Questions about Car Scanner Pro reading for 12v battery

[Fender66]

In the Forscan app, I have "12v Aux Battery" selected as of my items to monitor. The reading I get is usually between 14.0 - 14.5 volts. Is this normal? If so, why is higher than 12v nominal value?

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[MakinDoForNow]

In the Forscan app, I have "12v Aux Battery" selected as of my items to monitor. The reading I get is usually between 14.0 - 14.5 volts. Is this normal? If so, why is higher than 12v nominal value?

I don't have forscan but I would expect 12v aux battery to be the output of the dcdc convertor. Perhaps you need 12v monitored instead of 12v aux. With truck ready to drive you will see voltage on buss provided by either 12v battery but almost always whatever dcdc convertor or alternator is supplying to buss.

 

[HeyBales]

Because you have the truck running or in On position.

You really don't have an Accessory position for push-button start, despite what the manual says.

Once you hit the button with no brake pedal push - the 12V system throws the relay to bring the HVB online.
The 12VB is now being charged.

For another useful figure - find the PID for Bat_Curr_2 - it'll show you the Amps being delivered to the 12VB, to x.xx accuracy.

(well, as accurate as the battery sensor is anyway)

You might also see about using the V_Batt_BCM instead of the one you selected, and the BAT_ST_CHRG.

All 3 of those should be under the BCM module if the scanner splits them out by module.

 

[Mavster Mechanic]

In the Forscan app, I have "12v Aux Battery" selected as of my items to monitor. The reading I get is usually between 14.0 - 14.5 volts. Is this normal? If so, why is higher than 12v nominal value?

Normal.
Every car & truck on the road should be 14.x volt while the truck is on and driving. Should be 12.6 or a little above when the truck is off.

 

[Fender66]

Got it. Thanks.

 

[jet66]

I don't know the ins and outs of the hybrid system itself, but when charging a car battery, it's done at a 'float voltage.' It's basically a maintenance charge that offsets the natural discharge, keeping the battery chemistry and plates healthy. The 14-ish VDC is typical for a lead-acid 12VDC battery. (Lithium batteries are a little different.)

 

[Mavster Mechanic]

13.5v / 13.6v is a good "float" voltage.

Float means keep it where it is. Little to no charging or discharging. For charging you should be above 14 volts.

"A good voltage to charge a 12V Flooded Lead-Acid (FLA) battery is typically 14.4V to 14.7V for the main bulk/absorption charging phase. Once charged, the voltage should drop to a float level of 13.5V to 13.8V to maintain it. For maximum lifespan, avoid exceeding 14.8V at normal room temperatures and avoid consistent discharge below 12V."

Lead batteries are 2.1v per cell.
A 12 volt / 6 cell battery should rest at about 12.6v.

LiFePo batteries are 3.2v to 3.3v per cell.

A "12v" battery will be four cells. 12.8v to 13.2v will be a normal "average" resting voltage.

 

[DWV]

13.5v / 13.6v is a good "float" voltage.

Float means keep it where it is. Little to no charging or discharging. For charging you should be above 14 volts.

"A good voltage to charge a 12V Flooded Lead-Acid (FLA) battery is typically 14.4V to 14.7V for the main bulk/absorption charging phase. Once charged, the voltage should drop to a float level of 13.5V to 13.8V to maintain it. For maximum lifespan, avoid exceeding 14.8V at normal room temperatures and avoid consistent discharge below 12V."

Lead batteries are 2.1v per cell.
A 12 volt / 6 cell battery should rest at about 12.6v.

LiFePo batteries are 3.2v to 3.3v per cell.

A "12v" battery will be four cells. 12.8v to 13.2v will be a normal "average" resting voltage.

A 12v battery has 6 cells: 2.1 x 6 = 12.6 !

The 12v battery is only being charged when the dc inverter is told to charge, i.e. it is below the 80% level ; much of the time it will show 12.6 to 12.7v as is it not being charged. You are correct on start up, the voltage shows actual 12v batter voltage for an instant, before the DC inverter starts to charge it- if the voltage of the 12v battery is low enough to require charging.

 

[ZABSMAV]

A 12v battery has 6 cells: 2.1 x 6 = 12.6 !

The 12v battery is only being charged when the dc inverter is told to charge, i.e. it is below the 80% level ; much of the time it will show 12.6 to 12.7v as is it not being charged. You are correct on start up, the voltage shows actual 12v batter voltage for an instant, before the DC inverter starts to charge it- if the voltage of the 12v battery is low enough to require charging.

If you get the vehicle set so that it charges at around 14.71V until the AGM battery reaches 100% charge, it will recharge from whatever state of discharge it is in until it reaches back up to 100% and the voltage with the vehicle off is around 12.75V.

This is how Ford should have set them up at the factory, but for some reason set the maximum charge much lower. Now our 2023 hybrid Maverick Lariat gets back up to 100% fairly quickly.

 

[HeyBales]

A 12v battery has 6 cells: 2.1 x 6 = 12.6 !

The 12v battery is only being charged when the dc inverter is told to charge, i.e. it is below the 80% level ; much of the time it will show 12.6 to 12.7v as is it not being charged. You are correct on start up, the voltage shows actual 12v batter voltage for an instant, before the DC inverter starts to charge it- if the voltage of the 12v battery is low enough to require charging.

The whole stops charging at 80% rumor has been disproven multiple times.
Gotta get that incorrect tribal wisdom out.
Usually it drops to float charge from then on - 14.xV and less than 1A.
But sometimes it doesn't immediately.
But it still charges.

