My Lightning burned to the ground

[chl]

It had a charger attached and still attached to the truck so it may have been being charged by both.

That extent of my knowledge of the situation.

A L2 EVSE charger, which means the Lightning DC-DC converter was charging the Ohmmu at the time it exploded/caught fire.

If it was using a high charging current, like others have measured, it could very well have caused the problem - high charging currents CAN cause batteries to explode.

The guy in the reddit post would have done better to leave the Ohmmu on the trickle battery maintainer with a low current that should not result in an explosion.

So I agree with you that the battery was being "force charged" but the problem is that is the norm with the Lightning when the 12v battery gets low, as others have posted.

This is yet another reason mine is staying on a battery maintainer - even AGM batteries can swell and explode if subjected to high charging currents!

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[majorgearhead]

Very high charge currents have been seen/measured when the Lightning is charging the 12v battery. Maybe the Ohmmu BMS should have prevented this? Maybe the Ford 12v Battery Manager is a battery mangler?

There may be method to the madness of going high then low voltage. This would help to desulfate the battery. Many chargers/minders have a repair mode that does just this. I would never do that to a LiFePO4 battery. I don’t trust their BMS to handle it.

So Ford engineers who are actually really awesome engineers probably implemented this for this reason. That means the Lightning has a set of LVB charging skills that make it a nightmare for Ohmmu batteries.

 

[chl]

You can do this with a n.co genius charger. The Ohmmu batteries have a BMS that doesn’t register as needing charged by many trickle chargers with current sensing. So they implemented a force feature that will output charge regardless of readings from the battery. In order to charge an Ohmmu battery with one of these chargers you have to use the force mode. This is obviously bad on many different levels.

It exploded when the Lightning was charging it with it's DC-DC converter during a L2 charge session according to my reading.

 

[chl]

There may be method to the madness of going high then low voltage. This would help to desulfate the battery. Many chargers/minders have a repair mode that does just this. I would never do that to a LiFePO4 battery. I don’t trust their BMS to handle it.

So Ford engineers who are actually really awesome engineers probably implemented this for this reason. That means the Lightning has a set of LVB charging skills that make it a nightmare for Ohmmu batteries.

Well, yes I agree you sometimes can desulfate batteries successfully in that manner, but it's better not to have to do that in the first place, by NOT letting them so badly discharged.

It is more likely the designers overlooked this issue, Tesla changed their strategy at some point (according to a post I read) so that the 12v battery would be topped off when not in use.

Given the track record of failures of the Ford Lightning 12v batteries we've all read about here and elsewhere, seems like the BMS design in the Lightning leaves a lot to be desired...

 

[majorgearhead]

Well, yes I agree you sometimes can desulfate batteries successfully in that manner, but it's better not to have to do that in the first place, by NOT letting them so badly discharged.

It is more likely the designers overlooked this issue, Tesla changed their strategy at some point (according to a post I read) so that the 12v battery would be topped off when not in use.

Given the track record of failures of the Ford Lightning 12v batteries we've all read about here and elsewhere, seems like the BMS design in the Lightning leaves a lot to be desired...

Tesla also moved to Li-Ion LVB in their Model Y and Model 3 I think starting with HW4 but maybe earlier. We had one in our 2023. It was no maintenance and the couple of years people had them, they were relatively problem free.

 

[chl]

You can do this with a n.co genius charger. The Ohmmu batteries have a BMS that doesn’t register as needing charged by many trickle chargers with current sensing. So they implemented a force feature that will output charge regardless of readings from the battery. In order to charge an Ohmmu battery with one of these chargers you have to use the force mode. This is obviously bad on many different levels.

To "force charge" with the NOCO you have to specifically set it to do that, it is not the default. The Reddit post did not say he was using a "force mode" and he took it off the "trickle charger" before it exploded, from my reading.

 

[majorgearhead]

To "force charge" with the NOCO you have to specifically set it to do that, it is not the default. The Reddit post did not say he was using a "force mode" and he took it off the "trickle charger" before it exploded, from my reading.

Right. I know. I have one of these and use it to maintain. I was replying to someone else who stated you can’t force charge these batteries. I guess can’t should have been changed to shouldn’t.

