Stop safely now

[jthiesse13]

I got in my truck today and got this message saying stop safely now. The truck would only go into accessory mode and would not start. I just replaced the 12v battery at the dealer in March. When I looked at it, it’s swollen. Dealer tested it and says it’s fine. I’m having it towed and we’ll see what they say. I have little to no confidence that Ford will figure this out easily.

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[Heliian]

It won't be difficult for them to find the fault. It is unrelated to the 12v battery.

 

[Mal106]

If the 12v is swollen now, I would say that's your problem even if the dealer tested it. Often dealers will measure voltage as a test. That is not a test without a load. I would try a jumper box to see if an honest 12v fixes it.

Multi testers are cheap as are battery chargers and battery testers. My experience with EVs (4 so far) has been that the 12v battery is the weak point I have had that problem with all four.

12v... jump it, charge it, load test it.

 

[chl]

The little 12v battery icon is a giveaway about the issue.
Something in the 12v system.
Either the 12v battery itself, or perhaps the BMS - did the dealer reset the BMS?
Sometimes they don't know to do that!

LVB BMS reset

Make sure 12v battery is fully charged (drive an hour, or after an hour actively charging the HVB)
Start Accessory mode
flash high beams 5 times
step on brake pedal 3 times
red battery icon on dash should flash 3 times

If the dealer changes the 12v battery, they should do this, but they don't always. If they plan on keeping it overnight, there is a good chance they will - Just ask when you pick it up.

I like some other Lightning and other EV owners keep my 12v battery on a maintainer with an AGM mode when not in use.

The Lightning can subject the 12v battery to low SOC and high charging currents shortening the battery lifespan - those data points, SOC and charge current, have been measured by owners.

 

[rtk11226]

This just happened to me last week. I had load tested the battery a few months ago and although weak was still showing ok. When it happened I drove to my favorite fried chicken place and parked in a place with plenty of space around it. By the time the tow arrived the 12v battery was completely dead. Got it to the dealer and they replaced the 12v battery under warranty. All good now.

 

[jthiesse13]

It won't be difficult for them to find the fault. It is unrelated to the 12v battery.

This just happened to me last week. I had load tested the battery a few months ago and although weak was still showing ok. When it happened I drove to my favorite fried chicken place and parked in a place with plenty of space around it. By the time the tow arrived the 12v battery was completely dead. Got it to the dealer and they replaced the 12v battery under warranty. All good now.

hmm. That’s weird. I connected a different 12v battery from one of my company work trucks and it made no difference. The truck got towed today to the dealer so I’ll post updates when I get them. I’d really hate to have to get rid of this truck.

 

[chl]

If the 12v battery goes, then the HVB contactors will not close and the stop safely now can appear - it has happened to some owners.

But any part of the 12v system could be the problem.

In one case disconnecting the 12v battery for a few minutes then reconnecting worked, and in a couple others just turning the truck off and on a few times solved it, or letting it sit 40 minutes and it was gone. Those might also have involved a 12v glitch and HVB contactors not closing.

https://www.f150lightningforum.com/forum/threads/“stop-safely-now”-message.14471/

It could be something else of course.
I think I recall someone having chewed wires that caused it?

And if there is an HVB cell in a module failure, that message would appear as well.

Hope you are still under warranty and they can diagnose it quickly.

 

[rtk11226]

I tried disconnecting the 12v battery for 15 minutes and later, multiple starts… but it would only ever go into accessory mode. After a few hours the battery was completely dead. I did have raccoon damage to coolant lines and the wiring harness to the frunk 110v outlets ($1500 worth) but the tech said the 12v battery was the problem.

 

[chl]

I tried disconnecting the 12v battery for 15 minutes and later, multiple starts… but it would only ever go into accessory mode. After a few hours the battery was completely dead. I did have raccoon damage to coolant lines and the wiring harness to the frunk 110v outlets ($1500 worth) but the tech said the 12v battery was the problem.

So many things depend on the 12v system which is why I use a maintainer with AGM mode all the time on my Lightning and my 2012 Leaf (with now over 14 years on the original flooded battery).

 

[Mal106]

Interesting, I also have a2012 Leaf. The 12v has immobilized it twice.

 

[chl]

Interesting, I also have a2012 Leaf. The 12v has immobilized it twice.

Ha, yes, it happened to me after about 3 months of ownership - I got delivery in Dec of 2011 earlier than I expected and I had a long working vacation planned after the new year which would have me away for about 2 months. I asked the sales person what I should do while I was away, and he said leave it plugged in to the EVSE.

After a few weeks the car stopped communicating with me over the internet, and when I got back home the 12v battery was too low to start/boot up the car. After I got an extra long jumper cable and revived it with my 2001 Ford Ranger, I went out and bought a battery maintainer and it has been on that ever since.

I've had to add distilled water to it once or twice, but other than than no issues. Turns out the on-board timers use quite a bit of juice so now I keep them OFF until the night I want to charge at a lower utility rate.

Out of curiosity I did a test of the battery a month or two ago and it was at 80% SOC, which is the low end of 'good' for the battery.

One of the first things I learned in engineering school outside of the text books was from one of my professors who was ex-Navy and that was how to maximize the lifespan of a lead acid 12v battery by keeping it at 100% as much as possible, as well as avoiding extremes of temp of course.

I didn't ask for details but I presume when his ship was out to sea for an extended period of time in his day, some of it's systems depended on 12v batteries being healthy. No battery stores out there, lol.

Applies to car 12v batteries as well of course.

 

[Mal106]

After the second time on the Leaf, I added a battery Cutoff. I put one on the Lightning as well. If I'm gone for more than a couple days, I disconnect both.

 

[chl]

After the second time on the Leaf, I added a battery Cutoff. I put one on the Lightning as well. If I'm gone for more than a couple days, I disconnect both.

Yes, that's another way to do it.
Keeping a lead-acid battery at 100% as much as possible can extend the lifespan quite a bit, so that's been my choice of a solution to the problem.

 

[jthiesse13]

Just got this message from the dealer. First he said it was the 12v battery. Then when I called him and asked about this message he told me he hadn’t seen this yet. So I still don’t know if it’s just the 12v battery or the hi voltage junction box (or both).

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