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Re: DCQC charging rates

Posted: Tue Apr 23, 2019 6:50 pm
by GetOffYourGas
Interesting. Was your battery cold? That unit *should* be able to push at least 100A IIRC.

Re: DCQC charging rates

Posted: Sat May 04, 2019 6:05 pm
by JeffN
NeilBlanchard wrote:I used an EVgo unit (eastbound on Mass Pike, near Exit 13) and only got around 22kW, which is pretty disappointing.


Very likely due to a cold battery. And remember, the battery temperature changes slowly so it might be 45F outside when you charge but the pack itself may be colder from spending the night at 30F or whatever.

In any case, if you look at the graph in my article about cold weather charging you will see that the Bolt can be limited to only around 60A at 8-10C or 45-50F which implies around 22 kW.

https://electricrevs.com/2018/10/23/fri ... -coupling/

Re: DCQC charging rates

Posted: Tue May 14, 2019 8:35 pm
by NeilBlanchard
JeffN wrote:
NeilBlanchard wrote:I used an EVgo unit (eastbound on Mass Pike, near Exit 13) and only got around 22kW, which is pretty disappointing.


Very likely due to a cold battery. And remember, the battery temperature changes slowly so it might be 45F outside when you charge but the pack itself may be colder from spending the night at 30F or whatever.

In any case, if you look at the graph in my article about cold weather charging you will see that the Bolt can be limited to only around 60A at 8-10C or 45-50F which implies around 22 kW.

https://electricrevs.com/2018/10/23/fri ... -coupling/


I had driven it about 15 miles, so that doesn't seem likely. I think the EVgo unit in question was less than 50kW.

Re: DCQC charging rates

Posted: Wed May 15, 2019 1:03 pm
by JeffN
NeilBlanchard wrote:
JeffN wrote:
NeilBlanchard wrote:I used an EVgo unit (eastbound on Mass Pike, near Exit 13) and only got around 22kW, which is pretty disappointing.


Very likely due to a cold battery. And remember, the battery temperature changes slowly so it might be 45F outside when you charge but the pack itself may be colder from spending the night at 30F or whatever.

In any case, if you look at the graph in my article about cold weather charging you will see that the Bolt can be limited to only around 60A at 8-10C or 45-50F which implies around 22 kW.

https://electricrevs.com/2018/10/23/fri ... -coupling/


I had driven it about 15 miles, so that doesn't seem likely. I think the EVgo unit in question was less than 50kW.

Driving for only 15 minutes will have very little effect on the battery pack temperature, as noted in the article. You would have to drive at faster highway speeds like 70-75 mph (20+ kW output) for over an hour to really have much useful battery warming. It would help if the Bolt was able to share heat from the motor and and motor inverter into the battery like Tesla and the new Kia/Hyundai car’s can but the Bolt is unable to do that.

The Bolt also doesn’t have any “Winter Mode” to enable the driver to tell the battery heater to turn on before you arrive at a charging station. Tesla recently added that and the Kia/Hyundai models with a dedicated battery heater have a such a mode. There is a link to that in the article.

The only way to know your pack temperature for sure is to get an OBD II reader and the Bolt PID configuration file for your OBD reader app.

Re: DCQC charging rates

Posted: Wed May 22, 2019 5:40 pm
by NeilBlanchard
I said about 15 miles, not 15 minutes. That included a brief stint on the Mass Pike. I have been driving EVs for about 5 years, and over 50K miles. The battery pack wasn't too cold to take 50kW. The problem is the wimpy EVgo unit.

Re: DCQC charging rates

Posted: Thu May 23, 2019 10:42 pm
by JeffN
NeilBlanchard wrote:I said about 15 miles, not 15 minutes. That included a brief stint on the Mass Pike. I have been driving EVs for about 5 years, and over 50K miles. The battery pack wasn't too cold to take 50kW. The problem is the wimpy EVgo unit.

Oops, sorry about misreading that.

But, that implies that your 15 miles of driving was at slower city rates which wouldn’t necessarily warm the battery faster than 15 minutes of highway driving.

So, yes, I still think it is quite likely a cold battery issue. I know you’ve been around the block a few times (okay, a lot of times...) as an EV driver but the Bolt has a nearly 1,000 pound battery. It takes a lot to warm it up and what you are describing, whether 15 minutes or 15 miles, just isn’t going to make a lot of difference to a cold pack.

Ultimately, we’re both guessing. The way to know for sure is with an OBD reader.