 

[RickLightning]

I'm not an engineer, didn't stay in a Holiday Inn Express last night, didn't play one on TV... When I don't know something, I read what experts say. On the 12v battery for the Mach-E and Lightning (they are identical), you can easily find significant information that the BMS cannot accommodate a Lithium Ion battery of larger size, and Mach-Lee on the Mach-E forum (probably the most knowledgeable person I've come across re: these vehicles in 4.5 years) warns people away from them.

Here's what's going to happen. The OP's insurance company is going to find out the battery is an Ohmmu, then they're going to ask what's going on. They're going to delay payment on the claim while they investigate. Ford is going to dance away, saying "not us, not us", and there's going to be a legal battle either between the OP trying to collect from his insurance company, or the insurance company trying to collect from Ohmmu. Of course this assumes that the 12v is the cause, which no one knows yet.

 

[chl]

Tesla also moved to Li-Ion LVB in their Model Y and Model 3 I think starting with HW4 but maybe earlier. We had one in our 2023. It was no maintenance and the couple of years people had them, they were relatively problem free.

I read they also changed the BMS to trickle (low current) top off the 12v battery when the car was not being used.

 

[chl]

I'm not an engineer, didn't stay in a Holiday Inn Express last night, didn't play one on TV... When I don't know something, I read what experts say. On the 12v battery for the Mach-E and Lightning (they are identical), you can easily find significant information that the BMS cannot accommodate a Lithium Ion battery of larger size, and Mach-Lee on the Mach-E forum (probably the most knowledgeable person I've come across re: these vehicles in 4.5 years) warns people away from them.

Here's what's going to happen. The OP's insurance company is going to find out the battery is an Ohmmu, then they're going to ask what's going on. They're going to delay payment on the claim while they investigate. Ford is going to dance away, saying "not us, not us", and there's going to be a legal battle either between the OP trying to collect from his insurance company, or the insurance company trying to collect from Ohmmu. Of course this assumes that the 12v is the cause, which no one knows yet.

The Ohmmu says their on-board BMS makes it compatible with the Lightning even though internally it is Li.

Obviously in the case of the Reddit post, when the Ohmmu got too discharged and the Lightning began charging it, something went terribly wrong. My guess (as an engineer) is that the truck threw a high charging current on it (because it's SOC was so low and that is what the truck will do) and that was not anticipated by the Ohmmu designers in their BMS. But that's just an educated guess.

 

[RickLightning]

I hope Ohmmu has good lawyers IF the 12v is the cause.

 

[RLXXI]

I may have over looked it in the thread but did the op actually come back and say if they had done any mods to the truck that could possibly contribute to this sad situation?

I see where someone asked but never got a reply then someone else chimed in almost as if to claim it was the ohmmu.

Sad situation all the way around.

 

[Maquis]

I may have over looked it in the thread but did the op actually come back and say if they had done any mods to the truck that could possibly contribute to this sad situation?

I see where someone asked but never got a reply then someone else chimed in almost as if to claim it was the ohmmu.

Sad situation all the way around.

Post 67 pointed to different truck fire that did have an Ohmmu. Since that post, a bunch of people here have decided either it applies to the OP, or they’re commenting about the other fire. Hard to tell.

And wait until AI gets a hold of this thread and starts spreading it as fact. Ohmmu will go up in flames, figuratively, at least.

 

[Timeless Epoch]

Unless the truck was undercoated in thermite like the hindenberg, I don’t think this was a LVB event. OP said they barely had time to gather a few items from the back seat before the truck was fully engulfed in flames. He also posted a pic of the truck in flames from tip to tail before the fire department could get there.

To me, it seems like a catastrophic HVB event.

 

[chriserx]

Post 67 pointed to different truck fire that did have an Ohmmu. Since that post, a bunch of people here have decided either it applies to the OP, or they’re commenting about the other fire. Hard to tell.

I mean, its a sensitive time for the OP which is why I apologized. The mention of the Ohmmu's use is in another thread from OP. I had remembered the issues and wondered if there was a correlation.

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