12V Battery replacement with H4

[Maquis]

I’ll assume you meant to quote @Lyle, but I think his installation looks good and agrees with previously mentioned instructions.

You are correct on both points!

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[jwrezz]

Yeah, the Martin Rebuilds offer seems like the next battery change in a few years. So far my H4 is not old but is holding up just fine. The winter will be the real test tho. But will allow me to run my winch with no problems.

 

[Lyle]

I’ll assume you meant to quote @Lyle, but I think his installation looks good and agrees with previously mentioned instructions.
https://www.f150lightningforum.com/forum/threads/charging-12v-battery.16979/post-342220

Lyle, I believe you should have charged the battery to 100% on the bench and then reset the BMS upon install. That doesn’t explain the drain you seem to be experiencing, but the battery will not get to 100% because the BMS charges based on coulomb counting (energy counting), not voltage.
In the factory configuration it’s as if you have a 12 oz beer and a 12 oz glass. You pour your can in, take a swig and the BMS refills exactly one swig. Now you switched to a pint glass, started with it half full, told the BMS it was full, and when you take a swig the BMS puts exactly one swig back in. Battery always at 50% but BMS thinks it’s full because it put in what you took out.

Yes, I should have charged the battery to 100% before installing it. I would have done so with the Noco, but it only had those eyelet terminals and many others posted that I could just drive around for a while or charge the HVB and it would get to 100%. I didn’t rely on the truck to tell me what % I was, I used car scanner. But something must have been wrong because after I got it to 100% and waited a bit for it to settle and then did the BMS reset, it showed only 80%. It did fine today and it showed over 90% all day, but this weekend I might take it out and Jerry rig something to charge it externally with the Noco, I’m also a bit nervous because of the sparking, which should not have happened.

 

[bmwhitetx]

Yes, I should have charged the battery to 100% before installing it. I would have done so with the Noco, but it only had those eyelet terminals and many others posted that I could just drive around for a while or charge the HVB and it would get to 100%. I didn’t rely on the truck to tell me what % I was, I used car scanner. But something must have been wrong because after I got it to 100% and waited a bit for it to settle and then did the BMS reset, it showed only 80%. It did fine today and it showed over 90% all day, but this weekend I might take it out and Jerry rig something to charge it externally with the Noco, I’m also a bit nervous because of the sparking, which should not have happened.

CarScanner itself does not measure anything. It is reporting parameters provided by the truck. The initial SOCs were likely still related to the old battery.

Resetting the BMS does not tell it that the battery is fully charged and thus report 100%. It just tells the BMS to set the battery age to 0 months. The PCM determines the SOC based on BMS data. No need to fully charge before installing. Over time the BMS will figure out the characteristics of the new battery. I think you are just being a little impatient or overthinking it (guilty myself). 99% of new batteries are just slapped in there and the BMS isn't even reset. The BMS/PCM will figure it out.

I personally would not keep an unplugged maintainer permanently connected. Keep the eyelets on there (they are in the correct spots) but add a physical disconnect or SAE connector pair between the battery and charger. That’s what most do. It may be fine but ???

 

[Timeless Epoch]

@Lyle I think your charger install is not allowing the LVB BMS to calibrate, assuming it works the same as other Ford vehicles. As @Mikerson noted, a spark means its pulling a load. Even a relatively small load could stop the calibration routine.

Battery Monitoring Sensor

NOTE: Unless the battery is being replaced, DO NOT reset the battery monitoring sensor using the scan tool. This reset is reserved for new battery installation. This reset clears the learned battery data, the battery time in service, and affects the aging parameters, which have been learned since the installation of the battery.

The battery monitoring sensor is attached to the negative battery terminal which provides a ground to the sensor. The battery monitoring sensor is integrated with the negative battery terminal clamp and cable assembly and cannot be serviced separately. The battery monitoring sensor measures voltage, current and temperature of the battery and uses these inputs to calculate the battery condition, transmitting this information through the LIN circuit to the BCM. The battery monitoring sensor has a 2-pin connector providing battery voltage and LIN connections.

