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Options for Cooling my Roadster/Battery in the Summer Months

Discussion in 'Roadster' started by bpangburn, Aug 5, 2015.

  1. bpangburn

    bpangburn Member

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    St. Francisville, LA
    The battery coolant pump and OVMS "cooldown" have been pretty well exhausted in other threads so I'd like to discuss options for cooling the entire car. My basic problem is that in south Louisiana my car's current environment is over 30C from June to August which means that more or less, my battery coolant pump is running 24-7. Based on OVMS, My battery pack pretty much stays between 95 & 110F. It seems to me that running the pump for 90 days straight can't be great for the pump. I can run a cooldown, but find that it won't cool much past the point when the ambient temp and the battery temp equalize and that's nowhere near 30C.

    My car sits in a 2500 sqft shop with only minimal ventilation.

    Here are what I believe to be my options, but welcome any other suggestions from the group:
    1. Don't worry about it. Pump will hopefully last and battery staying between 95 & 110F for 90 days isn't that big of a deal??
    2. Move the car outside under a covered area. It will drop below 30C for at least a few hours each day BUT then it's more exposed to the elements, spiders, dust, etc.
    3. Move the car into the garage attached to my house and install an 18,000 BTU window unit. About 800 sqft to cool. Brick/wood/sheetrock installation with insulated doors, but no other insulation (plan years ago was to let the garage breathe a bit since it was not a conditioned space). I could also consider framing in one bay of the garage to significantly reduce the square footage.
    4. Install a garage door in the side of my living room and keep it in the house. My wife likely would not go for option 4.

    Feedback is appreciated.
     
  2. AEdennis

    AEdennis Active Member

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    4 sounds good... Give something else up to "get it done".
     
  3. djp

    djp Roadster 2.0 VIN939

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    Definitely option 4. Being able to drive the car indoors is one of the cool side benefits of electric motors. Failing that, option 3.
     
  4. ecarfan

    ecarfan Well-Known Member

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    Now that I only drive electric I have mentally designed a house with a sliding glass wall between the living room and a garage that would look like an ordinary room (no mess, very clean). So I recommend option 4.
     
  5. AEdennis

    AEdennis Active Member

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    Seriously... 3 might be better... Unless you feel like listening to the car as it charges...
     
  6. bpangburn

    bpangburn Member

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    Does anyone think that #1 is acceptable and that I'm being overly/unnecessarily concerned? I don't imagine that my situation is that unique.
     
  7. SabrToothSqrl

    SabrToothSqrl Active Member

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    I don't have a roadster, however now that I'm aware my Model S has a HVAC system just for the battery, I'm finding puddles under the car in my garage. This is my first summer of owning a Tesla, and now I'm noticing that my garage is pushing 85-90 degrees F. It has windows, but I don't lock the door between the garage and the house (nor want to), and often (always) leave the keys in the cars in the garage....

    So... do I crack the windows? leave the garage door up more? (leads to wildlife in the garage), or install a bathroom like vent? I did install a ceiling fan, but that doesn't actually cool the room, it just keeps me cool working in the garage.

    Should I care? I'm guessing the car can take the heat, and it's plugged into the house in the garage...

    In the winter it's not like I'm going to start heating that garage... even though I can tell the HVAC is running to warm the battery in winter... (garage is usually around 50 in winter), it's 'inside' the home.

    I'd love a glass view into my garage - something I could do, but it would lose a lot of heat/AC from the house...

    Long story short, I'm going to assume they put some thought into the thing and treat it like any other car. At least it's in a garage... many cars don't get that.
     
  8. shrink

    shrink Member

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    I'm in Phoenix and don't have a garage or carport. My Roadster is gets very, very hot during the day - and I actually think it would get hotter in a garage at night because they are typically not well ventilated.

    I have a few things I do and will share more after work today. There really is only so much that can be done. I'm leaning towards your #1 these days to be honest.

    FWIW - when I bought the car 2 years ago with 8100 miles CAC was 155-156. 2 years and 6000 miles later, I'm down to 151.47. The heat is tough on our cars and batteries, but alas, it is the environment in which we chose to live.
     
  9. ecarfan

    ecarfan Well-Known Member

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    So seriously... I think #3 is the best approach (powered by solar panels on your roof of course :) but if that is not possible then you'll just have to accept the situation and try not to worry about it.
     
