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

[Mach-Lee]

What are the codes? You may have a HVBJB issue. That will prevent 12v charging. Shouldn’t get below 40% on current software.

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[MoonRiver]

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...

I am changing my at least 33 months old battery with deltran battery tender twice a week. We only drive it less than 10 miles in a typical day. So I can't count on getting it charged by HVB.

 

[RickMachE]

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.

Yup. Totally agree.

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.


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.

1.3, not 3.1.

No, you don't disconnect the 12v. You connect to the two posts under the driver's side panel.

As to disconnecting, it depends how you set it up. Mine would be sitting would the hood closed, plugged in. Note on the seat - DISCONNECT BATTERY TENDER.

Open frunk. Unplug battery tender from leads, put cap on. Close frunk. Put battery tender in carport / garage / or in the frunk (before closing it).

Put note with battery tender.

Not real hard. Annoying, yes.

 

[Trick.Mach-E]

While I agree that these are true statements, how is the average car owner supposed to know these "rules"? I

Don't take Rick's perfect advice as an insult or that he's belittling you. The average user doesn't know these rules. There is nothing wrong with that. That's why there are mechanic's and internet know-it-alls! It's about experience. You are ahead of the game, you came here and asked about your issue. There has to be at least one stubborn Mach-E owner not only refuses to ask anyone for directions, but refuses to ask why the battery is dead and every morning goes out to the car to see if it will turn on.

And your experience with EV LVB issues are the same for ICE vehicles. If you jump a LVB to start the car and then only drive it a few miles, the battery will not be charged as well. Constant short trips in a ICE will also kill the battery and ICE owners will be told get a battery tender as well... or drive for a longer amount of time.

 

[desiato]

Thank you all for your replies and helpful advice and questions. Let me address a few things in bulk:

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.

It looks like I can select 40A, 32A, 24A, and 16A via DIP switches. I'll look into using a slower rate in general given our driving style, although I think I may have bigger problems (see below).

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?

I came home early thinking I would at least plug in the L2 charger to see what happens. Sadly, I got a charge fault, which makes me think I'm in HVBJB trouble.

What are the codes? You may have a HVBJB issue. That will prevent 12v charging. Shouldn’t get below 40% on current software.

To compound things, my OBD2 dongle is no longer functioning. I have ordered another one that should arrive tomorrow, but in the meantime I can't read out any codes. Are there other ways to confirm an HVBJB issue?

No, you don't disconnect the 12v. You connect to the two posts under the driver's side panel.
Not real hard. Annoying, yes.

After getting the charge fault above, I've set up the charger/tender based on this. Thanks.

Don't take Rick's perfect advice as an insult or that he's belittling you.

I didn't take it that way. I agree his advice was on point and I'm happy to have received it! I just needed to vent a little and I think Rick recognized it wasn't directed at him.

And your experience with EV LVB issues are the same for ICE vehicles. If you jump a LVB to start the car and then only drive it a few miles, the battery will not be charged as well. Constant short trips in a ICE will also kill the battery and ICE owners will be told get a battery tender as well... or drive for a longer amount of time.

I guess my disconnect here is that we haven't run into this at all in 3+ years of ownership of the vehicle, and I thought replacing the LVB would have solved the problem we had at end of the year/beginning of this year (that all 3+ year owners seem to run into!). But seeing the colder weather have this effect on a brand new LVB is concerning and frustrating. I remember checking its SOC yesterday and seeing close to 80%, so I thought we were all good. But, given my charge fault above, perhaps I have a bigger issue.

 

[steveg95]

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.

Where can I find the procedure for resetting the BMS? I am capable of switching out the battery and don't want to pay the dealer to do this.

 

[MoonRiver]

Where can I find the procedure for resetting the BMS? I am capable of switching out the battery and don't want to pay the dealer to do this.

https://www.macheforum.com/site/threads/12v-battery-faq.32744/

 

[steveg95]

https://www.macheforum.com/site/threads/12v-battery-faq.32744/

Thanks for the information. Seems like a strange procedure.

 

[MoonRiver]

Thanks for the information. Seems like a strange procedure.

It is strange that Ford made a supposed maintenance free EV that problematic. But fortunately the reset is straightforward.

 

[SoriceConsulting]

I've mentioned this in other battery related threads... It's kind of funny/ironic that we have a GIGANTIC battery in our cars that can't keep an eye on a TINY 12v battery and keep it topped off at all times...

 

[kltye]

Thanks for the information. Seems like a strange procedure.

Probably so it's not accidentally activated, since they state numerous times that it shouldn't be randomly used.

 

[SteveMach-ee]

Thanks for the information. Seems like a strange procedure.

Also, for those 6 hours, to make sure the car is not constantly woken up, keep any keyfobs and phone PAAKs away from the car. I wrapped my keyfobs in foil. I think this is in the FAQ.

 

[mkhuffman]

I've mentioned this in other battery related threads... It's kind of funny/ironic that we have a GIGANTIC battery in our cars that can't keep an eye on a TINY 12v battery and keep it topped off at all times...

Vampire drain. That's the reason.

 

[desiato]

Update! I came home early this afternoon to hook up the battery charger/tender and monitored the LVB SoC via the Android widget. It slowly climbed from ~38% to ~71% over the course of the afternoon. I decided to test the vehicle out so I disconnected the charger/tender and started the car. The only fault that popped up on the dash was "Frunk open!". I was able to reverse out of the driveway and pull back in.

I adjusted my Grizzl-E L2 charger to run at 24A output, connected it to the MME, set the target charge for 100% (HVB SoC was ~70%), and hit Start in the FordPass app. No charge fault, and it's been charging for ~15 minutes now. I'm going to stop it for now and then restart it much later tonight so it will be charging all through the night when things are coldest, and I'll check the LVB SoC in the morning.

I did notice that the charger/tender had its "charged" LED lit up even though the MME was reporting ~71% SoC for the LVB. Perhaps the battery wasn't truly at 100% when I installed it and reset the BMS? I did charge it for several hours prior to installation, but not fully overnight as recommended in the FAQ.

@Mach-Lee when my new ODB dongle arrives tomorrow, I'll pull codes. Anything specifically I should be looking for to point to a potential HVBJB or anything else of interest?

So, it seems that even the SSN was related to the very low LVB. I have the charger/tender in the frunk and the two panels still off, just in case the slow L2 charging doesn't bear fruit overnight. Thanks to all the help and advice, it seems like I have some solutions here!

 

[Garbone]

Well, here is my advice. Put the amps down to 24 amp and if the fault persists try the 16.

Our charger is set to 20 amps as anything above that her car faults out and stops charging. She has a 21 Job 1 also. Brought it into Ford a few times with no luck getting it fixed. May be a harness issue or a charger software thing.

Never have an issue keeping our 2 cars charged even with both daily drivers and at 20amps. Checked out this thread as it is almost time for our first new 12volt.

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