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All lead-based batteries dislike being discharged too deeply, or for too long a time.
By the way, when you replaced the battery two years ago, did you reset the BMS? If not, that might account for the battery not being charged properly.
Yes, I let the car sit after locking it for the normal bms reset and I did the forscan bms reset or scan tool bms reset, not sure which but I did one via letting it sit like the procedure calls out and then doing one thru a device. I'm going to pull up forscan maybe tomorrow and just grab what I have currently in there relating to the battery since the car won't be movable in a out 18 hours when we get 12-18 inches of snow lol
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Letting it sit does not reset the BMS. It just forces the BMS to reassess the state of charge. It must be reset either with something like ForScan, or by performing a short procedure with the ignition and brake pedal, which I can't remember exactly but can be found on the forum, as it's been discussed many times. The reset tells the BMS that the battery is new, so it adjusts the charging strategy accordingly. Simply letting it sit won't do that.
And conversely, it must never be reset unless you've just installed a new battery. Resetting it with an old battery in place spells trouble.
If you remember having done it with the device, then you're OK on this front.
 
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Letting it sit does not reset the BMS. It just forces the BMS to reassess the state of charge. It must be reset either with something like ForScan, or by performing a short procedure with the ignition and brake pedal, which I can't remember exactly but can be found on the forum, as it's been discussed many times. The reset tells the BMS that the battery is new, so it adjusts the charging strategy accordingly. Simply letting it sit won't do that.
And conversely, it must never be reset unless you've just installed a new battery. Resetting it with an old battery in place spells trouble.
If you remember having done it with the device, then you're OK on this front.
It was reset they the procedure and forscan

Forscan is to reset the days in service, letting it sit undisturbed for 8 hours is the process for resetting state of charge. 2 processes for different settings. Found that info in the forums awhile back just researched and found it again. I still have to pull up forscan but we got hit with 17 inches of snow and the cars stuck
 
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It reads as though the battery swap and FORScan changes occurred as part of or in concert with the Sync3 upgrade. I'm assuming the root problem was happening before the Sync upgrade.

It might simplify t-shooting these problems by reverting back to a traditional, Flooded Lead Acid (FLA) battery. I realize some of the FORScan settings might have been lost. Maybe we can help with that. Enclosed is some reference information I have.

There are three FORScan fields I'm aware of: Battery Technology, State of Charge and Case Size.

1. Battery Technology: Flooded Lead Acid or Absorbent Glass Mat (AGM).

2. State of Charge: the factory setting is 80%.

3. Case Size:

- If the factory battery, select, "BXT-96R-590"

- If an AGM, the closest comparable I can think of is, "AGM 70ah 600CCA H6 case". This is if an AGM was selected that most closely matches the factory battery. If you've installed something else, select the option which most closely matches that.

There is an additional setting, "Rate of Charge". Several references I found mention it's set at the factory, 80%.

https://www.mustang6g.com/forums/threads/battery-saver-message-on-a-new-battery.224209/

https://antigravitybatteries.com/he...FU_y0RvhbAvcWOjo9bdzx4DYkI5whYQ-2jDuLfecTTCQP

https://www.f150gen14.com/forum/thr...hanging-battery-charge-rate-in-forscan.21552/

As to parasitic losses, the only method I'm aware of to t-shoot is pulling fuses. Using an induction meter to measure the amount of current being discharged, pull one fuse, confirm if there have been any meaningful changes, re-insert fuse before going on to the next.

The 6G does have multiple processes that occur when the car is shut off. Even as those continue to work in the background, they should allow the car to be started as late as two weeks after last shutdown.

- BCM battery State of Charge measurements
- PCM emissions evaporation canister checks
- Door proximity sensors and contacts
- Trunk proximity sensors and contacts
- Hood ajar sensor
- Door ajar sensors
- Trunk ajar sensor
- Telematics modem and vehicle cellular system
- Bluetooth (802.15) interfaces (if enabled)
- Wireless (802.11) interfaces (if enabled)
- BCM background functions
- PCM background functions
- Interior motion detectors
- Vehicle movement detection
- Vehicle slope change detection
- Remote Transceiver Module (Intelligent Access)
- Engine Immobilizer (Passive Anti-Theft System (PATS))
- Driver-installed ancillary devices

Given that, I'd limit any draws as much as possible, as part of the t-shooting process:

