Another 12V battery post -- but this one is different? I don't have a garage!

[desiato]

Hi all,

I have a 2021 Job1 (I believe .. I'm right on the cusp with a July 2021 build date, drove off the lot in October 2021). I recently replaced the 12V battery following the great guidance from @Mach-Lee in the 12V Battery FAQ; thanks so much for all the great info there! All seemed well and I was able to observe very high levels of SOC for the 12V battery via CarScanner and the @kennelh's great Android widget.

However, we just had a deep freeze here in Boston and my wife was unable to take the car to work today because it wouldn't start, showing "Stop Safely Now" and throwing all the other various faults that are indicators of the 12V battery being low. A quick check of the widget showed an SOC of 50%.

Here are the factors of our lifestyle, home configuration, and driving habits that I think expose a design flaw in the 12V battery maintenance for this vehicle:

1. The car is regularly driven maybe 3 days/week, and only for about ~8-10 miles round trip. That represents my wife's commute.
2. Because of this, we only have to use our L2 charger once a week or even less
3. We live in a dense urban area of Boston. We are fortunate enough to have a driveway for parking our vehicle, but it is in no way secure like a carport or garage in a more suburban environment
4. Our L2 charger is fed from a NEMA 14-50 outlet that I had installed for this purpose. There is no 120VAC outlet close enough to use the L1 travel charger.

(Edit: adding some additional information as suggested by @JimmyMachE )

• The OBD2 dongle is only connected when I am using it. Otherwise it sits in the center console.
• The Android widget is configured not to request regular updates from the MME. It only does so when I manually request a refresh, or when it detects that the MME has reported new information up to Ford's servers.
• I should also mention that my wife and I both have key FOBs and when they are in the house they are far enough away from the vehicle that it does not wake up. I am the only one of the two of us that uses PaaK and I have the FordPass app set up so that this is only active when I open the FordPass app (i.e., I am intentionally using PaaK). So, we are minimizing the amount of vehicle wakeups from "passing by" with a key FOB or PaaK-enabled phone.

(end edit)

So, the basic issue is that we don't have the ability to recognize "cold weather is coming" and put the vehicle into a configuration where the 12V battery can be properly maintained. The HV SOC could be near 80% and so plugging it into our L2 charger and forcing a charge to 100% will still only bring a small amount of relief. I don't have the ability to adjust the charging rate of the L2 charger (non-smart Grizzl-E), or at least I don't want to go to the trouble of opening it up to make that adjustment all the time. As stated above, I can't use the L1 travel charger because it won't reach, and to my knowledge it will not work with an extension cord. I have used the "turn on the car and put the blower on 7" method to charge the 12V battery, but only when I can be at home and keep an eye on the vehicle; this is clearly not something I can do overnight, and sometimes we are both out of the house during the day for work.

So, what are we supposed to do? I'm concerned that our brand new (but 3-year-warranted) battery is already damaged or developing sulfates that need a long process to get rid of them, and it seems that this will permanently be an issue any time the vehicle is in a very cold environment. Did Ford not think about this living/driving profile when they designed the BMS?

Any advice is greatly appreciated! Thank you to all the great members of this forum. @Ford Motor Company I'd love to hear your thoughts on this.

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[flapjake314]

how new is brand new, what is the chance that it didn't even charge enough (given it only charges when you drive and/or are charging)

and apparently from the other thread going on in parallel one tip is to leave your doors unlocked...

 

[desiato]

how new is brand new, what is the chance that it didn't even charge enough (given it only charges when you drive and/or are charging)

I purchased it from Ford Parts and picked up from my dealership on Jan 8th. I hooked it up to a charger for several hours until it indicated the battery was fully charged, and then did the replacement procedure including resetting the BMS.

and apparently from the other thread going on in parallel one tip is to leave your doors unlocked...

As for leaving the doors unlocked -- which thread is this mentioned in? But that's not really an option for us given how exposed our vehicle is when it is parked. It may as well just be parked on the street.

 

[flapjake314]

I purchased it from Ford Parts and picked up from my dealership on Jan 8th. I hooked it up to a charger for several hours until it indicated the battery was fully charged, and then did the replacement procedure including resetting the BMS.


As for leaving the doors unlocked -- which thread is this mentioned in? But that's not really an option for us given how exposed our vehicle is when it is parked. It may as well just be parked on the street.

here you go: https://www.macheforum.com/site/thr...wont-open-with-external-12v.42269/post-909400

re: leaving doors unlocked parked on the street, if you leave nothing in your car it's kind of neither here nor there. tbh i know many people in major cities that purposely leave their door unlocked and windows down to prevent getting window smashed for coins...

but yeah i get that's a bit of a tradeoff. there is no other solution for now it seems

 

[desiato]

Do other EVs have similar issues with 12V battery management? Is this unique to the MME?

 

[Sikkun]

Sounds like your brand new battery wasn’t fully charged before installation and/or they didn’t reset the BMS properly.

But since you indicate that happened…could also just be a bad battery.

Also possible it’s an issue that isn’t the 12v battery.

 

[RickMachE]

I believe your problem is as follows:

1) You don't drive enough. 8 to 10 miles roundtrip is NOT enough to charge the 12v battery. Nowhere close.

2) You aren't charging enough. Charging once a week means the 12v has to be recharged from the HVB.

3) The 12v being recharged from the HVB was supposed to be fixed by an update. Either your 2021 didn't get it, or it's dropping so fast past the threshold that it's somehow missing being charged. @Mach-Lee or someone with more knowledge would be able to answer that.

