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

[Zprime29]

People are stressing way too much about SoH when we don't even know how it's being computed. 126kWh means you're down 4% from stated useable capacity. I just charged to 100% last night myself as I hadn't done that in a while and wanted to give the BMS a good "reset". It showed 127.7 this morning, so I'm down 2.5% at 48k miles. I think it's similar age to yours. I didn't look at SoH because I put no stock in that number.

I'm only concerned about my 100% capacity and the module/voltage variations. Your variations look great, they went down after you charged to 100% which is what we'd expect. The BMS did it's job and your battery looks completely fine to me. The capacity loss looks normal given what I've seen from Tesla battery life studies. The first few years we'll see a drop to around 90% and the loss slows down a lot there. I expect to have better than 85% at 10 years and better than 80% at 20 years. That'll be perfect for me.

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[Firn]

Fwiw I had 97.5% SOH and still only showed around 126kwh when charged to 100%. After a HVC repair my battery jumped to 100% SOH. Later in the year when my battery was warmer it showed 131.5kwh at 99% SOC, then proceeded to suck in electrons for a few more hours and still stayed at 131.5kwh.

A lot of factors go into both capacity and soh, one cannot be determined directly from the other.

In the end I agree though, the self reported SOH isnt terribly reliable.

 

[electricpig]

When you charge to 100% the next time, use your OBD scanner and check these numbers. Also the battery needs to be idle and warm but not hot. From the scanner software find the "actual SOC and not displayed AOC. It should say around 95%. Next find your actual kw in the battery. Divide the percent into that actual kw i.e. 123/0.95=129.47. This will give you your actual battery capacity at the current conditions. The last time I did this in June, I got 107 of the spec 107,4. This IMHO is the best way to determine SOH.nut be aware, conditions at the time wll change the reported stored kw, hence best at near ideal conditions.

 

[Traconesu]

When you charge to 100% the next time, use your OBD scanner and check these numbers. Also the battery needs to be idle and warm but not hot. From the scanner software find the "actual SOC and not displayed AOC. It should say around 95%. Next find your actual kw in the battery. Divide the percent into that actual kw i.e. 123/0.95=129.47. This will give you your actual battery capacity at the current conditions. The last time I did this in June, I got 107 of the spec 107,4. This IMHO is the best way to determine SOH.nut be aware, conditions at the time wll change the reported stored kw, hence best at near ideal conditions.

So you are deriving the SOH from the batteries calculated battery capacity by its rated battery capacity ?

 

[Firn]

When you charge to 100% the next time, use your OBD scanner and check these numbers. Also the battery needs to be idle and warm but not hot. From the scanner software find the "actual SOC and not displayed AOC. It should say around 95%. Next find your actual kw in the battery. Divide the percent into that actual kw i.e. 123/0.95=129.47. This will give you your actual battery capacity at the current conditions. The last time I did this in June, I got 107 of the spec 107,4. This IMHO is the best way to determine SOH.nut be aware, conditions at the time wll change the reported stored kw, hence best at near ideal conditions.

That isnt necessarily a fool proof method for finding SOH. The BMS doesnt "know" the energy to empty (kwh) in the battery, its just estimating based on voltage, temp, etc. To adjust that number it would need to calculate SOH, which would just then be the SOH value presented.

Point being, for the BMS to change the capacity it has to determine the state of health.

 

[Maxx]

I am hoping by the time battery is out of warranty, we will have other options (like this i3):

 

[electricpig]

Allthe.values relie on BMS calibration, and all interdependent. Others in other threads have reported having 99+% BMS reported BMS while having battery cell/module problems requiring replacement. So I don't trust that much. The BMS MUST know the amount of energy stored to calculate percentage, range, AND SOH. Hence some of those mentioned above would change to 100% and immediately fall to a much lower percentage upon start up. That would not happen unless the BMS knew there was much less available energy. Again these persons were showing high SOH reading. The stored energy value also changes widely with temp as would be expected. . With all that said, my understanding is that it uses Voltage for that calculation, again requiring correct calibration. No way to get around the BMS calibration using OBD reader.

With all that said SOH SOH combined with voltage variation when fully charged and cells are leveled can potentially indicate future issues. I just believe stored energy is a more fundamental metric indicator. So if I calculated 107 kwh capacity in what was rated at 107.6 kwh (this is the actual total for a SR), then I would feel very good about it. I don't try to assign a % SOH. Just know I'm in excellent shape. Btw, that was the number I got in June with 19K miles.

No matter what we use, it's all best guess from the BMS and OBD reader on the consumer end. Use what works for you.

 

[Firn]

Allthe.values relie on BMS calibration, and all interdependent. Others in other threads have reported having 99+% BMS reported BMS while having battery cell/module problems requiring replacement. So I don't trust that much. The BMS MUST know the amount of energy stored to calculate percentage, range, AND SOH. Hence some of those mentioned above would change to 100% and immediately fall to a much lower percentage upon start up. That would not happen unless the BMS knew there was much less available energy. Again these persons were showing high SOH reading. The stored energy value also changes widely with temp as would be expected. . With all that said, my understanding is that it uses Voltage for that calculation, again requiring correct calibration. No way to get around the BMS calibration using OBD reader.

With all that said SOH SOH combined with voltage variation when fully charged and cells are leveled can potentially indicate future issues. I just believe stored energy is a more fundamental metric indicator. So if I calculated 107 kwh capacity in what was rated at 107.6 kwh (this is the actual total for a SR), then I would feel very good about it. I don't try to assign a % SOH. Just know I'm in excellent shape. Btw, that was the number I got in June with 19K miles.

No matter what we use, it's all best guess from the BMS and OBD reader on the consumer end. Use what works for you.

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.

 

[Traconesu]

I am hoping by the time battery is out of warranty, we will have other options (like this i3):

Still a little over 4 yrs warranty left for me. Who knows where Battery technology will be in 4 yrs. Hopefully our batteries will last long past their warranty period.

 

[electricpig]

That isnt necessarily a fool proof method for finding SOH. The BMS doesnt "know" the energy to empty (kwh) in the battery, its just estimating based on voltage, temp, etc. To adjust that number it would need to calculate SOH, which would just then be the SOH value presented.

Point being, for the BMS to change the capacity it has to determine the state of health.

Of course not. Did not claim it to be full proof. I stated it relied on the BMS being calibrated, meaning accurate based on voltage. Also said all OBD readings relie on the BMS being correct, and that temp seriously affects these numbers. But it is a fundamental value to calculate many other values such as SOH.

 

[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.

 

[Firn]

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.

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.

 

[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.

 

[Firn]

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.

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.

 

[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.

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