solar powered secondary AC system for keeping cabin and battery temps down

Discussion in 'Prius v Accessories and Modifications' started by darknd666, Apr 18, 2026 at 6:59 PM.

  1. darknd666

    darknd666 Junior Member

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    I have this (seemingly) wild idea to use a mini AC compressor, solar panel, separate or additional 12v battery, and a fan, all to keep the cabin cool enough to not over heat the battery, thus degrading it.

    My first idea which was low cost would have been an exhaust fan that I would mount to the rear cabin vent exit, which I believe is where the battery fan blows its air out, or at least tries to. I have not attempted this yet because I have yet to put ceramic film on the windshield yet, I must exhaust the more common tactics forst before I venture down this road.

    Now for the parts. There does exist a coke can sized compressor that uses 300W max and is variable speed so 100-300 watts. In reality this only needs to cool the immediate area of the battery, I can isolate/insulate the battery but in the event of a failure would heat the battery up even worse...
    Obviously there exists batteries and solar panels as well as charge controllers to maintain the system electrically. To keep the system hidden and clean a 100ah lifepo4 would be sufficient given an isolated charging system, bonus points if I can get the inverter to charge it and shut of the secondary HVAC, or fan when the car is running, whichever happens to more viable.

    For the AC a condenser and fan could be mounted externally, underside in the rear. As the power requirements add up, a larger roof mounted solar panel to lug around would be paramount.

    After further thought, I realized the engineering feat this would be as the cooling parts of the compressor would need to pass to the battery fan...or I could just AC the cabin for second place results.

    Another related question I pose is how I could maintain the 12v OE car battery via solar to lessen the load on the inverter, maybe gain some efficiency?

    12V Mini Compressor
     
    #1 darknd666, Apr 18, 2026 at 6:59 PM
    bisco likes this.
  2. bisco

    bisco cookie crumbler

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    you've got too much time on your hands :p
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    #2 bisco, Apr 18, 2026 at 8:23 PM
  3. ChapmanF

    ChapmanF Senior Member

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    Some gen 3 trims did this. They put a 60W-rated solar panel on the roof, and used it to drive the HVAC blower up front, switching the intake mode to fresh automatically, in case you had it on recirc. So it would bring fresh air into the cabin. The air would find its own way to the rear quarter exits, going through the battery on the way. (And you thought air was stupid.)
     
    #3 ChapmanF, Apr 18, 2026 at 8:52 PM
  4. BiomedO1

    BiomedO1 Senior Member

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    #4 BiomedO1, Apr 18, 2026 at 9:35 PM
  5. darknd666

    darknd666 Junior Member

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    Where might I find one of these solar panels to retrofit? Or are they generic? Im assuming not sunce this was OEM.
     
    #5 darknd666, Apr 18, 2026 at 9:46 PM
  6. darknd666

    darknd666 Junior Member

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    #6 darknd666, Apr 18, 2026 at 9:47 PM
  7. rjparker

    rjparker Tu Humilde Sirviente

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    I assume this Rube Goldberg contraption is to cool the battery when the existing ac system is off. Otherwise there really is no need in a standard hybrid with variable capacity hvac.

    Sometimes people think electronics and batteries have the same cooling needs as humans, which might have been true in the fifties with vacuum tube computers and sensitive magnetic media but is not 75 years later, especially in vehicles when they are not running.

    If there was any evidence the hybrid battery needed more cooling when running (which there is not because it has relatively small capacity), I would go with a solid state thermoelectric unit which could heat or cool the assembly, ideally with air flow reconfigured into a recirculated system.

    But the btus, energy and money required makes the existing air cooled system just fine. If we were talking modern plugins or evs, liquid cooling and heating using the vehicle's heat pump is the clear choice. Tesla's integrated cabin and battery system with simultaneous heating and cooling is a benchmark for ultimate efficiency.
     
    #7 rjparker, Apr 18, 2026 at 10:16 PM
  8. darknd666

    darknd666 Junior Member

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    HVAC was bit of an extreme pipedream lol. If I could just get the fan to run when the car is off to evacuate the hot air or adapt the feature of the solar roof gen 3s that would suffice.
     
    #8 darknd666, Apr 18, 2026 at 10:19 PM
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