Yea, don't know what the OP is trying to ask for or do - but I know 0.6A is way too low. In Ready mode, the DC-DC converter is active and supplying power to all the cars' systems. If you want to find the total current draw, you'll need to clamp an inductive amp meter onto the main trunk cable of the DC-DC converter. If you clamp onto a branch circuit, your only going to get whatever current is flowing across that particular branch circuit. ie. clamping onto the Aux. battery cable, there could easily be 10A+ or more there, if the battery is receiving a charge. If you clamp onto your cigarette lighter power cable and nothing is connected to it - current draw is zero. Does that mean that there's no current flow in the car in ready mode? Hope this helps..... @frederw1701 Please rephrase or be more specific about what your trying to ask or do.
The OP's profile says 2018 Prime. I don't get why no body gets what the OP asked for. Other posters - good luck measuring the 12 volt system draw while it's charging in ready mode. sheesh 0.6 amps is to low? for what?
Some posters seem to be stuck on whether the current is measured in the HV or 12-volt system, while the OP only asked about baseline power draw and didn't specify which system. It's fine not to specify which system, because under the stated conditions (READY, stationary, accessories off), all of the power being drawn is coming from the HV battery anyway (assuming also the engine is stopped). and a Dr Prius reading of current from the battery is a perfectly adequate way to measure it. In those stated conditions, the power being drawn from the HV battery is pretty much all going to the DC/DC converter and coming out as 12 volts to power the car's various electronics. If the heat pump / air conditioner were in use, some would be going there too, but the OP stipulated accessories off. 0.4 to 0.6 amps from the 352-volt Prime traction battery = 140 to 212 watts = 11 to 18 amps at 12 volts. As the OP asked for 'power' and not 'current', just answering in watts would have done the trick, without getting into the weeds of how many amps at how many volts.
That answer is more in the realm of possibility; since power-off battery draw is around 50mA-250mA@12VDC - depending on manufacturers specifications. That can be measured by clamping the meter between the traction battery and DC-DC converter power cable. Again, Placing the meter clamp on a branch circuit will only yield the current going across that branch circuit. Hope this helps....
There is a PID that Dr Prius can simply show you, which is the current in/out of the traction battery, measured by the Hall sensor that's inside the battery case. Under the OP's stated conditions, that's really all you need. It shows you the current coming out of the traction battery, and under the stated conditions, essentially all of it is going to the DC/DC converter.
Yes, that's why I was very specific in my write-up. OP also asked how to safely measure it. Which I provided
I'm not sure there's any practical way to clamp a probe just at the DC/DC converter input. Unless something's different in the Prime, there's just one cable connecting the battery to the whole inverter/converter assembly. By taking the cover off, you may see a bent bus bar distributing the battery voltage to the boost converter, A/C power, and DC/DC converter, but I'd be surprised if there's enough clearance to clamp a probe ahead of just the DC/DC converter. And working under the inverter cover with power on isn't the safest. But as long as the car isn't using any propulsion power or A/C / heat pump, then the current into the DC/DC converter just is the current out of the traction battery, which you can read from the car without opening any covers.
