lvl 2 to 100% vs DCFC - what's better for long term battery health?

[MoreTrout]

My home and camp are about 200 miles apart and I make the trip up to 2 to 3 times a month, sometimes more. Right now I can make it pretty comfortably by charging to 85%, but that might not be true come winter. There are 2 DCFC on the route. One of them is an EA which surprisingly enough has performed remarkably well. Well, other than not charging me for the second session . I know that DCFC or any charging to 100% isn't the best for battery health over the long term, but does anyone know which is relatively better - DCFC on the way vs lvl 2 charging to 100%.

Edit: To avoid any confusion, I'm not talking about DCFC to 100% Probably better to state it this way:

Option 1: Home lvl 2 charge to 100% so I know I can make the 200 mile trip without stopping.
Option 2: Home charge to 70 or 85 %, then stop and DCFC back to 70 or 85% on the way.

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[R1Sky Business]

Level 2 to 100% as long as leave as SooN as it's fully charged.

 

[Dark-Fx]

Level 2 to 100% as long as leave as SooN as it's fully charged.

Every time I've attempted to time hitting 100% before leaving I've messed it up somehow. Usually still charging but really close, sometimes way under because my truck decided to phantom drain 10% overnight when I turned scheduled charging on.

 

[Joneholland]

Level 2 to 100% is totally fine for the occasional road trip.

DCFS is much much harder on the battery than that.

 

[R1Sky Business]

Every time I've attempted to time hitting 100% before leaving I've messed it up somehow. Usually still charging but really close, sometimes way under because my truck decided to phantom drain 10% overnight when I turned scheduled charging on.

strikes again

 

[R1Sky Business]

Level 2 to 100% is totally fine for the occasional road trip.

DCFS is much much harder on the battery than that.

Hopefully the estimated time to 100% is more accurate as OTA updates continue...

 

[Joneholland]

At 11.5kwh, I just set it to hit 100 and go to bed. Hasn’t failed me yet.

I don’t do scheduled Charging though because my PNW power is cheap all the time.

 

[Christopher]

I'd love to see scientific data behind this but I'd assume a slower L2 charging to 100% would be better than a DCFC as long as it doesn't sit topped off and you leave when it gets to 100%.

To my understanding you don't want to have the battery sit at a high SoC for a prolonged period of time, so if you charge to 100% and then start driving and get back down to 80% an hour later on a road trip, then that wouldn't be so bad. Again, would love to see battery degradation data behind this.

 

[ironpig]

Don't be scared of using Level 2 to 100% for long trips. I did it on average 2 times a month on a Model S and my battery was still in great shape after 8 years.

 

[Joneholland]

On a purely thermal management basis, dumping 11kw into a battery vs dumping 150kw doesn’t need a scientific study to validate

it’s amazing when you think about it. A single DCFS is putting the peak consumption of an entire street into your car.

 

[OEVA]

Sitting at 100% is the critical factor - how it gets there doesn't make much difference. The last % points are at near L2 rates even on a DCFC.

I understand your question to be should you charge to 100% or stop along the way to DCFC.
I don't think there is a significant difference to battery health between the two options - particularly since this is an occasional use case and not a daily occurrence. I would personally lean towards a DCFC stop instead of charging to 100% since 2-3 times a month is on the high end of occasional.

 

[MoreTrout]

Every time I've attempted to time hitting 100% before leaving I've messed it up somehow. Usually still charging but really close, sometimes way under because my truck decided to phantom drain 10% overnight when I turned scheduled charging on.

Not too worried about getting all the way to 100%. Currently 85% gets me there comfortably, so anything close to 100% is good enough. And the DCFC option is there on the route. I have been lucky with the phantom drain. Usually 1% a day, rarely 2%. I haven't used scheduled charging. Wonder if that somehow triggers additional things to wake up vs just manually starting the charge and having everything else shut down.

Level 2 to 100% is totally fine for the occasional road trip.

DCFS is much much harder on the battery than that.

At 11.5kwh, I just set it to hit 100 and go to bed. Hasn’t failed me yet.

I don’t do scheduled Charging though because my PNW power is cheap all the time.

Thanks. My suspicion was also DCFC was probably worse. Right now I just have the ~7.5 kw option on NEMA 14-50s at both sites. Planning to get a portable 40A EVSE to bump a little. My personal issue is my 8kW solar array peaks at 6.8-7.3 kW during peak hours, so my preferred charging time is mid day and I psychologically hate charging at night knowing I'm paying for all of it, and not knowing the source. Plan to upgrade my solar in 6-12 months with some kind of backup option, either Enphase's next gen battery or the truck if and when that happens. Might also add another 2-4 kW to the array.

 

[pc500]

You'll want to L2 to 100%. Nobody wants to sit at a DCFC to 100%.

This aside, the occasional 100% won't matter. On a disposable EV (Leaf) I do it 100% of the time. Get 3-4 years, sell it, battery still at 100%, and I don't care.

For the Rivian it won't make much of a difference. It's like smoking, its cumulative. Not going to get cancer smoking once per month.

 

[MoreTrout]

You'll want to L2 to 100%. Nobody wants to sit at a DCFC to 100%.

This aside, the occasional 100% won't matter. On a disposable EV (Leaf) I do it 100% of the time. Get 3-4 years, sell it, battery still at 100%, and I don't care.

For the Rivian it won't make much of a difference. It's like smoking, its cumulative. Not going to get cancer smoking once per month.

Thanks. I never planned to charge to 100% at a DCFC. My option was to charge to 100% on lvl2 so I had plenty to make the trip, or to make a stop on the way at a DCFC to get back to 70 or 85%. The DCFC is about 75 miles from my camp, so I can stop on the way to make sure I have plenty to finish the trip.

Went up last week and the EA charger worked great and never charged my account. I came back yesterday and the screen on the charger said it was free, presumable because of the holiday. If I keep getting free charging it is going to become a regular stop. It's by the minute billing which ends up being significantly cheaper than per kWh. They have 2 350 kW stations and both have worked great for me the 3 times I have stopped there. Doesn't hold the 205 kW peak for long, but sustains about 175 pretty consistently to 70%. The Taco Bell across the street is a nice bonus, and so far my cheap meals there have cost me more than charging my truck!

 

[cardad]

Went up last week and the EA charger worked great and never charged my account. I came back yesterday and the screen on the charger said it was free, presumable because of the holiday. If I keep getting free charging it is going to become a regular stop. It's by the minute billing which ends up being significantly cheaper than per kWh. They have 2 350 kW stations and both have worked great for me the 3 times I have stopped there. Doesn't hold the 205 kW peak for long, but sustains about 175 pretty consistently to 70%. The Taco Bell across the street is a nice bonus, and so far my cheap meals there have cost me more than charging my truck!

It sounds like you don’t even need to be charging at home. DCFC charges optimally when the battery is warmed and the SOC is below 10%. You could make it to your DCFC with 50% (or less) SOC unless it’s cold. Test it a few times to optimize your charging stop and your battery will be fine. If Rivian didn’t engineer their charging system properly that’s just another lawsuit for them later down the road. Of course, if that charging station isn’t working then so it just depends on how much faith you have in that charger.

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