12V Battery FAQ

[Ride_the_lightning]

That comment isn't factual, the DC/DC stays on as long as the ignition is ON regardless of door open. Voltage may change, but it stays on. Don't use accessory mode while tailgating to avoid 12V drain per the FAQ.


Have you used any 3rd party apps in the past that access vehicle data? Think hard. Here’s the list: Optiwatt, Recurrent, ev.energy, ABRP (OTA live data), Tronity, Charge Smart MA, SmartCharge Rewards, other power utility control/saver apps, FordPass plugins for HomeBridge or Home Assistant, phone widgets.

If so, you need to change your FordPass password to rule out polling.

I would not disable connected vehicle data completely, you won’t get OTAs and BlueCruise will stop working. Fix the root cause of the polling instead.

I meant turn connected services off for a few days to see if the problem clears up, then they can dig in more specifically to see what is causing the repeated polling. Turning it off permanently isn’t really a solution.

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[mkhuffman]

I feel like my wife worries about stuff that we don't need to worry about. She literally worries about everything. I love her, but it is a running joke between us.

You guys seem to be worrying too much about your LVB. Seriously. Lee posted a chart that shows how long a AGM battery should last depending on geographic weather conditions. If you keep your car in a garage, or you live in a mild climate area, your battery should last 5+ years. Reconditioning the battery periodically can help, and I am doing that. But if it starts to fail, just get a new one. What's the big deal?

I will take bets from anyone who wants to bet me. My car's LVB was at 45% SoC when I parked it on Monday. Any bets the battery is dead when I return on Sunday? My bet is no, it will be fine. Because the car will keep it charged as it should. (The car is unplugged and sitting in my garage.)

Any takers?

 

[ChehRob]

Kid wanted me to have a forward Cam, so got me one. It is powered via the cigarette lighter. Ford agency tech guy assured me that while it stays powered for a short time after turning off the car, it will not be a problem with draining the LVB.

ps - I was there today to get permanent license plates installed.

 

[RobbertPatrison]

I feel like my wife worries about stuff that we don't need to worry about. She literally worries about everything. I love her, but it is a running joke between us.

You guys seem to be worrying too much about your LVB. Seriously. Lee posted a chart that shows how long a AGM battery should last depending on geographic weather conditions. If you keep your car in a garage, or you live in a mild climate area, your battery should last 5+ years. Reconditioning the battery periodically can help, and I am doing that. But if it starts to fail, just get a new one. What's the big deal?

I will take bets from anyone who wants to bet me. My car's LVB was at 45% SoC when I parked it on Monday. Any bets the battery is dead when I return on Sunday? My bet is no, it will be fine. Because the car will keep it charged as it should. (The car is unplugged and sitting in my garage.)

Any takers?

Haha. Not taking it though I get your point. Unfortunately this is more than an inconvenience in my case. My first 12V battery lasted 13 month and the second barely 6 months. Both were covered under warranty, but it won't be later if this continues. With a bad battery OTA updates won't work and a few months later the car will brick.

Replacement 12V batteries of this type are hard to get and expensive. Plus: it is a pain to bring the car back to service.

The cause is clearly that the poor little battery is significantly drained and recharged at least twice daily. I need to find out what is sneakily draining this thing.

 

[MachE70]

It took 3 days of charging for mine to reach 100%.

My 12v LVB has been pretty well behaved in the 20 months I have owned my '22 Mach e GT; I have had only one recent OTA fail to install due to low battery (currently updated thru 6.13), and have had maybe 3 or 4 instances where the center screen was shut down due to low battery.

I recently drilled access holes in the frunk so I could charge the 12v LVB. It started at about 57% SoC according to my Ford online account, and quickly charged to 84% within the first 24 hours. Since then, it has only gained about 1% SoC each day. It finally hit 90% this morning after almost 5 days of continuous charging with my NOCO Genius2 2 amp charger. Does this sound normal? Is it taking so long because of the low amp charger and/or because maybe there is a lot of desulfation going on? Should I keep going to hit 100%?

 

[Mach-Lee]

My 12v LVB has been pretty well behaved in the 20 months I have owned my '22 Mach e GT; I have had only one recent OTA fail to install due to low battery (currently updated thru 6.13), and have had maybe 3 or 4 instances where the center screen was shut down due to low battery.

I recently drilled access holes in the frunk so I could charge the 12v LVB. It started at about 57% SoC according to my Ford online account, and quickly charged to 84% within the first 24 hours. Since then, it has only gained about 1% SoC each day. It finally hit 90% this morning after almost 5 days of continuous charging with my NOCO Genius2 2 amp charger. Does this sound normal? Is it taking so long because of the low amp charger and/or because maybe there is a lot of desulfation going on? Should I keep going to hit 100%?

I would keep going to >95% if you can. Is the light on the NOCO solid green yet? FYI the NOCO has a wimpy charge termination, it cuts out too soon so it will be very slow at the end.

 

[MachE70]

I would keep going to >95% if you can. Is the light on the NOCO solid green yet? FYI the NOCO has a wimpy charge termination, it cuts out too soon so it will be very slow at the end.

Yes, the light turned solid green after about 8-12 hours of charging. Maybe I need to get a different 5 amp charger.

 

[Mach-e4x]

I don't drive much and only charge at home, I have two EVSE's, one for L1 (Ford mobile)and one for L2 (Grizzle)charging when needed.
To keep the LVB happy on my car, I plug in the L1 charger, 120v, EVSE when the HVB is at about 50%. By the time the HVB pack is up to around 80% (all night) my LVB will be at 90%.
Before I was only using L2 so it only needed a short time to get the HVB from 60-80% charged and that was not long enough to keep the LVB happy.

