Down for the count :(

[kindofblue]

UPDATE:

Ford was able to assist the techs working on ours to determine the High-voltage fuse box and battery energy control module needing replacement. No eta. on dates of when parts will be in and when it will be fixed. This Friday will be 4 full weeks since the breakdown.

Well at least they've finally figured out what the problem is. I feel for you on the wait though.

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[dixiekidd88]

Well at least they've finally figured out what the problem is. I feel for you on the wait though.

Hopefully it is the right fix. But I will read the full writeup once its fixed and the warranty claim is filed with Ford. I am curious to see how much its going to cost lol

 

[cmtaylor963]

I got the dreaded Stop Safely Now last Friday with a low (but not dead) LVB. Car would not shift into gear, and disconnecting the battery did not clear the codes. After dealer replaced LVB, still throwing P0563 from the BECM. Dealer indicated they would need to order a new high voltage battery. I sent info from @mikeho to see if that would help.

 

[louibluey]

Here is an example plugged in (L2) from about 3:30 pm on Jan 17 to Jan 18 just after 1 pm. I got the Fordpass alert, 12V battery, service soon, which corresponds to when the DC/DC converter came on to charge LVB. Continues to be unclear why LVB had fallen to 50% soc at the beginning of this record. This is the new 50 Ah battery, which I believe to be in like new condition (working).

Note, where charging (plugged in L2) happened at a LVB soc of 35%.

LVB voltage vs. time over LVB soc vs. time, somewhat easier to read graphs. Marked the alert point on the lower graph, which agrees with the time of the message. DC/DC converter is on at the voltage high points, here 15.5V which is what DC/DC converter does on cold days.

 

[louibluey]

Is there a heavy cable connection from the LVB to BCCM?

No, the LVB is only connected to the DC/DC converter and the 12V fuse boxes for 12V distribution. All LVB charging is done by the DC/DC converter, the only charge path to the LVB.

 

[louibluey]

@louibluey I'm not sure about the specifics of them not wanting you to remove the 10mm sensor end of the (-) battery cable, my guess is they are worried about stress to the fragile sensor causing damage. The other end is much more robust. The service manual includes this specific warning:

NOTICE: Do not remove or install the M8 nut on the cable eyelet bolt while the battery monitor sensor is attached to the battery post as this causes damage to the sensor, connector, and possibly the battery post and case.

As someone who writes this kind of modification procedure, I can assure you that these types of instructions are typically dictated by a Mechanical Engineer that has completed a root cause analysis of failures that have occurred in the factory or in the field service environment. If that is the case, a Field Bulletin is usually distributed in advance of some sort of warning/caution markings being added to the product.

I hear you guys, and I am generally a follow the rules and guidance type engineer. But, I think we have all also experienced over reaction by rule writers. That may or may not be the case here.

If it was that critical to lift the other side of the cable, my first question is, why on earth is there not a note there at the negative terminal. I am very sure that every installer, and probably most techs are going to lift the BMS side, because as I mentioned it is a 10 second job, vs. 10 minutes for the other side. And, not knowing this caution (maybe thankfully so), I have carefully lifted the BMS side 50+ times, and have had no problems. Maybe they are worried about techs dropping the BMS back on the negative terminal? If I am working power off for an extended time, I carefully (and gently) tape the ground cable to the structural bar above with electrical tape.

Another difference is that the BMS side can be lifted by just removing the first panel under the driver's windshield. To remove the negative lug from under the 13mm negative post requires removal of the second side plastic cover.

I don't completely buy the physical manipulation argument, because the other side has a large ground lug with a hole and large locating tab that goes into an opening in the chassis. After the ridiculous number of turns to remove the negative jump post, then you have to man handle the same #2 cable (the cable is stiff, not like welding cable) which is connected to the other side of the fragile (?) BMS, just to get the darn lug out of the locating hole in the chassis. Alternatively (to get more room to maneuver the #2 cable), removing the structural chassis black bar over that area is suggested by the work shop manual, when changing the LVB. I have not removed the bar, I imagine another 10 minute job.

Another difference - When the negative cable clamp is removed from the neg battery terminal, it is not important to isolate the cable. It does not matter if the removed clamp touches ground. By contrast, if the Ford procedure is to leave the cable connected to the battery at the BMS side, and to remove the ground lug at the negative jump terminal, that removed lug is the "live" negative terminal, and must not touch ground during the time of intended isolation. Now, you also need to completely tape the removed ground lug (also part of the procedure in the WSM), absolute insanity as to good work flow.

I think most EVs have required a 12V disconnect at one time or another to get a cold boot. I very much doubt that the original designers envisioned removing the lug under the negative jump terminal versus 10 seconds to lift the BMS side.

It is well possible that a lot of BMS were being damaged, but the alternative procedure is slightly NUTs.

 

[SnBGC]

Here is an example plugged in (L2) from about 3:30 pm on Jan 17 to Jan 18 just after 1 pm. I got the Fordpass alert, 12V battery, service soon, which corresponds to when the DC/DC converter came on to charge LVB. Continues to be unclear why LVB had fallen to 50% soc at the beginning of this record. This is the new 50 Ah battery, which I believe to be in like new condition (working).

Note, where charging (plugged in L2) happened at a LVB soc of 35%.

LVB voltage vs. time over LVB soc vs. time, somewhat easier to read graphs. Marked the alert point on the lower graph, which agrees with the time of the message. DC/DC converter is on at the voltage high points, here 15.5V which is what DC/DC converter does on cold days.

So you are getting the 12v fault message while on plug?

This part of the graph confuses me. Is the volt reading system voltage or battery voltage? For decades I was always taught that 12.6v represented a fully charged battery so I took that to mean 100% SOC. Is that belief mistaken?

