Charging Sys-Full Description-Trigger Voltages-Test Results

[Big Blue]

Great writeup and thanks for the work. One question I still have. For those of us that disabled ASS in Forscan, what affect does this have on the BMS and the battery charging profile.

I'm one of those retired people who does mostly short in town trips with occasional longer trips. Truck may sit a few days between uses. I've had mine disabled in Forscan for over 2 years and had my battery replaced under warranty last August. Never had the features shut down to conserve battery. Thinking maybe just a bad battery.

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[airline tech]

When using the battery tester shown, the BT200, do you attach directly to the (-) battery terminal or body ground?

TopDon Tester:

I had to play with the different connection points, to get it to read good, and I found that if you do not have a solid good connection, the tool will read that as resistance and give you a bad test. For example, my current last test gave me 97% health, the pic I have with the post has 90%. So, the tool is a great tool and appears accurate, but just be aware that you need a very good connection point.

Pos: (+)
Used the top smaller nut on the bus bar, as going to the actual post provided inaccurate results. Battery Fail, that post has some protective insulation around it and hard to get a good solid connection.

Neg (-)
Directly to the post, as I was not charging it.

 

[got3fords]

TopDon Tester:

I had to play with the different connection points, to get it to read good, and I found that if you do not have a solid good connection, the tool will read that as resistance and give you a bad test. For example, my current last test gave me 97% health, the pic I have with the post has 90%. So, the tool is a great tool and appears accurate, but just be aware that you need a very good connection point.

Pos: (+)
Used the top smaller nut on the bus bar, as going to the actual post provided inaccurate results. Battery Fail, that post has some protective insulation around it and hard to get a good solid connection.

Neg (-)
Directly to the post, as I was not charging it.

Got it, thanks!

 

[airline tech]

Great writeup and thanks for the work. One question I still have. For those of us that disabled ASS in Forscan, what affect does this have on the BMS and the battery charging profile.

I'm one of those retired people who does mostly short in town trips with occasional longer trips. Truck may sit a few days between uses. I've had mine disabled in Forscan for over 2 years and had my battery replaced under warranty last August. Never had the features shut down to conserve battery. Thinking maybe just a bad battery.

Since, my ASS was disabled.at factory, I am not sure., some of my Forscan files still show ASS enabled but I have no switch and no dash display for it, I do plan on digging into what was actually done at build to disable it. Like I said in the post, that the voltmeter is a cheap way to monitor what the system is doing, and I am actually amazed how accurate it is or try the engineering mode, as I am curious what others have as a norm.

I have not dug deep enough into the Forscan (ASS Disable) to see exactly what is being changed in the Hex-Code to achieve it, I just know the BMS sensor is just a part of the system that will disable ASS as it relates to the battery having a voltage reading high enough to support an engine start draw, and it is geared toward not draining the battery down too low to where you are stranded at a light with a dead battery, that's the intent, anyways. I feel that word got out from the other forums and owners had a quick and easy way to disable the ASS, and just started pulling the BMS sensor and then it snowballed into a you got to do this, thing., without any research. I myself hate it and if I had it on the truck, it would be deleted as well.
You have cued my interest though, might have to dig into it.

 

[seasprite]

Nice job, and I thinking about boosting my soc, but I'll skip it for now. If in the future if I decide to I'll only go to 80%.

You do have me wondering if you switch to a flooded lead acid battery if you should reprogram the soc?

 

[airline tech]

Since, my ASS was disabled.at factory, I am not sure., some of my Forscan files still show ASS enabled but I have no switch and no dash display for it, I do plan on digging into what was actually done at build to disable it. Like I said in the post, that the voltmeter is a cheap way to monitor what the system is doing, and I am actually amazed how accurate it is or try the engineering mode, as I am curious what others have as a norm.

I have not dug deep enough into the Forscan (ASS Disable) to see exactly what is being changed in the Hex-Code to achieve it, I just know the BMS sensor is just a part of the system that will disable ASS as it relates to the battery having a voltage reading high enough to support an engine start draw, and it is geared toward not draining the battery down too low to where you are stranded at a light with a dead battery, that's the intent, anyways. I feel that word got out from the other forums and owners had a quick and easy way to disable the ASS, and just started pulling the BMS sensor and then it snowballed into a you got to do this, thing., without any research. I myself hate it and if I had it on the truck, it would be deleted as well.
You have cued my interest though, might have to dig into it.