 

[ocr_salty]

This is excellent, thank you for sharing!

I have had a lot of issues with the 12V battery system over the years, and it has blocked a number of updates until I go on a long journey and also gives me the "System off to save power" message a lot.

This is probably down to me using a third party software to enable my car to be charged overnight when it is best for the UK national grid (Octopus Intelligent) but this has now been agreed with Ford do they no longer block users. Just a pain that they didn't think hard enough about the 12V battery.

 

[RobbertPatrison]

This is excellent, thank you for sharing!

I have had a lot of issues with the 12V battery system over the years, and it has blocked a number of updates until I go on a long journey and also gives me the "System off to save power" message a lot.

This is probably down to me using a third party software to enable my car to be charged overnight when it is best for the UK national grid (Octopus Intelligent) but this has now been agreed with Ford do they no longer block users. Just a pain that they didn't think hard enough about the 12V battery.

After I got my 12V battery replacement I checked the behavior of my MME more closely. It takes its time to go to sleep: 15 minutes, while the USB plugs in the car are powered for up to 30 minutes. This means that the 12V battery constantly drains down and recharges, wearing out the battery. If I come home from a longer trip the state is full at ~91%. The next morning it is typically 72%, so 20% loss for not good reason. Sometimes it wakes up several times and the battery drains to below 50%. OTA software updates will not work below 80%, which means that they won't work most of the time.

 

[Logal727]

So, just to be clear, if I need to replace the 12v and the dealer ends up being out of stock of the OEM battery, I can replace with battery from different brand with same specs and size? Seeing a post on Reddit where dealer said battery would take 3 months to get.

 

[Mach-Lee]

So, just to be clear, if I need to replace the 12v and the dealer ends up being out of stock of the OEM battery, I can replace with battery from different brand with same specs and size? Seeing a post on Reddit where dealer said battery would take 3 months to get.

Yes.

 

[Aulander]

I read many threads about the 12V battery issues related to the udates installation, but this is what a member of the Ford Europe Staff in charge of OTA updates deployment, based in UK, answered to my question:

"The 12V battery statement is not true. There is no 80% 12V battery state of charge (SoC) limit for downloading an update. Provided the vehicle is not giving you a 12V battery warning message, then you should be OK. Even with warning messages, the update may still complete ok, depending on the specific issues being flagged."

 

[Mach-Lee]

I read many threads about the 12V battery issues related to the udates installation, but this is what a member of the Ford Europe Staff in charge of OTA updates deployment, based in UK, answered to my question:

"The 12V battery statement is not true. There is no 80% 12V battery state of charge (SoC) limit for downloading an update. Provided the vehicle is not giving you a 12V battery warning message, then you should be OK. Even with warning messages, the update may still complete ok, depending on the specific issues being flagged."

That statement is mostly true. He said there's no charge limit to DOWNLOAD an update, which is correct. The update will download when the vehicle is on. However, there IS a charge limit to INSTALL the update.

All OTAs have a 12V charge threshold for install, it varies by each update and is actually calculated in terms of amp-hour capacity available rather than percent. I said "about 80%" as a general guideline. If your 12V battery spends most of its time well below 80%, you will have trouble installing OTAs. Anybody that doesn't believe that hasn't been around here much to see all the issues and how they are usually solved by charging up the 12V battery.

He's also said this:

"The power management in the vehicle will also ensure that the update can be installed. In many cases it happens between an ignition off and ignition on cycle and is very quick. Where it's an update that requires the vehicle to be off for a short period for installation, the vehicle takes care of power requirements and you do not need to do anything with your 12V battery."

"Ensure" is a bad word choice, he should have said "verify" instead. First part is okay, but I disagree with the last statement. The vehicle does not automatically take care of the power requirements to install an OTA, so you do have to manually intervene with the 12V battery when your updates keep failing. It's not proactive with the 12V charging.

 

[hartmms]

I've been stuck on the 23-PU0722-DC-CHG3 level of update since Dec 16th. We don't drive much and I've noticed the 12v SOC is typically < 80% most of the time (OBDII reader and Torque app). Contributing to this lower chronic lower SoC situation is I'm sure the car is waking up some amount as I walk through the house with my phone. I also have the Home Assistant FordPass plugin installed configured to default poll rate (15 min).

I figured maybe it's stuck on OTA updates due to low SOC. I've got the NOCO genius 10 and plugged it into the correct connection points and charged it several times according to the NOCO green only LED. However, the car SoC never gets above 88%. It doesn't stay there for long. I will admit there the very first charging session where I had connected to the actual battery negative terminal. I now know that bypassed the BMS and may have caused it to be confused about the real SoC. I have done subsequent charging sessions to 100% according to the NOCO and did the BMS reset procedure once.

1) with a charger, shouldn't I be able to get to 100% SoC as measured by the car BMS?
2) I've got the frunk tub and panels off and noticed both front and back side of the battery have bulges in them. Maybe this is how the battery case was built. I know the batteries have vents, but can someone confirm the battery should have bulges like this?

Maybe I'm approaching this all wrong. I want to keep the PAAK and home assistant app and figured when the forums report there are OTA updates newer than what I have, I can just pop on the 12v charger, get the SoC above 90% and within a few drives the car will update. Maybe this approach won't work. Maybe I should stop fretting about what OTA updates I don't have. On the other hand, the software engineer in me wants to be sure my car is running the latest software, but not enough to pay $$$ for the ford diagnostic software to upload the code myself.

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