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12 volt warning in cold while plugged in

PV2EV

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After a long drive yesterday, overnight (at 30f) I got a warning that the LVB was low and I needed to plug in to a charger. However, I was plugged in, but the HVB was done charging. The LVB seemed okay this afternoon, but I still bought a Schumacher 12v battery charger (trickle 2amp to 6amp, charge (20amp) and engine start (80amp) to keep it charged as my truck sits for the next few days. I have questions:

1. Is there a way to keep this from happening without a 12v charger?

2. Although the LVB seemed fine, when I connected the charger started a gel charge at 20amp. Is that okay?

3. I could not figure out how to connect the charger to the positive post without the hood possibly hitting it, so I connected to the LVB directly. Any recommendations on how to do this and close the frunk?
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Monkey

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How up to date is your truck software? I don't know when it was added, but one of the semi-recent (within the last 4+ months) now has the HVB charge the LVB if it needs to, plugged in or not. The user manual is also updated to reflect that the HVB charges the LVB.

There are also LVB sensor problems and a new recall just issued within the past few days to address that. I went for several months without being able to install an update. Not even the dealership could make an update install, then all of a sudden it worked one day. I had a flurry of updates for about a week, then nothing since. And my 6.8 update finally downloaded the other day and is doing the fail to install thing like I went through before. The EV tech at my dealership thinks (hopes) the LVB sensor recall will address it. I think the parts became available to order yesterday or today.

When you plug in, are you on 240V or just 120V? I've seen some reports on other social media that some trucks are not maintaining the LVB as well if they're parked outside in the cold and plugged into 120V. Can't properly precondition on 120V either. You could also be experiencing a failing LVB. With proper operation and assuming no sensor/recall issue, there should be no need to use an additional charger to maintain it.
 
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PV2EV

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How up to date is your truck software? I don't know when it was added, but one of the semi-recent (within the last 4+ months) now has the HVB charge the LVB if it needs to, plugged in or not. The user manual is also updated to reflect that the HVB charges the LVB.

There are also LVB sensor problems and a new recall just issued within the past few days to address that. I went for several months without being able to install an update. Not even the dealership could make an update install, then all of a sudden it worked one day. I had a flurry of updates for about a week, then nothing since. And my 6.8 update finally downloaded the other day and is doing the fail to install thing like I went through before. The EV tech at my dealership thinks (hopes) the LVB sensor recall will address it. I think the parts became available to order yesterday or today.

When you plug in, are you on 240V or just 120V? I've seen some reports on other social media that some trucks are not maintaining the LVB as well if they're parked outside in the cold and plugged into 120V. Can't properly precondition on 120V either. You could also be experiencing a failing LVB. With proper operation and assuming no sensor/recall issue, there should be no need to use an additional charger to maintain it.
Good points all.

Have been getting updates regularly, including one two weeks ago, but not sure where I am at. I have not received a recall notice, but am in the dates whit which it applies, so that may be it. I am charging at 240/50amp.
 

mr.Magoo

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How up to date is your truck software? I don't know when it was added, but one of the semi-recent (within the last 4+ months) now has the HVB charge the LVB if it needs to, plugged in or not. The user manual is also updated to reflect that the HVB charges the LVB.
Uhm, I don't know what changes you're referring to, but the truck has always charged the LVB from the HVB if the LVB gets low enough, <40%.
Even if/when it's off and unplugged.

But, this (battery below 40% and the charger having to kick in) is also what triggers the warning.
 

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I found my LVB at 41% this morning. On my truck, HVB charges LVB while being charged itself, but not when the charging is complete even when it is connected (bellow 40% may be an exception). HVB also charges LVB when the truck is on (you don’t have to drive the truck for this to be happening). I think it will charge it when in accessory mode as well but not 100% sure about this one.

This is the first time I saw my 12V SOC this low. I am not sure if one of the updates is keeping the truck awake or what is going on. I will have to do a little more experiments to learn how this beast works.

I would say I have half the updates and missing the other half. My truck sometimes sits for 4 days at a time and most of my drives are short.
 
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Jim Lewis

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I think it will charge it when in accessory mode as well but not 100% sure about this one.
Yes, that's how I now keep my LVB above 70% SOC. My truck is parked in an insulated attached garage that's usually not too much different from our house temperature.

When plugged in and running in accessory mode, even though my HVB is at its charging limit to start with, the charging port LEDs are blue, and the highest level filled blue LED is flashing as if the HVB were being charged - but the HVB started out and stays at its charging limit (50% most days for me). As I charge the LVB above 80%, the charger current drawn is only ~1 A, as measured by CarScanner. And since the LVB battery % SOC is constantly rising, most of that 1 A of current must end up in the LVB. IIRC, a previous post of @TaxmanHog cited Ford literature that (implied?) the charging current replenishes the HVB %SOC as it charges the LVB.

Letting the secured truck idle in accessory mode for 1/2 hr to ~1 hr per day is sufficient to keep your LVB charged up if, like me, you don't drive your truck a lot every day. My OBDII device is always plugged, so it's easy to read the LVB SOC. But as discovered in another thread, there's always your Ford.com dashboard, Ford Account Dashboard | Ford Owner Support. It may help to refresh your FordPass app and wait ~30 sec before checking LVB SOC at Ford.com.

Too bad the LVB is relatively small and drains so quickly. The more frequent recharging of a small battery probably means it wears out that much faster.
 

