Cell Level Testing of the SK805A (Lightning Cell)

[MickeyAO]

I can't really go into our cell level testing that is entering its' 9 week (out of 20) but I do have a couple of comments.

First, I'm not selling. I'm approaching retirement, I bought the 8 year factory warranty, and I really love the truck...but doubt has crept in. I know my particular use case will not be a problem before the 8 years are up. There is an outside chance that I will trade in the wife's EV6 and my truck AFTER retirement to buy a Kia EV9 as we transition to a single vehicle family.

I will say that the delta is a HUGE issue for this cell, along with temperature (I would recommend keeping it under 45C)

I will also say our testing takes us outside of what the truck allowed during our road testing. Do not expect me to make any more post about this specific cell, but I will entertain generic questions based on my 13 years of experience on testing a wide variety of cells...and I still expect those with anecdotal information to refute what I see in actually testing cells for a living, down to the milliamp level.

If you don't know what I mean about delta, either bury your head in the sand and use your 20 years looking at Torque while driving an EV, or reread my previous post about cell testing insights.

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[Grumpy2]

Thanks for the update. ... I think

 

[sotek2345]

Mickey - trying to learn and hoping you will humor me, but my forum search-fu to find your previous post has failed and google isn't helping much either. I can see that delta has something to do with voltage change over time (and therefore related to high charge / discharge rates) but I am not sure if that is what you are getting at.

Any chance you could link to the old post you mentioned?

 

[Gimme_my_MME]

Just for clarification, you test the cells by themselves and not with any of the battery management systems that are at pack level?

 

[mr.Magoo]

Any chance you could link to the old post you mentioned?

https://www.f150lightningforum.com/forum/search/2497444/?q=Delta&c[users]=MickeyAO&o=date

Not Mickey, but advanced search by user is helpful...

 

[bmwhitetx]

...and I still expect those with anecdotal information to refute what I see in actually testing cells for a living, down to the milliamp level.

If you don't know what I mean about delta, either bury your head in the sand and use your 20 years looking at Torque while driving an EV, or reread my previous post about cell testing insights.

As my current signature tag says: ”Without data, you’re just another person with an opinion“.

Lots of folks on here without the data you have but they sure think they’re right with their anecdotal “data”. You have my attention.

 

[PreservedSwine]

The general feeling of that post is unsettling, coming from someone with technical knowledge and data at their disposal.

I know next to nothing in this arena, and in my world, the Delta could refer to any number of things.
What does it refer to in this case?

 

[Zprime29]

I will say that the delta is a HUGE issue for this cell, along with temperature (I would recommend keeping it under 45C)

The temperature bit is a little alarming for those of us in hot summer climates. Yesterday my battery temp was as high as I've ever seen it. Edit to add...it was on a level 2 charger at work all day. Kinda shocked it was this high.

 

[Grumpy2]

I know next to nothing in this arena, and in my world, the Delta could refer to any number of things.
What does it refer to in this case?

Post 5 above is the place to start. Much good information available.

 

[Grumpy2]

Yesterday my battery temp was as high as I've ever seen it.

Remember the 123 number isn't the battery temp. The upper left bar indicates the battery temp and that "gauge" seems to indicate brackets from 1/4 to 3/4. I am hoping those brackets indicates operating temperature range.....

 

[Scorpio3d]

So… I really don’t know anything about all of this. I’m trying to learn since I now own a giant battery operated vehicle. I purchased mine with the max trailer tow package because I felt the extra cooling would be beneficial even though I don’t haul trailers often.
Will the additional cooling of the max trailer tow package be beneficial for this scenario, even not when towing?

 

[Scorpio3d]

The temperature bit is a little alarming for those of us in hot summer climates. Yesterday my battery temp was as high as I've ever seen it. Edit to add...it was on a level 2 charger at work all day. Kinda shocked it was this high.

That does seem high! I have never seen mine above the 50% line in the middle. What was your outside temp?

 

[Grumpy2]

With the additional cooling of the max trailer tow package be beneficial for this scenario, even not when towing?

Max tow provides a dedicated coolant loop for the battery, therefore should help. I have max tow also and just returned from a 1200+ mile trip involving 103 outside temperatures and the battery still gets hot, similar to post 8 above.
I have read test result literature of other cells that have shown the importance to avoid the large depth of discharge deltas at very high temperatures.

The Battery Management System software will hopefully handle this issue as best as possible.

 

[Zprime29]

Remember the 123 number isn't the battery temp. The upper left bar indicates the battery temp and that "gauge" seems to indicate brackets from 1/4 to 3/4. I am hoping those brackets indicates operating temperature range.....

Yep, was referring to the meter at the top. The outdoor temp display has been in the 120's several times and the battery meter was barely half that. I thought being plugged in and charging would keep the cooling on. Since I didn't have any warnings flashing I'm guessing it's OK by Ford's estimation. It's their warranty so I'll trust it.

That does seem high! I have never seen mine above the 50% line in the middle. What was your outside temp?

Yeah, can't trust that parking lot temp of 123F. It dropped to 117F once I got driving. Forecast high was 112F, my home weather station reported 109F.

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