How to Recondition/Service Your 12V Battery

[dtbaker61]

Already ran it ON for 16 hours overnight (with 30 minute time-out off) last weekend. Also just drove 1000 miles early this week. Carscanner shows no abnormal drain.

This morning it started up, showing 14.8v. So I sat in the car for 40 minutes at 14.8 to boost the LVB, with radio and air off. Turned it off. 10 minutes later it was showing 11.8 to 12.1 and SSN. Pretty sure it's a failing LVB.

Hhhmmmmm, one other case I remember from months ago turned out to be a loose connection behind the fusebox. Hard to check since y have to pull frunk tub to get to it

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[Shayne]

Already ran it ON for 16 hours overnight (with 30 minute time-out off) last weekend. Also just drove 1000 miles early this week. Carscanner shows no abnormal drain.

This morning it started up, showing 14.8v. So I sat in the car for 40 minutes at 14.8 to boost the LVB, with radio and air off. Turned it off. 10 minutes later it was showing 11.8 to 12.1 and SSN. Pretty sure it's a failing LVB.

Story of my ownership of the mach-e for the first 2 winters and early signs showing possibly of a third. Started first month (winter 1) and continued again all last winter. AGM do not go bad in a year unless they are being drained too low and/or are not being maintained right. They already told me a bad 12V (fix 2 and yes the mach-e killed a good battery in under a year) then a brand new one proceeded to die in short order. I did not receive the fix for the third time until the second winter was over and it warmed up again.

I think yours is not a defective 12V if it worked that long and most likely the car crapping it out due to poor maintenance and drain while parked. I am also thinking yours may sit for extended periods of time also based on your occupation. Poor (non-existent) 12V maintenance logic when sitting is my guess and your battery is now crapped. Hope you get it figured out as it may help here. Doesn't sit well at all (plugged or not) so far for me and the cold magnifies that. Ford should forget Alexa and concentrate on maintenance logic for the 12V is my opinion. This deep sleep stuff produces no monitoring of anything and makes for a really stupid smart car.

 

[dbsb3233]

Story of my ownership of the mach-e for the first 2 winters and early signs showing possibly of a third. Started first month (winter 1) and continued again all last winter. AGM do not go bad in a year unless they are being drained too low and/or are not being maintained right. They already told me a bad 12V (fix 2 and yes the mach-e killed a good battery in under a year) then a brand new one proceeded to die in short order. I did not receive the fix for the third time until the second winter was over and it warmed up again.

I think yours is not a defective 12V if it worked that long and most likely the car crapping it out due to poor maintenance and drain while parked. I am also thinking yours may sit for extended periods of time also based on your occupation. Poor (non-existent) 12V maintenance logic when sitting is my guess and your battery is now crapped. Hope you get it figured out as it may help here. Doesn't sit well at all (plugged or not) so far for me and the cold magnifies that. Ford should forget Alexa and concentrate on maintenance logic for the 12V is my opinion. This deep sleep stuff produces no monitoring of anything and makes for a really stupid smart car.

Sounds reasonable. I had no problem until the last week. That's 28k miles and lots of road trips (2/3rds of those miles). But mine also sits in the garage at home a lot, often not even being started for 3 days at a time. No daily commute so no fixed routine of 30 miles a day or anything. I also only plug it in maybe once a week (although I don't think plugging in really affects it).

I did a few tests and remote starting and setting departure times both turn on the DC-DC feed. I could see the voltage meter jump to the normal 13-14v range when either of those started conditioning the car. So maybe I'll set a daily departure time just to give it a routine LVB boost. (Although honestly, I'm not sure if just a ~10 minute boost is actually a good thing or a bad thing for AGM batteries?)

Your broader point hits the nail on the head though. None of this should be necessary because Ford should program the car to automatically charge the LVB in the way to properly maintain the AGM battery. This "deep sleep" thing drives me up the wall. The car should NEVER go into such a deep sleep that it doesn't monitor and maintain the LVB (unless the HVB is below like 10% or something). I don't care if it costs me a few% off overall efficiency. Just maintain the damn LVB properly.

So, I'm curious... has you car been doing the same as mine when the LVB started wearing out prematurely? Did you start getting Stop Safely Now messages at power-on where the car would only go into Accessory Mode?

 

[Mach-Lee]

Your broader point hits the nail on the head though. None of this should be necessary because Ford should program the car to automatically charge the LVB in the way to properly maintain the AGM battery. This "deep sleep" thing drives me up the wall. The car should NEVER go into such a deep sleep that it doesn't monitor and maintain the LVB (unless the HVB is below like 10% or something). I don't care if it costs me a few% off overall efficiency. Just maintain the damn LVB properly.

So, I'm curious... has you car been doing the same as mine when the LVB started wearing out prematurely? Did you start getting Stop Safely Now messages at power-on where the car would only go into Accessory Mode?

