12V Battery Status Indicator

[Jerrytball]

there is no display of 12v 'health' anywhere.

you can display voltage, but that doesn't tell you anything about capacity on the 12v battery. voltage anywhere between 12.4-14.5v on the 12v is to be expected regardless of health.

I’m confused a little bit. I’m talking about when I do a scan and it says state of health or state of charge rather 91% charge just like on the big battery. It shows state of charge 85 or whatever in a separate window it does show like 13.5 V so I’m not sure exactly what we’re talking about here. I thought the whole point was you could see the percentage of your 12 V battery strength like it used to be on the website before they took it down

Sponsored

 

[dtbaker61]

I’m confused a little bit. I’m talking about when I do a scan and it says state of health or state of charge rather 91% charge just like on the big battery. It shows state of charge 85 or whatever in a separate window it does show like 13.5 V so I’m not sure exactly what we’re talking about here. I thought the whole point was you could see the percentage of your 12 V battery strength like it used to be on the website before they took it down

'State Of Charge' (SOC) is expressed in %, and is is supposed to show the % of capacity remaining in the battery; units of capacity are kW-hr.

The HV Lithium system 'counts' Whr in and out of the HV battery by measuring current (amps) x voltage = watt-hours output or charged. The counter resets to 100% when you do a full charge and hits the end-of-charge voltage and then starts counting all over again. With Li batteries the voltage curve is very flat between 20%-80%, so you can't tell what % you are at by voltage, you have to 'count' watt-hrs in and out. If you reset the counter at 100% with a full charge, and then drive to 10%, the voltage curve is steep enough enough to be fairly accurate to reset the 'low set point'.... then the system can calculate the total 0%-100% capacity, compare that to 'original', and that is your HV State Of Health (SOH), expressed as % compared to 'new'. We are seeing 3 yr old MMEs reporting SOH around SOH=95%

Does that help you understand the difference between SOC and SOH for the HV battery ?

The point of confusion may be that the 12v battery capacity is NOT MEASURED or tracked because watt-hours in and out are not counted for the 12v battery. we can see the Voltage, which corresponds directly to SOC. But since energy in/out is not tracked, SOH is unknown. we just go by the 36 month warranty, and replace soon after that.

When the 12v system is working correctly, the 12v battery gets charged frm the HV battery when it needs it and/or when ever the MME is 'on'.

There have been some 'bugs' in the 12v and OTA software that have caused some (mostly '23s) to over-discharge the 12v during OTAs, and cause all kinds of problems. Once @Ford Motor Company issues a 'fix', then the 12v should maintain itself properly.

 

[Jerrytball]

'State Of Charge' (SOC) is expressed in %, and is is supposed to show the % of capacity remaining in the battery; units of capacity are kW-hr.

The HV Lithium system 'counts' Whr in and out of the HV battery by measuring current (amps) x voltage = watt-hours output or charged. The counter resets to 100% when you do a full charge and hits the end-of-charge voltage and then starts counting all over again. With Li batteries the voltage curve is very flat between 20%-80%, so you can't tell what % you are at by voltage, you have to 'count' watt-hrs in and out. If you reset the counter at 100% with a full charge, and then drive to 10%, the voltage curve is steep enough enough to be fairly accurate to reset the 'low set point'.... then the system can calculate the total 0%-100% capacity, compare that to 'original', and that is your HV State Of Health (SOH), expressed as % compared to 'new'. We are seeing 3 yr old MMEs reporting SOH around SOH=95%

Does that help you understand the difference between SOC and SOH for the HV battery ?

The point of confusion may be that the 12v battery capacity is NOT MEASURED or tracked because watt-hours in and out are not counted for the 12v battery. we can see the Voltage, which corresponds directly to SOC. But since energy in/out is not tracked, SOH is unknown. we just go by the 36 month warranty, and replace soon after that.

When the 12v system is working correctly, the 12v battery gets charged frm the HV battery when it needs it and/or when ever the MME is 'on'.

There have been some 'bugs' in the 12v and OTA software that have caused some (mostly '23s) to over-discharge the 12v during OTAs, and cause all kinds of problems. Once @Ford Motor Company issues a 'fix', then the 12v should maintain itself properly.

So my only concern was mostly the 12 V battery and that’s what we were seeing on the Ford website and that’s all I’m saying is you can’t see that on the Ford website anymore like it used to say state of charge was 91% lotta people thought that used to be The high voltage battery, but now it just shows the SOC for the HV battery on that website so I was really only concerned about the 12 V battery so like I said when I run that scan if it says the state of charge on the 12 V is 91% I’m thinking well that’s good enough to leave it overnight in case I get an update because I’m gonna charge it tomorrow or I’m gonna drive it tomorrow so I just wanna make sure my 12 V battery is down around 50 or 60% that’s why I do that scan and when I see it at 91 or 97% I know my 12 V battery is good because it’s only a year old. Here’s a screenshot of what my high voltage battery looks like at one time.

 

[ocdxfv]

Yes I did. I did not want to risk it. Went with mobile service from Ford dealer for $280 installed.

That sounds like a fair price. I did mine at home and it was a bit more complicated than a typical 12v change out. But when I do it again in 2027, it should be faster and easier ?

