Cell Level Testing of the SK805A (Lightning Cell)

[vagabond7846]

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.

This whole post comes across as "Im smarter than you, if you ask the right question maybe youll get lucky". Either share the information you have or don't waste our time with this click bait.

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[Scorpio3d]

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.



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.

Yes, I would call the temperature reading in the truck a guess o meter as well! We had a cold front the other day so we are only in the middle to upper 90s this week. But I know Arizona gets much hotter than here but it is a dry heat

 

[Scorpio3d]

This whole post comes across as "Im smarter than you, if you ask the right question maybe youll get lucky". Either share the information you have or don't waste our time with this click bait.

If you read Mikey‘s other posts, you will realize that he cannot share specific information from his job because he has an NDA. We are fortunate that he is able to answer some of our questions just not having to do with the specific work, they do!

 

[Zprime29]

This whole post comes across as "Im smarter than you, if you ask the right question maybe youll get lucky". Either share the information you have or don't waste our time with this click bait.

There are a lot of folk who argue with his statements (which are in line with published academia). I like to give him a little slack for being jaded that people prefer to believe their own ideas vs science. And as @Scorpio3d mentioned, he won't share data due to work obligations and not wanting to get fired, especially so close to retirement!

@MickeyAO Knowing that you haven't finished testing yet, do you have a hunch on where the results may be? Could you ball park where you think our batteries are in terms of better/worse than others you've tested? As in, are they middle of the road in reliability or slightly better/worse than the competition?

 

[vagabond7846]

If you read Mikey‘s other posts, you will realize that he cannot share specific information from his job because he has an NDA. We are fortunate that he is able to answer some of our questions just not having to do with the specific work, they do!

I am saying *this post in particular* is not informative since there is no data, just an opinion based on an observation of something that no one else has access to. Secondly if someone is truly worried about an NDA, you don't even make a post like this in the first place, you are already liable for breaking the NDA.

 

[Zprime29]

I am saying *this post in particular* is not informative since there is no data, just an opinion based on an observation of something that no one else has access to. Secondly if someone is truly worried about an NDA, you don't even make a post like this in the first place, you are already liable for breaking the NDA.

I agree that everything on the internet should be taken with a heaping tablespoon of salt. That said, I've seen enough from Mickey that I trust his judgement. It's not dissimilar from the threads on home backup solutions. Sure, someone can claim to be a licensed electrician with X number of years under their belt. Do you trust them? Why? It's healthy to do you're own research but when the advice from someone, over a couple years is consistently in line with your research then you tend to trust them a little more.

 

[Mashedtators]

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.

Do you still suggest charging to 85% for daily driving?

 

[Maquis]

Secondly if someone is truly worried about an NDA, you don't even make a post like this in the first place, you are already liable for breaking the NDA.

Since he likely knows what’s in the NDA he signed and you have no clue what it says, I’m calling BS.

 

[Scorpio3d]

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.

I recently signed up for Tesla electric as I have installed the power wall 3 so my rate from 12 AM to 4 AM is lower per kilowatt hour (Not that that entirely matters because I will be offsetting most of my use by selling back KWh during the day )I figured that is the coolest time of the day anyway (up until sunrise). I assume that this would be better than charging when my solar is in full production in the middle of the day due to heat.
Dallas area similar climate to you!
Should I charge to your recommended 85% SOC every day? or just when I get down to a certain percentage?
I drive my truck every day most days 20 or 30 miles some days many more. Also, any other insight you can provide for my situation. I apologize if you have already answered these questions in some form but I have read through most of the other posts on battery and SOC. I usually keep my vehicles for many years and plan on keeping this one at least the eight years of the battery warranty. Unless the next generation is just unbelievably better but even then at least five I would imagine.

 

[Zprime29]

Should I charge to your recommended 85% SOC every day? or just when I get down to a certain percentage?
I drive my truck every day most days 20 or 30 miles some days many more. Also, any other insight you can provide for my situation. I apologize if you have already answered these questions in some form but I have read through most of the other posts on battery and SOC. I usually keep my vehicles for many years and plan on keeping this one at least the eight years of the battery warranty. Unless the next generation is just unbelievably better but even then at least five I would imagine.

From what I've learned, writing from memory here, he charges to 85% for his personal use case but doesn't recommend that for someone who is interested in maximizing the life of the battery. The published papers that have come out say (and I'm paraphrasing the cliff notes) keep it close to 50% SOC as possible and the smaller the depth of discharge the better. I.e. multiple small charges are better than one big charge.

I used to do 80-85% but bumped it down to 70% and try to charge daily when possible. I accept that I won't have an ideal battery (summer heat plus road trips doing DCFC from 20-80%). But I minimize where I can and I think that'll be good enough. If I see nasty weather coming I bump my charge to 90%. I'm not fully worried until Mickey says he is selling before he retires.

 

[Sneakypetie78]

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

123 per the temp at the bottom of the instrument cluster there...

I was in Palm Desert last weekend with mine, and a purported 124 degrees outside. I did see my temp gauge above middle, like his, but never went outside of that. To me, it noted that is warm, and, I figure cooling in process to get it back down to middle range. Never got any warnings. I did although google "what temperature is ok for an F-150 Lightning EV battery?" Results said that Ford tested the battery from -40 to 140 F. I relaxed a tad and let the warranty be my peace of mind. I did pull it in the garage on that day though, just to get it off of the pavement outside.

 

[ctuan13]

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.

Thanks again for the insight! So yeah, definitely DON'T be a dumbass like me and forget that you unhitched your trailer at the charging station and fail to account for reduced range to get to the next stop. Basically don't let it die completely

But I will say the good news in my case is it does appear that the module voltage variance and SOC variance does seem to be rebalancing over time with repeated AC charging cycles and specifically aiming to only cycle the battery within the 40-90% range.

Obviously, we know @MickeyAO recommends 85% SOC display for daily use, but towing my teardrop across the country, 90% is a necessity out west in these charging deserts!

 

[sysop1]

Really perplexed about this post. The tldr seems to be

“I’m a battery expert and the battery Ford uses sucks and I’m selling my truck before the battery warranty expires. Please don’t ask me questions as I’m an expert and I can’t share any info”

Did I miss any parts?

 

[Grumpy2]

I will entertain generic questions based on my 13 years of experience on testing a wide variety of cells...

From my reading it seems labs place the cells in an accurate constant temperature oven and perform many of the tests while changing the temperature as required for each test.
Using this approach the entire exterior surface of any cell tested will be exactly that temperature.

However, EV's use various methods to cool the cells from air to various surfaces in contact with liquid tubing. None of these actual cooling methods are equal to a constant temperature oven. It seems only immersing the cells in liquid would be similar to the lab oven method, and no EV builder is attempting that.

How can the lab test be equated to real life cooling of cells? No matter the method used by the manufacturer to cool the cell, it seems there will be a heat gradient, perhaps significant, within the cell which may change the ultimate test result and effect the "life" of the cell.

 

[lakeguy55]

Even Ford can't seem to figure out what to recommend. From their website,

If you click on "Battery Life Tips and Tricks", it takes you to a page where that topic is nowhere to be found. If you search their site for the topic, you get this,

Selecting either of the first 2 topics takes you to a page not found error.