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Discussion Starter · #1 ·
I finally got the battery down enough to go DC charge today, 80 degrees outside, battery prep for charging 30 minutes before, started at 22% SOC 238 kW, ramped up to 260 kW at 59% SOC, and at 60% started ramping down, all the way down to 100 kW at 64%, so I unplugged. Charger dispensed 98.9 kWh in 25.5 minutes.

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Volt, Polestar 2, R1T, Livewire One
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Did you hit the info screen and precondition? Curious what your amp rate was.

My local EVGo would hit 495A on the Rivian. I regret charging my livewire there since it's a per-minute rate instead of energy consumed. Ended up costing like $1.12/kWh
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That charge rate looks like the same rate that Kyle Conner got on an ABB charger in Phoenix that was limited to 350A. But on PlugShare that appears to be a Signet unit with 500A rating.

That EVGO charger does not look like the same model that EA uses. My Mach E can charge faster on a Signet 150kw charger than it can on an ABB 350kw charger, because it can take 450A.
 

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Discussion Starter · #6 ·
Probably a 350 A limited charger. The pack volts @ 22% SOC would be about 670 VDC. 238 kW would be 350 A. A 500 A charger would be close to 340 kW at this SOC. This pack can easily suck up 500 A in optimal conditions.
So I need to find a better charger? It takes forever to run that battery down around town, I am convinced normal driving mixed city highway the HummerEV has way more than 329 mile range, but over 60 MPH, she gets thirsty.
 

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Discussion Starter · #7 ·
That charge rate looks like the same rate that Kyle Conner got on an ABB charger in Phoenix that was limited to 350A. But on PlugShare that appears to be a Signet unit with 500A rating.

That EVGO charger does not look like the same model that EA uses. My Mach E can charge faster on a Signet 150kw charger than it can on an ABB 350kw charger, because it can take 450A.
It was rolling great until 60%, then the charging curve craps out.
 

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Discussion Starter · #8 ·
Did you hit the info screen and precondition? Curious what your amp rate was.

My local EVGo would hit 495A on the Rivian. I regret charging my livewire there since it's a per-minute rate instead of energy consumed. Ended up costing like $1.12/kWh
View attachment 2490
I did not hit the button, I was busy talking to a car reviewer from Driving Sports TV, he was there charging a vehicle he was reviewing. but I got a better deal on the charge then you did, actually, I got better price then charging at home, check this out...

Thank you for using the charging station at Whole Foods Bellevue (BLV) - 888 116th Ave NE, Bellevue, WA. Your charge session has ended. The total duration of this session was 00:25:55 and the energy charged was 98.419 kWh. Your total cost for the session was $7.25.

There are 3 other GM funded EV-Go stations around here that have the Signet 350 kW, I will try a different one next time and hit the button to get the data.
 

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Just curious @Tom E-Tron, have you been charging back up at home each night, or you just went for several days until you could get the battery SOC down low enough to DC charge? I am just trying to learn what is best, and I thought that those of you who already own EVs said that it's best to plug in each night.
 

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I would think, plugging it in every night would always keep it at 100%?
Is that not the case??
Two of my friends have Tesla’s and they plug them in every night when they get home from work. They say they are fully charged every morning when the leave for work.
Sounds like a good idea???
 

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I would think, plugging it in every night would always keep it at 100%?
Is that not the case??
Two of my friends have Tesla’s and they plug them in every night when they get home from work. They say they are fully charged every morning when the leave for work.
Sounds like a good idea???
Yes, it’s best practice to plug in every night so that the car is charged to the recommended percentage (90% for Tesla, 80% for the Hummer I believe) in the morning. Tom intentionally ran his down so he could supercharge and get a sense for how fast it charges and other data.
 

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Discussion Starter · #13 ·
I would think, plugging it in every night would always keep it at 100%?
Is that not the case??
Two of my friends have Tesla’s and they plug them in every night when they get home from work. They say they are fully charged every morning when the leave for work.
Sounds like a good idea???
We do not charge our EV's every day, but usually 50-90% when we do. We do not long cycle them, but go a couple days between charges.

@Msv5010 Yes, I wanted to get an idea of the HummerEV's DC charging curve for road trip planning, it seems the Hummer charges well to 60%, so my plan on a road trip would be to stop every 150 miles and charge from ~10-60% to make the best time. Basically a 20 minute stop every 2 hours, would be less if you can find 500 amp chargers. There is no reason to stay at the charger once the charge rate drops below 125kW, move on.
 

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We do not charge our EV's every day, but usually 50-90% when we do. We do not long cycle them, but go a couple days between charges.

@Msv5010 Yes, I wanted to get an idea of the HummerEV's DC charging curve for road trip planning, it seems the Hummer charges well to 60%, so my plan on a road trip would be to stop every 150 miles and charge from ~10-60% to make the best time. Basically a 20 minute stop every 2 hours, would be less if you can find 500 amp chargers. There is no reason to stay at the charger once the charge rate drops below 125kW, move on.
Yup, thanks for doing that and sharing your findings. I suspect I will have to use DC chargers more often with the Hummer and I was a bit concerned with the charging curve. Shouldn’t be a big issue though if it can charge to 60% fairly quickly seeing as I’m not expecting to go more than 150-200 miles in it on a regular basis.

That said, I’m waiting on the SUV and max range is still a mystery.
 

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Discussion Starter · #17 ·
Ultium is supposed to be more tolerant of high charge levels. You won't see enough degradation over the life of the vehicle to get it out of a warranty-able capacity. I'd still not regularly charge to 100% though.
Ya, Andy Oury said charge the Hummer however you want. Ultium batteries are designed to be durable, robust, and tolerant, and also cheap to manufacture. That being said, I like to take care of things and know charging to 80 percent daily is better for the overall life. I would only charge to 100% if heading out on a road trip.
 

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Ya, Andy Oury said charge the Hummer however you want. Ultium batteries are designed to be durable, robust, and tolerant, and also cheap to manufacture. That being said, I like to take care of things and know charging to 80 percent daily is better for the overall life. I would only charge to 100% if heading out on a road trip.
There's still quite a bit of regen headspace at 100%. Not like the Bolt EV at all. I was surprised that I'd still be able to come to a stop at modest speeds.
 

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There's still quite a bit of regen headspace at 100%. Not like the Bolt EV at all. I was surprised that I'd still be able to come to a stop at modest speeds.
The regen on the Mach E still works fine at 100%. I have noticed that with the new Bolt battery, if I charge to 100%, the regen is still pretty good. With the old battery it was essentially gone at the top. I think GM has left a bit more room in the new battery, it is rated at 64kwh, rather than 66kwh like they were claiming in 2020.
 

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GM has a patent for their Ultium BMS software system that continuously monitors charging, thermal, battery peak kW discharge, etc and recalculates expected battery life on the fly to adjust the boundaries it allows for battery “ abuse” to ensure it meets warrantied life. Your battery nannie is watching over you, whether you want it or not:) I‘ll post a link when I get back to my computer.
 
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