Ok, my curiosity got to me. and I found something interesting. Now it appears that the only settings that I see altered in the As-Built files for mine are: 2 Files, related to the switch.

Mine: IPC: 720-01-01 (2F0F-1464-7251) Factory A-Start Deleted - No Switch Installed
2021 FX4 -IPC: 720-01-01 (2F0F-3464-7271) With A/Start

720-01-01 (XXXX-3XXX-XXXX) to (XXXX-1XXX-XXXX), you are disabling ASS. but this is in the IPC.

Note: How the auto unlock is tied into the ASS, might be something to note for reference when you lose both A/Start and are having issues with unlocking the truck.

and this file in the FCIM

Mine: 7A7-01-01 (0076-80DC-1496) (Ass-Disabled) (No-Switch-Installed)
Compare: (XXXX-X1DC-XXXX) (Ass-Enabled) (Switch Installed)


So, my question, has anyone tried changing those two codes, to disable it, you may have to disconnect the ASS switch to obtain a result without any DTC codes though.

The reason I am pointing this out is due to:

My BCM File: The one that gets changed. - Slave exists BMS Configure is the same as the 2021 Ranger I am using as a compare truck (As-Built Files)
I am talking about the one that is listed for the A/Start Delete in the Wiki, so as far as the BCM sees it, A/Start for mine is still enabled but that's it.

Mine and As-Built Compare.

BCM: 726-48-02 (0100-0000-0179) (ASS Enabled)

And to Disable (X0XX-XXXX-XXXX), this is what it gets changed to.

So, to point out that Ford did not change this file to disable the system, I do not know why, but it was left for a reason.

So, to clarify, I have my ASS disabled from the factory and only have 2 known hex codes changed and it is not the BCM code that others are using to delete it.

So, to answer what does disabling ASS using Forscan, actually do, within the BMS, well I do not have a positive answer, but I think it is doing one of 2 things.

Slave Exists BMS Configuration, I think all this does is it tricks the system into thinking that the battery voltage is below 11.3 Volts, thus keeping it from activating. I was attempting to find the post about owners still seeing a vehicle charging message in the IPC, when they have disabled ASS by this method. If they are constantly seeing the message, then I would be correct. But this is my best logical guess.

or

It's the same things as Disconnecting the BMS sensor, just by code vs disconnect.

I guess I have another test to perform and that's change the BCM code and see what it does.
Unless anybody knows for sure.

 

[got3fords]

So after reading this great write up this morning, on the way home I paid more attention to my battery status guage that plugs into the cigarette lighter. Normal driving, DRL on, the battery voltage was always right around 14.33V. Off pedal, coasting downhill it got to about 14.61V. Then with the auto headlights on, coasting downhill in nuetral, nothing changed. The voltage never got below 14.31V. Park in driveway, shut everything off, wait till lights go out but could not wait till display screen shut off. 12.55V.

 

[airline tech]

So after reading this great write up this morning, on the way home I paid more attention to my battery status guage that plugs into the cigarette lighter. Normal driving, DRL on, the battery voltage was always right around 14.33V. Off pedal, coasting downhill it got to about 14.61V. Then with the auto headlights on, coasting downhill in nuetral, nothing changed. The voltage never got below 14.31V. Park in driveway, shut everything off, wait till lights go out but could not wait till display screen shut off. 12.55V.

Ok, sounds normal, and by the voltage (driving) I am thinking temp was around 32 deg or below.

Just to clarify, when I say coasting downhill, I am referring to still in drive, and the rotation of the drive axles (while coasting) is providing an engine braking effect which will enhance the boost charge.
So, neutral will have no effect as the driveline will be disconnected - (motive power wise)
And, since you were already in the 14's charging range, you only will see a small boost charge if any at all.

 

[airline tech]

I plan on performing a further detailed test, that I should have performed, and I am referring to the fact that some owners are reporting that they have no issues with the battery while set at 90% or with BMS Disconnected.

When I made my observation in those modes of operation, I made my noted opinion on the battery being overcharged, but in reality, I believe it was overheating the battery, thus the smell.
The battery itself will not take any more charge that it can hold, thus the high surface charge I was seeing at shutdown. The extra voltage on the battery, higher resistance as it gets full, increases the heat on the battery.

