70%, 80%, 90%?? For those charging at home, what threshold do you use?

[bbulkow]

it was my understanding that the 2023 MME with the LFP should be charged to 90% when the older ones should be charged to 80%. I could be wrong. I have a charge schedule set to charge from Midnight to 5am to 90%.

I thought the manual says "100% for LFP, 90% for NMC" (2023.5's).

There was that nice video from a battery chemist who said "always be charging", and you'll wear your battery more by waiting until you get to 40% or 30% before charging. Little charges are less stress. Didn't Ford say the same thing?

I have no idea why people would disregard Ford's advice on the matter, and avoid DCFC when possible, and charge to either 90% or 100% depending on chemistry, and on NMC, reserve 100% charges for days where that 10% is going to come in handy. I believe they also advise charging every day (leave it plugged in), although I'm not sure I saw that in a manual.

I have NMC and I charge to 85%. My SoH meter (you all can go check yours) shows really minimal degradation after 17k miles, and I'll be happy at 150,000 miles.

Go check your SoH, because probably, when the battery pack is too worn to be useful, it'll be time to scrap your car and it'll be worth zero - just like *theoretically* you can replace engines on cars but *practically* it's not worth it because a body / interior with 150k miles isn't worth putting a new engine into. There's no sign that battery replacement is going to be cheaper than engine replacement, even if battery prices come down 4x, it'll probably be around what a new engine is these days, which is still in the impractical zone.

(To the person who pointed out Apple's charge system: Android's attempt to save batteries is a bit different. They attempt to slow-charge overnight, so they figure out when "overnight" is for you, then charge at as low a speed as possible so that it'll be full when you start using it in the morning. I think this is primarily because Android phones need 100% to get through a good day, mine certainly does, and avoiding the low 10% is probably better than avoiding the high 10%. If you start using your phone during this, it'll pop a notif and say "dude, want to charge fast"? So they charge to 100% but they do it as slow as possible. It would be interesting to be able to choose "charge to 90" *and* slow charge at night.... And, it would be really nice if windows laptops got some similar trickery, I just replaced a battery on my main laptop....)

Sponsored

 

[Zardoz]

I’ve set mine to charge to 90% between 10pm and 6am (mostly to allow the battery to cool).
I think that with the extra battery overhead, you’re totally safe at 90%, but you could be more conservative and go with 85%, as this would roughly work out to 80% of the total battery capacity.

For SR battery: 75.7 kWh x 0.8 = 60.56 kWh
60.56 kWh/70kWh = 86.5%

This math works out very similar for an extended range battery and I use this same logic when charging solely at home and charge to 85% when the car will be left overnight. When leaving the car on the charger for a long time (weeks) I usually set it to 60%.

With that said I usually charge to 50% at home and 90% at work. I do this because it is cheaper and it won't be at a 90% charge for long.

Also, I ALWAYS plug in when I'm at home, even if the battery won't charge. I want the car to have an AC source; if it gets too cold or hot it can maintain the high voltage battery, or if I want to remote start the car it won't cycle the battery for no reason. (I know it is insignificant, but I do it anyway).

Edit: I have an NMC battery. LFP would be different.

 

[ATL]

I have a 124 mile RT commute 5 days a week, in addition to any errands before work (rarely), at lunch (occasionally) or after work (often). Given that, I plan to charge each evening. I do have the option of charging at work via a standard 120v plug in, if needed.

In the Ford Pass app, I do not have the option of setting a maximum charge level; only charging times; or the option to charge to 100%. I am generally home by 7p and leave again between 7 and 7:30a, so I set it to charge from 8p to 7a and will see what that gets me to. Last night I charged when I got in at 7p to 7:30a and was at 94%, so that should work. Will adjust accordingly but being able to set the level would help.

Was that in an earlier iteration of the app which is no longer available, or am I missing something?

You should be able to do this in the app, under vehicle-charging-preferred times. BUT... Most of us find it much more reliable to set it in the charging app in the car. There's an odd requirement, but you have to charge-at least a little bit-one time at any given location, then you can name it and set a preferred charging level for that location.i think you'll find this function to be very useful.

 

[KarenW]

You should be able to do this in the app, under vehicle-charging-preferred times. BUT... Most of us find it much more reliable to set it in the charging app in the car. There's an odd requirement, but you have to charge-at least a little bit-one time at any given location, then you can name it and set a preferred charging level for that location.i think you'll find this function to be very useful.

Thank you!

