We own EVs. Ask Us Anything.

[J Alynn]

I’ll answer in several comments.

One general rule is that the cost to run the inverter, onboard charger (for AC—L1 and L2—charging), and other electronics is essentially constant. Lower current through those usually means longer run-time, which means that constant power draw by the electronics leads to lower efficiency.
Example:
Using an L1 EVSE vs a low-amperage L2 EVSE vs a mid-amperage L2 EVSE vs a max-amperage L2 EVSE. Assume the onboard charger (AC to DC converter) requires 200 watts. This will be different for different brands, etc.; this is just illustrative.

• L1 = 1.4 kW draw from the wall. 200 watts goes to the onboard charger, 50 watts goes to the EVSE. That means, discounting any heat generated, only 1.15 kW goes to the battery. So you get an 82% efficiency.
• L2 @ 15 A = 3.6 kW draw from the wall. 200 Watts to onboard charger, 50 Watts to EVSE, ignore heat generated. 93% efficiency
• L2 @ 25 A = 6 kW: 96% efficiency
• L2 @ 48 A = 11.5 kW: 98% efficiency
• L2 @ 80A = 19.2 kW: 99% efficiency
• L2 @ 80A = 19.2 kW: 97% efficiency

There are other losses, so these numbers are inaccurate as you go to higher currents, mostly because of joule heating. So you won’t see much better energy efficiency above about 48 A. And this isn’t the efficiency of the entire system, just that one component. You’re going to see around 95-97% efficiency maximum.

@cyu

I won’t pretend to understand all of this but I like to read it anyway and look some stuff up…

I did date a Jules in college and she was hot, but I don’t think that counts here…

I was thinking of a family jewels joke but realized that would be inappropriate. Same boat but I always appreciate Space educating us.
I’m thinking @cyure is probably just mumbling math, math, math…..

 

[cyure]

@cyu
I was thinking of a family jewels joke but realized that would be inappropriate. Same boat but I always appreciate Space educating us.
I’m thinking @cyure is probably just mumbling math, math, math…..

MATH!

 

[strider]

For all of the normies on here, don't worry about it. This matters WAY less in an EV than in an ICE. Why? No transmission. In an ICE, the engine is going from zero efficiency (at idle) to max efficiency (at some rpm less than redline) to less than max efficiency (rpms above that max efficiency value) over and over again, every time you change gears. EVs don't have that variability built into every acceleration and deceleration event. Punching it will eat up tires of course, but there is no appreciable loss of range (though you or your passengers may lose their lunch). So while geeking out on a message board while we wait for our Scouts can be fun, once you get your Scout, just drive it