CHAdeMO adapter with ChargePoint 50kW DC charger - only getting 18kW once battery is like half full

[notsure11]

I have a 2018 M3 LR. I've been using a ChargePoint DC 50kW charger (it looks like this) with a CHAdeMO adapter. When the car battery is below 50% or so, I get 46~47kW. But then once the car battery is over 50% or so, it only charges at 18 kW (and even slower once it gets closer to full). Is this normal?

For example, this morning, I had ~40%, and it started charging at 46~47kW. Initial estimate to charge limit (90%) was only 45 minutes. But 10~15 minutes later, it's slowed down to 18kW and Tesla app shows 1 hour and 20 minutes remaining.

I've also had charging abruptly stop with a message on the car screen saying communication error, so CHAdeMO adapter hasn't been all that reliable for me.

Thank you.

 

[GtiMart]

Is it "when the battery's over 50%" or is it "after 10-15 minutes of charging"? Maybe something gets warm between the cable or the adapter and throttling happens. Have you tried arriving there at say 60% SOC and plugging in to see of you get the 46-47kW then?

 

[Rocky_H]

Yeah, I'm going to concur. That's below the normal battery charge tapering curve. Something is throttling the speed for some reason--probably heat. That may be in the charge port, or maybe even in the CHAdeMO station itself. A lot of the early CHAdeMO stations were built expecting short charging sessions like the LEAF and other small batteries would have. Many of these stations didn't have enough cooling for long charging sessions, so when Teslas with triple the battery size started using them, they would overheat and handle that in various ways.

I agree with @GtiMart 's suggestion, that you can isolate that variable by starting your charging session over 50% and see if it starts off fast or slow. That would tell you if it's because of heat build up over time or not.

 

[davewill]

You should also try a different brand of CHAdeMO station. It could be some sort of software incompatibility between that station and the adapter. I know there have been firmware updates on the CHAdeMO adapter, but there's no easy way to update it.

 

[cwerdna]

Yep. OP, are you willing to post the location of the CHAdeMO charger so we can take a look on Plugshare?

 

[notsure11]

It’s at work for employees, so it doesn’t show up on PlugShare (or ChargePoint app unless you are connected to the company).

 

[RayK]

It's been several years since I've used the ChargePoint station as described in OP's post. I had them at work and when I used them with my own CHAdeMO adapter, I don't recall having any problems with them tapering off that much. It would start at 40ish kW and lower to about 25-30 after about 80% was reached. Similar performance today when using the ChargePoint station near me (different model - photo from Google):

The only time I've received less than 20kW is when there's been a problem with the station. I had confirmed this by switching to the adjacent station and getting "full" power.

edit: As to the lower power.... it would start out at around 20kW and never increase.

 

[notsure11]

Today I plugged in when the car had 59% battery. It started charging at around 47kW but over the next several minutes it gradually went down to 38kW. And then suddenly the car screen displayed “Charging adapter fault, Unplug and retry”. And immediately after that the charging slowed down to 18kW.

I unplugged it and tried again, and now it’s charging at 34kW at 69%. It has only been a few minutes, but it looks to be going lower as it charges. Now 33kW at 70%.

 

[RayK]

To me that sounds like a thermal problem with the adapter. Is there only one ChargePoint CHAdeMO station at your work? If so, I'd try to find another station and see if that makes a difference. Alternately, it might help to ask around your workplace and see if other people who use a Tesla CHAdeMO adapter are having the same problem. Or for that matter, any Nissan LEAF owners who use the CHAdeMO handle by itself. You could also try to convince another Tesla owner to try charging their car with your adapter and see what happens.

You can use Plugshare to see if there's another CHAdeMO station around your area; just set the filters to only report on those handles. Electrify America seems to have several in SF, as well as EVgo. You may have to sign up for an account. Both have pay-as-you-go plans which charge about what Tesla peak pricing does.

I assume that you have tried Supercharging your car and it works as expected. That would say that any issue is not in your car.