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One additional point to the previous posts. When the LVB drops below the threshold and the HVB kicks in to charge it, my 2023 Lariat ER also puts the truck in deep sleep mode which kills remote actions on FordPass and updates to Ford.com. Ford.com shows the last LVB SOC the truck sent, which may not be the current SOC. I haven't checked this since my recent 6.5 update - they may have updated this in more recent Power Up releases.
Side note: 6.8 update tried multiple times then gave up. I now get the message that the update will be released later. I'm hoping this will have some updates to the deep sleep action.
 

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Just had my 12V battery replaced due to bulletin. No issues since. Funny that I thought the bad battery was the reason I was not getting my updates I was ready for the 6.0.5 update prior to the battery replacement, and now, after the battery was replaced, that update does not come up as a pending update, and the truck has not been updated with it yet.
 

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there's always your Ford.com dashboard, Ford Account Dashboard | Ford Owner Support.
I assume this is what you are talking about? I had NO idea this was LVB SOC. I thought it is just wrong info for HVB SOC like many other places. Seriously, how am I suppose to know when it is right next to range with no specific label? In my defense in this case 52% HVB SOC getting me 96 miles is not that far off for standard battery pack. This was a big help (before the refresh, the info was four days old). Now if you can show me where to find this info on FordPass?


Ford F-150 Lightning 12 volt warning in cold while plugged in 1705069759820


I seem to be loosing more than 10% SOC from LVB every day. Is this high?

I tried charging on accessories mode and didn’t work out well. It charged at slower rate and by the time it timed out, It added only 4% and when it timed out charging, something was still consuming power and it took it down much quicker than it was charging.

Having the truck completely on worked much better. It took half hour before it timed out and it added 10% in that time. It was at little over 15V and 1.2 amp coming out of HVB. By end of that half hour, it added 10%. and it was at 0.9 A and 15V. This was from 50% to 60% SOC. I think the current may be lower at higher SOC. Still much healthier than accessory mode that was in 14V territory and 0.6-9.0 A. Not sure if I should turn off power down timer and change it or just do 10% at a time. Do you know any downside in having the truck on for a longer period without driving it?
 
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RickLightning

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I assume this is what you are talking about? I had NO idea this was LVB SOC. I thought it is just wrong info for HVB SOC like many other places. Seriously, how am I suppose to know when it is right next to range with no specific label? In my defense in this case 52% HVB SOC getting me 96 miles is not that far off for standard battery pack. This was a big help (before the refresh, the info was four days old). Now if you can show me where to find this info on FordPass?



I seem to be loosing more than 10% SOC from LVB every day. Is this high?

I tried charging on accessories mode and didn’t work out well. It charged at slower rate and by the time it timed out, It added only 4% and when it timed out charging, something was still consuming power and it took it down much quicker than it was charging.

Having the truck completely on worked much better. It took half hour before it timed out and it added 10% in that time. It was at little over 15V and 1.2 amp coming out of HVB. By end of that half hour, it added 10%. and it was at 0.9 A and 15V. This was from 50% to 60% SOC. I thing the current may be lower at higher SOC. Still much healthier than accessory mode that was in 14V territory and 0.6-9.0 A. Not sure if I should look for that 0.5 hour limit and change it or just do 10% at a time. Do you know any downside in having the truck on for a longer period without driving it?
I'm confused. You tried charging on Accessories Mode? That's not a thing. To charge the LVB, you either start the truck (and turn off HVAC and headlights), turn off the shutdown timer, and lock it for a while, or drive it. Accessories mode will use the LVB.

There is no downside to running the truck like above. HOWEVER, a much less expensive method would be to simply properly connect a Battery Tender. Negative connection to ground screw / post, not the battery.

Tip - constantly checking the 12v battery status via any app, or bluetooth connection, awakens the vehicle and.... drains the 12v battery.
 

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I'm confused. You tried charging on Accessories Mode? That's not a thing.
Yes. I just made it a thing. It just turned out not to be a good thing. It does charge LVB. My SOC went up by 4% in 20-30 minutes. HVB must be somehow still connected in accessory mode. It is just inefficient and impractical.

If there is no downside in leaving the truck on longer than half hour, it is more convenient than using battery tender, especially now that it looks like I have to do this frequently with my driving habits. unless you know a trick that helps LVB lose less of it’s SOC every day. I don’t keep the scanner hooked up but I may have had Fordpass running on my phone.
 

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Yes. I just made it a thing. It just turned out not to be a good thing. It does charge LVB. My SOC went up by 4% in 20-30 minutes. HVB must be somehow still connected in accessory mode. It is just inefficient and impractical.

If there is no downside in leaving the truck on longer than half hour, it is more convenient than using battery tender, especially now that it looks like I have to do this frequently with my driving habits. unless you know a trick that helps LVB lose less of it’s SOC every day. I don’t keep the scanner hooked up but I may have had Fordpass running on my phone.
Every time you look in FordPass you're going to awaken the vehicle. Every time you pass close with a FOB or PaaK you're going to awaken the vehicle. Losing a few percentage points a day, i.e. 3 to 5%, is normal. The vehicle SHOULD recharge the 12v when it gets low, like 40%, without use. I just don't want it that low.

The lower you let it go, the longer it has to run to raise it up. For me, a Battery Tender solves the problem.
 

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Every time you look in FordPass you're going to awaken the vehicle. Every time you pass close with a FOB or PaaK you're going to awaken the vehicle. Losing a few percentage points a day, i.e. 3 to 5%, is normal. The vehicle SHOULD recharge the 12v when it gets low, like 40%, without use. I just don't want it that low.

The lower you let it go, the longer it has to run to raise it up. For me, a Battery Tender solves the problem.
My LVB SOC always used to hover between 70% and 90%. Not sure if something has changed with one of the updates, or it is simply me driving less in winter. I will pay closer attention to what you listed.
 

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