Smart Charge charging system determines the optimal voltage setpoint for the charging system and communicates this information to the voltage regulator. The Smart Charge charging system is designed to set a DTC when a charging system fault is present. All of the DTC can set continuous faults, but not all DTC's set as on-demand faults.

The smart regenerative charge system primary strategy is stored in the BCM. The BCM receives information relating to the battery condition from the battery monitoring sensor via a LIN. The BCM calculates and sends the set value needed for the generator charging voltage via the HS-CAN to the PCM. The PCM then adjusts the value received (if necessary) and sends it to the generator via a different LIN. The charging voltage is adjusted depending on various parameters, such as the current level of engine efficiency. The smallest possible set value for the generator voltage is 12.2 volts, while the maximum charging voltage can be anywhere between 14.5 and 14.9 volts. However, when the battery is in a refresh phase, the voltage may occasionally reach up to 15.2 volts. These refresh phases are required when the battery charge status is 80% over long periods of time, which increases the risk of sulfation in the battery cells.

The PCM simultaneously controls and monitors generator output. When the current consumption is high or the battery is discharged, the PCM raises engine speed as needed to increase generator output. The generator charges the battery and at the same time supplies power for all electrical loads. The battery is more effectively charged with a higher voltage when the battery is cold and a lower voltage when the battery is warm.

The PCM turns off the generator during cranking to reduce the generator load and improve cranking speed. Once the engine starts, the PCM slowly increases generator output to the desired voltage.

The PCM reports any charging system faults and sends a message through the HS-CAN to the BCM. The BCM then sends a message over the MS-CAN to the IPC, which controls the charging system warning indicator. If equipped with a charging system warning indicator, the IPC turns the indicator on or off. If equipped with a message center, the IPC displays the corresponding message to notify the driver of the condition.

Under certain circumstances, the charging system may have a concern but still keeps the battery charged while the vehicle is running. The LIN is normally used to initiate charging, but with a fault in this circuit the generator self-excites or begins charging on its own. The charging system warning indicator is illuminated and/or the corresponding message to notify the driver of the condition is displayed and the generator operates in a default mode (approximately 13.8 volts).

 

[DFNMAN]

Mine is usually between 12.8 and 13.8 and occasionally goes to 14.2. I have a 2.7L.

 

[2Jeeps&PatriotX1]

Flipping through the menu screens today on the interstate, I noticed 15.2V while doing 75mph. Yes, we have interstates with that speed limit here in CO.

 

[cowman]

2.7 OBX has been showing battery voltage anywhere from 14.5 - 15.1V on my gauges the majority of the time. Seems excessive compared to normal ranges when searching for the answer (couldn’t find anything specific to the Bronco)

Is this a typical range for this battery/alternator?

My OB 2.7 does the same thing...

 

[Razorbak86]

Nominal and desired voltage of a 12v auto battery when not connected to vehicle is 13.6v. It takes charging at higher than 13.6 to keep it at 13.6 charging voltage (output of your alternator) of 15v is of no particular concern and in no way, in my experience, evidence of a problem at all.

LiFePO4 Battery Voltage Charts (12V, 24V & 48V) - Footprint Hero

I‘m not sure that a 12V 100Ah LiFePO4 battery — popular for off-grid solar power systems and often used as a drop-in replacement for 12V lead acid batteries — is the correct baseline to use when talking about the Bronco’s OEM lead acid battery. According to that link, the LiFePO4 battery is fully charged at 14.6V (or 13.6V resting).

The Bronco’s OEM lead acid battery is a typical, “12V” car battery, but each cell is actually 2.1V, so a “12V” battery is actually fully charged at 12.6V.

The full operating range when the vehicle and charging system are both active is anywhere from 12.6V to just a little over 15.0V (i.e., the green range shown on the chart below).

This chart is listed on the BatteriesPlus Blog at the link below, which provides lots of useful information.

Source: How Do I Find The Voltage of My Car Battery

How Many Volts Should a 12-Volt Battery Have?

A 12-volt battery is standard in most modern vehicles. It consists of six cells, each of which contains 2.1 volts of power at full charge. Therefore, a car battery is considered fully charged at 12.6 volts or higher when the engine is off. When you start your car, your battery's voltage will drop for a short time before climbing back up to its running voltage. During the starting process, a healthy car battery should have a voltage of 10V or higher (although this can be lower in instances of cold weather). Once the vehicle is running, this measurement will be slightly higher. This is because your alternator is actively charging your battery. With the engine running, your battery's voltage should be somewhere between 13.5 and 14.7 volts.

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