DJG
Well-Known Member
- Thread starter
- #1
I've noticed something interesting when charging at home that I'm curious if others have picked up on. The long story short, I think the true charging efficiency at the full 48amps is only about 78% (i.e. there are 22% charging losses). However, the kicker is that that's the maximum efficiency from a percentage basis, because it's a fixed loss from running cooling/fans. I did a slow charge at only 8amps from the vehicle settings, and I think that only had about a 25% efficiency, or 75% losses.
Here's the detail. I'm running the CP Home Flex (not really Flex anymore, but I'll end with that) on a 60a circuit. When running at the full 48a, the CP app shows that it is sending just over 11kw to the vehicle (not quite the 11.5kw is theoretically should be with 48a x 240v). The Rivian app actually shows it charging at 11kw, though that's a rounded number and perhaps it's actually something like 10.5kw. Nevertheless, that's not important for this purpose, as I'm comparing to what the CP app reports as the power being delivered to the port.
However, when I look at the actual charging stats, including total kw delivered (verified by change in SoC), the punch line is that it is only charging at a total net rate of about 8.5kw. When I ran it at 8a, about 2kw was the starting point, but from a time to charge standpoint it was less than 1kw, which is essentially L1 outlet speed.
So, I think what's happening is that there are normal/expected charging losses (from previous vehicles on my same system I'd say those could be anywhere from 5-10%, my eTron reported a charge rate of about 10.2kw which may even be less efficient than the Rivian if you stop there). However, the R1T runs the fans (possibly compressor at times too) far more/longer than the Audi ever did. So, I think what's happening is that there is an additional 1.5-2.0kw that is lost through this cooling, so that from a charging time perspective, you are only getting 8.5kw as the max charging rate.
I'm curious to hear others thoughts on if they concur or if there is something up with my personal experience.
P.S. I just found out when trying to go into the CP app to change the amp setting for the charger, that CP removed that feature from the Flex (which is where it got it's name from) due to what they called a "safety" issue. It makes zero sense because the max is set by the circuit at install, and the only flexibility that exists is to lower it to something less than maximum. In any case, you can call CP and they can change the setting for you, but you no longer can do that via the app. It's less of an issue with the Rivian since you can adjust in vehicle, but that reverts back to 48 every time, whereas in CP it would stay at whatever you set it at.
Here's the detail. I'm running the CP Home Flex (not really Flex anymore, but I'll end with that) on a 60a circuit. When running at the full 48a, the CP app shows that it is sending just over 11kw to the vehicle (not quite the 11.5kw is theoretically should be with 48a x 240v). The Rivian app actually shows it charging at 11kw, though that's a rounded number and perhaps it's actually something like 10.5kw. Nevertheless, that's not important for this purpose, as I'm comparing to what the CP app reports as the power being delivered to the port.
However, when I look at the actual charging stats, including total kw delivered (verified by change in SoC), the punch line is that it is only charging at a total net rate of about 8.5kw. When I ran it at 8a, about 2kw was the starting point, but from a time to charge standpoint it was less than 1kw, which is essentially L1 outlet speed.
So, I think what's happening is that there are normal/expected charging losses (from previous vehicles on my same system I'd say those could be anywhere from 5-10%, my eTron reported a charge rate of about 10.2kw which may even be less efficient than the Rivian if you stop there). However, the R1T runs the fans (possibly compressor at times too) far more/longer than the Audi ever did. So, I think what's happening is that there is an additional 1.5-2.0kw that is lost through this cooling, so that from a charging time perspective, you are only getting 8.5kw as the max charging rate.
I'm curious to hear others thoughts on if they concur or if there is something up with my personal experience.
P.S. I just found out when trying to go into the CP app to change the amp setting for the charger, that CP removed that feature from the Flex (which is where it got it's name from) due to what they called a "safety" issue. It makes zero sense because the max is set by the circuit at install, and the only flexibility that exists is to lower it to something less than maximum. In any case, you can call CP and they can change the setting for you, but you no longer can do that via the app. It's less of an issue with the Rivian since you can adjust in vehicle, but that reverts back to 48 every time, whereas in CP it would stay at whatever you set it at.
Sponsored