Now, I based my theory on the smell I noted and the surface charge, but to be completely fact based, I am planning on hooking up Forscan and testing after a drive what the battery temp is reading. I will be looking at battery temperature readings and how far they climb.

Drive @ Factory 75% as a baseline Temp
Drive @ 90%
Drive With BMS Disconnected

This way I can provide everyone with accurate results and will include pics of the results.

Plus, from my last post regarding A/Start, I am curious about how disabling it in the BCM code, what effect does it have on BMS itself.
These types of things are what frustrates me, somebody puts out a code to disable A/Start and gives you a statement of: Slave Exists BMS Configure, well what exactly is the code changing in configuration, is it the BMS (system) or just changing one of the input parameters required for the A/Start system to enable and leaving BMS functional otherwise.
I truly applaud, the effort but release what precisely is being altered, when you write it to code.

 

[RangerBill]

TopDon Tester:

What is your opinion of the TopDon battery tester? Does it seem to be accurate?

 

[airline tech]

What is your opinion of the TopDon battery tester? Does it seem to be accurate?

I have not played with it enough to tell for sure, but I have noted that it will read battery voltage easily. But when you go and do the battery test, your results can be flawed due to it is measuring resistance during this test and if you do not have a tight solid connection between the clamps and the posts, you will end up with a failed battery result, when its actually good and 97% health
The positive post is the one that is hard to get on and I found that instead of connecting directly to the positive post, use the hex nut on the bus bar, to get better results.
The reason for the inaccurate results is that the tester results are including the resistance between the clamps and the connection points.
But, for the price it gives owners a way to perform a quick battery test and appears accurate as long as you have a valid connection point, so I highly recommend if you have an initial bad test result change the connection point on the positive clamp and perform the test again.

 

[IdahoRanger]

The part I found interesting was the charging when below 45d. We can go 6 months with mostly below freezing temps and a couple months in the 90's- 100's. My 2019 may sit for 4-5 days without driving and then I do only short trips with a couple of times a month 100+ mile trips. Still on original battery and knock on wood no signs of starting trouble or warning messages.

Ass is disabled with my Livernois tune.

Maybe the cold weather helps due to the higher charging you noticed. I did get the jump starter to carry since the inevitable is bound to happen.

 

[Trigganometry]

The rotten egg smell noted with changing the charging rate over 80% was interesting. I recently bumped mine from 75% to 90% and have had no smells. But it is something I will monitor now.

Great write up @airline tech

My 2020 XLT was a 70% SOC setting from factory. I did a BMS disconnect about a month after getting the truck to disable ASS.

After that got a copy of Forscan and tweaked to my hearts desire. One thing I did change was SOC to 90%. After doing that years ago my going to sleep messages in FordPass and Sync display stopped.

I’m in the NE so cooler temps for the most part most of the year. I, like OP have never smelled the battery. I also have a digital voltage monitor in my acc plug. Most of the time I’m seeing 12.2V at rest. What I noticed at 90% setting is pretty constant charging voltages during normal driving. So that would be mid 13’s somewhere.

 

[AzScorpion]

Great write up @airline tech

My 2020 XLT was a 70% SOC setting from factory. I did a BMS disconnect about a month after getting the truck to disable ASS.

After that got a copy of Forscan and tweaked to my hearts desire. One thing I did change was SOC to 90%. After doing that years ago my going to sleep messages in FordPass and Sync display stopped.

I’m in the NE so cooler temps for the most part most of the year. I, like OP have never smelled the battery. I also have a digital voltage monitor in my acc plug. Most of the time I’m seeing 12.2V at rest. What I noticed at 90% setting is pretty constant charging voltages during normal driving. So that would be mid 13’s somewhere.

Which digital voltage monitor did you get Rick? I have a few in my Amazon list but I'd rather get one I know works well.

I'm not smelling my battery either, We have to draw the line somewhere! Between smelling our oil, smelling the battery what's next? Smelling our dampers??‍?

 

[IdahoRanger]

I'm not smelling my battery either, We have to draw the line somewhere! Between smelling our oil, smelling the battery what's next? Smelling our dampers??‍?

Just don't smell the stuff on the window.

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