Gen5 prime/phev battery temp management

Discussion in 'Gen 5 Prius Technical Discussion' started by Templeton, Jun 19, 2025 at 11:22 PM.

  1. Templeton

    Templeton Member

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    How does the gen5 prime/phev manage traction battery temperature while charging in warm conditions?

    I know the gen5 hybrid has a fan (with a filter) that circulates cabin air through the battery to cool the traction battery while charging. But the phev lacks this fan and filter. l have read that the car uses coolant lines to manage battery heat. OK, but does that mean that the air conditioner or heat pump starts up on its own while the car is off (but plugged in and charging) to cool and circulate coolant through the battery cooling system?
     
  2. KMO

    KMO Senior Member

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  3. KMO

    KMO Senior Member

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    Actually, there are options to disable heating and/or cooling while charging, so you're free to stop it using power for temperature control.

    But then it would need to slow or stop charging while the battery wasn't at a good temperature.
     
  4. Templeton

    Templeton Member

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    Thanks, interesting.

    Any idea if this also happens when you charge a rav4 prime/phev in hot conditions, will that car also automatically turn on the heat pump to cool the battery while the car is off and charging?
     
  5. Trollbait

    Trollbait It's a D&D thing

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    It is the same cooling system.
     
  6. Templeton

    Templeton Member

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    Not exactly.

    The rav4 prime/phev also has the cabin air battery cooling fan (with filter) just like the hybrid rav4 and hybrid gen5 prius. And it turns on during charging.

    So when a rav4 phev is charged in hot conditions, do both systems (battery cooling fan plus heat pump with circulating coolant) turn on?
     
  7. KMO

    KMO Senior Member

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    Correct, it's using the cabin air for cooling, same as the G4 Prius PHEV.

    But the overall behaviour is the same - as necessary when charging it will run the A/C to cool the cabin or turn on the battery heating elements, unless you've disabled those options.

    Edit: Just noticed you're asking about the fan. Subtle distinction there. Not 100% sure, but I'd imagine it would always use the fan. The cooling option would be about whether it runs the A/C to cool the cabin.
     
    #7 KMO, Jun 20, 2025 at 11:23 AM
    Last edited: Jun 20, 2025 at 12:03 PM
  8. Templeton

    Templeton Member

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    So the rav4 phev will turn on the a/c to cool the cabin air which will the cool the battery? Or it will turn on the heat pump or a/c to cool coolant in the lines that run directly through the battery?

    Or both?
     
  9. KMO

    KMO Senior Member

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    Oops, okay, I'm out of my depth here - I'd forgotten the RAV4 had liquid-cooling, something I should have remembered.

    I thought you were saying it had only battery air-cooling, so I believed that and inferred behaviour from the G4 Prius.

    Having both sorts of battery cooling seems unlikely, so I've checked, and it seems that the air cooling you're talking about is for the charger, not the battery.

    That's the same as the G5 Prius, except the Prius doesn't have any visible vents for the charger fan.

    So, like the G5 Prius, I'd expect that the cooling option would be about directly cooling the battery with the refrigerant, and it's not going to bother running cabin AC just to help the charger fan.
     
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  10. Templeton

    Templeton Member

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    No worries, thanks for your input.

    Where do you go to check to learn more details about which systems work when, and on which car?
     
  11. KMO

    KMO Senior Member

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    Toyota's (paid) technical doc services have a "New Car Features" document for each model which goes into that level of detail.
     
  12. Templeton

    Templeton Member

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    Darn.
    (on the paid part)
     
  13. Gokhan

    Gokhan Senior Member

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    The new-car features (NCF) manual will not help you on this, as it doesn’t discuss owner-operating details like in the owner’s manual. The owner’s manual is your best friend on this.

    In the Gen 4 Prius Prime PHEV, I have the A/C air-cooling option enabled, but I have never seen it kicking in. I have seen something like “Would you like to turn on the A/C to cool the battery?” on the display a couple of times, but it disappears in two seconds before you can take any action. I am guessing it might never kick in in Gen 5 either.

    Gen 6 (RAV4 PHEV) now has coolant (as in ethylene glycol, not A/C refrigerant) cooling that couples with the engine cooling circuit through a heat exchanger, which can both cool and heat the battery. The system also has a high-voltage PTC coolant heater. So, it is an improvement over both Gen 4 and Gen 5.
     
    #13 Gokhan, Jun 20, 2025 at 2:14 PM
    Last edited: Jun 20, 2025 at 2:22 PM
  14. Templeton

    Templeton Member

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    So have any gen5 phev or prime owners here ever experienced while charging in very hot conditions having the heat pump (or a/c?) start up on its own automatically while the car is off (but plugged in and charging) to cool and circulate coolant through the battery cooling system?

    Just wondering if this ever happens in the real world.
     
  15. Trollbait

    Trollbait It's a D&D thing

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    I suspect no one has put the time in watching a charge session to see if happens. Does the app monitor and log battery temp during charging? Its use will increase charge time from the energy diversion, but then again, so will a hot battery.
     
