Starting to get LVB 12v warnings...

[chl]

https://www.ford.com/myaccount/account-dashboard

Ahhh, thank you.
Now I see it.
It's 70% so obviously that's not enough for the update.
Problem identified at last!

Thank you everyone who helped!

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[GoodSam]

Ok, Account Dashboard for Low Voltage Battery Charge Level, vs. Vehicle Dashboard for the High Voltage battery Charge Level - why is @Ford Motor Company taking so long to clarify the Account page is the Low Voltage battery, and why post that info there instead of on the Vehicle page?

 

[chl]

I put the 12v on a trickle charger thinking that would raise the percentage charge and then I'd try to do the update one more time.

But as I watched the account dashboard percent charged number, it showed the voltage percentage going DOWN! What the? Makes no sense. Has to be a bad sensor.

I looked in the manual to see what it says about the LVB.

CHARGING THE 12V BATTERY
Your vehicle has a high voltage to low voltage energy transfer feature that keeps
the 12 volt battery charged by the high voltage battery. If the 12 volt battery level
is low, the high voltage battery transfers energy to the 12 volt battery when the
vehicle is off.

Does that mean FULLY charged? It should.

Yet the update requirements (on-line and in the FordPass app) explaining why an update might not have worked say one of the prerequisites is:

Your vehicle was driven for a minimum of 30 minutes before avoiding low battery.
Note: This will help ensure you have enough battery charge to complete the update, but is not a guarantee.

Seems a bit contradictory to me, and awkwardly worded maybe needs a comma after "before" perhaps?

Does the Lightning charge the 12v battery when the vehicle is OFF or ON (driving), or BOTH?

Does that 30 minute drive requirement maybe apply to the ICE F-150 where the engine has to be running to charge the 12v battery?

Is 30 minutes ON enough for the Lightning? Because, having the vehicle ON did raise the reported LVB percentage a small amount, very very slowly, like 2% after 30 minutes, if the sensor is reporting correctly.

If the reported percentage is accurate, having the truck OFF hasn't been keeping it charged as the manual suggests is the case.

So, I'm thinking that if used a voltmeter, the LVB battery would likely read the full terminal voltage of 12v plus, and that the issue is the BM Sensor (aptly named?) reporting an incorrect LVB percentage since Ford wants to replace the sensor. Unless the voltage transfer depends on the sensor voltage measurement - but it is reporting a low percentage, so that should have triggered a transfer.

The other possibilities are:
1) a bad battery or
2) a bad high-to-low voltage transfer feature (circuitry) the manual refers to, or


Time and a replacement sensor Monday will tell.

 

[Jim Lewis]

@chl. The LVB will also charge if the truck is plugged into a charger (FCSP in my case) and the truck is turned on in full-accessory mode (when plugged in, if you step on the brake and push start, the truck enters full-accessory mode, for instance). I drive very little and I've kept my LVB in the 70% to 80% SOC by running my truck while parked in the garage plugged into my FCSP for an hour or two a day. I shut off all accessories, turn off the headlights, etc., and, AFAIK, only a (cooling?) fan is running even in an 86F garage while letting the truck sit in full-accessory mode plugged in.

You might want to buy an OBDII reader. There are some very inexpensive ones on Amazon. I have one or two of those. I read the OBDLink web blurb on the value of their readers (more expensive! $$$). The one I use the most is an OBDLink MX+. OBDLink claims their readers are more secure and consume less LVB battery power if left plugged in when the vehicle is off (the MX+ claims only two ma draw). You can also use the MX+ with the proper equipment with FORScan if you're considering getting into that in the future.

But just an inexpensive reader that works with a smartphone app like Car Scanner would allow you to read your LVB voltage and % SOC directly. I haven't relied on Ford's online LVB % SOC reading much. It may be slow to update, especially with the new version of the FordPass app et al.

 

[chl]

OK, thanks, the manual didn't say what charge level would trigger the energy transfer to the LV battery from the HV battery so I wondered about that.

Does Ford have this documented somewhere?

A pretty strange set-up, esp since to get/install updates, 80+% charge is required it seems.

They could have/should have allowed for energy transfer during updates so there would not be the issue of low 12v battery - I mean how much energy does it take to write code into a memory? Not much, unless it is not a solid state device holding the code, even then.

