LVB Charging: Is there a way to force it to keep the battery charged?

[Mike G]

I agree, the BMS can drift.

But how did you measure your SOC?
Are you relying on the truck to tell you the SOC?

Lots of evidence that's not very accurate - batteries that needed replacing even though CarScanner or other OBD reading program said the "SOC" was fine.

If you want to know for sure, do a bench type check, disconnect the battery from the truck, fully charge it, read the terminal voltage, then let it settle for at least 1/2 hour (the longer the more accurate), then read the terminal voltage again, if it falls significantly, that's an issue.

Or use a battery tester: the battery is a 35Ah with 380 CCAs for your test, after fully charging as above and letting settle for the most accurate results. What you really want to know is the SOH, the capacity compared with a new battery, that gives you an indication of how the battery is doing and whether it is on its last legs.

Of course, if you haven't seen any warning signs, update failures, weird system behavior, low battery warnings, then you are probably OK for a while.

Want to make the battery last its optimum lifespan?
Use a maintainer.

I have a Foxwell BT705 coming from Amazon in a couple of days and it will be interesting to see the difference between what my Lightning and Mach-E are reporting to Ford and what the tester shows. I can also use the internal resistance value it provides to estimate the useful remaining life:

From ChatGPT:
For AGM batteries:

• ~4–6 mΩ → Strong, healthy
• ~6–8 mΩ → Mid-life, still reliable
• ~8–10 mΩ → End-of-life approaching
• 10+ mΩ → Failure likely soon

Rough rule of thumb:

Once you pass ~8 mΩ, you’re often within months, not years of failure.

So we'll see if my (roughly quarterly) BMS Learned value reset strategy has been paying off or whether I'm about to be left dead in a shopping market parking lot somewhere.

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[chl]

I have a Foxwell BT705 coming from Amazon in a couple of days and it will be interesting to see the difference between what my Lightning and Mach-E are reporting to Ford and what the tester shows. I can also use the internal resistance value it provides to estimate the useful remaining life:

From ChatGPT:
For AGM batteries:

• ~4–6 mΩ → Strong, healthy
• ~6–8 mΩ → Mid-life, still reliable
• ~8–10 mΩ → End-of-life approaching
• 10+ mΩ → Failure likely soon

Rough rule of thumb:

Once you pass ~8 mΩ, you’re often within months, not years of failure.

So we'll see if my (roughly quarterly) BMS Learned value reset strategy has been paying off or whether I'm about to be left dead in a shopping market parking lot somewhere.

Depending on driving frequency and length, as well as load (accessories, etc), these batteries are mostly failing within the 3 year warranty period it seems from reading the posts.

With no maintainer, AGMs are predicted to last up to 5 years.

On a maintainer, any lead-acid battery will last at least twice that usually absent damage, short circuits, etc.

 

[JamboneMan]

Ok, I read through this entire thread, like twice. For powering a dash cam while parked, only if I keep the vehicle on will the LVB stay maintained with the HVB, correct? The LVB will not charge from the HVB when the vehicle is off and dropped to some pre-defined low voltage (not connected to EVSE)? I'm still a little confused, sorry.

Also, I have a Viofo A329S coming this week and planning to install myself. I will be using the HK6 ACC Hardwire Kit which will allow me to set a cut-off voltage for parking mode. I'm not sure which value I'm going to use to set the cut-off, looking for a suggestion for the factor AGM battery.

Ideally I would like to use the buffered camera recording while parked but still maintain the battery but I'm guessing that's not possible. It would be great to use a charger in the frunk to charge the LVB with ProPower but it will cut off when less than 100-watts, sucks. This is just really stupid. The HVB should always charge the LVB when required at all times and conditions.

 

[chl]

I am curious if anyone has figured out a way or possibly a setting i can change to make the truck keep the LVB at a higher voltage?

I ask this, because i just bought a Viofo A329T dashcam setup and after installing it this week, the next moring my truck wouldn't turn on. I checked the 12v battery, because i think its the stock one from 2022 still and the voltage was very low, so i removed it and charged the battery up and the truck responded just fine afterwards as if nothing happened. The very next morning the battery was dead again with low voltage, so i recharged it again and took it to be tested at the parts store, which they said it was still in good condition. When i installed the battery back in the truck, i left the dash cam unhooked and the last 2 days its been just fine, no more dead battery in the morning.

Ford: We wish there was, and we wish they would change the algorithm, and yes they could but the battery issue has been a thing in F-150's even before the Lightning, there is so much energy in the HVB it wouldn't be a big drain to keep the 12v topped off to 100% all the time and extend the battery lifespan, but it is just not a priority to Ford...alas...

I keep my 12v on a maintainer with an AGM mode when not being used.

If you want you dash cam on all the time you should get a maintainer.
If not, then use the mirror connection which turns off with the truck and this adapter:

https://www.amazon.com/dp/B088P4VFQ7?ref=ppx_yo2ov_dt_b_fed_asin_title

That's what I use with my dash cam.

 

[mr.Magoo]

Or use a dashcam battery, or create your own secondary battery setup.
Both options work well.
Dashcam batteries are lithium so they won't charge in the winter if it's cold where you live.

 

[JamboneMan]

Or use a dashcam battery, or create your own secondary battery setup.
Both options work well.
Dashcam batteries are lithium so they won't charge in the winter if it's cold where you live.

I will plan to do a stand alone battery system for the dash can if I am not happy with park mode using the LVB AGM battery. I still need to figure out where to set the hard cut off for the AGM. For short term parking, less than 2-hours, I'll probably just leave the truck on. I am more concerned with parking at work for 8-10 hours. I would like some recording capability, like low bit rate to time lapse recording.

 

[chl]

I will plan to do a stand alone battery system for the dash can if I am not happy with park mode using the LVB AGM battery. I still need to figure out where to set the hard cut off for the AGM. For short term parking, less than 2-hours, I'll probably just leave the truck on. I am more concerned with parking at work for 8-10 hours. I would like some recording capability, like low bit rate to time lapse recording.

If you turn off as much of the other stuff, lights etc. as possible, and leave the truck ON with the power down timer OFF, I wonder how many kWhs would be used in 8-10 hours?

Not many I imagine, though I haven't down any measurements others may have?

If the truck is ON it will/should keep the 12v battery charged and the dash cam powered.

 

[potato]

Well you know with this new fangled lead acid battery technology, we have to give new manufacturers like Ford who just started making cars some time to figure it out.

Oh wait

 

[JamboneMan]

If you turn off as much of the other stuff, lights etc. as possible, and leave the truck ON with the power down timer OFF, I wonder how many kWhs would be used in 8-10 hours?

Not many I imagine, though I haven't down any measurements others may have?

If the truck is ON it will/should keep the 12v battery charged and the dash cam powered.

Roger, that's what I'll probably do until I can save for a dash cam battery. It would be great if I could use a small inverter to keep the dash cam powered during parking with the HVB. The dash cam probably doesn't draw enough power to keep PPOB on with the truck off, bunmer. There has to be a better solution.

 

[chl]

Roger, that's what I'll probably do until I can save for a dash cam battery. It would be great if I could use a small inverter to keep the dash cam powered during parking with the HVB. The dash cam probably doesn't draw enough power to keep PPOB on with the truck off, bunmer. There has to be a better solution.

A small battery maintainer plugged in to the utility (120v outlet) might be a solution as well.
The added benefit is keeping the 12v battery at 100% as much as possible extends the lifespan quite a bit.

See this thread for ideas about that:

https://www.f150lightningforum.com/forum/threads/charging-12v-battery.16979/

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