  16. Quovadis007

    Quovadis007 New Member

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    I almost always charge my Prius Prime 2024 (9800 km) at home in the garage, and try to use the electricity from my PV as much as possible.
    For this I use the standard home charger type 2 and the Prius is set to max, at home this is max 10A. The voltage here is 220 V, via my PV inverter I see that the voltage on the low voltage network in the street, in practice fluctuates between +/- 224 V (no sun) to 245 Volt on a sunny Sunday.
    The charging cable is connected to a stop contract where I can follow the consumption "live" if necessary and the app shows this for up to 12 months.

    Until today, I saw on a sunny day, (with empty battery) at the beginning, a consumption of 2250 watts, which after 3 hours rose to 2325 watts, after 4h55, the calibration of the battery starts and this consumption drops to 955 watts in 10 minutes, after 15 minutes, the battery is then fully charged = 11.45 K-watts.
    My Prius is usually in the garage (closed in the shade) during charging, today inside = 24°C, (72°F) because outside it is currently 33°C, (92 °F).

    But today (afternoon) I noticed that, the charge started at 2350 watts (normal for an afternoon with 240 volts) but already after 1 hour dropped to 2100 / 2080 watts, ???? the last 25 minutes the calibration went normally.

    Because the battery was not completely empty at the start, I do not know whether the charge caused extra energy (total only 7.45 K-watt
    The fan of the inverter in the car was running normally, the air conditioning in the car was not activated. There was no error message.

    At the start, the car stated a charging time of 2h50, which eventually became 3h 40, I have never seen such a deviation.

    Could this decrease in the current consumption be due to the slightly higher temperature in the garage?
     
  17. Gokhan

    Gokhan Senior Member

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    According to the manual, the battery cooler kicks in before charging starts when the battery is hot, not later during charging. Chances are that it only happens when the car is plugged in after having been driven in the BEV mode in high speeds in a hot day. I never charge my Gen 4 immediately after it is driven.
     
    #17 Gokhan, Jun 21, 2025 at 4:18 PM
    Last edited: Jun 21, 2025 at 4:24 PM
  18. Gokhan

    Gokhan Senior Member

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    So, the maximum current limit is 10 A with the Toyota charger in the UK? In the US, some people use it at 240 V through a plug adapter, and they still get 12 A at 240 V as they get at 120 V.

    Third-party Level 2 chargers can charge the Gen 4 at 3.3 kW and the Gen 5 at 3.5 kW.
     
  19. Quovadis007

    Quovadis007 New Member

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    On a 220/240 Volt connection with 1 phase (standard for private individuals), every EV and PHEV in the world may only charge at 10 A, to prevent overheating of the electricity cable in the house. The car must detect this 1 phase itself.

    Public charging stations must always work with 220/240 3 phase. (standard for companies)

    The public low voltage is always 220 / 240 volts. with 3 phase throughout Europe.
    But private homes get a "standard" 220/240 volt, 1 phase connection (40 A). To get a 3 phase connection you have to pay +/- £ / € 1000 / 1500 extra, depending on the local network. (Companies always have 3 phase connections)
    (In the UK, older houses have 1 phase of 100 A)

    On a public charging station (is always 3 phase, at least in Europe...) my Prius 5 charges up to 16 A (I noticed that in practice this fluctuates between 14A and 15A, due to the local Volt voltage differences)

    Because every EV and PHEV can charge for a longer period of time (+1 hour) with 16A, an EV and PHEV may only charge up to 10A with 1 phase in the whole world. (2400 watts + 1 hour).
    An oven and electric hob are connected to a 32 A fuse here, (UK old houses 40A) but never consume continuously (+ 1 hour) 7200 watts for cooking, which is why this can and may be done on 1 phase. (50% cooking on natural gas, but this varies greatly from country to country)

    Every EV and PHEV, “must” in the whole world, automatically check whether the incoming electricity comes from a 1 phase or 3 phase connection.

    Some rogue charging station companies, sell in the EU, private charging stations for home, with 32 A fuse on a 1 phase connection of 220/240 v. When the owner notices that his EV or PHEV charges slowly, this seller says that it is due to a fault in the car….because the connection can effectively provide 7200 watts of electricity.

    But yesterday I noticed that my Prius Phev 5 charged for 1 hour at 9.9A (2360 W / 238 V) and then dropped to 8.66A (2080 W / 240 V) for about 3 hours. Previously this only fluctuated according to the mains voltage. (Usually between 225 V and 245 V with a lot of sun and little consumption in my street)
     
  20. Gokhan

    Gokhan Senior Member

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    There is practicality no three-phase charging in the US. That's because the residences get two phases from a center-tap transformer (120 V each from the center-tap neutral and 240 V between them). Car charging sockets are equipped with a single phase and neutral as a result, the neutral becoming the second phase for Level 2 (240 V) charging.

    The maximum Prius Level 1 (120 V) current in the US is 12 A. I believe those who connect the OEM charger with a plug adapter to a 240-V outlet still get 12 A. For third-party Level 2 chargers, you get 3.5 kW/240 V = 14.6 A for Gen 5 (3.3 kW or 13.8 A for Gen 4).
     
    #20 Gokhan, Jun 22, 2025 at 5:55 AM
    Last edited: Jun 22, 2025 at 7:06 AM