Ford Quality

[chl]

It’s an antitheft device. My understanding is it pulling voltage data every 5 minutes.

As for the issue, sometimes I’ll go weeks without experiencing it. Other times it’ll happen serval times in a row. Sometimes only once. It appears to be very random.

Sorry but that randomness DOES sound like it could be a 12v battery or 12v system issue.

For the sake of brevity, I am not going to go into the complicated explanation of why your monitoring method is not showing it, or why the 15v you/it measured is misleading.

Just trust what others above have said, put you 12v on a maintainer overnight one time (or do a slow EVSE charge overnight) and see if it occurs.

Here is a link about he different ways to charge up the 12v battery:

https://www.macheforum.com/site/threads/how-to-get-failed-otas-to-install.29749/

This post form the Mach-e forum goes into depth about these 12v AGM batteries:

https://www.macheforum.com/site/threads/how-to-recondition-service-your-12v-battery.11069/

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[ClevelandBeemer]

Sorry but that randomness DOES sound like it could be a 12v battery or 12v system issue.

I think it’s worth a conversation. If my monitoring method shows 13.1 to 13.3v when parked and the truck off for hours, how’s that misleading?

Also how is the 15v when running misleading? Does that not mean that the dc to dc inverter is charging the battery as it should?

FYI, I have a trickle charger which I’ve placed on the 12v before, just to rule out this very thing. Guess what still happens? Through this forum and other sites I’ve also received feedback that other non-EV Fords have this same issue. Ford’s that have much more robust 12v batteries. Is it possible in all cases, the 12v could be low? Perhaps. Is it likely? No.

 

[Dahveed]

I think it’s worth a conversation. If my monitoring method shows 13.1 to 13.3v when parked and the truck off for hours, how’s that misleading?

Also how is the 15v when running misleading? Does that not mean that the dc to dc inverter is charging the battery as it should?

FYI, I have a trickle charger which I’ve placed on the 12v before, just to rule out this very thing. Guess what still happens? Through this forum and other sites I’ve also received feedback that other non-EV Fords have this same issue. Ford’s that have much more robust 12v batteries. Is it possible in all cases, the 12v could be low? Perhaps. Is it likely? No.

My 2020 Ranger that I had before the Lightning did the same thing, like you just mentioned. Just one of those things, I guess. I never put a lot of thought into it. It shuts up so quick that I wasn't too concerned about it.

 

[chl]

I think it’s worth a conversation. If my monitoring method shows 13.1 to 13.3v when parked and the truck off for hours, how’s that misleading?

Also how is the 15v when running misleading? Does that not mean that the dc to dc inverter is charging the battery as it should?

FYI, I have a trickle charger which I’ve placed on the 12v before, just to rule out this very thing. Guess what still happens? Through this forum and other sites I’ve also received feedback that other non-EV Fords have this same issue. Ford’s that have much more robust 12v batteries. Is it possible in all cases, the 12v could be low? Perhaps. Is it likely? No.

1) Terminal voltage is not the same as voltage under load and the terminal voltage will "settle down" as someone else mentioned above some time after the charging - read the thread that I posted the link to about the nuances of AGM batteries if you want more info

2) 15v may be charging the 12v but will it top it off to 100% - not necessarily and probably not

3) Which Fords? Do they have as much parasitic draw as the Lightning? Do they use a BMS like the Lightning and other F-150's?

Yes it is an EV issue - my 2012 Nissan Leaf is always on a maintainer after the first time it ran down too low to start the Leaf a month or two after I bought it in 2011 - yes that 12v battery is now 14+ years old and still starts the Leaf and things run fine - because it is always on a maintainer when not in use.

But it is also an F-150 ICE issue - plenty of YouTube videos about it.

The trouble seems to be the 12v system BMS - it never really tops off the battery, and then as a result, sulfates can become permanent and over time build up on the plates, and when charging, because the BMS let the battery get so far discharged, the charging currents are very high which can lead to venting and loss of water, both of which lead to early demise of a battery that could last 14 years (like my Nissan Leaf AGM).

