How to Recondition/Service Your 12V Battery

[JimmyMachE]

yeah, but MME has to be 'on' to power ODB, doesn't it? .... so it won't show the 'resting' voltage of the LVB...

Yes, but on the other hand the 12V battery SOC is harder to obtain, here you get it immediately.

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[louibluey]

what is really a wild card is the 'voltage sag' with temperature and/or loads. With a relatively small battery like our MME LVB.... even 'small' loads will pull down the voltage. So anything that 'wakes up' the computer, security, puddle lights, Frunk light might be pulling the LBV voltage down considerably.... until the MME is 'on' and the onboard dc-dc feeds it.

The most accurate read would probably require having the MME 'on' for several hours, park, and disconnect the LVB so there are NO loads, let it settle, and then measure

Okay, so I ran the charger with charging cycles for about 24+ hours total (over two days, but the charger turned off two or three times by itself). This morning, I ran the charger for a couple of more hours (MME off), disconnected the charger, and then disconnected the LVB ground terminal in MME. I measured the battery terminal voltage at the one hour points, over five hours.

charger off, not yet disconnected, 9:44am, 13.1V,
LVB ground terminal lifted - disconnected from MME at 9:50am, 13.1V,
10:52am - 13.0V; 11:50am - 13.0V; 12:50pm - 13.0V; 1:50pm - 13.0V; 2:50pm - 13.0V.
Temps from 11:50am to 2:50pm between about 49F and 55F.

So, not sure this says anything directly about LVB capacity (available Ah), but these measurements probably indicate that my 12V LVB is fine, now at 100% SOC. Also, this LVB does not appear to have any significant internal leakage, at least not over this five hour time frame.

When I began the process, while connected to MME (MME not awake as best as I could tell) I measured 12.1V at the jump terminals (LVB connected to MME). I think, this open circuit 13.0V charged result means that either LVB just needed a good charge and/or it was also reconditioned (the charger cycles).

I got the new Motorcraft BHAGM-H3 12V LVB from Rock Auto today, but I don't want to distract from post #1 of this thread, and I don't want to hijack this thread; maybe I will start a new thread for looking at the spare battery, and if I can get some good AC impedance measurements, maybe compare it to my MME LVB, along with the milliamp test described above.

 

[generaltso]

Set it to 13.7V power supply and let it sit.

Okay, I picked up the Clore PL6100 from a friend and hooked it up. It reported that the battery was 60% charged (12.4V). When I started power supply mode at 13.7V, the battery immediately started pulling just over 20A and slowly dropped to 11.22A after 5 minutes. After an hour, it's pulling 2.9A. I'm planning to let it go all weekend.

 

[generaltso]

Okay, I picked up the Clore PL6100 from a friend and hooked it up. It reported that the battery was 60% charged (12.4V). When I started power supply mode at 13.7V, the battery immediately started pulling just over 20A and slowly dropped to 11.22A after 5 minutes. After an hour, it's pulling 2.9A. I'm planning to let it go all weekend.

After 3 hours, it’s down to 350mA.

 

[louibluey]

After 3 hours, it’s down to 350mA.

How did it go with the PL6100 over the weekend?

 

[generaltso]

How did it go with the PL6100 over the weekend?

After 24 hours it was down to about 150mA, and it’s still around that now after another 24 hours. If it’s still the same tomorrow, it’s probably as good as it’s going to get, so I’ll disconnect it and see if I get the fault message again.

 

[dtbaker61]

How did it go with the PL6100 over the weekend?

I'd love to hear what the LVB battery rests at after you put it back in the MME and drive for a day or two, and check after the MME has been 'off' for a couple hours.

I tried giving the on-board charger a chance to bring it up by turning MME on, disabling auto-off, and leaving it on overnight. I was thinking that the dc-dc holding at 13.45 would bring the LVB up to a resting voltage around 13.......

But, it didn't.