 

[louibluey]

So you are getting the 12v fault message while on plug?

This part of the graph confuses me. Is the volt reading system voltage or battery voltage? For decades I was always taught that 12.6v represented a fully charged battery so I took that to mean 100% SOC. Is that belief mistaken?

So you are getting the 12v fault message while on plug?
Yes, MME was in the garage, plugged in (chargepoint flex 48A capable).

iPhone was BT off, fob was in a steel pot on the other side of the home. I did forget to turn off iPad and Apple watch, not sure if they could have been FordPass active, I don't think so, but not sure.

Is the volt reading system voltage or battery voltage?
The graph is literally the BMS reported voltage. BMS has a wire that wraps around directly connects to the 12V LVB + terminal. BMS is mounted on the 12V negative terminal. The last BMS wire is the one wire LIN data bus stream. This is the voltage BMS is sending to BCM. When active, 25 times a second, at rest, once every 15 minutes. The LIN monitor connects directly to ground, and at the BMS, the +12V, and LIN wires.

For decades I was always taught that 12.6v represented a fully charged battery so I took that to mean 100% SOC. Is that belief mistaken?
This is more a @Mach-Lee question. We have mostly been going by the graph he posted. The still complicated question is how to use the graph resting (when there is very little load on LVB) versus loaded, say when MME lights come on.

Also, yes!, that is one of the most important questions, WHY and how does MME keep taking LVB down to 12.3V to 12.5V loaded (e.g. frunk light on. If the frunk is left open, frunk light out seems to correspond to MME rest), voltages many of us are seeing often, parked in the garage.

 

[Mach-Lee]

This part of the graph confuses me. Is the volt reading system voltage or battery voltage? For decades I was always taught that 12.6v represented a fully charged battery so I took that to mean 100% SOC. Is that belief mistaken?

That's true of a flooded lead battery, but with an AGM the voltage is a bit higher. 12.5V on an AGM is about 70% charge at 25ºC so it's a little strange the BMS is pegging the SoC at 40% and dropping if the readings are correct. Temp could be a factor but it still seems extreme.

@louibluey I probably missed this, but have you cross checked your derived values with reality? 12.5V is really 12.5V? SoC matches scan tool value? No calibration offsets?

 

[louibluey]

That's true of a flooded lead battery, but with an AGM the voltage is a bit higher. 12.5V on an AGM is about 70% charge at 25ºC so it's a little strange the BMS is pegging the SoC at 40% and dropping if the readings are correct. Temp could be a factor but it still seems extreme.

@louibluey I probably missed this, but have you cross checked your derived values with reality? 12.5V is really 12.5V? SoC matches scan tool value? No calibration offsets?

Good point. I will verify again with scan soc (ForScan or FDRS) and by DMM and report back.

I drove this afternoon, voltage might be higher again. I have noticed that DC/DC converter runs continuously, at least in the cold. Maybe it is because the aux hv contactor closes for cabin heat?

 

[mikeho]

I got the dreaded Stop Safely Now last Friday with a low (but not dead) LVB. Car would not shift into gear, and disconnecting the battery did not clear the codes. After dealer replaced LVB, still throwing P0563 from the BECM. Dealer indicated they would need to order a new high voltage battery. I sent info from @mikeho to see if that would help.

Yes, please use the info I had! My dealer originally though that they would also need to replace the HVB, but that's $24K (under warranty, thankfully) and will take almost 2 weeks to get shipped to the dealer. The junction box is much faster and easier to change, I believe. Though they still need to remove the entire battery from the car to get to the junction box.

 

[mikeho]

UPDATE:

Ford was able to assist the techs working on ours to determine the High-voltage fuse box and battery energy control module needing replacement. No eta. on dates of when parts will be in and when it will be fixed. This Friday will be 4 full weeks since the breakdown.

Do you have Ford Options? See about calling for a refund on the monthly payment. I've been meaning to do that, but I haven't had time to yet. Your car has to have been in the shop for at least a month to get the refund.

 

[NoVAguy]

Do you have Ford Options? See about calling for a refund on the monthly payment. I've been meaning to do that, but I haven't had time to yet. Your car has to have been in the shop for at least a month to get the refund.

This.

I actually had the dealership initiate this on my behalf. I honestly didn't even know/think about doing this. They brought it up when I had an extended downtime due to the glass recall work. Doesn't hurt to ask the dealership to get this taken care of for you. It was the 3rd line item on my invoice.

 

[louibluey]

That's true of a flooded lead battery, but with an AGM the voltage is a bit higher. 12.5V on an AGM is about 70% charge at 25ºC so it's a little strange the BMS is pegging the SoC at 40% and dropping if the readings are correct. Temp could be a factor but it still seems extreme.

@louibluey I probably missed this, but have you cross checked your derived values with reality? 12.5V is really 12.5V? SoC matches scan tool value? No calibration offsets?

Verified from about 92% soc to below 55% soc with voltages here (too far off topic to post details here). One of the advantages of the LIN monitor is that it keeps reporting and logging when MME is off. Logging through sleep is possible even where it slows to one point per 15 minutes (Forscan stops reporting, when MME goes to rest). So, logging for longer periods plugged in or unplugged is easy. The LIN monitor also keeps going through the most drastic load shedding (because the BMS is directly on the 12V battery, and connects directly to both the positive and negative terminals of the LVB).

 

[dixiekidd88]

Do you have Ford Options? See about calling for a refund on the monthly payment. I've been meaning to do that, but I haven't had time to yet. Your car has to have been in the shop for at least a month to get the refund.

No, not with the mileage that it is driven (140 or so a day). Traditional financing with a very large down payment, going to see about compensation for the monthly payment and get the vehicle delivered to us since we are 6 hours away.

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