[HelloHummerev]

I only use DC fast charging with Electrify America.

(Starting to charge with about 10%-20% battery)

The last 10 times or so I have charged my truck it jumps to about 170KW within 10 seconds and about a minute later starts bouncing between 50KW-120KW very erratically, jumping up and down all over the place, instantly and after about 5-10 minutes of that goes back to 170KW for about 20 minutes and than once it hits 75 percent goes down to about 50KW but remains very steady.

I have gone to a few different EA chargers that are all 150KW. No 350 in my area. They all peg around 170-180KW on the 150 ones.

The jumping of the charge does not seem normal or is this the new normal?

 

[azbill]

This is most likely the "pack switching" that needs to occur to keep the two pack halves running the HVAC balanced during charging. The Hummer battery normally runs at 400V, and that is the voltage used by the HVAC system to cool the battery. During charging, the Hummer puts the battery into 800V mode by placing two halves of the battery in series, instead of parallel. One half at a time runs the HVAC and the two halves can get out of balance because of that, so it will switch which half is driving the HVAC after some time period. During the switching it has to drop the power level temporarily. It is also likely that at 75% it actually switches back to 400V charging.

Check out this video:

 

[Dark-Fx]

Are you navigating to the charger or forcing the truck to pre-condition before charging?

 

[HelloHummerev]

When the battery is really low there is no way to pre-condition. I have tried pre-conditioning the battery before as well and still this is a new thing it is doing.

Prior to this voltage bouncing all around - it never did this. Always stayed steady for me.

 

[HelloHummerev]

I watch the video as well, mine is bouncing from 50-120 2 or 3 times per second. The numbers are all over the place.

 

[Shaved Ice]

Mine recently started this at EA charging stations as well, albeit I haven’t fast-charged at other brands in recent memory. It doesn’t effect charging times so I’m not concerned.

 

[Nebula1701]

Someone caught a Silverado charging:

I think EA just has issues with the Hummer or GM's double stacked pack in general.

 

[azbill]

Is this cycling on the charger screen, or is it also in the truck? I know the truck displays miles/hour rather than kw, but is that display also showing this behavior?

 

[Tom E-Tron]

Is this cycling on the charger screen, or is it also in the truck? I know the truck displays miles/hour rather than kw, but is that display also showing this behavior?

Truck instrumentation might be too slow to show this, but that video is weird, I have not seen an EV charge like that before.

 

[HelloHummerev]

Truck instrumentation might be too slow to show this, but that video is weird, I have not seen an EV charge like that before.

That video is exactly what my truck has been doing on the screen inside the truck and the screen on the EA charging station. I dont really care, my truck charges just fine. One of these days I will get a house so I can charge it where I live, but I have been charging my truck using EA about once a week.

 

[HelloHummerev]

I feel like its some software thing going on at EA stations. But who knows.

 

[Tom E-Tron]

I feel like its some software thing going on at EA stations. But who knows.

Seems its an EA/GM thing if even prototypes are doing that....

 

[Dark-Fx]

Definitely never saw anything like that in my truck before. It could be the bug where the EA station is delivering more than requested current and the vehicle is telling the station to back off significantly, and it ends up flapping instead of faulting out like some other vehicles are?

 

[HelloHummerev]

Its just weird, because I have probably charged at EA at least 20-25 times where this never happened. Here in massachusetts they charge by the minute, so it is an absolute steal to charge one of these beasts. There is some funny law that you cant charge by the KW. My average is usually $10 to get to 80% and I leave. Best deal around. If you stay past 80% its no longer a deal. You can spend $20 to get to 95-100%.

 

[Nebula1701]

Sounds like a new EA bug they have to work out if it just started...

 

[HelloHummerev]

Last 2 months or less I noticed it.

 

[Littleshopofguitars]

Yea, but erratically changing voltage can’t be good for the battery…

 

[azbill]

Sounds like a new EA bug they have to work out if it just started...

I have seen reports of two things happening at EA stations and causing issues with all vehicles:

1) Providing higher power than requested
2) Having too much ripple on the DC output

There were some reports by Rivian owners that #2 was causing charging to fail, and this erratic behavior seems related to this. Also, very recently EA stations caused damage to three different vehicles: Bolt, Lightning and a Rivian. The Bolt ended up being totaled by the insurance company. Here is one of the reports:

Ford F-150 Lightning Reportedly Bricks After "Loud Pop" at Electrify America Station

The driver says the Ford F-150 Lightning was totally unresponsive after that noise.

www.motortrend.com

 

[Nebula1701]

@HelloHummerev Take a video and share it with @RateYourCharge on twitter show what EA issue you are having. Also to rule out it being the Hummer find a EVGO station.

 

[azbill]

Someone caught a Silverado charging:

I think EA just has issues with the Hummer or GM's double stacked pack in general.

Looks like an engineer had a laptop recording the session in the truck, so hopefully they can identify what is going on.