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

[Triggerhappy007]

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

I had a new 15 Focus EV that had to have the battery replaced after 18 months and a new 19 Leaf that also needed a new battery after a year. I heard that Hyundai/Kia EVs are having more 12V problems than us.

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[Mach-Lee]

@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?

SOBDM or BECM codes are most important. You can also drive the car and send me your VIN and I can let you know what's up in most cases.

 

[Snakebitten]

I had a new 15 Focus EV that had to have the battery replaced after 18 months and a new 19 Leaf that also needed a new battery after a year. I heard that Hyundai/Kia EVs are having more 12V problems than us.

LV battery issues have threads on so many makes/models these days. It's actually odd that there are some that don't!

In my opinion they all have a couple of things in common, and they are both things that didn't really exist just a few years ago.

1. Connected services and all kinds of approach features have vehicles "awake" much of the time they are parked. It's very much an intentional parasitic draw.

2. On ICE/Hybrid vehicles, especially, the hell-bent march to squeeze every .001 of a mpg across the manufacturers fleet CAFE, has led to incredibly sophisticated low voltage battery management systems that intentionally prevent alternators from presenting a charging load on the crankshaft full time. So no longer do our vehicles simply run the alternator as an alternator just because the armature is spinning.

I too had a Nissan Leaf (2018) and it was fairly well known to have anemic LV battery charging strategy, as well as my wife's 2013 C-Max.
Visit the Gen14 F150 forum. LV battery SOC issues are perpetually discussed, even on brand new trucks.

 

[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...

Vampire drain. That's the reason.

Please explain.

 

[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...


Please explain.

Accessing the power stored in the massive HVB requires multiple system to turn on that monitor the battery and cool/heat it. These systems are a lot of overhead, causing the HVB to drain. You park your car and while it sits there the HVB loses charge. Maybe after 5 days in the airport parking lot is loses 20% or more of the charge in the HVB. That's vampire drain.

For years Tesla had a issue with vampire drain. Rivian had a big issue with vampire drain until the Gen2 was released, but still people are complaining about it. Ford has managed to minimize the load on the HVB when the car is off, practically eliminating vampire drain. Consequently the LVB does see more stress and doesn't last as long as in a older ICEVs.

Personally I greatly prefer Ford's approach and I have no problem replacing the LVB every 3 years.

 

[67 Stang Convertible]

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...


Please explain.

Frankly, I'd be more interested in you sending us a video of you playing that beutiful piano!!!

 

[SoriceConsulting]

Frankly, I'd be more interested in you sending us a video of you playing that beutiful piano!!!

I have a very much work-in-progress YouTube channel.
@SalvatoreSorice

Feel free to check it out and thanks for the compliment! The piano is a Steinway Model B that came from the New Jersey Performing Arts Center.

 

[Mike G]

OP had a OTA show up on the 14th as well. Sometimes they produce strange aftereffects until the car goes through a few key cycles. Might have been a combination of the OTA and low SOC on the 12V battery. It's showing 86% at 12.5V right now.

My car (and truck) tell me when it's cold outside I should leave the EVSE plugged in. Seems to work. I get SMS alerts to tell me the charger has finished charging occasionally as it bumps the charge back up while it's just sitting parked. Temps got down to 5F here earlier this week and no issues when I went to use the car. Seems to be working as intended. I just leave my charger set to the 48A setting it's always been on.

 

[Mike G]

Oh, and to the OP, congrats on getting BC 1.3 as an OTA on the 8th. This is the first time I've actually seen that in the system. It updated the CCM, CMR, IPMA, and PSCM...all in one go!

I'm glad they finally got that worked out.

 

[67 Stang Convertible]

I have a very much work-in-progress YouTube channel.
@SalvatoreSorice

Feel free to check it out and thanks for the compliment! The piano is a Steinway Model B that came from the New Jersey Performing Arts Center.

Bravo!!! Beautiful Playing!!!

 

[desiato]

OP had a OTA show up on the 14th as well. Sometimes they produce strange aftereffects until the car goes through a few key cycles. Might have been a combination of the OTA and low SOC on the 12V battery. It's showing 86% at 12.5V right now.

Wow, for a second I was wondering how you figured this out, and then I looked at my post history and saw I previously posted in the thread asking for FDRS OTA update status lookups!

I'm wondering if I should try to get the LVB SoC up to 100% over the weekend? Just attach the charger/tender and let it run?

Oh, and to the OP, congrats on getting BC 1.3 as an OTA on the 8th. This is the first time I've actually seen that in the system. It updated the CCM, CMR, IPMA, and PSCM...all in one go!

I'm glad they finally got that worked out.

Yep, the first OTA was right around when I was replacing the LVB. I was a little suspicious of the timing, but happy to have finally gotten some updates after ~6+ months without any.

 

[Mike G]

I'm wondering if I should try to get the LVB SoC up to 100% over the weekend? Just attach the charger/tender and let it run?

If this LV battery is new, then I'd just drive it around for about an hour and then do the BMS reset dance before shutting it down to put it on the charger.

 

[desiato]

A quick update now that I got my replacement ODB dongle. It seems I may have an HVBJB issue? After reviewing the HVBJB FAQ, it looks like I have the following relevant DTCs, as reported by CarScanner:

• BECM
  • P0AA2(00) Archive (inactive)
    Hybrid battery positive contactor - circuit stuck open
    Status: Confirmed, Test failed since last DTC clear
  • P0D10(00) Archive (inactive)
    Status: Confirmed, Test failed since last DTC clear

I'm not sure how to interpret "Archive (inactive)" and "Status: Confirmed" both being shown.

I replied in @Mach-Lee 's cold weather thread with the same info. The recall site lists no active recalls for my vehicle, so I'm trying to figure out what's up and what my approach with a dealer should be. Ideally they can read these DTCs remotely, confirm I need a replacement HVBJB, and schedule an appointment for when the tech and part are available so my vehicle isn't sitting around useless.

 

[jksu]

great context and perspective.

and a contrast to different companies' approaches and priorities (lots of features-dog mode, etc) vs conservative/avoid drain.

Accessing the power stored in the massive HVB requires multiple system to turn on that monitor the battery and cool/heat it. These systems are a lot of overhead, causing the HVB to drain. You park your car and while it sits there the HVB loses charge. Maybe after 5 days in the airport parking lot is loses 20% or more of the charge in the HVB. That's vampire drain.

For years Tesla had a issue with vampire drain. Rivian had a big issue with vampire drain until the Gen2 was released, but still people are complaining about it. Ford has managed to minimize the load on the HVB when the car is off, practically eliminating vampire drain. Consequently the LVB does see more stress and doesn't last as long as in a older ICEVs.

Personally I greatly prefer Ford's approach and I have no problem replacing the LVB every 3 years.

 

[desiato]

Another update: I spent the weekend with the charger/tender on the battery (still in vehicle) to give it a nice 24-36hrs of constant charging. I also drove for a couple of hours on Saturday. Sunday night, the HVB was at 52% so I had it charge to 100% overnight. First thing this morning, the car reported the LVB had 99% SoC and 13.2 V. However, checking again an hour or so later, it's already down to 12.5V and 95%. Is this normal/expected in "feels like 21F" conditions?

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