  10. stevejust

    stevejust Pati ≡nc ≡

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    I've given this a lot of thought. I have a Roadster in Texas. I have a detached garage. We're having a streak of 100+ degree F days. Sorry, I mean somewhere about 39 degrees Celsius.

    It is not impossible for me to air condition the garage (during the day) because I have a 9kW solar array, and during the production day produce far more than my home and cars can use. But the garage is not insulated at all. In fact, one of the walls is made almost entirely out of this stuff (translucent plastic covering framing).

    So, between the essentially plastic wall, and the garage door itself, even with the excess renewable energy I produce I'm having trouble justifying climate controlling the garage. Maybe a swamp cooler? Or just a fan to help circulate the air might work? I can't imagine an external fan would actually help that much, though.

    Finally, to bury the lede so to speak, I sprung a leak in my cooling system earlier this year, and had to have the coolant pump replaced at @900 earlier this year.
     
  11. bpangburn

    bpangburn Member

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    I really didn't think about framing in one bay of the garage for the Roadster until I started writing this, but an 8000 BTU AC will run on 110 and easily keep the space at 80F. Just the acquisition costs of 18k vs 8k will cover a lot of the materials for the wall. Irony is that with other commitments, it will have to be a winter project. Fingers crossed on the pump.
     
  12. djp

    djp Roadster 2.0 VIN939

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    Running the pump continuously is kinda pointless if the pack is at ambient temperature and all cells are within a few degrees of each other. The car has enough temperature sensors to know this, I'm surprised the firmware isn't smarter.
     
  13. ernst

    ernst 't is een grijze.

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  14. gregd

    gregd Member

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    I presume you've tried the Range Charging trick. What were the results? (This is doing at least an hour or so charging in Range mode, then manually stopping it before it gets to what a Standard charge would get to. You have to plan your driving and charging a bit, to have the pack no more than about 60% - 70% SOC when you start.)

    I live in the foothills, east of Sacramento. Not quite as hot here at night, but the highs can top 100F. I've had pretty good luck (maybe 75%) getting the pack cool enough for the pump to turn off, then thermal mass keeps it off until the next drive. Range charging uses the A/C to actively cool the pack, so it's not a good idea if you're going for option #4. Too noisy...
     
  15. markwj

    markwj Moderator, Asia Pacific

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    That is pretty much what OVMS cooldown does. It runs a low-amperage range mode charge until it sees the HVAC cycle on then off. It then switches to performance mode for a minute, before switching back to range mode charge. Rinse and repeat. Doing that, I find I get about 1degree celcius drop in maximum pack temperature, for each 10 minutes.

    The cooling can be sped-up by stopping-and-starting the charge (instead of the range-performance-range trick), but would be pretty onerous on the contactors (and relays in the EVSE on the wall). I have seriously investigating implementing a FREEZEDOWN option in OVMS to do that.

    But, I've held back for wondering why the roadster won't use HVAC more when charging. It seems to have an internal timer to stop it cycling the HVAC on too often. My best guess is they don't actually want to cool too much or too fast. They don't want a large temperature difference across different parts of the system, so only run the HVAC for a short while during charging. Perhaps bathing high 30's cells in low single digit coolant is not good for pack health.

    Back to the original question, disregarding cooldown, I would choose option #1. Don't sweat it. Keep the pack as cool as possible using cooldown, and keep the car ventilated and in the shade. If the pump runs, so be it.
     
  16. bpangburn

    bpangburn Member

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    Location:
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    #16 bpangburn, Aug 6, 2015
    Last edited: Aug 6, 2015
    So I went for a drive last night and then made the car sleep outside (charging). Woke up this morning and AFAIK for the first time in two months, the pump was off (OVMS battery reading of 84F). I was finally able to check the coolant level and learned two things: 1. I had slightly overfilled it when pouring into the frothy mix (explaining the overflow puddle underneath) & 2. I didn't have the cap on all of the way (I generally turn things until snug, but if you turn slightly more, it actually stops. n00b mistake I suppose, but that explains seeing a bit of coolant around the reservoir and hopefully there is no crack). Annual service is in a few weeks and I hope to flush & pressure check.

    Leaning toward parking it outside on nice nights for another month or so and then framing in a bay in my garage this winter.

    Thanks for all of the input.
    tesla_outside.jpg
     

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