 

[dtbaker61]

So my only concern was mostly the 12 V battery and that’s what we were seeing on the Ford website and that’s all I’m saying is you can’t see that on the Ford website anymore like it used to say state of charge was 91% lotta people thought that used to be The high voltage battery, but now it just shows the SOC for the HV battery on that website so I was really only concerned about the 12 V battery so like I said when I run that scan if it says the state of charge on the 12 V is 91% I’m thinking well that’s good enough to leave it overnight in case I get an update because I’m gonna charge it tomorrow or I’m gonna drive it tomorrow so I just wanna make sure my 12 V battery is down around 50 or 60% that’s why I do that scan and when I see it at 91 or 97% I know my 12 V battery is good because it’s only a year old. Here’s a screenshot of what my high voltage battery looks like at one time.

if the software was working correctly, you really don't have to worry about the 12v at all. It will call for a charge when it needs it.

OTAs are 'supposed' to check state of charge before they start, and knowing how long they take, not start an OTA unless they calculate the 12v will last thru the OTA. Unfortunately, older 12v throw the calculations off, and can kill the 12v.

One maybe less worrysome way to prevent surprises is to turn auto-updates OFF until you hear about something you want. Then, turn OTA back on, and leave your MME 'on' overnight with auto-off disabled. This will do two good things:
a. de-sulfate the 12v for longer life
b. be certain that 12v is charged to 100% SOC before OTA.

 

[Jerrytball]

if the software was working correctly, you really don't have to worry about the 12v at all. It will call for a charge when it needs it.

OTAs are 'supposed' to check state of charge before they start, and knowing how long they take, not start an OTA unless they calculate the 12v will last thru the OTA. Unfortunately, older 12v throw the calculations off, and can kill the 12v.

One maybe less worrysome way to prevent surprises is to turn auto-updates OFF until you hear about something you want. Then, turn OTA back on, and leave your MME 'on' overnight with auto-off disabled. This will do two good things:
a. de-sulfate the 12v for longer life
b. be certain that 12v is charged to 100% SOC before OTA.

I’ve done the remote start, but I don’t think I’ve ever started the car and left it running. My question is because I don’t have a garage. Can you lock the car while it’s running?

Also, I think I asked this somewhere else but I believe I’ve left the car running and plugged in at home and charge the car while it’s running, but I don’t think a DC fast charge. Let you leave the car running because when I was plugged into EA the other day, although I wasn’t charging, it seemed like it put the car in accessory mode as soon as I plugged in. Is it different?

 

[dtbaker61]

I’ve done the remote start, but I don’t think I’ve ever started the car and left it running. My question is because I don’t have a garage. Can you lock the car while it’s running?

yes

Also, I think I asked this somewhere else but I believe I’ve left the car running and plugged in at home and charge the car while it’s running, but I don’t think a DC fast charge. Let you leave the car running because when I was plugged into EA the other day, although I wasn’t charging, it seemed like it put the car in accessory mode as soon as I plugged in. Is it different?

you have to disable the 'auto-timeout' setting as well.

 

[Jerrytball]

yes


you have to disable the 'auto-timeout' setting as well.

So if I disable auto timeout, and I plug in at a fast charge station level three the car should stay running if it’s running because I mean, I can understand turning auto timeout off, and if I didn’t in the car would shut off eventually, but soon as I plugged in the car went into accessory mode, so I just thought that was strange.

 

[dtbaker61]

So if I disable auto timeout, and I plug in at a fast charge station level three the car should stay running if it’s running because I mean, I can understand turning auto timeout off, and if I didn’t in the car would shut off eventually, but soon as I plugged in the car went into accessory mode, so I just thought that was strange.

you don't need to do anything with timeout at a L3 station.... only if you are leaving the car on overnight.

 

[Teslaeata]

Mine is only showing 67%
When to replace?

Not just because LV SoC is at 67%.

It can drop to 40% and still sit there for 48hrs or until it drops further to 30% before the DV/DC converter is programmed to start charging it.

If no other signs exist which are symptomatic of the need for LVB replacement, I wouldn’t worry.

 

[Vgkfan]

I read your post and after watching the charge value it appears to be the charge is the main battery not the 12 volt battery.

At the time I posted that the information was correct, but it has recently been “fixed“ unfortunately.

 

[nlions]

Ford.com Then sign in>account>(yourname)account. The charge level is actually your 12v charge level.

My charge level on Ford.com is not the 12 volt battery, it's the big guy.

 

[alexgorod]

if the software was working correctly, you really don't have to worry about the 12v at all. It will call for a charge when it needs it.

Unless the battery can't hold any charge - there are some reports in this forum about cars dying right after they were shut down.

If no other signs exist which are symptomatic of the need for LVB replacement

What signs?

My car is almost 3 years old and I am planning to replace the LVB even though I don't see any signs, but I don't know what to look for.

 

[doogie63]

What about one of these to keep an eye on voltage https://a.co/d/5goFbcd

 

[zvez]

My charge level on Ford.com is not the 12 volt battery, it's the big guy.

ford "fixed" that about three weeks ago so we no longer get 12v SOC

Sponsored