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Battery cooling

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by MarkySparky, Jul 6, 2023.

  1. MarkySparky

    MarkySparky Junior Member

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    Does anyone have any information on traction battery cooling airflow? As in, measured pressure differential, CFM, etc.? I have two, 2007 (Gen2) Prii, one has high battery temperature issue, the other does not. I have recently serviced both batteries and fans/ductwork, and both are clean. I just posted another post here earlier today listing what I have done regarding maintenance work and testing. I like seeing measurable numbers results, not "I think there's an improvement" or "butt dyno says"... I'm thinking of purchasing a manometer to measure pressure differential and airflow on both cars to compare them, as well as for other uses to be determines, such as some future aerodynamics experimenting (see Measuring Aerodynamic Pressures for example). Has anyone also done any aero mods, not like the radical ones over on ecomodder.com, I'm thinking maybe a little better chin spoiler, better body undercladding especially around the back axle and bumper area, maybe a better rear spoiler?
     
  2. Tombukt2

    Tombukt2 Senior Member

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    Yeah buy a manometer do all that no problem Not sure what it's going to tell you usually when your battery is overheating or having temperature issues it's not because the fans not working or trying to run air across the battery maybe it's real hot out you have the windows open because you don't like air conditioning? Don't know. It's usually some conditions in the car batteries old and high resistance is showing it's ugly head. Etc etc don't know from here but you should have a good idea you're rebuilding batteries so you know some of the deal with electrical flow and not electrical flow and heat build up etc so if you have any of that going on then you're taxing the system as it is is in its original state and all the manometers in the world aren't going to make any difference I mean if you got the fan running and it's unobstructed you should have the same air flow that Toyota had when they design the system etc etc I can't even imagine what kind of flow you're going to get it's going to be extremely low I have a manometer I use an air conditioning duct work I can't imagine it's going to work in this little but yeah I guess it will yeah but I mean unless you would be able to see the obstruction. At least the kind that would cut the airflow like you're thinking is missing and then just putting your hand over the vent in the car by the seat and then going out to the back where the air comes out if you know where that is and you should feel that stuff. On very hot days. I have the air conditioning on not set at 76 but said it low and air on usually second to third fan speed. That keeps the cabin cool enough and when I'm running the car good it sucks that cool air from the cabin across the battery out the back seems to work okay I'm in Central North Carolina I don't really have any battery overheating problems but I'm also not trying to run 90 mph everywhere on the highway about 73 is what I do somewhere in there I'm usually in the slow lane paying attention to other things.
     
    ANDRAS RIMELY likes this.
  3. pasadena_commut

    pasadena_commut Senior Member

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    It would be a PITA, but if you swap the fans and the problem moves with the fan, then you need a new fan. If it doesn't, then you know both fans are good (so no need to swap them back) and the problem is elsewhere.

    I pulled a spare fan from a car in the pick a part lot to experiment with. Haven't gotten around to it, but did notice that when spun by hand the junkyard one did not turn nearly as easily as the one in my car (from when I cleaned it). Stupid fan design has a pressed on or molded on cage and no obvious way to lubricate the motor. I'm guessing that these do work less well as they age and the lubricant gets used up.
     
  4. mr_guy_mann

    mr_guy_mann Senior Member

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    Get a budget Uni-T amp clamp (UT-210E) and measure fan amps on both cars while commanding the fan ON at different speeds.

    Posted via the PriusChat mobile app.