They very latest software does manage the 12V correctly from what I've seen. It will automatically recharge when it gets down to 30-40% before the car won't start. You should not be getting deep sleep messages, I never get those. However with a bad battery, it will go dead too fast before the car can recharge it. The programming assumes a certain minimum battery capacity is available, if not then there will be issues like you're seeing.

Shayne had his HVBJB replaced twice? I believe his contactors were intermittently sticking and going into an error state, which caused the 12V battery to not be charged sometimes.

Hopefully with a new battery and once you're updated all the way to the 3.5.4 level with latest powertrain, APIM, gateway, and TCU software the deep sleep messages will go away. Since you have a FE, you should really find someone to fully update your car, every single module.

Lead acid batteries want to stay fully charged, they do not like being run dead. That kills them in a hurry. Constantly topping up is not an issue, they differ from lithium in that regard.

 

[dbsb3233]

They very latest software does manage the 12V correctly from what I've seen. It will automatically recharge when it gets down to 30-40% before the car won't start. You should not be getting deep sleep messages, I never get those. However with a bad battery, it will go dead too fast before the car can recharge it. The programming assumes a certain minimum battery capacity is available, if not then there will be issues like you're seeing.

Shayne had his HVBJB replaced twice? I believe his contactors were intermittently sticking and going into an error state, which caused the 12V battery to not be charged sometimes.

Hopefully with a new battery and once you're updated all the way to the 3.5.4 level with latest powertrain, APIM, gateway, and TCU software the deep sleep messages will go away. Since you have a FE, you should really find someone to fully update your car, every single module.

Lead acid batteries want to stay fully charged, they do not like being run dead. That kills them in a hurry. Constantly topping up is not an issue, they differ from lithium in that regard.

I have noticed some changes lately as you noted. I don't think I get the deep sleep message anymore. And when I swipe down in FP to refresh, it actually does it now! (Although sometimes it takes two swipe attempts.)

Hopefully that means it's improved the LVB monitoring and maintenance as well. Never made sense to me that with so much power stored in the HVB, they were so stingey using it to maintain the LVB 24x7 (and perform some other basic functions 24x7).

 

[JimmyMachE]

10 minutes later it was showing 11.8 to 12.1 and SSN. Pretty sure it's a failing LVB.

Please check the 12V battery SOC in Car Scanner when it shows 11.8-12.0V? How many %SOC the 12v battery loses overnight?

 

[Shayne]

Sounds reasonable. I had no problem until the last week. That's 28k miles and lots of road trips (2/3rds of those miles). But mine also sits in the garage at home a lot, often not even being started for 3 days at a time. No daily commute so no fixed routine of 30 miles a day or anything. I also only plug it in maybe once a week (although I don't think plugging in really affects it).

I did a few tests and remote starting and setting departure times both turn on the DC-DC feed. I could see the voltage meter jump to the normal 13-14v range when either of those started conditioning the car. So maybe I'll set a daily departure time just to give it a routine LVB boost. (Although honestly, I'm not sure if just a ~10 minute boost is actually a good thing or a bad thing for AGM batteries?)

Your broader point hits the nail on the head though. None of this should be necessary because Ford should program the car to automatically charge the LVB in the way to properly maintain the AGM battery. This "deep sleep" thing drives me up the wall. The car should NEVER go into such a deep sleep that it doesn't monitor and maintain the LVB (unless the HVB is below like 10% or something). I don't care if it costs me a few% off overall efficiency. Just maintain the damn LVB properly.

So, I'm curious... has you car been doing the same as mine when the LVB started wearing out prematurely? Did you start getting Stop Safely Now messages at power-on where the car would only go into Accessory Mode?

It always booted and could be navigated but does not go into gear. I got SSN and every other message they can throw at you every time the 12V was dead but I think they may have corrected that to one message now? Charge fault when plugged and no sense to unplug and plug back in. Unplug and start it. You can go back through my posts here but I also sat in it in sub-zero temps for an hour a day to see what it does. It did not do well in maintaining the 12V and I finally saw a huge drop over night which forced me to give up. When it had finally killed the first 12V after less than a year it showed the first time when I was 200 miles from home and it sat in a driveway for 2 days visiting. It charged that time and got me home but it did it again at home after sitting a couple of days. The charger was put on it again. The charger errored out saying the battery was bad which was confirmed by the dealer. It still got me to the dealer after charged. Runs off the alternator (dc-dc) after boot. Dead 12V's are a symptom not the cause. People that drive more than us may not see my problem I think.

The best solution I have come up with is to double plug it 240V and 120V 12V charger. If you remember the early demos always had a 12V charger hooked up to them and this post was created for when you get your brand new vehicles as it may have sat for a while and the car does not maintain it itself. Hope you brought that 12V charger on your trip and port holes are a requirement for me.

