Gen5 battery vent: where is it?

Discussion in 'Gen 5 Prime Charging' started by Templeton, Dec 13, 2024.

  1. Templeton

    Templeton Junior Member

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    On the rav4 prime, the battery air cooling vent is on the rear wall of the rear passenger footwell (on the non-driver side). But on our gen5 prius prime, there is nothing there. But yet, when I charge the car, I clearly hear a fan running, so there must be a vent somewhere. If yes, where is it? And, if there is indeed a batter cooling vent somewhere, is there a vent filter that should be checked, cleaned, and/or replaced?
     
  2. bisco

    bisco cookie crumbler

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  3. Templeton

    Templeton Junior Member

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    Thanks, but I already searched.

    But I found no hits on the gen5 prime intake vent location and about my other questions (battery is not on the same place as on a hybrid, I think).
     
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  4. RandyPete

    RandyPete Active Member

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    The Gen5 PP is unlike earlier Gens when it comes to traction battery cooling. It does not use air to cool the battery. It uses the cars climate control system and heat pump to cool/heat the traction battery as needed. There is no air vent or fan or filter. The noise you hear when you charge the Traction Battery is a fan on a small inverter located in the hatch area of the car that provides some 12v power when the traction battery is being charged. I could not find an air duct or exhaust port for this device fan.
    The 2023 & 24 traction battery is not inside the car, it is under the car and accessed and serviced by getting under the car and accessing it like an older transmission or transfer case. It gets disconnected electrically and climate control lines disconnected, and then is lowered from the bottom side of the car to the shop floor.
     
    #4 RandyPete, Dec 13, 2024
    Last edited: Dec 13, 2024
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  5. Trollbait

    Trollbait It's a D&D thing

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    The battery is outside the cabin on the Prime. The gas tank actually sits above it.

    "The noise you hear when you charge the Traction Battery is a fan on a small inverter located in the hatch area of the car that provides some 12v power when the traction battery is being charged."
    It also supplies 12V power while the car is running; it's the alternator replacement. It is also under the rear seat of the Rav4 Prime, which that vent is for. There might also be the onboard charger being serviced by that fan.
     
  6. RandyPete

    RandyPete Active Member

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    There is no alternator in a PP (as you know). When the car is in READY mode, the 12v Inverter/charger (part of the Traction battery inverter) provides 12v power to run the 12v system in the car and charge the 12v battery It is located under the hood, next to the fuse box assembly.
     
  7. Trollbait

    Trollbait It's a D&D thing

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    I did say that 'it'(the DC to DC converter) replaced the alternator.;) Can't run an off the shelf car radio or spark plugs off the 400V to 800V coming from a hybrid battery.
     
  8. RandyPete

    RandyPete Active Member

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    The DC-DC Converter that supplies 12v DC to run the car when in the ready mode is adjacent to the DC-AC converter under the hood. I don't think the DC-DC converter in the back of the car is used except during traction battery charging effort by AC power source.
     
  9. Templeton

    Templeton Junior Member

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    Wow, there are two DC-DC converters on the hybrid or the phev, or both?
     
  10. RandyPete

    RandyPete Active Member

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  11. Trollbait

    Trollbait It's a D&D thing

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    That sounds like being unnecessary. If so, why is a fan running in the back while the car is in ready? The converter isn't getting hot when not being used?
     
  12. KMO

    KMO Senior Member

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    There isn't a fan running in the back in ready in the PHEV.

    In the HEV there is, but that's cooling the battery.

    The PHEV has the standard main DC-DC converter in the drive system, and it needs a second auxiliary one for use when charging, because the drive system's high voltage section is isolated from the HV battery while charging.
     
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  13. RandyPete

    RandyPete Active Member

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    I think this is where I got the idea that there are two DC-DC converters in the '24 gen5 Prius Prime,
    (I note that your prius prime is a Gen4 KMO. So I was mistaken that the info was for a a Gen5).

    But a recent video posted by weber State college indicates that the DC-DC converter located in the inverter housing under the hood provides the 12v DC power when the traction battery is being charged.
     
    #13 RandyPete, Jan 11, 2025
    Last edited: Jan 11, 2025
  14. KMO

    KMO Senior Member

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    My current view is that there still is a second DC-DC converter, cos you can see the wiring and fuse, which then suggests the systems can still be isolated - otherwise why retain the second?

    My guess is it activates the main one for 12V charging (as was happening in that video), My Room mode or HV battery cooling, but otherwise leaves the main system off. More investigation required.
     
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  15. KMO

    KMO Senior Member

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    It occurs to me that we don't know the car was actually charging the HV battery in that video for certain. He had no instruments on it. It could conceivably have decided to charge the 12V battery first.

    He mentioned the green 'charging' light being on, but that doesn't mean 'charging', just 'drawing AC power'. It comes on when just heating the HV battery before or after charging.

    So no definite evidence of it breaking the 'only one system accessing the HV battery at a time' rule yet. (Although I still suspect it does).
     
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  16. Templeton

    Templeton Junior Member

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    Yes, l don't see any vent or fan.

    But, when l charge my priusP, l clearly hear a sound in the back half of the car somewhere that sounds remarkably like a fan running.

    If this is not a fan, any idea what this sound might be?
     
  17. KMO

    KMO Senior Member

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    That's the fan on the charger. But you won't hear it in READY.
     
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  18. Templeton

    Templeton Junior Member

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    Yes, of course, I am not hearing it in 'ready' mode, I am hearing it when charging my phev at home (car is stationary).

    So, if there is charger fan, there must be airflow and some kind of vent, no? Any thoughts as to where the intake (or output) vent to this fan might be?
     
  19. Trollbait

    Trollbait It's a D&D thing

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    Photo of the charger(it's under the storage tray) shows vent ducting. A fan for cooling it sits underneath.
     
  20. KMO

    KMO Senior Member

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    Presumably it needs little enough airflow it doesn't need a dedicated vent inlet from the cabin, it just slurps in from the underfloor of the rear storage.

    There's no clear ducting for its inflow air - it possibly comes in from the underside of the charge unit - looks like it's got a bit of a gap there. There's a fan on top, and a duct from that towards the rear side body air outlet.

    And I'm guessing they figure that that under-plastic-foam area is already clean and filtered enough as it is.