 

[Homestead]

I charge to 80% every night at 9PM , the car has LFP batteries.
Then 2-3 times a month I charge to 100%
Our current rate is 8.39 cents kWh during off peak times.

 

[mkhuffman]

I charge to 80% every night at 9PM , the car has LFP batteries.
Then 2-3 times a month I charge to 100%
Our current rate is 8.39 cents kWh during off peak times.

In order to keep the BMS properly calibrated, it is a good idea to charge all battery types to 100% and let it go down to at least 20% every once and a while. Maybe monthly isn't necessary, but I wouldn't go a year without doing it.

 

[mkhuffman]

You do realize when you go to sell it, the buyer will check the wear level of the battery, and give you a lower price? Battery state of health (SoH) can be read in a moment using a Bluetooth OBD2, and I predict will be the new "miles" when buying a used EV. I'd certainly pay a lot more for a 97% SoH than an 80% SoH used EV, not even close.

If you need 100% you need 100%, of course, but if you've got a NMH battery following Ford's recommendation to charge to 90% - assuming that still avoids DC fast charges - will, I predict, save you money in the long term. Why not do it?

Everything in your post is correct. However, my real world experience from what I have seen personally and in this forum does not provide a clear corelation between battery SoH and charging behavior.

SoH is impacted by a lot of factors. I am beginning to think charging behavior is a minor factor compared to all the others. And the biggest factors I think are battery age and the amount of kWh charged (regardless of target charge level) or used.

Your advice is good, but I just don't think it matters much in the real world use of our cars. Battery age is the biggest factor, IMO, and there is nothing you can do about that. You can drive your car less, and reduce the impact of what I think is the second biggest factor, but mileage is also used for valuation in that case.

 

[Homestead]

In order to keep the BMS properly calibrated, it is a good idea to charge all battery types to 100% and let it go down to at least 20% every once and a while. Maybe monthly isn't necessary, but I wouldn't go a year without doing it.

Haven't seen any recommendations for depth of discharging other than not going below 20%.
Are there any?

 

[mkhuffman]

Haven't seen any recommendations for depth of discharging other than not going below 20%.
Are there any?

When calibrating the BMS in my car I think I took it down to 10%. Several times I have arrived at home with close to 0% SoCD. As I posted in response to another, I seriously doubt this behavior measurably impacts HVB SoH. I think it does, but it is so small compared to other impacts on SoH.

I am not aware of any guidance other than 20%. It is a good rule to keep the battery above 20% if you can. But I wouldn't stress out about it.

 

[Snakebitten]

If you had been well versed in the battery management of the Nissan Leaf, which is code for YOU being the battery management system engineer, the Mach-E is a such a no-stress advancement.

It took me monitoring all the available PIDs of the Mach-E for the first few days to finally conclude that I can just charge, drive, and enjoy this EV! ????

So liberating!

By the way, I have no justification of being cautious with my daily charging strategy. I chose it simply because it's so effortlessly repeatable and I have no reason to deviate.

Target is 70%
Emporium is set at Leafs previous max. (28Amps)
~50 mile commute and including pure hooliganism when I can safely get away with it, I consume about 20% SOC

I could skip charging every other day, but I'm a creature of routine. It's just my nature.

 

[4sallypat]

In order to keep the BMS properly calibrated, it is a good idea to charge all battery types to 100% and let it go down to at least 20% every once and a while. Maybe monthly isn't necessary, but I wouldn't go a year without doing it.

I always charge mine to 100% on L2. There's an SOC buffer built in so I don't worry.

On L3 fast chargers, I stop at 90% because it gets very slow....

 

[MellowJohnny]

<snip>

SoH is impacted by a lot of factors. I am beginning to think charging behavior is a minor factor compared to all the others. And the biggest factors I think are battery age and the amount of kWh charged (regardless of target charge level) or used.

Do you think it would be useful for the manufacturers to introduce a metric like "total kWh" over lifetime of the battery? Similar to the way hours are used to track the use of an airplane engine rather than using "distance".

 

[HoosierMachE]

90% every day during off peak times. 100% before a long trip.

 

[Jim D]

I think you are fine setting it to 90% or below. For me, I have mine set to 85% and will hit the charge to 100% button when it is charging at night if I know I will be going on a trip the next day that is 150 miles or more.

me too

 

[KarenW]

I still cannot set a charging level for my 23MME P RWD ERB via Ford Pass or in the car. The options I seem to have are a) 100% or b) setting a custom charging time.
There is no sliding scale for desired charging level as I've read about so far. Is there some setting I'm missing? It is not an option for me under charge settings either.

Sponsored