Yesterday after sitting for a week I pushed the button 3 times and the door did pop but that slow sluggish style that says I don't want to (know that sign now and it is getting cold again). It booted so I drove it for over an hour (never powered off). When I got back home I grabbed the OBD2 (I should not need one of these) and the LVB was at 80% after the trip. I have gone in for all module updates and the car is totally up to date as of early October (one GSM and have received 3.5.3 OTA now). Informed them I want the best chance that this makes it through a winter. We will see but early signs is nothing much has changed. HVJB and BECM installed this April. It is a lot better bug wise with the software updates hoping the deep sleep issue is also corrected.

Mine will draw power for 10's of hours now not charging the HVB and steady at set charge. Grizzle flashing car charging port flashing happily. I know tech that is why I got the dumb one but now I am thinking I should have got the smart charger for this car. I am ahead of myself and it has yet to cause a melt down this winter not even cold yet. Just did not like a sluggish door pop and not seeing 90%. Double plug worked from December to April this year.

@SnBGC wondering if your trick to not to burn up the HVB when in its deep sleeps at high ambient temps would work on 12V maintenance also?

So I charger it up to 85% then set the charge schedule to 80%?
Leave it plugged.

 

[mkhuffman]

I have noticed some changes lately as you noted. I don't think I get the deep sleep message anymore. And when I swipe down in FP to refresh, it actually does it now! (Although sometimes it takes two swipe attempts.)

Hopefully that means it's improved the LVB monitoring and maintenance as well. Never made sense to me that with so much power stored in the HVB, they were so stingey using it to maintain the LVB 24x7 (and perform some other basic functions 24x7).

I agree with Lee - if your modules have not been updated, that should be top priority. I did a test last year and my car was NOT maintaining my LVB when the EVSE was not connected. In February I had the dealer do all the updates and then tested again. I was able to confirm that the car maintained the LVB when not plugged in and off.

Before software updates:

After software updates:

The HVB charging finished at the 1:00 mark. At around the 8:00 mark, I disconnected the charger. You can't really tell when I disconnected the charger because now the car is maintaining the LVB just like it was when connected to the EVSE.

BTW - the LVB was draining so fast because I was monitoring the car with a OBDII scanner and CarScanner. Normally the LVB should never discharge that quickly, unless there is something else draining it.

 

[Shayne]

They very latest software does manage the 12V correctly from what I've seen. It will automatically recharge when it gets down to 30-40%

Wish Ford would discharge one of these H2O batteries to 50% and throw it in a controlled -20F for a couple of days than take it out and see what resistance across the terminals they get. Something that does not let the contact close? Old school simple engineering for M.Eng.'s that an't too bright.

Dude send me that 3.5.4 like yesterday. I will believe it when I see it. I should expect a call from my dealer any day now?

 

[Shayne]

After software updates:

Always like graphical data. 40% now right.

 

[dbsb3233]

Please check the 12V battery SOC in Car Scanner when it shows 11.8-12.0V? How many %SOC the 12v battery loses overnight?

I did. This was no more that 10 minutes after sitting in the car with it fully on for 40 minutes while it showed 14.8v (a DCDC feed). Then I moved it to the L2 charger, powered off, plugged in and got red circle lights. Got back in and tried to start it... SSN and goes straight to Accessory Mode. Checked Carscanner CBS showing only 11.8. Floated between 11.8 and 12.1. Finally ticked up to 12.2 and let me start it.

Didn't lose any HVB SOC overnight. 49% before and after. Not sure what the LVB SOC was the night before, but still showed 81% during SSN. That's odd.

 

[Shayne]

Screenshots shot consecutively last winter after new 12V installed. I found the BMC and coolant temps a bit bizarre in the second one.

After an hour or so it stops feeding the 12V amps. It did not appear that soc mattered and never hit 90%. Struggled hard to get it to 80%.

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[dtbaker61]

Please check the 12V battery SOC in Car Scanner when it shows 11.8-12.0V? How many %SOC the 12v battery loses overnight?

can't use ODB2 while MME is 'off'.
You have to leave the hood up and check manually w voltmeter while MME is sleeping

 

[Mach-Lee]

I did. This was no more that 10 minutes after sitting in the car with it fully on for 40 minutes while it showed 14.8v (a DCDC feed). Then I moved it to the L2 charger, powered off, plugged in and got red circle lights. Got back in and tried to start it... SSN and goes straight to Accessory Mode. Checked Carscanner CBS showing only 11.8. Floated between 11.8 and 12.1. Finally ticked up to 12.2 and let me start it.

OK, that's the first time you mentioned you got a charge fault! That right there will drain the 12V battery if you leave it like that. The charge fault is probably the cause of the 12V going dead.

If you ever get a red ring error, UNPLUG it before it drains the 12V! Red ring errors need to be figured out because they drain 12V batteries. That's going to be an issue with your EVSE or charge port most likely.

 

[Shayne]

can't use ODB2 while MME is 'off'.
You have to leave the hood up and check manually w voltmeter while MME is sleeping

This is true but does not keep you from watching it after you power off. Not sure of exactly what it is feeding you after powered off however.

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