How often to charge to 100%?

[bc1]

It seems to me that we are talking about much to charge a battery up to in order to achieve the most longevity in years. Right now the Lightnings haven't been around long enough to get a track record.

So, what about rating the battery by the total number of miles driven? I've had my 2025 with 131 kwh battery for about 7 months now and just turned over 12,000 miles. I know the ford vehicles with the 5.4L engine that is taken care of can get up to 400,000 miles or so and many much less. My 1998 Expedition I just sold had 313,000 miles and was doing fine. Usually when the engine goes, the vehicle goes to the junk yard.

Guess I'd like to hear from some with high mileage on their trucks and how the charge rate affected them assuming there are some out there that have a 100,000 or 200,000 miles on one yet. And maybe we don't have enough high mileage vehicles yet to get a track record.

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[Maquis]

So, what about rating the battery by the total number of miles driven?

Of all the factors influencing battery health, miles driven will probably show the least correlation.

 

[ctuan13]

For NCM/NMC batteries, top end balancing is needed far less frequently than with LiFePO4 batteries. This is for two reasons, (well sorta one , but it has two consequences).
1. NMC batteries have a wider, more varied voltage curve (I.e. at any given point along the SOC curve, the voltage is distinct and varied enough to give a pretty accurate idea of SOC) - this means that even if there is a colmbmeter used to measure SOC that eventually gets mildly out of calibration due to inefficiency and losses, etc, the BMS can use voltage to give a pretty accurate measure of SOC.
2. LiFePO4 batteries on the other hand, have a very very flat voltage curve. Until they're nearly full or nearly empty there is very very little voltage variation. This means they must use a columbmeter to measure SOC and inevitably due to inefficiencies and losses, that shunt device will slowly slip out of calibration, leading to erroneous and inaccurate SOC readings. But not only does the SOC accuracy of the entire pack suffer, the inter-cell balance is far more likely to slip, because unlike an NMC chemistry battery, there isn't enough voltage differential at the middle SOC levels to balance cells.

So by regularly charging to 100%, not only do you reset the accuracy of the shunt-type device providing a more accurate SOC, you allow the voltage differential to grow large enough between cells to allow for the BMS to actively balance them.

What do I do? I most often charge to 85-90% displayed (this is different than SOC actual, where 90% displayed is actually 85% SOC actual). And then a few times a year I'll charge to 100%.

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