12 volt warning in cold while plugged in

[Heliian]

If you plan on charging your battery, disconnect it and charge it fully. To test your battery accurately, get a load tester. The 12v soc that Ford is showing is a calculation that may not be accurate especially if your bms is bad.

Battery tenders at 2a don't do much either, especially when voltage gets higher and it will take a day or more to bring it up.

Battery capacity is the real measure of battery health.

Sponsored

 

[Maxx]

You brought the same issue up in a different thread a while back, and I pointed out then that it's perfectly possible to charge the LVB in Accessory Mode if the truck is plugged into a charger.

I have checked this several time and it does not have to be plugged in to charge LVB. It is not intuitive and I didn’t expect to see it work this way but you can clearly see in the scanner current is coming out of HVB and LVB SOC going up when in accessory mode unplugged. I always thought HVB is disconnected unless you turn on the truck. May be DC to DC converter is hooked up to HVB before the contractor that feeds the motors. I don’t know how it works but this is what I see.

p.s. I am still losing 10% SOC a day from LVB and have not figured out why since others report I should be bellow 5%.

 

[TaxmanHog]

I have checked this several time and it does not have to be plugged in to charge LVB. It is not intuitive and I didn’t expect to see it work this way but you can clearly see in the scanner current is coming out of HVB and LVB SOC going up when in accessory mode unplugged. I always thought HVB is disconnected unless you turn on the truck. May be DC to DC converter is hooked up to HVB before the contractor that feeds the motors. I don’t know how it works but this is what I see.

p.s. I am still losing 10% SOC a day from LVB and have not figured out why since others report I should be bellow 5%.

Could be the contactors feeding DC/DC inverters are active in accessory mode, or they
intermittently cycle depending on the LVB SOC.

 

[Maxx]

Could be the contactors feeding DC/DC inverters are active in accessory mode, or they
intermittently cycle depending on the LVB SOC.

I have seen it work at 50% and 68% but when it stopped, I was losing charge faster that I gained. Not sure if it was because of scanner talking to my phone or something else.

 

[TaxmanHog]

I have seen it work at 50% and 68% but when it stopped, I was losing charge faster that I gained. Not sure if it was because of scanner talking to my phone or something else.

It's only been one day since I change the LVB BMS to the new version, but so far the SOC checks have always been above 75%, much better than the 30's, 40's & 50's for low's

 

[Maxx]

It's only been one day since I change the LVB BMS to the new version, but so far the SOC checks have always been above 75%, much better than the 30's, 40's & 50's for low's

If you were getting those numbers, then I may not be as special as I thought (losing 10% a day). Please keep us posted on how you do in upcoming weeks. Did you change it yourself? Or took it to dealer? If you did it, did you have to reset or reprogram anything? My BMS ends with -AD and I got the recall notification.

I was going to wait until I hit 10,000 mile and do all CSPs together but if this improves my life, I may do it ahead of others.

p.s. on accessory, LVB charges at slightly lower voltage than when truck is on (less than 15V vs more than 15V).

 

[TaxmanHog]

If you were getting those numbers, then I may not be as special as I thought (losing 10% a day). Please keep us posted on how you do in upcoming weeks. Did you change it yourself? Or took it to dealer? If you did it, did you have to reset or reprogram anything? My BMS ends with -AD and I got the recall notification.

I was going to wait until I hit 10,000 mile and do all CSPs together but if this improves my life, I may do it ahead of others.

p.s. on accessory, LVB charges at slightly lower voltage than when truck is on (less than 15V vs more than 15V).

I sprung for the part myself and changed it, no special reprogramming needed, other than to retrain the Frunk with a manual close, then cycle the cabin switch to confirm it opens and closes.

 

[PV2EV]

A few on this thread have said that 2a trickle wont cut it, so last night after driving for an hour, in the mid teens I hooked up the LVB to the boost charger and it selected 20A so I left it there. I was also charging the HVB on a 50A charger.

12 hours later and the SOC is 35%!! Also, 9 hours in at 6am the alarm triggered without an apparent cause (very low LVB?). This is frustrating. Hoping the TSB solves this for good.

 

[Jim Lewis]

I have checked this several time and it does not have to be plugged in to charge LVB. It is not intuitive and I didn’t expect to see it work this way but you can clearly see in the scanner current is coming out of HVB and LVB SOC going up when in accessory mode unplugged.

Here are screenshots of what I see entering Accessory Mode in various ways. IIRC, I turned the headlights from Auto to Full Off before taking any screenshots for any of the three Accessory Mode schemes. All accessories like FAN and AC on the Sync screen were off, too.

The LVB would seem to be charging faster if the truck is plugged in in Accessory Mode as the applied LVB voltage is significantly higher. Someone more knowledgeable about truck electronics would have to explain what the various sensor current readings mean. Sorry if I should have captured more sensor readings in one screenshot by figuring out how to dismiss the keyboard display on my phone created by typing "current" as the desired sensor filter in CarScanner Pro.

Truck Unplugged. Just press Power Button.
Notice just the battery icon on the lower right dash(pic #1), the reduced applied LVB battery voltage(pic #2) compared to two other schemes below.

Truck Plugged In, Just Press Power Button.
Notice both the battery icon and the charger icon on the lower right dash(pic #1), and the higher applied LVB battery voltage(pic #2) compared to the previous scheme above.