Once I get the replacement battery sensor tomorrow, I hope things go better with updates.

 

[TaxmanHog]

Electrical System Overview for up-fit Lightnings

 

[chl]

@chl. The LVB will also charge if the truck is plugged into a charger (FCSP in my case) and the truck is turned on in full-accessory mode (when plugged in, if you step on the brake and push start, the truck enters full-accessory mode, for instance). I drive very little and I've kept my LVB in the 70% to 80% SOC by running my truck while parked in the garage plugged into my FCSP for an hour or two a day. I shut off all accessories, turn off the headlights, etc., and, AFAIK, only a (cooling?) fan is running even in an 86F garage while letting the truck sit in full-accessory mode plugged in.

You might want to buy an OBDII reader. There are some very inexpensive ones on Amazon. I have one or two of those. I read the OBDLink web blurb on the value of their readers (more expensive! $$$). The one I use the most is an OBDLink MX+. OBDLink claims their readers are more secure and consume less LVB battery power if left plugged in when the vehicle is off (the MX+ claims only two ma draw). You can also use the MX+ with the proper equipment with FORScan if you're considering getting into that in the future.

But just an inexpensive reader that works with a smartphone app like Car Scanner would allow you to read your LVB voltage and % SOC directly. I haven't relied on Ford's online LVB % SOC reading much. It may be slow to update, especially with the new version of the FordPass app et al.

Thanks. I am hoping once the replacement battery sensor is installed tomorrow, things will go better.

Seems like a software fix to allow the LVB to be charged enough to do updates when required would be a good idea @Ford Motor Company

I mean how much energy does it take to do an update anyway?

They suggest it takes 22 minutes in the message about the update on FordPass.
Writing memory takes a minuscule amount of energy compared to what is stored in the HVB.

So if the storage is Solid State, it might require 8 watts to write -- 0.008kW x 0.37h = 0.00296kWh.
If the storage is an SSD, maybe 20 watts --0.020kW x 0.37h = 0.0074kWh.
For an HDD, write may require 6.4w -- 0.0064kW x 0.37h = 0.0024kWh.

Some additional electronics would be running of course, the modem and processor(s).

But how much energy could all that add up to, compared to driving down the highway?

The 12v battery is 35Ah according to some posts.
at 12v, 20W requires 20/12 amps = 1.7A (1.66666...)
35Ah / 1.7A = 20h -- in other words, the 12v battery if fully charged could supply 1.7A for 20 hours.

But in practice it is not a good idea to deplete the 12v battery completely.

Another post said that when the 12v battery gets to 40% (35Ah x .4 = 14Ah) the DC-DC converter starts supplying energy to the 12v battery from the HVB. In other words when 21Ah have been used (35Ah - 14Ah = 21Ah).

So lets say the battery is at 80% required for updates, but you don't want to go below 14Ah (the 40% level) -- 35Ah x .8 = 28Ah; 28Ah - 14Ah = 14Ah; 14Ah / 1.7A = 8.2h

So if the draw is 1.7A for the SSD write, the 12v battery at 80% could provide that for 8.2 hours before reaching the 40% charge level.

Now the draw during an update is going to be more than that 1.7A, that was just for the SSD based on an assumption from measured amounts that at 12V, about 1.7A is required to write an SSD (the 20W).

So how many Amps would 22 minutes need to be to go from 80% to 40% from 28Ah to 14Ah, that is to use up 14Ah?

22 minutes is approx. 0.37h; so 14Ah/0.37h = 37.8A is the current draw from a 35Ah 12v battery at 80% for 22 minutes to get to the 40% (14Ah) level.

37.8A x 12v = 454watts
454watts for 22 minutes = 0.454kW x 0.37h = 0.167kWh

The SR HVB can hold 98kWh.

Using 167Wh of the energy stored in the HVB to do an update would be hardly noticeable!

Even assuming some loss of energy in the DC-DC conversion to 12v, using the HVB to provide the power needed for the updates seems like a no-brainer to me since it would have an insignificant effect on the level of energy stored in the HVB.

So just have the DC-DC converters ON when doing updates.

If there is a technical reason not to, I'm interested in hearing about it.

 

[chl]

I saw it in a post somewhere too, from a measurement by an owner I think. Just wondered if Ford bothered to put in writing anywhere.