- Remove, at least temporarily, any non-factory items (radar detectors, cameras, etc.)
- If an aftermarket amplifiers and sub-woofer is involved, disconnect those
- Within Sync, turn off all external interfaces (Wi-Fi, bluetooth, phone pairing, etc.)
- Remove the fob and lock the car when not in use. Keep the fob at least 10 feet from the doors and trunk
- Confirm interior lights are off and remain off
- Confirm hood, doors and trunk close well

There's the chance that, while you were and possibly continuing to deal with a parasitic loss, without knowing all the FORScan changes, the car might not be charging the system back to it's full potential. I'd at least confirm the batt settings I pointed out. Other Members might provide more still.

It would also help to confirm the state of the existing battery. A parts store can do a load test. IDK if they'd have a charging service, where you could drop it off for an overnight top-up.

battery options bcm 000.webp


battery options bcm 001.webp
New development. Installed my shift knob and went to start the car, clicked and tried to start but sounded terrible. Threw in a jump box and lost all power. No green light on start button, no response to anything. Readjusted clamps a few times and let it sit and finally got it started, engine sounded rough, knocking almost but it seems to have gone away now that it's started up. But I have a dead sync 3 screen now no response from it and steering assist fault message on the dash. Any idea what the ever loving crap is going on with this car? Just issues with it dying before never a dead screen or anything else until know. Only things that are diff are the light controller and middle dash gauges are unplugged but I've never had an issue with those being unplugged before.
 

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Any idea what the ever loving crap is going on with this car?
In your initial post, you mention you've been dealing with a power-related problem for some time. Since, there've been some changes, including a battery, Sync upgrades and setting changes via FORScan. The vehicle is showing signs of a bad connection, possibly a large parasitic drain and maybe a faulty alternator or battery.

You've tried to correct these issues, but there remain a lot of questions, a lot of areas that have changed and a good amount of unknowns. I don't feel you have all the tools or references to tackle that. I think it's best you search for a good local mechanic or Ford dealership, then turn the vehicle over to them.

As part of the initial discussion of the history of these issues and what's been done thus far, advise the technician FORScan was used to change some settings related to electrical generation and power management.

To stay on-topic while ensuring everything is brought up, have some high-level bullets or points made out and talk through those. Rough-out a story line.

If at a Ford dealer, see if they can baseline the current build by re-flashing the Body Control Module, Powertrain Control Module or both. This might affect the changes you made to Sync, but I think we're past that: the vehicle is barely functioning.

I'd want the following diagnosed, in this order:

1. Review all physical connections involving the battery, alternator, starter and under hood fuse block. Ensure all are in the correct place, of the right type and secure.

2. Disconnect and isolate anything that is not Ford OEM. Cameras, radar detectors, aftermarket sound systems, etc.

3. Confirm the Body Control Module (BCM) and Powertrain Control Module (PCM) are programmed correctly. However they can do that, probably using Ford Diagnostic and Repair Software (FDRS).

4. Charge the battery completely, overnight if necessary and perform a load test. If not meeting the standard, replace. Note to the technician: the existing battery is an Absorbent Glass Mat (AGM), not a Flooded Lead Acid (FLA).

5. Start the car. Confirm the alternator is putting out the required amount of power, is being managed by the BCM and PCM correctly. If not working as expected, diagnose and repair.

6. Once items 1-5 are confirmed good, investigate the possibility of a large parasitic loss and any alarms.

7. Residuals. Anything that still is not working correctly.

Mechanics in my area are $150 an hour. Some shops charge flat diagnostic fees. It depends. What I described is a lot. It could take a good bit of time. I'm lacking ideas on alternative paths.

8. Only after the car has been returned to a consistent, well-running state, consider buying and installing a battery tender.

I didn't get a sense of how often you drive, but if the vehicle is driven infrequently or for short trips, a tender could be worthwhile, to keep the battery charged up while conditioning it for the best long-term health.

There are several good brands, including Ford Performance, Battery Tender and NOCO.

Tenders can be attached with simple clips, but it'd be better if a connector was installed outside the vehicle, so you can hock up whenever you like.

https://www.mustang6g.com/forums/threads/batter-tender-battery-connection.172738/

Ford recommends vehicles of this generation are driven every two weeks for a given amount of time. Even doing that, internal and off-line functions can weigh on any battery. A tender will allow you to leave the car connected for months without having to worry about it.