 

[DWV]

The whole stops charging at 80% rumor has been disproven multiple times.
Gotta get that incorrect tribal wisdom out.
Usually it drops to float charge from then on - 14.xV and less than 1A.
But sometimes it doesn't immediately.
But it still charges.

I didn’t say it stopped charging at 80% but that it starts charging at 80% or below. If one follows the charging or battery voltage continuously you will see it from battery voltage which is normally 12 6 to 12 eight on a charge battery when the DC inverter is “charging“ it will show 14.5 to 14.7 when the DC inverter stops charging it will drop down to the 12 V battery voltage.

In my 2024 hybrid it is either at battery voltage of 12.6 to 12.7 or is that the inverter voltage of 14.5 or slightly higher mm in

 

[HeyBales]

I didn’t say it stopped charging at 80% but that it starts charging at 80% or below. If one follows the charging or battery voltage continuously you will see it from battery voltage which is normally 12 6 to 12 eight on a charge battery when the DC inverter is “charging“ it will show 14.5 to 14.7 when the DC inverter stops charging it will drop down to the 12 V battery voltage.

In my 2024 hybrid it is either at battery voltage of 12.6 to 12.7 or is that the inverter voltage of 14.5 or slightly higher mm in

Then the way you phrased it keeps the incorrect info going.
"The 12v battery is only being charged when the dc inverter is told to charge, i.e. it is below the 80% level "

Since it still does receive charge above 80% Ford SOC. 85% on the other hand once it drops that low ....

So your readings and actions show the method in this thread might still be useful to your battery.
https://www.mavericktruckclub.com/forum/threads/hybrid-12v-battery-mystery-solved.81553/

And would have been useful when mine was at this state after install. It read 85% mere seconds before I could get this screen shot.

 

[ZABSMAV]

I didn’t say it stopped charging at 80% but that it starts charging at 80% or below. If one follows the charging or battery voltage continuously you will see it from battery voltage which is normally 12 6 to 12 eight on a charge battery when the DC inverter is “charging“ it will show 14.5 to 14.7 when the DC inverter stops charging it will drop down to the 12 V battery voltage.

In my 2024 hybrid it is either at battery voltage of 12.6 to 12.7 or is that the inverter voltage of 14.5 or slightly higher mm in

That was the point I was making is that Ford evidently set the vehicle to only provide the standard charge current when the battery SOC dropped below 80% and then when it reached 80% switched to trickle charging (around 1 amp). By changing the programming to tell it any time it is less than 100% to give the standard charge and not stop that amperage until the battery reaches 100% SOC. That is how all other vehicles with a standard alternator function. Now on our short trips around town the battery is normally almost completely recharged whereas before it never got above 80% SOC due to the switching to trickle charge. Now until it reaches the proper 100% SOC it charges at 14.75V.

 

[DWV]

Then the way you phrased it keeps the incorrect info going.
"The 12v battery is only being charged when the dc inverter is told to charge, i.e. it is below the 80% level "

Since it still does receive charge above 80% Ford SOC. 85% on the other hand once it drops that low ....

So your readings and actions show the method in this thread might still be useful to your battery.
https://www.mavericktruckclub.com/forum/threads/hybrid-12v-battery-mystery-solved.81553/

And would have been useful when mine was at this state after install. It read 85% mere seconds before I could get this screen shot.

Thanks for the information and attempt to help. I’m pretty much convinced that all individual vehicles do not behave the same way with respect to charging or discharging. Why I have no idea.

I have relayed this situation before when I proactively change flooded battery in my 2024 to AGM battery. Flooded battery operated as seems to be more or less normal in the Wood stop visibly charging at 80 to 81%. The AGM when installed given a full charge, BCM reset, and overnight relearn. Mysteriously began operating at 90 to 91% charge level no intervention on my part no use of for scan or anything else. Just the battery change in the reset relearn.

I also commented about a long nighttime drive with headlights on that brought the indicated charge up to 95 or 96%; due to the fact of the lights being on for several hours of driving.

So I really don’t have a problem. I have a mystery and everybody’s mystery is not exactly the same.

 

[ZABSMAV]

Thanks for the information and attempt to help. I’m pretty much convinced that all individual vehicles do not behave the same way with respect to charging or discharging. Why I have no idea.

I have relayed this situation before when I proactively change flooded battery in my 2024 to AGM battery. Flooded battery operated as seems to be more or less normal in the Wood stop visibly charging at 80 to 81%. The AGM when installed given a full charge, BCM reset, and overnight relearn. Mysteriously began operating at 90 to 91% charge level no intervention on my part no use of for scan or anything else. Just the battery change in the reset relearn.

I also commented about a long nighttime drive with headlights on that brought the indicated charge up to 95 or 96%; due to the fact of the lights being on for several hours of driving.

So I really don’t have a problem. I have a mystery and everybody’s mystery is not exactly the same.

We just took a short drive across town of 10.9 miles and the SOC before turning the vehicle on started at 89%. The drive took a total of 22 minutes and the SOC, when reaching home, was 96%. It was charging at 14.75V all the way home and when the Maverick was turned off it was at 12.62V.

Had we driven several more miles it would have reached a 100% SOC and the voltage would have read right around 12.75.

I can say that thanks to our dealership's persistence in working on our problem (which they have told me was a problem happening to almost every hybrid Maverick that they have sold and continue to service) our problem with deep sleep has finally been solved. We have not had even one single deep sleep issue since this was done by the dealership (the 100% SOC setting).

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