Monitor your 12Volt battery

[Jimrpa]

The quiescent current (parasitic draw) is an average over the past 24 hours, it's measured by the BMS system when the car is off. It won't change or update while the car is on. You don't have to get out or do anything special, just use the Car Scanner app with an OBD reader.



See my note about having them fix the grille shutters.

The welcome lighting likes to keep going off when you store your keys within 40' of the car at home. You aren't going to be in the garage when it keeps turning on, so you probably have no idea unless you have video surveillance on the parked car.

Ah, I thought there was something odd about the welcome lighting. I go to the garage without my phone or keys, and sometimes it will come in at random.

Sponsored

 

[DarkStang]

I tried to test what the 12v amp draw is on the car when turned off, doors closed, sitting for a while. According to CarScanner it’s saying -5A which is obviously huge, but I think a good deal of that is probably the OBD dongle itself. Only way to see for sure would be using my multimeter but haven’t gotten around to that. But I did see that within an hour of letting it sit off with ODB plugged in at -5A, I lost over 12% SOC. Hoping it’s just the OBD and not some other computer process that draws that much when waking up.

But does anyone know why the 12v amps shift from negative numbers when car is off to positive when on? Does positive mean it is taking a charge from the HVB and negative is a drain on the LVB?

 

[dtbaker61]

Ah, I thought there was something odd about the welcome lighting. I go to the garage without my phone or keys, and sometimes it will come in at random.

if you hang keys on a hook near the vehicle, or have FordPass and BT active on your phone.... it will 'wake up' on Proximity and stay on for 10 minutes at a time; which draws a pretty large amount of energy from the little 12v.

I have Fob in foil, hidden in car for emergencies and valet/service

...and typically stop either BT or force-stop FordPass when I am home since my home office shares a wall with the garage and I go in-out to my garage shop multiple times a day.

 

[Mach-Lee]

I tried to test what the 12v amp draw is on the car when turned off, doors closed, sitting for a while. According to CarScanner it’s saying -5A which is obviously huge, but I think a good deal of that is probably the OBD dongle itself. Only way to see for sure would be using my multimeter but haven’t gotten around to that. But I did see that within an hour of letting it sit off with ODB plugged in at -5A, I lost over 12% SOC. Hoping it’s just the OBD and not some other computer process that draws that much when waking up.

But does anyone know why the 12v amps shift from negative numbers when car is off to positive when on? Does positive mean it is taking a charge from the HVB and negative is a drain on the LVB?

So you have to understand that the process of reading data from the vehicle keeps it awake. If you’re actively pulling data, the CAN busses are kept awake which does drain the battery in only a few hours. I’ve left Car Scanner running on my phone by accident after going inside, and later noticed it was still talking to the car from inside the house. The data log from that showed the 12V getting drained quickly like you saw.

So it’s very important to hit the red “Disconnect” button when you’re done using Car Scanner. Don’t forget.

Yes, negative current means the battery is draining, positive means the battery is charging. And again, you can’t use the scan tool to measure live draw current because doing so keeps the car awake.

 

[Maquis]

if you hang keys on a hook near the vehicle, or have FordPass and BT active on your phone.... it will 'wake up' on Proximity and stay on for 10 minutes at a time; which draws a pretty large amount of energy from the little 12v.

I have Fob in foil, hidden in car for emergencies and valet/service

...and typically stop either BT or force-stop FordPass when I am home since my home office shares a wall with the garage and I go in-out to my garage shop multiple times a day.

When my car is in my locked garage, the fob stays in the cup holder. Nothing I do in my garage causes the car to make up or do anything.
I only mention this, because it might be a better idea to leave the fob in the car, rather than hang it on a hook in the garage.

 

[Jimrpa]

if you hang keys on a hook near the vehicle, or have FordPass and BT active on your phone.... it will 'wake up' on Proximity and stay on for 10 minutes at a time; which draws a pretty large amount of energy from the little 12v.

I have Fob in foil, hidden in car for emergencies and valet/service

...and typically stop either BT or force-stop FordPass when I am home since my home office shares a wall with the garage and I go in-out to my garage shop multiple times a day.

It’s very possible the fob is within 40’ of the car (more like 20’ - it’s in a box in the living room). I always leave Bluetooth turned on on my iPhone because Apple Watch. However, my phone usually stays in the house when I’m running out to the garage (no need to carry it around because Apple Watch). So that leaves me with the mystery of the car randomly turning on welcome lighting ?

 

[Shayne]

"The quiescent current (parasitic draw) is an average over the past 24 hours, it's measured by the BMS system when the car is off."

The last part of the sentence is important. The quiescent current probably does NOT measure power draw in active state whenever electronics is woken up by some internal logic or external polling (Fordpass, 3rd party apps) in a locked vehicle.

Total energy draw overnight should probably be assessed by the drop in the %SOC of the 12V battery from evening to next morning. Of course, one should account for normal (or abnormal if degraded) battery self-discharge rate, and slight SOC fluctuations due to temperature change in a lead-acid battery.

High quiescent current (50+ mA) is probably a circumstantial evidence of such frequent wake-ups in a locked car, especially if paired with a significant drop in the 12V % SOC overnight.

I thought it may be when powered off with FP etc. taken into account and hence wide fluctuations? Not sure how it is measured did not know it was over 24 hour period either. Guess it is never off if it is monitoring when it is off. I just wanta push the button and it boots then goes in gear I do not monitor it too much when it is.

They should be able to figure out how to maintain the 12V with some of that AI a huge battery and a 240V feed. Mine has been good all winter not really monitoring it as it boots.

Wonder if it could be design that at start the 12V closes the contacts to the main battery and then the main battery (dc/dc power supply) boots the rest (most). Don't count so much on the 12V to boot the whole system and all the modules. Reducing 12V draw at boot should reduce it need for health. Not sure but if the 12V is too low it does not go in gear.

It’s very possible the fob is within 40’ of the car (more like 20’ - it’s in a box in the living room). I always leave Bluetooth turned on on my iPhone because Apple Watch. However, my phone usually stays in the house when I’m running out to the garage (no need to carry it around because Apple Watch). So that leaves me with the mystery of the car randomly turning on welcome lighting ?

Enjoy it when it happens Key is near and moves? Is the watch a key can it be doing it?

 

[Jimrpa]

I thought it may be when powered off with FP etc. taken into account and hence wide fluctuations? Not sure how it is measured did not know it was over 24 hour period either. Guess it is never off if it is monitoring when it is off. I just wanta push the button and it boots then goes in gear I do not monitor it too much when it is.

They should be able to figure out how to maintain the 12V with some of that AI a huge battery and a 240V feed. Mine has been good all winter not really monitoring it as it boots.

Wonder if it could be design that at start the 12V closes the contacts to the main battery and then the main battery (dc/dc power supply) boots the rest (most). Don't count so much on the 12V to boot the whole system and all the modules. Reducing 12V draw at boot should reduce it need for health. Not sure but if the 12V is too low it does not go in gear.


Enjoy it when it happens Key is near and moves? Is the watch a key can it be doing it?

Ford never had PAAK functionality for the Apple Watch app and they pulled the Apple Watch app entirely several months ago.

 

[DarkStang]

I’ve never been able to I understand the difference in these readings. 12V Battery Current is what I understand to be the draw from the LV battery. But there are others.

For DC-DC HV, is it showing current that is leaving the HVB to charge the LVB? Also don’t understand what DC-DC LV is measuring. I was thinking maybe that is current coming from the HVB and stepped down to 12v to run accessories. But not sure What the 12v battery current sensor is showing then.

Sponsored