A battery maintainer will top off the battery using a trickle of a charge 1A for example, so it will result in sulfates NOT becoming permanent and charging currents NOT being excessively high.

Using a maintainer once in a while is not necessarily good enough.

Like I said, it might be the 12v battery - it could also be another problem in the 12v system, like the broken/shorting or disconnected wire mentioned in post 14 of the thread that @chriserx mentioned.

Of course it could be the HVB battery management system or some other component in the mix.

All I meant was determining the real SOC and SOH of the 12v battery is difficult and probably unreliable with sensing every 5 minutes or so. Would have to take it out and load test it to be sure it is healthy.

 

[ClevelandBeemer]

1) Terminal voltage is not the same as voltage under load and the terminal voltage will "settle down"

2) 15v may be charging the 12v but will it top it off to 100% - not necessarily and probably not

3) Which Fords? Do they have as much parasitic draw as the Lightning? Do they use a BMS like the Lightning and other F-150's?

Yes it is an EV issue - my 2012 Nissan Leaf is always on a maintainer after the first time it ran down too low to start the Leaf a month or two after I bought it in 2011 - yes that 12v battery is now 14+ years old and still starts the Leaf and things run fine - because it is always on a maintainer when not in use.

But it is also an F-150 ICE issue - plenty of YouTube videos about it.

Hey there! Tis been a long week but I’m finally circling back to this.

1. Yep, I understand voltage sag under load. That said after scouring my logs, I can’t find any voltages lower than 12.6v. It seems to update fairly quickly, potentially as little as every 15 seconds based on me rapidly updating my tracker. In fact, I see that the battery is currently at 15.4v with the truck plugged into its EVSE in for about 30 minutes or so.

2. You are 100% correct. Scanning via OBDII just shows the SoC the BMS thinks the 12v battery is at. That said, it’s the data point I have. The BMS has to be semi-accurate or we’d see more 12v catastrophic failures of Motorcraft 12v batteries.

3. I’ve seen people mention the ICE F150, Mach E, and 2024 Escape.

Again, I’m not sure this is a 12v issue. I don’t doubt, that a 12v with super low SoC could cause such goofy behavior, yet all signs point to adequate SoC from my 12v battery. I’ve driven German cars for over 29 years and I’m hyper familiar of the electrical gremlins that surface when the 12v SoC is too low. In the three times I’ve experienced this, I’ve been able to meter the battery at 11v or lower. That’s not the case with my current battery.

 

[PJnc284]

In fact, I see that the battery is currently at 15.4v with the truck plugged into its EVSE in for about 30 minutes or so.

When the truck is actively charging the hvb, it will charge the 12v. Yours must not sit very much if you're usually seeing 13.1. I barely saw that immediately after shutting the truck off much less now that I have a hardwired dashcam.

Yesterday I drove to work, didn't charge, went to lunch and then went home. Looks like it dropped about 12.5V-12.6V overnight. Was 18F when I left this morning. Went to work this morning and charged where the voltage was floating around 13.5V. My drives are fairly short so doesn't do a great job of keeping the 12V topped up. At this point the battery is a little over 2 year old.

 

[ClevelandBeemer]

When the truck is actively charging the hvb, it will charge the 12v. Yours must not sit very much if you're usually seeing 13.1. I barely saw that immediately after shutting the truck off much less now that I have a hardwired dashcam.

Yesterday I drove to work, didn't charge, went to lunch and then went home. Looks like it dropped about 12.5V-12.6V overnight. Was 18F when I left this morning. Went to work this morning and charged where the voltage was floating around 13.5V. My drives are fairly short so doesn't do a great job of keeping the 12V topped up. At this point the battery is a little over 2 year old.

Nice! Out of curiosity what are you using to track voltage?

One important detail I’ve left out is my battery is only 1 year old. I have nothing aftermarket that’s drawing power from the battery with the truck powered off sans the tracker.

 

[PJnc284]

It's an el-cheapo monitor from Amazon. https://www.amazon.com/dp/B01MT4583U

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