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Idling with AC running ok?

Discussion in 'Gen 2 Prius Main Forum' started by J.D. Sowers, Jul 25, 2022.

  1. tracy ing

    tracy ing Active Member

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    Sitting parked with the AC on is no more stressful than driving the car to work, this is from my car parked with the ac on and engine cycling on and off, it is NO BIG DEAL for the modules, it is NOT discharging deeper or charging higher or harder.

    Where do people get these theories from and then post them, i will never know.

     
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  2. tracy ing

    tracy ing Active Member

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    Here is a very scientific based chart on this
    "during half-hour exploitation, the battery’s level of charge has varied from 41% to 75%, which
    is narrower scope than the information announced by the car’s manufacturer
    ,"

    International Automotive Conference (KONMOT2018)
    IOP Conf. Series: Materials Science and Engineering 421 (2018) 022041
    IOP Publishing
    doi:10.1088/1757-899X/421/2/022041

    NOTE you can also do a pretty good determination on how the pack is by timing how long it runs on batteries and how long the ice runs to charge it back up (assuming hot day max ac windows down)

    ALSO NOTE I was able to keep a car on the road with a bad pack while i rebuilt a pack, by draining the heck out of the pack to BALANCE the modules together better, AC ON FULL, CAR IN NEUTRAL, it will not charge, it will run the pack way down, and you will get codes as the 14 volts fails.

    ac1.png
     
    #22 tracy ing, Aug 10, 2022
    Last edited: Aug 10, 2022
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  3. Chelsea Felker

    Chelsea Felker Junior Member

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    wow great info about the place for a hybrid battery! I may need one soon…and a head gasket
     
  4. lech auto air conditionin

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    My Prius C is used as a heavy duty work vehicle for work every day. It leaves at 6:40 6:55 AM most every day and returns back and gets parked. 730 to 830 at night the engine gets turned on in the daytime and never gets turned off while it’s driving between jobsites continuously Eileen all day on with the air conditioning on Max even in the winter time the air conditioning is on.. 2012 Prius C air conditioning never turned off since the day I drove off the show room floor brand new. Idle time every day, roughly 10 to 12 hours of on time without ever being turned off, except for filling up for gas at the gas station..
    Carries 800 pounds plus of tools and equipment and supplies inside the vehicle depending on which days and work type anywhere from 300 to 1000 pounds on a custom made rack on the roof has a tow hitch that will carry anywhere from 700 lb on a 4x4 trailer up to 5 x 9 trailer with 2000 pounds on it.
    This car has 173,000 miles on it still with the original front brake pads.

    there is two times I know of when the air conditioning draws a lot of extra power from the high voltage battery that will keep the engine, running a lot more often and even almost constantly, especially if the battery pack is getting towards the end of its life.

    Scenario number one is when somebody over charges it by two or 3 ounces of refrigerant. The high side pressure surges up to hovering somewhere right around 400 psi.. this is enough to keep it running, and give you some cooling, even though it will be poor cooling . But the excessive amperage from the high-pressure will draw a excessive amount of amperage from the battery, and the owner may notice that the engine constantly comes on at stoplights because they constantly have to keep charging the high voltage battery..


    The other scenario is when the refrigerant charge on a hot day is low by a few ounces. The sensors sense that the air conditioning cannot satisfy the cabin air temperature. The customer has sit down low so the computer does not know that it’s low on refrigerant, so it keeps spinning up to compressor to a higher and higher rpm, trying to move enough Refrigerant Pass expansion valve through the evaporator to produce some cooling.

    But because the refrigerant level is low, it constantly does not satisfy the setpoint. Therefore the computer will keep commanding the compressor to go all the way up to 6000 or 7000 RPMs constantly drawing more power from the high voltage battery without ever satisfying it becomes a continuous drain

    In a perfect, ideal, refrigerant, charge everything working correctly the air conditioning system with the right amount of refrigerant would easily satisfy the setpoint, and as it approaches, it starts spinning down the compressor. Lowering the RPMs lowering the amp draw on the battery. This is the normal good method that draws very little power because there’s enough refrigerant to easily performed the job it is called upon to do..

    The compressors in these cars in properly taken care of I never allowed to go without refrigerant from a leak, outlast the life of the vehicle they never break down.
    Compressors don’t die they are murdered.
    Either by the Technician Hwy, Services them

    Or by the customer who neglect them who drives them until he notices the cooling, doesn’t work too well
    By that time, it’s too late, the compressor has been running extremely hot and higher RPMs for a long time this often reduces their lifespan.
    Some people get lucky and some people are not. Depending whether they have to go to the expense of replacing a compressor
     
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  5. rjparker

    rjparker Tu Humilde Sirviente

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    Do you think it is possible to graphically trend compressor rpm or amps to judge refrigerant level?
     
