GMC HUMMER EV Forum | HummerChat.com banner
81 - 100 of 110 Posts

· Registered
GMC Sierra, Bolt, Sky, Mach E
Joined
·
901 Posts
One thing I was wondering after my last post was if the EA power electronics back in the EA cabinets that convert incoming 480 VAC to 800 VDC might have a thermal issue. The Hummer is about the only EV that would press them to their full 350 kW power output in real world charging conditions. Two of the three "breaks" didn't go down to zero kW. I would expect a temporary full shutdown would probably be required for actual pack "switching" (It did go to zero at the 15% SOC switch break). Instead, the charging power just throttled down to about 90 kW, which might indicate either an EA or Hummer thermal issue.
So I have been thinking more about these flat spots and am convinced the two sessions with the 85kw flat spots are due to the charger itself thermal limiting. The other two sessions seem to be the truck itself lowering the charge rate.

Also, there are variations in what current the EA chargers can output, that is one of the main reasons they have switched to a new design and are swapping out older units. I suspect the two sessions with lower peaks were done on chargers with less than 500A capability. Kyle previously charged a Hummer in Phoenix on an ABB unit with a 350A limit and got 240kw peak, when he started the charge.

It would be interesting to see a Rivian and Hummer charge on the same unit to see what happens, since they can both pull 500A. I do not know if anyone has set up an OBD scanner for the Hummer yet, to be able to get detailed data. It has been figured out for most of the other EVs.
 

· Registered
Joined
·
149 Posts
So I have been thinking more about these flat spots and am convinced the two sessions with the 85kw flat spots are due to the charger itself thermal limiting. The other two sessions seem to be the truck itself lowering the charge rate.

Also, there are variations in what current the EA chargers can output, that is one of the main reasons they have switched to a new design and are swapping out older units. I suspect the two sessions with lower peaks were done on chargers with less than 500A capability. Kyle previously charged a Hummer in Phoenix on an ABB unit with a 350A limit and got 240kw peak, when he started the charge.

It would be interesting to see a Rivian and Hummer charge on the same unit to see what happens, since they can both pull 500A. I do not know if anyone has set up an OBD scanner for the Hummer yet, to be able to get detailed data. It has been figured out for most of the other EVs.
Yes...I agree. We're probably looking a various combinations of Hummer pack-switching, charger cable or power electronics thermal limiting, and perhaps some EA charger pre-programmed amp derating. Tom mentioned he found the charging went "better" when he DIDN'T pre-condition. I wonder if those "better" session are the blue and yellow sessions that didn't go over 300 kW, but had only one dip and no 80-kW low flat spots? I think we've seen that anecdotally from other people's charge sessions where they perhaps didn't get pre-conditioned and the rate never quite got to the 300 kW level even at low SOC's.
 

· Registered
GMC Sierra, Bolt, Sky, Mach E
Joined
·
901 Posts
Question about charging!
At what state of charge should the hummer be in to draw the max amps?
And should the battery be conditioned before charging?
Anyone have an answer?
Based on the patent data posted in #18 on this thread, starting anywhere between 0 and 50% could result in max current initially. But that has not been verified yet.

Pre-conditioning is typically only needed in cold weather to warm the battery for charging. So I would say in winter months definitely pre-condition, spring and fall, maybe. In summer it would not be needed.
 

· Registered
Joined
·
152 Posts
Based on the patent data posted in #18 on this thread, starting anywhere between 0 and 50% could result in max current initially. But that has not been verified yet.

Pre-conditioning is typically only needed in cold weather to warm the battery for charging. So I would say in winter months definitely pre-condition, spring and fall, maybe. In summer it would not be needed.
Thanks, for the info, my electrician wants to come by and check the current draw to see if the wire he used needs to be changed. He used a 6-gauge wire with a 60amp breaker for a 60ft run from my panel to the charger. He says the cripple creek charger draws a max of 48amps and it should be okay...I feel 4-gauge would have been better...but I'm a printer not an electrician!
 

