Never let your PB sit for more than a few days or the software goes weird, I guess

[Snakebitten]

What I don't get is that the hybrid battery could probably be used to help keep the 12v charged while it sits for long periods, but I guess they have kept that completely separate (thought I think the 12V is still charged by the hybrid battery when in electric only mode)

The 12V battery is ONLY charged by the HV battery. Not only in EV mode, but at any time that the truck is "on" AND the DC/DC converter is enabled.

That converter is the digital alternator on a Powerboost since there is no traditional belt driven alternator.

Ford could charge the 12V battery when the truck is parked and off, if they wanted to enable the DC/DC converter for a short period of time to accomplish that. It would need a considerable amount of management code written to ensure the HV battery doesn't get taxed below its operational range though.

Ford has chosen the simpler route of deep-sleep if the 12V battery(s) drop below a threshold.

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[RSKTakR]

Honestly guys, I never had anything serious, like being stranded but near constant electrical gremlins of the screen rebooting, remote feature shut downs, deep sleep warnings and eventually, a, Check Charging System Soon, warning. Constantly trying to remember to leave the fob in the house, while walking past it, to avoid waking it up. Never dared do anything radical, like listening to the radio while off and was frequently putting it on a charger.

What cured it all, was something @UGADawg96 tried about resetting the BMS.

Charged the batt directly to the posts (not to the BMS) until the charger went to float. Then immediately reset the BMS and like magic, poof, all the gremlins are gone and have stayed gone, for exactly 2 months straight. Not a peep of trouble out of it.

Even dared to listen to the radio while I was cleaning it recently and no more worrying about where the fob is.

Do yourselves a favor and give it a shot. It appears that somehow, the charge the BMS thought the batt had and what it really had, were out of sync and now they're back in.

2 months later, its all good.

What is the BMS reset procedure?

 

[CAG61]

How do I get the percent charge for that battery?

 

[mdn14]

Why does OP have the picture of a ford lightning in his FordPass but is asking about a Hybrid?

 

[VRFlyer]

This is actually a new 12v battery from the dealer. Couldn't be more than 4 months old! Interestingly, I had expected the truck to start from deep sleep mode but it started almost like normal, just the infotainment screen took an extra second or two to turn on. Normal sounding chimes and all.

This might be a software glitch accompanied by a low-VOLT issue.

 

[Davexxxx]

What is the BMS reset procedure?

 

[RSKTakR]

Ok thanks... and what is the purpose of doing the BMS reset? Is there a reason it would need to be done?

 

[Davexxxx]

Ok thanks... and what is the purpose of doing the BMS reset? Is there a reason it would need to be done?

Other than it is done when installing a new battery, I don't know but it solved all the battery issues I was having, without needing anything more than I described.

The only side effect I've noticed (other than no more batt problems) is for the first day, it seemed radio presets had disappeared but they were back by the next day.

 

[Groovicles]

Why does OP have the picture of a ford lightning in his FordPass but is asking about a Hybrid?

The OP has no idea. When I got the truck even the dealer didn't know why the Lightening was showing on the app.

 

[RSKTakR]

Other than it is done when installing a new battery, I don't know but it solved all the battery issues I was having, without needing anything more than I described.

The only side effect I've noticed (other than no more batt problems) is for the first day, it seemed radio presets had disappeared but they were back by the next day.

Ok. I don't have any battery issues yet, but I do still have the stock battery and my truck only has like 1009 miles on it so far. My truck sits in my garage m-f for the most part and doesn't get turned on or anything so I'm just getting prepared in case it starts lol.

 

[PaulGrun]

What is the BMS reset procedure?