When you do have things sorted, we'd appreciate a simple follow-up. I'd be interested in if you've been dealing with one or two things, or something more complex.

Good Luck. :please:
 
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In your initial post, you mention you've been dealing with a power-related problem for some time. Since, there've been some changes, including a battery, Sync upgrades and setting changes via FORScan. The vehicle is showing signs of a bad connection, possibly a large parasitic drain and maybe a faulty alternator or battery.

You've tried to correct these issues, but there remain a lot of questions, a lot of areas that have changed and a good amount of unknowns. I don't feel you have all the tools or references to tackle that. I think it's best you search for a good local mechanic or Ford dealership, then turn the vehicle over to them.

As part of the initial discussion of the history of these issues and what's been done thus far, advise the technician FORScan was used to change some settings related to electrical generation and power management.

To stay on-topic while ensuring everything is brought up, have some high-level bullets or points made out and talk through those. Rough-out a story line.

If at a Ford dealer, see if they can baseline the current build by re-flashing the Body Control Module, Powertrain Control Module or both. This might affect the changes you made to Sync, but I think we're past that: the vehicle is barely functioning.

I'd want the following diagnosed, in this order:

1. Review all physical connections involving the battery, alternator, starter and under hood fuse block. Ensure all are in the correct place, of the right type and secure.

2. Disconnect and isolate anything that is not Ford OEM. Cameras, radar detectors, aftermarket sound systems, etc.

3. Confirm the Body Control Module (BCM) and Powertrain Control Module (PCM) are programmed correctly. However they can do that, probably using Ford Diagnostic and Repair Software (FDRS).

4. Charge the battery completely, overnight if necessary and perform a load test. If not meeting the standard, replace. Note to the technician: the existing battery is an Absorbent Glass Mat (AGM), not a Flooded Lead Acid (FLA).

5. Start the car. Confirm the alternator is putting out the required amount of power, is being managed by the BCM and PCM correctly. If not working as expected, diagnose and repair.

6. Once items 1-5 are confirmed good, investigate the possibility of a large parasitic loss and any alarms.

7. Residuals. Anything that still is not working correctly.

Mechanics in my area are $150 an hour. Some shops charge flat diagnostic fees. It depends. What I described is a lot. It could take a good bit of time. I'm lacking ideas on alternative paths.

8. Only after the car has been returned to a consistent, well-running state, consider buying and installing a battery tender.

I didn't get a sense of how often you drive, but if the vehicle is driven infrequently or for short trips, a tender could be worthwhile, to keep the battery charged up while conditioning it for the best long-term health.

There are several good brands, including Ford Performance, Battery Tender and NOCO.

Tenders can be attached with simple clips, but it'd be better if a connector was installed outside the vehicle, so you can hock up whenever you like.

https://www.mustang6g.com/forums/threads/batter-tender-battery-connection.172738/

Ford recommends vehicles of this generation are driven every two weeks for a given amount of time. Even doing that, internal and off-line functions can weigh on any battery. A tender will allow you to leave the car connected for months without having to worry about it.

When you do have things sorted, we'd appreciate a simple follow-up. I'd be interested in if you've been dealing with one or two things, or something more complex.

Good Luck. :please:
All good points, I street park so a tender isn't really an option since I have no hook ups, I already have a new battery on the way but I want to resolve the issues myself before paying a shop to do it (last shop that had this car caused thousands of dollars in damage and I'm still dealing with those issues). I checked forscan today, I reset the State of charge to 80% but I left the battery type as the closest one (my battery is 62ah 660 cca, the closest option was agm 70ah, 600cca) so I chose that option but fixed the state of charge being higher. It's currently on a tender and I will disconnect the negative terminal maybe tomorrow and attempt to see if it has a draw with a multimeter
 

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Turn the Wi-Fi off. If it's not configured it will hunt for a network all night long. Disconnect the BMS sensor on the battery cable. It's a ring around the cable near the battery. You will get a error code but just ignore it for now. With the sensor disconnected the alternator will charge at 100% and not 80%. Start the car and measure the voltage at the battery. It should read better than 14.5v. Go for a long drive. If the car does not start the next day then the battery is toast.
 