  6. Tombukt2

    Tombukt2 Senior Member

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    That Prius c sounds like my generation too almost the exact equal as far as running amount of tools in the car towing capability I do not have a roof rack I'm too lazy to pull stuff off of it and set it on the ground so I go the trailer route My flow trailer is inches off the ground stuff slides right off and it's on the ground no need to lift actually but I'm getting older and lazier now but your Prius c sounds exactly like my generation too. If I was to buy a new Prius today it would be a c because it's the equal to the generation two with crappier tail lights and poor headlights so I just stick with the generation too same engine and everything Good choice.
     
  7. douglasjre

    douglasjre Senior Member

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    No but if I put my hand on the low P pipe coming out of the firewall I can....
     
  8. douglasjre

    douglasjre Senior Member

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    Lech: I like the way you use that car. Some people would waste a Ford f350 for that job. They're the ones that drive around with the strobing yellow lights like "look at me I'm important...i have a job" Fuel bills would be their nemesis and their " truck" (aka passenger vehicle) never sees it's full potential

    I use turd gems to pull trailers. I can get 30mph w the AC running all day and haulin
     
  9. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    #29 Mendel Leisk, Aug 15, 2023
    Last edited: Aug 15, 2023
  10. lech auto air conditionin

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    with a factory correct charge it would be pretty accurate.

    Because it’s done in commercial on larger scale, we have to do this in commercial and when you’re designing heat exchangers.

    Since I actually suck at formulas, and I have the memory of a goldfish

    is formulas if you know how many pounds of air and yes, I’m talking about pounds of air. If you have the temperature and humidity the actual weight of the air per cubic foot or meter or whatever unit of measure you choose will vary how many BTUs of energy are stored in the given quantity of air that you’re moving across a coil.

    That includes Your, Condenser and Your Evaporator. Because each refrigerant has a capacity of so many BTUs per pound.

    How many pounds you pass through your evaporator

    You could come up with your BTUs, and how many watts of energy it requires

    The problem with variable speed systems it’s like large commercial VRF systems.

    Do you have these variable speed fans especially two speeds that will flow different amounts of air over the coil

    Do you have a Verbal compressor that will want to change speed

    And we know when we’re overcharged on these microchannel and Condenser is just a little bit send the head pressure through the roof. Which requires more amp draw, but this will change weather to 65° day outside or a 95° day outside.. to completely different WATT draw from the motor, given the same overcharge quantity

    The same goes for under charge. The problem with the variable speed motors the computer senses. The system is not satisfying after I give her period of time and temperature difference not knowing the system is low on refrigerant it pumps, more speed and more watts into the motor to speed up..

    Toyota already has their built-in software through Toyota TechScan, that uses the sensors of temperature and pressure to interpolate whether the system is close to being fully charged or not.

    Most all the major manufacturers in commercial and residential, especially commercial HVAC, have software because of their variable speed compressors that use all the pressure transducer‘s, and the temperature sensors of the inlet and outlet temperature of the air from the evaporator and condenser the inlet outlet temperature of the refrigerant line going into the expansion valve coming out of the expansion valve and coming out of the evaporator to take the superHeat. The same goes for the Condenser so they can get the. .

    And they do not do this, and it’s normal operation mode

    Through the software, they said it into a test mode that takes over

    And looks at the ambient air temperature of the inside door, air temperature, and will set the unit based on that into a test mode

    To use it sensors that are placed in precise locations that they have tested during their development of the product to tell you whether the system is low or high on refrigerant charge.

    This is what we need in cars, especially the new electric vehicles with heat pumps.

    But for some reason, I don’t think the manufacturers will be so friendly to us, especially out here in the private industry

    On your old residential, for example 10 seer or 13 seer, six speed, condenser motor, fix speed, PCS, evaporator blower motor with some refrigerant line temperatures and white draw we could figure we were OK region.

    But then you jump to a little mini split and try to do the same thing and you’re just guessing because we’re back to the variable displacement, variable speed.

    And then we have one more wrench to throw into the gears and muck things up

    cheap poor quality, aftermarket, condensers that I’ve talked so much about

    That completely messed up the refrigerant charge and heat caring dissipation capacity of condensers.

    Throws a known good system into chaos.

    You’re talking a Toyota Denzel condenser that has 21 cooling fins per inch and then buying the cheap $80 condenser that only has 14 cooling fins per inch trying to dissipate the same amount of heat,

    On top of that instead of having 54 refrigerant cooling passage tubes, the aftermarket one might only have 48 Refrigerant passage tubes

    And then, when you cut the refrigerant passage, tubes, open and look inside

    You’ll see that the OEM DENSO might have 15 or 18 little tiny micro fins inside the tube, increasing its surface area to dissipate heat

    But when you cut open the aftermarket cheap condenser refrigerant tube, you’ll see six fins to dissipate heat.