What would I do?

I would buy a Battery Tender, and connect it to the car in periods like this. There are endless older threads about dying 12vs. Many of us cut ports in the driver's side panel for the jump posts. Some of us also added a plug on the side for a Battery Tender. Whenever I go away for 2 weeks or more, I put the vehicle we don't take on the Battery Tender for that period of time.

I learned this with my 2013 F-150. Got 7 years out of the original battery.

My son's 18 month old replacement of a replacement battery on his 2018 Edge just died because he failed to follow my advice. They drive daily, but not enough to charge the 12v. He will now be charging it on a Battery Tender at least once a month...

 

[kltye]

50% SoC for the LVB is low, but it isn't that to prevent starting. Have you had your HVBJB replaced? Since you have an OBD dongle, can you see if any codes are being thrown? The LVB probably isn't being charged by the HVB at this point, so you might want to do it quickly and also have precautions in place to be able to access the vehicle cabin in case the LVB dies. You can check to see if the LVB is being charged if its voltage is above 12.9V or so.

 

[desiato]

50% SoC for the LVB is low, but it isn't that to prevent starting. Have you had your HVBJB replaced? Since you have an OBD dongle, can you see if any codes are being thrown? The LVB probably isn't being charged by the HVB at this point, so you might want to do it quickly and also have precautions in place to be able to access the vehicle cabin in case the LVB dies. You can check to see if the LVB is being charged if its voltage is above 12.9V or so.

When this happened previously (and what prompted me to replace the original battery), I'm not sure what the SOC was but I got a "Service Vehicle Soon" message instead of "Stop Safely Now". It was still driveable in that condition. After charging the 12V battery up from the HVB using the blower method, I was able to start the vehicle with no error messages.

The current 12V battery is now reporting 11.9V (39%), and this morning I got "Stop Safely Now". I have never had the HVBJB replaced. When I get home today I am going to try the blower charge method again to see if this makes all the error messages go away like last time.

Should the vehicle be charging the LVB from the HVB under these conditions even if the car is off?

 

[highland58]

If your charger can be adjusted to a lower rate (20A rather than 40A for example) like my Charge Point Home Flex can, that will help as the LVB gets charged during the HVB charge. A lower rate takes longer to charge, so the LVB gets charged more.

 

[kltye]

When this happened previously (and what prompted me to replace the original battery), I'm not sure what the SOC was but I got a "Service Vehicle Soon" message instead of "Stop Safely Now". It was still driveable in that condition. After charging the 12V battery up from the HVB using the blower method, I was able to start the vehicle with no error messages.

The current 12V battery is now reporting 11.9V (39%), and this morning I got "Stop Safely Now". I have never had the HVBJB replaced. When I get home today I am going to try the blower charge method again to see if this makes all the error messages go away like last time.

Should the vehicle be charging the LVB from the HVB under these conditions even if the car is off?

I don't recall at what SoC the DC-DC converter is activated (40% I think?) to charge the LVB when the car is off. When the car is on - even in accessory mode - it should charge the LVB, assuming the HVBJB isn't dead. SSN usually isn't caused by LVB issues. Also, does the HVB charge from your L2 charger at this point?

 

[superdave80]

I can't use the L1 travel charger because it won't reach, and to my knowledge it will not work with an extension cord.

As long as the extension cord is rated for high amperage (i.e. 'heavy duty') it will work fine.

 

[desiato]

I believe your problem is as follows:

1) You don't drive enough. 8 to 10 miles roundtrip is NOT enough to charge the 12v battery. Nowhere close.

2) You aren't charging enough. Charging once a week means the 12v has to be recharged from the HVB.

While I agree that these are true statements, how is the average car owner supposed to know these "rules"? I know this is shouting into the wind a bit.

3) The 12v being recharged from the HVB was supposed to be fixed by an update. Either your 2021 didn't get it, or it's dropping so fast past the threshold that it's somehow missing being charged. @Mach-Lee or someone with more knowledge would be able to answer that.

At the same time that I was having the same issue other 2021 owners were having, and which prompted replacing the LVB, I also got the BlueCruise 3.1 update and then the more recent gateway module update, and these came after many months of not having received any update at all. I do seem to remember getting a battery-related update a long time ago, but there's no way for me to be sure.

What would I do?

I would buy a Battery Tender, and connect it to the car in periods like this. There are endless older threads about dying 12vs. Many of us cut ports in the driver's side panel for the jump posts. Some of us also added a plug on the side for a Battery Tender. Whenever I go away for 2 weeks or more, I put the vehicle we don't take on the Battery Tender for that period of time.

Thanks for the suggestion. I have such a device (I used it to fully charge the replacement battery before installation). Do I have to disconnect the battery from the vehicle to do this? It will be a bit ridiculous to have to align my schedule with my wife's to go to the car with her to disconnect the tender on the mornings she needs to use the car, but I suppose this is better than having a non-driveable car and needing a tow, etc.

 

[MoonRiver]

I purchased it from Ford Parts and picked up from my dealership on Jan 8th. I hooked it up to a charger for several hours until it indicated the battery was fully charged, and then did the replacement procedure including resetting the BMS.


As for leaving the doors unlocked -- which thread is this mentioned in? But that's not really an option for us given how exposed our vehicle is when it is parked. It may as well just be parked on the street.

I'd cracked the hood open to leave an access to the battery jump points.

 

[mccdeuce]

Even though you do not need the mileage boost why not leave the car plugged in all the time with a max target charge percentage?

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