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Turn the Wi-Fi off. If it's not configured it will hunt for a network all night long. Disconnect the BMS sensor on the battery cable. It's a ring around the cable near the battery. You will get a error code but just ignore it for now. With the sensor disconnected the alternator will charge at 100% and not 80%. Start the car and measure the voltage at the battery. It should read better than 14.5v. Go for a long drive. If the car does not start the next day then the battery is toast.
I have a new battery right now but my old battery was reading on the dash as 14.9-15.0 volts. The battery is an agm and says anything more than 14.4 for 5 min can cook the battery and damage it. Also what wifi do you mean? Dashcam wifi or sync 3.4 system?
Letting it sit does not reset the BMS. It just forces the BMS to reassess the state of charge. It must be reset either with something like ForScan, or by performing a short procedure with the ignition and brake pedal, which I can't remember exactly but can be found on the forum, as it's been discussed many times. The reset tells the BMS that the battery is new, so it adjusts the charging strategy accordingly. Simply letting it sit won't do that.
And conversely, it must never be reset unless you've just installed a new battery. Resetting it with an old battery in place spells trouble.
If you remember having done it with the device, then you're OK on this front.
Hm I wonder if this is why it's charging at 14.9-15 volts now. Was in forscan changing state of charge back to 80% where I had previously changed it to 95%. While there I reset the bms with a non fully charged battery. I'm going to install the new one today and reset bms again, do I need to do the sit for 8 hours untouched + forscan reset?
 

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I think the BMS reset with ForScan will also update its information about the state of charge, but I'm not 100% sure.
 
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I think the BMS reset with ForScan will also update its information about the state of charge, but I'm not 100% sure.
I guess I can do both tonight, I'll install battery and reset it then let it sit. I gotta get it into the garage first tho cuz my coolant is vanishing. That stuff just goes from max full to bottom of overflow real quick sometimes lol. I'll kill 2 birds with one stone
 

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I have a new battery right now but my old battery was reading on the dash as 14.9-15.0 volts. The battery is an agm and says anything more than 14.4 for 5 min can cook the battery and damage it. Also what wifi do you mean? Dashcam wifi or sync 3.4 system?

The wifi in sync 3. Configure it to your network, then shut it off.


Hm I wonder if this is why it's charging at 14.9-15 volts now. Was in forscan changing state of charge back to 80% where I had previously changed it to 95%. While there I reset the bms with a non fully charged battery. I'm going to install the new one today and reset bms again, do I need to do the sit for 8 hours untouched + forscan reset?
 
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Not sure how to configure it, here's a pic of what it looks like and then I turned it off. I also turned off automatic updates in case that was also searching. I think I also found an issue leading to some of this, the xs power battery terminal for negative side is too small. Clamp maxed out (impossible to tighten any father I fully maxed it out) and I can force it to the side and then wiggle it off fully hlby hand no tools and with not much force. It's the clamp coming loose since the battery terminals are tight (hopefully not damaged right since they call out 8 ft lbs and I used a 3/8 torque wrench that's 20-150 husky brand but had a line for 10 ft lbs so I went to that but it's def tighter than 10 but it's holding).

20260307_124711.webp


20260307_124703.webp


20260307_125616.webp
 

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Not sure how to configure it, here's a pic of what it looks like and then I turned it off. I also turned off automatic updates in case that was also searching. I think I also found an issue leading to some of this, the xs power battery terminal for negative side is too small. Clamp maxed out (impossible to tighten any father I fully maxed it out) and I can force it to the side and then wiggle it off fully hlby hand no tools and with not much force. It's the clamp coming loose since the battery terminals are tight (hopefully not damaged right since they call out 8 ft lbs and I used a 3/8 torque wrench that's 20-150 husky brand but had a line for 10 ft lbs so I went to that but it's def tighter than 10 but it's holding).

20260307_124711.webp


20260307_124703.webp


20260307_125616.webp
Yes those are the WiFi screens. And yes battery terminal is a good find. That needs to be swapped out.
 
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Yes those are the WiFi screens. And yes battery terminal is a good find. That needs to be swapped out.
What do I swap it with? I don't know what brand makes a good replacement terminal and the forums just recommend the ones I have but what I have doesn't work
 

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What do I swap it with? I don't know what brand makes a good replacement terminal and the forums just recommend the ones I have but what I have doesn't work
I would suggest that the oem would be best. Any local dealer, Ebay, several online parts stores will have them. Or contact one of our fourm sponsors that are Ford dealers. $20-$30 or so.
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