It was 12.85 before I started.... left it 'on' overnight, NOT plugged in, with connection points measuring 13.45.... turned off, let it rest for half hour..... LVB still sitting at same 12.85

What I did notice in the ODB data was that the motor and battery temps were sitting at 60F and 70F in my 55 deg garage, so some energy was obviously bled off there.

I would really love to know exactly what the charge parameters are for the LVB, from Ford! i.e.
- what LVB voltage calls for charge ? 12.6 ?
- does it have a multi-stage charge curve ?
- what V signals 'end of charge' ?
- does the MME have to be plugged in to top off the LVB? while 'on', or 'off'.?

I just wish we knew what the voltages are SUPPOSED to be as measured at the connection points with MME 'off' and sleeping, so we can have confidence that everything is working as designed.... or tell for sure that battery was damaged or software update is needed.

 

[Mach-Lee]

After 24 hours it was down to about 150mA, and it’s still around that now after another 24 hours. If it’s still the same tomorrow, it’s probably as good as it’s going to get, so I’ll disconnect it and see if I get the fault message again.

Sounds like it's done then to me. I would have expected the final current @ 13.65V to be less than 100 mA, but we don't know what the idle current draw is on the Mach-E. Joe, you may want to test the float current with your new battery vs. your current one to see if there are differences there.

 

[louibluey]

Sounds like it's done then to me. I would have expected the final current @ 13.65V to be less than 100 mA, but we don't know what the idle current draw is on the Mach-E. Joe, you may want to test the float current with your new battery vs. your current one to see if there are differences there.

Okay, I just put it on to cook. Been testing with this new one all day, minor loads, but a lot of them, so I think it is just charging for the moment. The power supply is in constant voltage mode, 13.649 V (funny old hp limited bits). I am graphing the voltage and the current, both exponential like curves for now, current is just falling through 328 mA, and the battery terminal voltage is at 13.511 V (driven by the power supply).

10:00pm 29 minutes "charging", just went below 200 mA.
10:05pm 35 min, 13.565V batt V, 190 mA
10:20pm 49 min, 13.573V, 173mA (definitely slowing down)
10:43pm 1 hr, 12 min, 13.584, 148mA
11:02pm 1 hr, 31 min, 13.590, 133mA probably last point for tonight, I think it is safe to run overnight, the DMM monitoring current is fused at 3A, and Voltmeter a high z input.

Maybe 13.65V is just a bit too high for this battery for float current? We'll see what the current looks like in the morning.

 

[louibluey]

I'd love to hear what the LVB battery rests at after you put it back in the MME and drive for a day or two, and check after the MME has been 'off' for a couple hours.

I tried giving the on-board charger a chance to bring it up by turning MME on, disabling auto-off, and leaving it on overnight. I was thinking that the dc-dc holding at 13.45 would bring the LVB up to a resting voltage around 13.......

But, it didn't.

It was 12.85 before I started.... left it 'on' overnight, NOT plugged in, with connection points measuring 13.45.... turned off, let it rest for half hour..... LVB still sitting at same 12.85

What I did notice in the ODB data was that the motor and battery temps were sitting at 60F and 70F in my 55 deg garage, so some energy was obviously bled off there.

I would really love to know exactly what the charge parameters are for the LVB, from Ford! i.e.
- what LVB voltage calls for charge ? 12.6 ?
- does it have a multi-stage charge curve ?
- what V signals 'end of charge' ?
- does the MME have to be plugged in to top off the LVB? while 'on', or 'off'.?

I just wish we knew what the voltages are SUPPOSED to be as measured at the connection points with MME 'off' and sleeping, so we can have confidence that everything is working as designed.... or tell for sure that battery was damaged or software update is needed.

We have a pretty good indication that there are minor problems, so many of us are getting the FordPass 12V LVB warnings. I think by working together over several cars, and several batteries, we will understand more, even though we have no technical data from Ford on LVB care and feeding (both by MME and us).

