Battery has built-in headroom?

[MickeyAO]

It's impossible to discharge a lithium chemistry below a certain voltage (depending upon the chemistry … I don't purport to have a table of all these numbers memorized, I'd just google it and compare nmc with lfp, etc.) and impossible to charge above a certain voltage … approaching those limits defines the performance envelope of the pack (complicated by ambient temperature and cooling system performance.)

I would beg to disagree with the 'impossible' part of your statement...I regularly discharge cells to -4.2V (yes, negative voltage which is hard to do but we have a method to meet the standard) and more than 6 V while testing to the SAE J2464 standards.

As long as the BMS is operating normally, it should be impossible for YOU to do these things with normal operating conditions and equipment.

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[F-150 Prius]

I would beg to disagree with the 'impossible' part of your statement...I regularly discharge cells to -4.2V (yes, negative voltage which is hard to do but we have a method to meet the standard) and more than 6 V while testing to the SAE J2464 standards.

As long as the BMS is operating normally, it should be impossible for YOU to do these things with normal operating conditions and equipment.

you're talking about RC batteries, a few milliamps

 

[Akbrian]

you're talking about RC batteries, a few milliamps

It is possible to drain o Lithium battery to zero. The damage done is not good though. a low voltage cutoff or BMS to ensure the battery isn’t overly discharged is what stops us from over draining the cells and harming then. But if not charged they will continue to drain In fact low SOC for extended period time is the only thing that will void the ford warranty.

 

[MickeyAO]

you're talking about RC batteries, a few milliamps

I'm not talking about RC batteries...I'm talking about the cells harvested from many of the electric vehicle batteries we have dismantled.

 

[greenne]

Of course the optimist in me is hoping Ford will open up a bit more usable capacity thru OTA updates and increase range.

Hoping that once Ford is reasonably satisfied in the battery dependability they will feel comfortable opening it up a bit more like they did with the MME.

 

[kenfaber62]

Tesla also locks out a portion of their battery from use, they are just less conservative than Ford.

Yes, they do and when a hurricane was about to hit FL several years ago. Tesla unlocked the full range so that everyone who was trying to get out of the path of the storm could have their best chance of doing so. I assume they restored the old limits after a month or so.

 

[RickLightning]

So the latest Munro video mentioned that the ER battery is an actual 144Kwh, while only 131 is available to the user. My math says that's about 10%. So does that mean that Ford built in the extra at the top, the bottom, split between both? And how does this affect the conventional wisdom of not charging to 100%?

Your math needs fixing.

1- 131/144 =9%.

The Mach-E was released with 88 of 98.7, or 89.2%. It was upped for 2022 and retroactive to 2021s, to 91 or 92.2%.

131 of 144 is 91%. I wouldn't expect more, they're already close to the Mach-E percentage.

Darren Palmer last year said they will be looking at battery usage, and abuse, and over time they expect to more individually tweak things like capacity and charging curves. If you always charge to 90% and rarely DCFC, you MAY see more capability than if you DCFC daily and drive like a maniac. Note - his exact words were different, but that's the gist.

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