· Registered
Volt, Polestar 2, R1T, Livewire One
Joined
·
1,225 Posts
Thanks, for the info, my electrician wants to come by and check the current draw to see if the wire he used needs to be changed. He used a 6-gauge wire with a 60amp breaker for a 60ft run from my panel to the charger. He says the cripple creek charger draws a max of 48amps and it should be okay...I feel 4-gauge would have been better...but I'm a printer not an electrician!
Hummer should be able to pull 48A literally anywhere in the charge curve. Even at 99.5% it should still max out an L2 charger.
 

· Registered
GMC Sierra, Bolt, Sky, Mach E
Joined
·
901 Posts
That’s why he figured 6 wire would be fine!
We just checked it with the battery at 62% I had it on the charger for 1 hour and it was pulling a steady 26 amps the whole time!
Will that change when it is down to 20% SOC?
Your charger is not working right if it is only outputting 26A. It should provide 48A all the way until near the end of charging. I have not seen a manual for this charger, but maybe it has some setting in it to adjust the maximum current? The reduction in current based on SoC is only applicable to DC fast charging, not for L2 charging.

I have two ChargePoint Home Flex units that are plugged in to 50A beakers and I set the current limit to 40A when I installed them. Do you have a manual for the Clipper Creek to see if it has settings?
 

· Registered
Joined
·
152 Posts
Your charger is not working right if it is only outputting 26A. It should provide 48A all the way until near the end of charging. I have not seen a manual for this charger, but maybe it has some setting in it to adjust the maximum current? The reduction in current based on SoC is only applicable to DC fast charging, not for L2 charging.

I have two ChargePoint Home Flex units that are plugged in to 50A beakers and I set the current limit to 40A when I installed them. Do you have a manual for the Clipper Creek to see if it has settings?
Thanks for the info. When I get back home tonight, I will look into that!
 

· Registered
Joined
·
307 Posts
I spoke with Cripple Creek tech service today!
He said the charger doesent control the amp draw it’s basically a on off switch. it will give whatever the vehicle draws, up to 48 amps (HCS60) so at 65% SOC why does it only draw 26 amps?
And what’s the difference between a DC charger and a level 2 charger like the Cripple Creek?
 

· Registered
Joined
·
468 Posts
I spoke with Cripple Creek tech service today!
He said the charger doesent control the amp draw it’s basically a on off switch. it will give whatever the vehicle draws, up to 48 amps (HCS60) so at 65% SOC why does it only draw 26 amps?
And what’s the difference between a DC charger and a level 2 charger like the Cripple Creek?
If it's now drawing max then check your breaker/wiring etc. As seems more like you support 30 amps?

DC chargers feed direct current straight into the battery. Your home uses AC (alternating) so your truck's on-board charger has to convert it for storage to DC into battery ultimately.
 

· Registered
GMC Sierra, Bolt, Sky, Mach E
Joined
·
901 Posts
I spoke with Cripple Creek tech service today!
He said the charger doesent control the amp draw it’s basically a on off switch. it will give whatever the vehicle draws, up to 48 amps (HCS60) so at 65% SOC why does it only draw 26 amps?
And what’s the difference between a DC charger and a level 2 charger like the Cripple Creek?
How are you determining the 26 amp output? Is the truck displaying the kw provided while charging (my Bolt does that)? The charger has no knowledge of the circuit breaker size, so if that were wrong the breaker would trip.

Maybe the charger is wired incorrectly with one leg to neutral, and in that case you are running at 120V and the truck would limit the current to 12A. I would have the electrician come out and check the voltages in the charger, unless you have a meter to be able to do that yourself. In a normal 240 circuit, there are 4 wires, but the charger only uses 3 of them, the two hot wires (240V) and ground. If you put a voltmeter between the unused neutral and either hot wire, you have 120V.

I am suggesting this because on other forums, some people have found this incorrect wiring in the EVSE.
 

· Registered
Joined
·
152 Posts
Measuring 26 amps with an amp probe, both at the main panel and at the charger. And yes, the voltage is 120 at both hot leads when measured to neutral.
The electrician is coming by next week, I will have him double check everything.
So, the bottom line is, there is no adjustment in the Hummer to choose Rate of Charge other than Level 1 (120V) and Level 2 (240V) and the State of Charge doesn't affect the Amperage Draw!
That being said, the issue must be with the Charger or the wiring, Yes??
 
81 - 100 of 110 Posts
Top