Truck Plugged In, Step on Brake Pedal When Pushing Power Button.
Notice only the charger icon on the lower right dash(pic #1) compared to the previous two Accessory Mode schemes. Applied LVB voltage is ~same for scheme #2 just above and higher than when the truck is not plugged in (scheme #1).

 

[Maxx]

Here are screenshots of what I see entering Accessory Mode in various ways

Great shots. Thanks for sharing. I have been passively using the scanner occasionally for specific purposes but now you got me excited enough to customize my own screens and start looking at stuff closer to learn how this thing works.

 

[PV2EV]

A few on this thread have said that 2a trickle wont cut it, so last night after driving for an hour, in the mid teens I hooked up the LVB to the boost charger and it selected 20A so I left it there. I was also charging the HVB on a 50A charger.

12 hours later and the SOC is 35%!! Also, 9 hours in at 6am the alarm triggered without an apparent cause (very low LVB?). This is frustrating. Hoping the TSB solves this for good.

Man this is getting annoying. LVB SOC is 7%, frunk won't close, and now the HVB won't charge (repeated orange fault light)!!! Assuming this is due to the LVB SOC, I will keep a 20A charge on it overnight and wrap it in blankets to try to keep it warm.

Any other suggestions?

 

[Jim Lewis]

I will keep a 20A charge on it overnight and wrap it in blankets to try to keep it warm.

You might want to charge the AGM at a lower rate. If you search the Internet, rapid charge rates for sealed AGM batteries are not recommended for various reasons relative to the long-term lifespan of the battery. I thought I read a post somewhere on the forum in the past that suggested that Ford made tending the LVB tough because they didn't want owners messing around with charging the AGM and messing it up. An example article that suggests 10A as a charging limit or follow the manufacturer's recommendations, etc. How To Bring an AGM Battery Back From the Dead (motortrend.com)

On the security alarm, I used to battery tend my Honda Accord's 12-volt. Where I live, we have a lot of wildlife, including feral cats. I'd lock the car doors while I had the hood open a crack. I didn't realize that locking the car armed the entire security system, including the hood and trunk. So, a couple of times in the middle of the night, while charging up my 12-volt battery, a cat or raccoon must have climbed over my hood, made it move, and triggered the security system. From then on, I left the car doors unlocked while battery tending and never had the security alarm sound again (as it was off), which I'm sure the neighbors appreciated. I don't know if you had your truck locked with the frunk partly opened, and the Lightning security system works the same way, but it's something you might look into.

 

[RickLightning]

Man this is getting annoying. LVB SOC is 7%, frunk won't close, and now the HVB won't charge (repeated orange fault light)!!! Assuming this is due to the LVB SOC, I will keep a 20A charge on it overnight and wrap it in blankets to try to keep it warm.

Any other suggestions?

Make sure you have connected to the battery properly. If you are not using the jump posts, make sure the negative connection is not on the negative battery terminal, it must be on a ground or on the post where the BMS is, otherwise the SOC will be wrong.

 

[PV2EV]

You might want to charge the AGM at a lower rate. If you search the Internet, rapid charge rates for sealed AGM batteries are not recommended for various reasons relative to the long-term lifespan of the battery. I thought I read a post somewhere on the forum in the past that suggested that Ford made tending the LVB tough because they didn't want owners messing around with charging the AGM and messing it up. An example article that suggests 10A as a charging limit or follow the manufacturer's recommendations, etc. How To Bring an AGM Battery Back From the Dead (motortrend.com)

On the security alarm, I used to battery tend my Honda Accord's 12-volt. Where I live, we have a lot of wildlife, including feral cats. I'd lock the car doors while I had the hood open a crack. I didn't realize that locking the car armed the entire security system, including the hood and trunk. So, a couple of times in the middle of the night, while charging up my 12-volt battery, a cat or raccoon must have climbed over my hood, made it move, and triggered the security system. From then on, I left the car doors unlocked while battery tending and never had the security alarm sound again (as it was off), which I'm sure the neighbors appreciated. I don't know if you had your truck locked with the frunk partly opened, and the Lightning security system works the same way, but it's something you might look into.

Thanks Jim and Rick for the great tips (the charger starts at 20A then dropped to between 2 & 6As overnight, and I will go connect to the ground post as the frunk is stuck open).

I am 300 miles for home and currently SOL with 0% SOC. Does anyone know:

1. The best (or recommended) jump start procedure?

2. A suitable Group H3 AGM replacement battery (seeing 450CCA and 600CCA models)?

Thanks,

Anthony

 

[Tom M]

Thanks Jim and Rick for the great tips (the charger starts at 20A then dropped to between 2 & 6As overnight, and I will go connect to the ground post as the frunk is stuck open).

I am 300 miles for home and currently SOL with 0% SOC. Does anyone know:

1. The best (or recommended) jump start procedure?

2. A suitable Group H3 AGM replacement battery (seeing 450CCA and 600CCA models)?

Thanks,

Anthony

Anthony,

It looks like Auto Zone carries an H3 AGM battery: https://shop.advanceautoparts.com/p...20-cca-525-ca-60-min-reserve-capacity-h3-xev/

I don’t have any experience with this battery myself, but it may be locally available.

I have charged my 12v battery with the pos and neg leads disconnected. I used a standard automotive 12v battery charger with an AGM mode. The 12v BMS can be reset by a series of highbeam headlight flashes and break applications, if I recall.

Sponsored