Charging to 80%, does it really matter?

[leelazer203]

I think it can be hard to find a balance. I can't charge at home or at work so I have to fast charge all the time. I charge to 100% because by the time i get back home from the charger it could be as low as 90% depending on how far away I had to travel to charge.

[aljack42]

Go Green Autos appears on YouTube regularly and has featured detailed measurements of SoH on old Ioniqs with mega-miles, showing zero degradation even over 100000 miles. Of course the battery construction, management and chemistry may well be different, but the videos are reassuring.

[RichR]

I think it can be hard to find a balance. I can't charge at home or at work so I have to fast charge all the time. I charge to 100% because by the time i get back home from the charger it could be as low as 90% depending on how far away I had to travel to charge.

That's fine - you're not leaving it at 100% for any length of time. I guess that you're only leaving it at 90% for a day at most before you use it and it's down another 10% too. The absolute safest level is around 50% for lithium based cells to be left in if unused (this is why those of us into RC aircraft and drones have a 'storage charge' setting on our LiPo chargers). But obviously that's not making best use of the energy storage available in the car. If you've got a smaller battery (eg a 60) then even more so. I tend to charge my 80 when it gets down to about 30% and take it to 80%, unless I'm going on a longer trip when I'll take it to 100% the night before. When I charge at public chargers, I only add enough to get to my next stop (plus a buffer), so perhaps taking it to 60% or 70% only. No point going into the >80% where charging speed gets much slower on rapid chargers unless I need that range.

[tiger tony]

I bet its a VAG corporate decision with this default 80% to potentially reduce the number of degraded battery claims in a few years time !!!!!

[Powerstar]

We’ve owned a BMW i3 for 4.5 years which we charge from a dumb home charger. As the car has no facility to limit charging at any percentage we have always charged to 100% overnight.

Thankfully the car is still showing no reduction in mileage capability. Fingers crossed this continues.

[Aragorn]

Interesting topic which makes me wonder what these cars will be worth in 8 years time.
Personally I wouldn't touch an electric car of that age for fear of the battery failing at great cost no doubt.

Anyone feel the same or am I way off?

Go look at the prices of other 8 year old EV's...

A 2015 LEAF that can barely drive the length of your street is still selling for 8-10 grand or more. Significant premium over a similar age/size ICE.

8 years from now, EV demand will be higher than now, with limited numbers of older cars available (simply due to the number currently on the road) so theres no reason to imagine they'll somehow be worthless then.

[Aragorn]

I think it can be hard to find a balance. I can't charge at home or at work so I have to fast charge all the time. I charge to 100% because by the time i get back home from the charger it could be as low as 90% depending on how far away I had to travel to charge.

I think thats a fair point. Clearly, if you need the capacity then use it. But for someone charging one or twice a week, they can probably manage only charging to 80 or 90%. Unfortunately you simply have to accept that by always rapid charging, and always filling the battery to a high SOC, your going to degrade it faster than you would not doing those things.

[Aragorn]

I bet its a VAG corporate decision with this default 80% to potentially reduce the number of degraded battery claims in a few years time !!!!!

I mean, yeah ofcourse. Its not really a secret is it? Charging to high SOC does reduce battery longevity.

VAG could tell you "By the way, charge to 80% when possible to make the battery last longer", or they could ignore it and not say anything and have the batteries wear out sooner.

Are you really suggesting the latter is desirable from anyones position?

Its a bit like the dilemma i see with people moaning about the battery heater reducing their winter range.... And then others moaning the car doesnt rapid charge fast enough because the battery is too cold. Everything is a balance. At least with this, they've given you a slider on the dash, told you why it defaults to 80% and left the rest up to you.