The battery monitoring sensor has to be calibrated at regular intervals. This occurs during a rest period or when the battery closed-circuit current is less than 100mA. The rest period must last for at least 3 hours. The time-frame in which a calibration must take place is 7 days. If the system has been unable to carry out a calibration within this time then it is impossible to confirm the exact state of charge of the battery. Any devices left attached to the power socket that draw in excess of 100mA (or less depending on other battery loads) will prevent a battery monitoring sensor calibration.

The battery monitoring sensor is an input to the Electrical Energy Management software. If the sensor malfunctions due to wiring issues or failure, a DTC will be set. In most cases the Electrical Energy Management functions will be turned off until the sensor operation is restored If the battery monitoring sensor is removed from the battery negative post, all internal parameters except battery time in service reset to a standard setting. These parameters will be relearned during normal calibration intervals. If the battery has been charged or jump started by connecting directly to the battery post or to the battery monitoring sensor, force an internal reset by removing the battery monitoring sensor from the battery negative post then reconnecting.

~Source: ⁠Forum.forscan

 

[Mikerson]

Perhaps this is the cause of sparking?

“IMPORTANT: You must wait at least 15 minutesafter vehicle shutdown before removing 12V battery cables or terminals. The DC/DC converter is still active during this time, and you may short something out if you try to disconnect the battery too soon.”

From Mach-Lee’s excellent lvb faq.

 

[Maquis]

Perhaps this is the cause of sparking?

“IMPORTANT: You must wait at least 15 minutesafter vehicle shutdown before removing 12V battery cables or terminals. The DC/DC converter is still active during this time, and you may short something out if you try to disconnect the battery too soon.”

From Mach-Lee’s excellent lvb faq.

The Mach-E does that to mitigate the fact that there is no mechanical way to open the doors from the outside. Shutting the car off with a dead battery could result in an infant getting locked in the backseat. This gives you 15 minutes to get into the car after shutting it off if the battery dies. I don’t think the Lightning does this, since we have a mechanical key and door handles.

 

[Lyle]

Perhaps this is the cause of sparking?

“IMPORTANT: You must wait at least 15 minutesafter vehicle shutdown before removing 12V battery cables or terminals. The DC/DC converter is still active during this time, and you may short something out if you try to disconnect the battery too soon.”

From Mach-Lee’s excellent lvb faq.

I’m not sure if I waited 15 minutes after turning the truck off before I disconnected the battery. I didn’t see this mentioned anywhere else in the dozens of messages I read from others changing out the battery. I parked the truck inside the garage and then took everything out of the trunk and got prepared. Maybe it was 15 or more minutes, but I’m not sure what that has to do with me reconnecting the battery like 45 minutes later after I cut the battery tray. I guess I’ll try to call Noco and ask them why it would have sparked. I haven’t plugged it in to try to trickle charge the battery yet.

 

[Lyle]

CarScanner itself does not measure anything. It is reporting parameters provided by the truck. The initial SOCs were likely still related to the old battery.

Resetting the BMS does not tell it that the battery is fully charged and thus report 100%. It just tells the BMS to set the battery age to 0 months. The PCM determines the SOC based on BMS data. No need to fully charge before installing. Over time the BMS will figure out the characteristics of the new battery. I think you are just being a little impatient or overthinking it (guilty myself). 99% of new batteries are just slapped in there and the BMS isn't even reset. The BMS/PCM will figure it out.

I personally would not keep an unplugged maintainer permanently connected. Keep the eyelets on there (they are in the correct spots) but add a physical disconnect or SAE connector pair between the battery and charger. That’s what most do. It may be fine but ???

Ok, yeah that makes sense, Car Scanner is just a software program that is reading information from the ODB port. I should have tested the battery with a multimeter before I installed it and used the Noco to charge it up to 100% before putting it in.

The Noco I bought was designed to be permanently installed. The eyelets on the battery side of it are 3/8” and I think the posts on the battery cable assembly are 1/4” so they are a bit loose until you get the nut tightened down. I called Noco and they said it was probably something else causing the sparking, like maybe the other items connected to that post like the BMS sensor. I probably should have pulled the negative terminal off the battery to install the Noco. For that matter, I probably should have had both terminals off the battery and installed the Noco cables and then reconnect the battery.

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