    So anything you had as a baseline on how the original OEM was supposed to draw current through the motor gets tossed out the window it no longer applies.


    This is why all these old bonehead logs who think $80 aftermarket condenser is just as good because it blows cold air over their hand when they’re finished have a very flawed thought process. . Along with the shake, the cans single hose can guys who judge that is correct buy a cold dash temperature in some rule of thumb, high side pressure they’re looking for or low side.

    By the way, there’s a new Facebook group (Automotive HVAC Technicians)
     
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  11. lech auto air conditionin

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    i’ve upgraded all the lights with those stupid expensive Japanese ultra high performance, LEDs, that blind everybody like a supernova coming towards them. I love it I don’t care about anybody else my old eyes can see good now at night time.. actually, night time looks like the time now
     
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  12. lech auto air conditionin

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    Hand-O-Meter
     
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  13. lech auto air conditionin

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    So many people make fun of me in my little Prius when I pull up to the commercial contractors HVAC warehouse supply house.
    They all have big trucks. They get 9 miles to 14 miles to the gallon here in San Francisco couple thousand dollars in parking tickets for not being able to find parking and parking illegally just to get parking near the job site. Spending literally 20 minutes to 40 minutes looking for parking or parking a few blocks away if necessary downtown San Francisco..

    $1200-$1400 plus every month and fuel bills

    And because you have a high gross weight vehicle with a large carrying capacity like a pick up truck or a van. In my business because we carry gases that are compressed and flammable gases, and sometimes toxic on our business insurance gets jacked up $1200 a month just because of that..

    Because I’m in a subcompact car that is under a weight limit and has such a small interior capacity. There is no listing for my vehicle. I am out of the restriction zone for jacking up my insurance so I save $1200 a month and that is a month just for not having a pick up for van to carry the chemicals and gases that we do in our business in HVAC..

    My fuel bill is $350-$395 a month now

    If I have my high mileage tires, I get 70,000 miles out of my tires that cost me $70 apiece

    If I use my ultra performance summertime only racing tires, which I usually try to only use when I’m pulling a trailer

    I only get ten thousand miles out of them my gas mileage drops twelve miles to the gallon and they cost me $145 apiece but damn they stop fast and handle like my tires grip the ground like super glue.
     
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  14. lech auto air conditionin

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    Yeah, it was a rough hot day here at 77° in San Francisco and then the fog rolled in later and cool it down. San Francisco is gifted with mothers natures, air conditioning..
     
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  15. rjparker

    rjparker Tu Humilde Sirviente

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    Tom has a way with words. My personal opinion is manufacturers will have to make residential, light commercial and automotive refrigeration smarter, more reliable and more instrumented to allow fewer techs to handle more systems. First they need to protect the power and control electronics such that environmental exposures and heat does not kill them. Routine field brazing may have to go as well. I can see heat pumps twenty years from now lasting 20-30 years, most without repairs. Hvac techs will be licensed and will require more control knowledge and tools than other trades.
     
  16. douglasjre

    douglasjre Senior Member

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    Resistance of copper wires drop as T drops. Why doesnt Toyota bathe MG1/MG2 in R134a?
     
  17. douglasjre

    douglasjre Senior Member

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    The pickup operators think they have "trucks." It's not a truck boys. Your registrations says passenger vehicle. It's a truck when u have a diesel, air brakes, and need a CDL to operate it. SMH.

    Prius saves u like $2k/m. That's 24k/yr. Pickup tires with high load capacity are 350/each. Can't imagine daily driving that. I have a Vette, motorcycles, etc. But use two Priuses for daily driving. TY very much. Ppl who make fun of us for choosing a sensible daily driver r foolish. A sports car is not a sensible daily driver. Nor is a pickup w 7500lb load capacity
     
  18. pasadena_commut

    pasadena_commut Senior Member

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    California DMV registers most pickup trucks as commercial vehicles, just like a semi or other "real truck".

    Commercial Vehicle Registration - California DMV

    Insurance rates for vehicles registered commercial that are actually used for commercial purposes tend to be higher than for the same vehicle used as a personal vehicle.

    Thankfully I have never needed to deal with any of these complications since I have only ever owned regular passenger cars.
     
  19. lech auto air conditionin

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    And when you’re in a truck and you carry hazardous materials, flammable materials and compressed gases, your insurance rates skyrocket. For your registered business vehicle.
     
  20. rjparker

    rjparker Tu Humilde Sirviente

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    107f in the shade in Central Texas this afternoon. The v had already driven 30 miles and was parked in the sun for an hour. Followed by another 35 minute drive.

    IMG_2728.jpeg

    Compressor RPMs follow: IMG_2727.jpeg IMG_2729.jpeg IMG_2731.jpeg IMG_2734.jpeg

    Notice the drop to zero at time 34:00. This was a stop sign with the momentary drop on acceleration. Maybe 3 seconds.

    Odd.