Charging to 100% … better to do it right before you leave?

[diranged]

If your going on a road trip where you plan to charge to 100%, I’m curious if it’s better to do the final charge (85->100) right before you leave… or better to more slowly charge up the night before?

In both cases I’m talking about AC charging… but I’m talking about whether it’s better to charge at say 20-30 the night before, or max the charger out at 42A just for the few hours before you go?

I’ve read conflicting information.. some articles saying “keeping an EV battery at 100%” is bad, while others saying “charging an EV battery to 100% is bad”.

I’m curious if anyone has any good links to publications that talk about this in depth?

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[Gabe1aron]

from what I’ve learned over 6 years of owning EV’s, both are bad.

However, if youre going to charge to 100%, you don’t want the battery to linger at 100% for long. Meaning once it gets to 100%, you want to get on the road within an hour. So your strategy of going from 85-100 just before you leave is best.

Also, when you charge over that last couple of hours, youre also preconditioning and therefore improving efficiency when starting out with a worm battery.

I charged to 100% occasionally for a long trip using this method and I saw less than 10% decline in range over 4 years with my 2016 Model S

 

[diranged]

Thanks for the response.. my feeling was to do the last charge shortly before we leave. I will note that I’ve seen a few articles that say “don’t unplug and go, give the car an hour or two to cool down” after charging up that far. Their premise is that you don’t want to leave with a hot battery I think?

I’m probably going to just charge from 85 to 95, and then let the car sit while we finish packing..but I’m genuinely interested in the underlying technical benefits of one approach vs another.

 

[crashmtb]

Last EV trip I did I charged to 100%, drove to my house, street parked overnight, loaded up in the morning and left at about 95%
this gave a comfortable 25% left by the first charging stop.
6 year old Tesla that is almost always charged to 100%ish, often does long highway trips using most of the battery.
showing 4% battery degradation.

it really depends on how much reserve you need/want.

don’t worry about battery health so much. BMS will take care of itself.

 

[electruck]

You're splitting hairs over the last few hours of charging. 20A vs 48A isn't going to have any meaningful impact on battery life. And if Rivian believes charging at 48A at 98% charge is bad for the battery, the BMS should be tapering the charge. If you have 48A available, use it and let the vehicle manage the charge rate.

 

[mini2nut]

Our Model Y charging routine: a gentle 24 amps until charged to 85%.

 

[sub]

And if Rivian believes charging at 48A at 98% charge is bad for the battery, the BMS should be tapering the charge.

Agreed, and that is the same way that I know that consistently driving my ICE vehicle at 7000 rpm isn't bad for the engine because if it was the manufacturer's engine control CPU would be tapering the throttle input.

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