How Much Battery Capacity And Range Has My Ford F-150 Lightning Lost After 3 Years and 38,000 Miles?

[electricpig]

Again, how much energy that is contained in the battery is an estimate, it cannot be directly measured. IF the energy to empty value changes then the battery is accounting for the SOH. It either ignores that completely and the energy to empty is an estimate, or it uses its calculated SOH value.

Battery module failures can come from a LOT of factors, most of them unrelated to "SOH". SOH is a degredation metric but module failures can happen from errant temp readings, overly high or low cell voltages, an out of bound value, a failed test, unusual heating, an internal fault in the BMS, or many other factors, all of which are unrelated to SOH.

In the end both energy to empty and SOH are internally calculated metrics, neither is inherently more accurate than the other. Plus, as I have directly measured, the energy to empty maxed out and yet the pack continued to absorb energy for quite some time, indicating the capacity value is not strictly a direct reporting.

Which I stated multiple times that it is based on BMS calibration, meaning accuracy, and that all of these are at the mercy of the BMS. But contained energy is a fundamental that the other values outside of other fundamentals such as voltage and voltage variation, are calculated from, and is therefore a more fundamental value. However, it is very subject to temperature as I have said multiple times.

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[electricpig]

Again, a State of Health estimate is also necissary for the BMS to estimate the capacity. Using voltage (and temp) would only calculate the original (as manufactured) capacity and would not give you the state of health.

In order for the BMS to provide an accurate capacity value it has to determine the state of health. There is no reason to believe that the state of health it uses is any different or less accurate than the one it reports.

I disagree, as the BMS counts the added energy through charging, and energy usage while driving. Colombs can be measured without SOH. The BMS also gets a reference from the charger or EVSE. You can't get to SOH without knowing how much energy is there.

Neither of us knows for sure how Ford does everything, so maybe we just have to agree to disagree.

 

[electricpig]

So you are saying the BMS could be using something other than direct measurement of voltage and temp to determine capacity. Like a SOH calculation that is used to bias the energy calculation.

Thats literally what I have been saying all along.

There is zero reason to believe that that calculation is any more, or less, accurate than the SOH value reported. It is also an estimation, meaning capacity is also an estimation.

Yes , and non of those require SOH. SOH is derived from those values, not the other way around.

 

[Yansolo31]

At just north of 41k miles, 100% SOH on the hvb when checked this am

 

[WaterboyNorCal]

As others have said, the SOH metric from the BMS isn’t a “perfect” measurement, and it does vary with the conditions (SOC, temperature, charging/calibration patterns, etc.) so we all need to take it with a grain of salt. For example, my 2023 XLT SR showed 97.5% when I first ran CarScanner about a year ago (Nov 2024) when the truck had about 28k miles on it. A few months later, in March 2024, with about 34k miles, the SOH had dropped down to 96%. I ran the “calibration procedure” a few weeks later and the SOH was showing 97% in late March/April. By July, the SOH was at 98% and by August, 98.5%. Just today, the SOH was up to 99%, and my odometer is at 49k.
Clearly the SOH is a metric that can vary quite a bit, and as Tom from State of Charge points out, the only way to truly test degradation is to charge from zero and see how much energy the battery can store. It also seems clear that Ford has designed a battery that does not deteriorate as quickly (at least not initially) as many other EVs, including Tesla vehicles. This may be due to the relatively large buffer and recommendation to avoid charging past 90% until you need the range, or could be due to the specific battery chemistry or cooling system. Regardless, it is definitely encouraging information.

 

[TaxmanHog]

I used car scanner for the first time today, this is my Soh [97.5 %] after 3+ years at about 88% Soc

The past several days / weeks I've been drawing down my SOC from 100% to 10%, had a longer Sunday drive to attend the commissioning of a American Legion Riders club charter, the weather was nasty so instead of riding the Road Glide, I took the Lightning, this allowed me to draw down the balance of charge on the round trip. Later yesterday evening I pumped the SOC back up from 10% to 100% overnight. Then commenced with or short drive routines today, only 11 miles so far and the SOC is still at 100% displayed.

This is the state of health data screen from Car Scanner this afternoon, health improved to 98% variation increased to 0.012v

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