Amen to the second reply.

From my napkin calculations, using the HVB energy to power the DC-DC converter to keep the 12v battery charged during a back-up would use an insignificant amount of the HVB stored energy.

Curious as to why they don't do that.

And why they'd let the 12v battery get so low, 40%, before topping it off? Not great for the 12v battery longevity!

It ought to be topped off every time the vehicle is on at a minimum.
And when off too, like any GOOD trickle charger will do, with regulation to keep the voltage around 13.2vdc or whatever is nominal for the type.
Lead-acid batteries love to be at full voltage, they last longer that way.
Unlike Li-ion batteries.

 

[TaxmanHog]

So just have the DC-DC converters ON when doing updates.

If there is a technical reason not to, I'm interested in hearing about it.

Controllers responsible for the the H to L energy transfer could in some situations be the target of an update, that said and adding in the potential maximum energy demands with ancillary systems running puts a heavy demand on the LVB exhausts it quickly. The update of CMOS (etc) is a tiny trickle of the energy demands in the process.

No, I don't have [F] documents to back these opinions, similarly expressed by other trusted members of the forum.

 

[chl]

Controllers responsible for the the H to L energy transfer could in some situations be the target of an update, that said and adding in the potential maximum energy demands with ancillary systems running puts a heavy demand on the LVB exhausts it quickly. The update of CMOS (etc) is a tiny trickle of the energy demands in the process.

No, I don't have [F] documents to back these opinions, similarly expressed by other trusted members of the forum.

Well a smart update process would download the update, store it, and then install it after a reboot, like Windows does with big updates. So all the things to be updated can still be on line until the update is installed after reboot.

I did the calculations about taking the 35Ah 12v battery from 80% to 40% (28Ah to 14Ah) assuming 80% is required to initiate the update and 40% is when the DC-DC converters are programmed to kick in (info gathered from a different post), and assuming the 22 minutes the update I was supposed to get is the time to use the 12v battery for the update.

It is a very small amount of energy compared to the HVB storage.

The whole idea of only topping off the 12v when it gets to 40% seems a bad idea for the 12v battery life. Any lead-acid battery prefer to be at 100% for longevity.

AGM's (Absorbed Glass Mat, fiberglass mats saturated with acid and pressed between lead plates, so a type of lead-acid battery) need to have an adequate charge or else they are subject to sulfation. AGM batteries should never go below 50% I have heard. But Ford goes with 40% so I read.

 

[Jim Lewis]

Microsoft Copilot answers on the care and feeding of AGM batteries:

AGM batteries perform best when kept close to **100% State of Charge (SoC)**. In typical use, their SoC might fluctuate between 100% and 70% due to alternating charge and discharge cycles¹. Here's a breakdown of AGM battery voltage ranges:

- **75-100% SoC**: Voltage between 12.2V and 12.6V.
- **50-75% SoC**: Voltage between 11.6V and 12.0V (recharge recommended).

Remember that maintaining a higher SoC helps prolong battery life and reliability. If you're using AGM batteries in a boat or RV, knowing the SoC helps estimate remaining runtime and prevent over-discharge¹.

Source: Conversation with Copilot, 7/21/2024
(1) AGM Battery State of Charge – workshoppist.com. https://workshoppist.com/agm-battery-state-of-charge/.
(2) AGM Battery State of Charge – workshoppist.com. https://bing.com/search?q=AGM+batteries+state+of+charge+tolerance.
(3) Understanding The Agm Battery Voltage Chart: A Comprehensive Guide. https://chargerblog.com/agm-battery-voltage-chart-2/.
(4) A Detailed Guide to AGM Batteries - Alpha Batteries. https://www.alpha-batteries.co.uk/blog/a-detailed-guide-to-agm-batteries/.

AGM batteries can start to get damaged if they remain at a **low State of Charge (SoC)** for extended periods. Typically, when the SoC drops below 50%, it can lead to sulfation—a process where sulfate crystals form on the battery plates, reducing capacity and performance. To prevent damage, aim to keep AGM batteries above 50% SoC whenever possible.

 

[TaxmanHog]

Public call for anyone with a 72 hour license doing updates to peruse the electrical diagnostic references manual to get specific answers related to stock configurations, we can then compare notes with what is stated in the POLICE package handout for up-fitters.

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