I am far far from an expert...but here's my understanding.
The so-called State of Charge (SOC) is a derived value based on the measured voltage at the battery.
It's very difficult/impossible to measure the SOC which involves detailed measurement of the charge (coulombs) flowing into and out of the battery to calculate the current SOC. As I understand it, this "coulomb counting method is mainly a laboratory tool.
Fortunately, it is possible to 'estimate' the current SOC since there is a known relationship between the measured voltage and the SOC. But that relationship depends on a host of factors including among others the age of the battery. This relationship is captured in a family of look-up tables in the BMS. The BMS knows which look-up table to use based on, among other things, the age of the battery.
When you do a BMS reset, you are telling the BMS which of those look-up tables to use; thus a so-called BMS reset is intended to be used when installing a new battery. It gives the BMS a new baseline from which to start when it goes about estimating the current SOC.
But it's even more complex than that. The estimate of the SOC is based on reading the battery's resting voltage. The problem is that the battery's voltage is literally all over the map while the truck is in use. And worse, because of the weird magic of a chemical battery, the 'actual' so-called resting voltage that the BMS needs to calculate the SOC correctly, isnt reliable until the battery has been at rest for several hours - sometimes up to 8 hours.
So what the BMS does is to wait patiently until your truck has been idle for awhile and the so-called resting voltage is stable. Then it takes a snapshot of that voltage and resets its idea of the SOC accounting for many other factors like battery age, environmental conditions, the phase of the moon and so on. Then, the next day while you're driving around, it does it's best to keep its guesstimate of the SOC up to date based on what it was the last time it re-calibrated itself overnight.
That's my crude layman's understanding of how the BMS works in these trucks. It's a marvelous piece of engineering that, on-balance works pretty well.
So the answer, as I understand it, is that resetting the BMS resets the BMS' idea of the age of the battery. Many folks have reported having good luck doing a BMS reset to solve a host of electrical gremlins. I wouldnt discount for a minute the idea that the BMS may periodically lose its mind and 'forget' everything it once knew about the battery that's in its care and that a BMS reset 'reminds' the BMS to start paying attention again.
I hope this is both helpful and not too wikdly far afield.

 

[Davexxxx]

Ok. I don't have any battery issues yet, but I do still have the stock battery and my truck only has like 1009 miles on it so far. My truck sits in my garage m-f for the most part and doesn't get turned on or anything so I'm just getting prepared in case it starts lol.

Knowledge is power.

 

[Henfield]

Just a thought. If abandoning your truck for an extended period of time, shut the automatic updates off. Typically as the battery charge drops it will be unable to take any updates so shutting it off might just help a little.

 

[Snakebitten]

I am far far from an expert...but here's my understanding.
The so-called State of Charge (SOC) is a derived value based on the measured voltage at the battery.
It's very difficult/impossible to measure the SOC which involves detailed measurement of the charge (coulombs) flowing into and out of the battery to calculate the current SOC. As I understand it, this "coulomb counting method is mainly a laboratory tool.
Fortunately, it is possible to 'estimate' the current SOC since there is a known relationship between the measured voltage and the SOC. But that relationship depends on a host of factors including among others the age of the battery. This relationship is captured in a family of look-up tables in the BMS. The BMS knows which look-up table to use based on, among other things, the age of the battery.
When you do a BMS reset, you are telling the BMS which of those look-up tables to use; thus a so-called BMS reset is intended to be used when installing a new battery. It gives the BMS a new baseline from which to start when it goes about estimating the current SOC.
But it's even more complex than that. The estimate of the SOC is based on reading the battery's resting voltage. The problem is that the battery's voltage is literally all over the map while the truck is in use. And worse, because of the weird magic of a chemical battery, the 'actual' so-called resting voltage that the BMS needs to calculate the SOC correctly, isnt reliable until the battery has been at rest for several hours - sometimes up to 8 hours.
So what the BMS does is to wait patiently until your truck has been idle for awhile and the so-called resting voltage is stable. Then it takes a snapshot of that voltage and resets its idea of the SOC accounting for many other factors like battery age, environmental conditions, the phase of the moon and so on. Then, the next day while you're driving around, it does it's best to keep its guesstimate of the SOC up to date based on what it was the last time it re-calibrated itself overnight.
That's my crude layman's understanding of how the BMS works in these trucks. It's a marvelous piece of engineering that, on-balance works pretty well.
So the answer, as I understand it, is that resetting the BMS resets the BMS' idea of the age of the battery. Many folks have reported having good luck doing a BMS reset to solve a host of electrical gremlins. I wouldnt discount for a minute the idea that the BMS may periodically lose its mind and 'forget' everything it once knew about the battery that's in its care and that a BMS reset 'reminds' the BMS to start paying attention again.
I hope this is both helpful and not too wikdly far afield.

Wow!
You just became a bookmark that will save me the effort of ever answering that question, as well as some others, ever again!

Awesome!

 

[PaulGrun]

Just a thought. If abandoning your truck for an extended period of time, shut the automatic updates off. Typically as the battery charge drops it will be unable to take any updates so shutting it off might just help a little.

I'm not sure that will help. My understanding is that you cannot block automatic updates except by disconnecting the modem (TCU? I always get the modules confused).
The setting to which I think you are referring allows you to prevent an update that would render your truck inoperable for a short period of time. Ford lets you block or delay those. I think.

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