Why would the AC drain the hybrid battery??

These electric AC need lots of energy... The 12volt system just powers up the computers and lights, the hybrid battery pack and electric motors via the inverter ensure your AC gets that power. One of the things I like about my Project Lithium pack upgrade is it pumps out higher amps so the engine doesn't run as often to keep the battery pack charge. I'm way more chill during a heat wave like the one we have right now thanks to upgrading to LiFePo4.

 

12v turns the car's computers on and lights things up. Then it turns on the relays that turn on the high voltage battery. After that the HV battery runs everything in direct cooperation with inverter and motors, including the starting of the engine.

 

The 12V system on a Prius runs all of the "minor" electrical loads - lights, fans, controls, and all of the computer systems (the brains).

The High Voltage system is used to power the heavy loads - the two hybrid drive motor/generators (MG1 &MG2), the A/C compressor, and the DC-DC converter (that takes HV battery voltage and steps it down to around 14V to power the 12V system and charge the 12V battery. (the brawn).

The hybrid drive system uses a combination of MG1 & MG2 & the Internal Combustion Engine to: start the ICE, move the car, charge the HV battery, regen braking. Without the HV system working, the car can't do anything or go anywhere.

Posted via the PriusChat mobile app.

 

Just after 15 minute mark he describes the A/C 3 phase AC circuit.

 

why did you buy a new battery?

 

Fixed.

 

this is true, the 12v aux battery does other things besides starting the car. When I bought my Prius with a bad 12 volt battery (as well as the HV battery) I got stranded in the middle of the road when my jump starter turned off (auto-shut off mode) The 12 volt just wouldn't hold a charge. I initially thought that it works like conventional cars where the HV battery takes over and just charge the 12 volt battery but it wasn't the case. I replaced the jump starter with a 12 volt lead acid and disconnected the bad battery and I was able to drive it around without any issues.

 

I had greenbean on my Camry hybrid 4 yrs ago, still doing great!

 

The Prius ac pulls around 2800 watts (3300 watts peak observed) as it is initially cooling a 116f car down to 75f in five minutes. If that was a window unit in your house, at 115 vac, the window unit would draw 24.3 amps. 2800 watts in a Prius is feeding a 3 phase variable speed compressor that ramps the power down as the setpoint is reached.

For comparison a 12,000 btu Midea inverter window unit uses 12 amps at 115 vac. The Prius power to the ac system is enough to run two of the Midea 12,000 btu window units, or a combined 24,000 two ton system.

The inverter takes the nominal 201vdc battery voltage and inverts it to a high voltage variable frequency power supply for the compressor. It still draws around 500 watts after setpoint is reached.

Ambient 102f today:
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In another thread I noted that the voltage in the weak traction battery in our 2007 collapses quickly when the car stops for any length of time, (set to 72 degrees, recirc air, medium fan, outside temp >90F, direct sun). To prevent that I had been turning the A/C off at all stops. Since then I have been experimenting a bit with this and have found that the battery can last 15 minutes or more while the car is stopped if the fan speed is reduced to the lowest (not off) level. Similarly, increasing the temperature setting from 72 to 74 also makes it last longer. Presumably combining the two would work even better, but I have not yet tried that yet. Anyway, in terms of comfort, the car is much cooler after either of these approaches than when the A/C is turned off completely (but left in recirc air mode, do not let it default to outside air).

Unclear to me if the better endurance is because of lower current or less power being drawn from the battery. Yes, I know they are very closely related. An iffy battery may not handle a short bout of high current even if the corresponding total power draw could be delivered over a longer period without voltage collapse.

 

Was this the same Green Bean Battery installer who broke your Prolong cable during the installation?

Did you keep the broken prolong cable?

 

This is (similar) gen 3, with orange cable running to the AC compressor: