Battery charging beyond 80 percent

[Dr Dave]

I agree with this. It's simply a fact of lithium chemistry, unless there is some special sauce in there to somehow prevent the bad reactions, and I don't think that any exist as yet.

I actually don't want to argue this one. I know a lot of people don't have as much time as I do to fiddle with the end of charge. So for them it's almost certainly not worth worrying about. For me, it is.

I disagree with this. The battery has a 7 year warranty, the latest BMS has lowered the upper end to the point where regen works when the battery has charged to 100%. I always fill to 100%.
As Kithmo said in post #10 'what's the point of only using 80% of the battery at the beginning of its life when you may only have 80% to use later down the line when the battery is older.' You are effectively reducing the range of your new car by 20%, not in my world.
Range is King, you do not want to be stuck down a wet, cold, country lane in winter because a diversion re-routed you and you have no charge left.

 

[macd2401]

Interesting conundrum. If you accept that batteries have to be balanced for their health, then you have to accept running them up to full charge. If you never charge them beyond 80%, then they'll never be balanced

As others have said, as long as you're not leaving the car sitting at 100% (or 0%) for weeks or months, then just charge and use as you need it. If you DO have to put the car into extended storage of some sort, then best practice is to have the battery sitting around the 60% mark. That's the level that almost all consumer LiPo type batteries are supplied from the manufacturer at. It's the level that most LiPo chargers will bring a battery to for a storage charge. And at that level, the battery will last for an age. I have a LiFe battery, which I believe is the same chemistry as our car batteries, which had been in storage for a very long time. Gave it a dust down and a charge up, works fine.

 

[Gomev]

....
As Kithmo said in post #10 'what's the point of only using 80% of the battery at the beginning of its life when you may only have 80% to use later down the line when the battery is older.' You are effectively reducing the range of your new car by 20%, not in my world.
Range is King, you do not want to be stuck down a wet, cold, country lane in winter because a division re-routed you and you have no charge left.

Add in that you shouldn't run it less than 20% ( I have heard this from some quarters !) and you are left with only 60% battery to play with

 

[biffo]

Add in that you shouldn't run it less than 20% ( I have heard this from some quarters !) and you are left with only 60% battery to play with

Given that some of the big battery Audis (and others) are charging at 150kW until 80% and then linearly dropping to around 50kW up to 100% - I wonder if the charging rate accepted by the car, or even the voltage stored in the battery (300-450V seems common range - but sure I've read that some are planning much higher), will have an impact of the degradation.

I suspect there must be an optimal voltage for a certain battery chemistry to be stored at, and charged at, for longevity. Which might not be the same as the values for performance, etc.

I wonder what percentage the reported Tesla which did 200,000 miles and maintained 90% capacity was charged to - although, given those mileages, it would have remained fully charged for very long.

 

[JodyS21]

First time I used a rapid charger it went from 21% to showing 100% on hv battery gauge in 45 mins which I couldn’t understand because everybody says it slows down massively at 80% yet mine didn’t seem to the only info I know is it delivered 31.2 kw in that time.

You only charged to 94% not 100% as per your other thread.

 

[Coulomb]

If you never charge them beyond 80%, then they'll never be balanced

I do charge to 100% (display % obviously) once per month, and try to use it as soon as possible afterwards, preferably within hours.

Perhaps I should add that I may be especially sensitive to battery degradation, as my other EV is a first generation leaf with a warranty replaced battery that has high internal resistance, and after just 2 years on the second battery has about half range. I'm not saying that my charging regime had anything to do with that, just that battery health is something I'm probably more acutely aware of than most.

Edit: I'm also in a sub-tropical climate, which doesn't work well with the early Leaf battery chemistry.

 

[Paulnz5]

Yes. I have also read numerous articles about charging in the 20-80% range to optimise battery life. We therefore only charge when range gets to 75km or lower the following morning we are up to 80% using the granny charger.
On Fridays we need 100% for a long trip so charge all night Wednesday and Thursday to achieve that.

 

[macd2401]

I'm not saying that my charging regime had anything to do with that, just that battery health is something I'm probably more acutely aware of than most.

Edit: I'm also in a sub-tropical climate, which doesn't work well with the early Leaf battery chemistry.

I doubt it's your charging regime, more likely it's the lack of active battery cooling on the Gen 1 Leaf. The MG does a good job of keeping the batteries cool in most charging scenarios. It's one of the things that swayed me away from the Leaf early in the selection process.

 

[Miles]

Just to add … I always charge the ZS EV to 100% on the 7 kW AC wall unit. I usually cut the 75 kW off at between 80% and 90%. This is more to do with cost and time rather than battery concerns.
All my Tesla mates and the EQC400 owner friend argue black and blue that I should follow their lead and stay under 80%. The argument continues among friends.

IMO charge to need.

 

[Frank]

Just to add … I always charge the ZS EV to 100% on the 7 kW AC wall unit. I usually cut the 75 kW off at between 80% and 90%. This is more to do with cost and time rather than battery concerns.
All my Tesla mates and the EQC400 owner friend argue black and blue that I should follow their lead and stay under 80%. The argument continues among friends.

IMO charge to need.

Hi Miles,

I have had EVs since 2019 and I have charged them ALL every night on my wall charger to 100% no matter what the SOC was. I have never had any problems with either my main battery or the 12v battery.

I will continue to do this as long as I have EVs, I let the BMS and the warranty worry about the battery.

All the best

Frank

 

[Maurice Beck]

I haven’t read anywhere about recommending not charging beyond 80%. The packs are designed for this. I think you may have confused charging on a rapid past 80% where it generally slows down. It’s fine to fully charge your pack. The general advice is don’t leave it fully charged or discharged for long periods and if you don’t need to then running between around 30-80% charge is great. If you need to 100% charge and use - go ahead!

I have tried to charge past 80 percent without success on my home charger but it will not go higher than 80

 

[Cocijo]

I have tried to charge past 80 percent without success on my home charger but it will not go higher than 80

You need to check the settings and see if you have the 80% charging limit setting enabled.