A few things feel promising. No one has reported a dead battery yet that could not be saved, at least not recently. The worst one was that GT fellow who's car arrived 12V LVB depleted, but they even got that one recharged.

Ford is likely working the problem too. We have no idea if low 12V is contributing some of the recent problems while driving (possibly unrelated), however I plan to be sure my 12V LVB is in reasonably good soc, at least near term.

My plan is to try to take regular measurements with a portable digital tester. I am going to try this one: KONNWEI KW710 Car Battery Tester 6V 12V 24V, Battery Load Tester Automotive 100-2000CCA Digital Auto Battery Analyzer Alternator Starter Tester for Car Truck Motorcycle Marine ATV SUV. It claims to measure soc, internal R, and capacity. It's a bit of a shot in the dark; I have no first hand experience with this company or these digital battery testers.

Also, as others have pointed out, those doing OBD can read voltage and soc from MME, and still others are running voltmeters plugged into the 12V MME outlet.

 

[louibluey]

11 hrs 31 mins screen prints. Now at 11hr48min, 13.565V, 33.3 ma.
(there was probably a short National Grid power dip/glitch overnight)

 

[generaltso]

Sounds like it's done then to me. I would have expected the final current @ 13.65V to be less than 100 mA, but we don't know what the idle current draw is on the Mach-E.

My meter is not very accurate below 1A, so the draw may have been less than that. But it should be good enough to tell that it wasn't really decreasing anymore. It looked about the same this morning, so I disconnected the charger. The battery measured 13.3V a couple minutes after disconnecting it. I'll let it sit for a few hours and see where the voltage settles.

 

[dtbaker61]

My meter is not very accurate below 1A, so the draw may have been less than that. But it should be good enough to tell that it wasn't really decreasing anymore. It looked about the same this morning, so I disconnected the charger. The battery measured 13.3V a couple minutes after disconnecting it. I'll let it sit for a few hours and see where the voltage settles.

and then let us know where it settles after you re-install in MME... and then where it settles after a couple days of driving!

I'm looking forward to seeing how a new and 'full' LVB behaves.... i.e. what 'sleeping' voltage measured at the connection points *should* be for a battery you know know is good.

 

[generaltso]

and then let us know where it settles after you re-install in MME... and then where it settles after a couple days of driving!

I never actually took the battery out of the car, I've just been charging it in place.

Two hours after I disconnected the charger, the battery still measures 13V. I just opened the door to check the voltage drop, and the voltage dropped to 12.25V with the car awake (interior and frunk lights on, etc.). I'll measure it again when the car goes back to sleep.

 

[dtbaker61]

I never actually took the battery out of the car, I've just been charging it in place.

Two hours after I disconnected the charger, the battery still measures 13V. I just opened the door to check the voltage drop, and the voltage dropped to 12.25V with the car awake (interior and frunk lights on, etc.). I'll measure it again when the car goes back to sleep.

.....I am VERY very curious.... I've left my hood up, access plugs pulled, and turned off my phone Bluetooth so the MME doesn't wake up when I approach. My LVB is consistently 12.85v while MME is asleep as long as no lights are on, no doors open, etc. I suspect that the background loads are pulling the voltage down from 'full' VOC of 13, and this is about as good as can be expected, and 12.85 while sleeping is 'full'.

I was surprised to see how much interior, door, and frunk lights pulled down the voltage (with MME 'off'), and glad to see that your fresh new battery was pulled down basically the same as mine... which eliminates the worry of seeing the LVB at 12.2-12.4 with just a couple lights on, or the door open.

This is leading me back to how to help people that do not have access to external chargers feel more comfortable that their LVB is in good shape.

My working hypothesis is:
- if the sleeping LVB is 12.8+ , all is well
- if showing < 12.8, with no lights on or doors open,
in-car LVB charge-to-full may be accomplished by:
- plugging in
- turning MME 'on'
- disabling auto-off timer
- leaving overnight

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