I'd like to get a better understanding of the relationship between the ICE and the batteries. Are these statements true? 1. The 12v battery is only charged by the HV battery. 2. The 12v battery is never charged by the ICE 3. The HV battery is only charged by the ICE (and regenerative braking) 4. Assuming the car is in READY mode and PARK, the 12 volt battery should never loose its charge (assuming the ICE can self-start -- i.e. gas in the tank). 5. Likewise, assuming the car is in READY mode and PARK, the HV battery will always be kept charged. 6. The A/C runs solely off the HV battery. 7. The various electrical accessories (e.g. USB port, 12v cigarette) run solely off the 12v battery. I did a search and read a bunch of threads to lead me to these conclusions, but wanted to make sure I was understanding this correctly. Finally -- extra credit -- assuming that the Prius is going to be used for overnight camping (i.e. sleep in the vehicle) are there any other things to consider from an electrical perspective (not exhaust perspective, whether camping is a good idea, etc.) Thanks!!
1. The 12v battery is only charged by the HV battery. The 12 volt battery is only charged by the inverter. The inverter may be getting power from the HV Battery or the Motor/Generators. 2. The 12v battery is never charged by the ICE True 3. The HV battery is only charged by the ICE (and regenerative braking) True, via the M/Gs. (in the PHEV, line current also charges the HV Battery, but lets ignore that) 4. Assuming the car is in READY mode and PARK, the 12 volt battery should never loose its charge (assuming the ICE can self-start -- i.e. gas in the tank). True 5. Likewise, assuming the car is in READY mode and PARK, the HV battery will always be kept charged. True, although it cycles it's charge, so it may only have 2 bars 6. The A/C runs solely off the HV battery. The A/C compressor runs off the inverter, which may be charged by the HV Battery or the M/Gs. The rest of the A/C is 12 volt. 7. The various electrical accessories (e.g. USB port, 12v cigarette) run solely off the 12v battery. They run off the 12 system which will be battery powered when not in Ready and Inverter powered when Ready. Nothing is directly powered by the HV Battery but the inverter, Both M/Gs are AC, as is the A/C compressor. All the DC load is nominally 12 volts. This is plodding but clear.
Technically the gen3 compressor runs on high voltage dc routed from the hybrid battery through the large Inverter with Converter Assembly. The compressor takes the hv dc and uses an internal inverter to create ac power for its variable speed motor.
I was gonna say that you need to look at wiring diagrams to understand the energy flow. @rjparker has got it covered.
4 and 5 are right (until the fuel runs out). All the rest are simplified in ways that let reality escape. The true statements aren't any more complicated really. They just have to be simple in better ways. a. There is a 12 V DC bus, and there is a high-volt DC bus. b. The 12 V battery is being charged whenever the voltage on the 12 V DC bus exceeds its own. c. The only ways power gets onto the 12 V DC bus are from the 12 V battery, or from the DC/DC converter, which is powered from the HV DC bus. d. When the DC/DC converter is on, its output voltage is higher than the 12 V battery's, so that battery gets charged. e. The HV battery is being charged whenever the voltage on the HV DC bus exceeds its own. f. The only ways voltage gets onto the HV DC bus are from the HV battery, or from the transaxle whenever there is a net surplus (that is, (power from engine − power to wheels) > 0), thinking algebraically ("power to wheels" is negative in regen braking; "power from engine" is negative in engine braking). g. The A/C compressor runs solely off the HV battery bus (and the rest of the A/C off the 12v bus). h. The various electrical accessories (e.g. USB port, 12v cigarette) run solely off the 12v battery bus. I've left out some details like the inner working of the transaxle (besides whether it has a net power surplus to or net draw from the HV bus) and the doings between the HV bus and the A/C compressor, which are details not needed to follow points a–h.
Doesn't the inverter get power from the hv battery? So the inverter is really powered by the HV battery. And when the engine is not running, the generators are not rotating so they are not powering the inverter. Aren't the generators turned by the hv battery, when the engine in not on, and the vehicle is moving?
I'm not sure the point of these questions—to make the details seem bewildering and keep neophytes out of the club? Once we remember to think of the 12-volt bus and not just the 12-volt battery, and the HVDC bus and not just the HV battery, the artificiality of those questions can be seen. The power that is placed on the 12-volt bus by the DC/DC converter is taken from the HVDC bus. When the car is READY, the flow of power on the HVDC bus isn't always in one direction or the other. There may be a net surplus of power from the transaxle flowing toward the HV battery, or a net flow the other way, or little net flow at all. It changes from moment to moment in use of the car. but in any of those cases the DC/DC converter gets the less-than-two-kilowatts of power it needs from that bus, to convert down and put onto the 12-volt bus. The DC/DC converter is located inside the "inverter with converter assembly", but it's a different thing from the inverter proper.
