Nominal Discharge Current of HV Batt in Park & Off

Welcome, Chan.
Good idea on looking at Torque or some such app for the current draw if you're curious.

Ready and park. Among other things, it's running the coolant pump & 12v trickle charge you mentioned, plus several ECU computers, the battery cooling fan at probably its lowest speed, dashboad lights, a boatload of sensors that may or may not draw current, and probably other stuff I can't think of right now.

Off. There is zero load on the HV battery as the main safety relay disconnects it from the car.

 

Perhaps someone with nothing else to do will come along a see if their's is the same as yours. I'm just not curious enough about it to warrant a special investigation and have a very busy life, especially right now. If I happen to connect to the car for some significant reason, I'll look at that. I remember looking at it before with the PiP I had and seem to remember a current draw similar to what you see in the Prime.

On the other had, there are lots of people who really love to do this stuff and, hopefully, one will have your info before long.

 

Without making a special trip to look at it right now, what you're seeing seems about in line with what I've seen in my Gen 3.

 

Hi Chan

I have been recording data on my Prius for a few months and was also very fascinated by the Prius electronic parameters. I also Idle at 1 or 2 amps. Here is a recent example dataset I collected with a BAFX dongle and Torque in which I idle for about 30 seconds at 0mph at the beginning of the run, pulling about 1.7 amps. (Note this is was testing EV mode, I was toodling around the block, so there is no ICE activity) Link: Priscope (also note the page is a bit slow to load) Now, my batteries were at about 16.5 volts at this time, so my total volts was about 231volts, so 231 x 1.7 is about 390 watts - assuming that the OBDII data is measuring what I think it is measuring. Here's another dataset, a chilly morning where at 0mph I was pulling about 3-4 amps, probably with my cabin heater on and possibly my headlights ( link: Priscope ). I also posted a few picture files on this post, you can click to see them zoomed in but the pics don't allow as much info as the webpage chart.



I was comparing it in my mind to back when I used to build desktop personal computers from components like motherboard, hard drive, and power supply. It was normal for a PC to pull a few hundred watts and require a matching power supply. I was wondering how things are nowdays so I found this calculator:

Power Supply Calculator – PSU Wattage Calculator | Newegg

It is interesting, a pretty average desktop PC configuration will still, even these days, pull about 300 watts.

So I figure my Prius is running several computers, and although I have no direct measurement evidence, I still figured it sounded reasonable to pull a few hundred watts of power at idle. In fact I just found this old PriusChat thread where people discuss how many computers the Prius has:

Prius Computers (ECU's) | PriusChat

(HV ECU High Voltage ECU, ECM Engine Module, Transmission ECU, Skid Control ECU, ECB ECU, EPS ECU, Battery ECU, Power Source Control ECU, Air Conditioning ECU, Meter ECU, Body ECU, Transponder ECU, Smart ECU, Navigation ECU, Gateway ECU)

Then on top of that there is the Vacuum Fluorescent Display in the combination meter (the speedometer), and fluorescent backlight and LCD in the Multi Function Display. Both of these displays require quite a bit of power.

And the things that others mentioned - brake pressure, 12v charging, etc. Not to mention alot of this is going through a DC-DC converter to drop the 200+volts down to about 12volts, which has efficiency losses which I assume will be expressed as increased temperature in the Inverter coolant fluid. ( Weber Auto has some great youtube videos showing the converter / inverter situation )

However. I am not sure how to measure exactly which components are using how much energy! That is a very interesting question.