Cooling the batteries

13

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  • WaterWheel
    WaterWheel Registered Users Posts: 385 ✭✭✭
    edited September 2018 #62
    Adding ice means more than just $2 a day.      it means the time and fuel stopping every day during the warmer months to purchase and add the ice.

    The largest roadblock to using a water bath (chilled, iced, or just water out of the hose) is building a water tight box which can be easily filled and drained that also has a vent fan, screened air intake holes, and a lid.     The box needs to withstand water pressure pushing out on the sides for 10+ years, have a liner than can resist 35% sulfuric acid (EDM is best but PVC should last over 10 years in light acid) and a drain that can also withstand being in a low concentration of acid for 10+ years. 

    If there is a problem with the drain or liner that box full of batteries is too heavy to move so it needs to be built right the 1st time.       In my case I do worry about the $20 pump holding up since I don't know what plastic it is made of or how the vinyl insulated cord will hold up but the tiny bit of acid diluted in 70 gallons of water shouldn't be a problem.     The water lines are also heavy vinyl.       

    Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor

    21 SW280 panels on Schletter ground mount

    48v Rolls 6CS 27P

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  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    edited September 2018 #63
    I wonder if one could purchase a plastic water utility or holding tank and cut the top off of it.

    I am available for custom hardware/firmware development

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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,889 ✭✭✭✭✭✭
    #64
    Still far less to worry about than a boat on the ocean :)

    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,101 ✭✭✭✭✭
    #65
    Pretty, Van Gogh'esk  graphic.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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  • softdown
    softdown Solar Expert Posts: 3,891 ✭✭✭✭
    #66
    WaterWheel said:
    Adding ice means more than just $2 a day.      it means the time and fuel stopping every day during the warmer months to purchase and add the ice.

    The largest roadblock to using a water bath (chilled, iced, or just water out of the hose) is building a water tight box which can be easily filled and drained that also has a vent fan, screened air intake holes, and a lid.     The box needs to withstand water pressure pushing out on the sides for 10+ years, have a liner than can resist 35% sulfuric acid (EDM is best but PVC should last over 10 years in light acid) and a drain that can also withstand being in a low concentration of acid for 10+ years. 

    If there is a problem with the drain or liner that box full of batteries is too heavy to move so it needs to be built right the 1st time.       In my case I do worry about the $20 pump holding up since I don't know what plastic it is made of or how the vinyl insulated cord will hold up but the tiny bit of acid diluted in 70 gallons of water shouldn't be a problem.     The water lines are also heavy vinyl.       

    I was merely suggesting to try it once, if convenient, and see what results are obtained. . 

    An idea (for future applications) on a battery box - an old chest freezer offers pretty good insulation and robust construction.

    Water pumps normally last several years if the manufacturer is good. I've used hundreds. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    #67
    Once you know how much ice/day is needed, then you can calculate the exact size chiller needed (for similar conditions).

    I am available for custom hardware/firmware development

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  • WaterWheel
    WaterWheel Registered Users Posts: 385 ✭✭✭
    edited September 2018 #68
    I'm now firmly of the opinion that a 1/6hp chiller would have been sufficient.      The current 1/4hp chiller draws 320 watts, a 1/6hp chiller draws about 230 watts.  

    The 1/4hp chiller is easily keeping the batteries around 75 degrees running 4 hours a day and if left running 8-10 hours would cool the batteries into the high 60's.
    2700 lbs of batteries sitting in 570 lbs of water.      3/4" plywood box with no insulation except 1.5" thick layer of 2x4s under the box (raised to make space for floor drain)  with air gaps between them... see picture post #35.
    Box lid left open but will be closed during the winter.

    Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor

    21 SW280 panels on Schletter ground mount

    48v Rolls 6CS 27P

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  • WaterWheel
    WaterWheel Registered Users Posts: 385 ✭✭✭
    edited September 2018 #69
    I was curious if the cooler water temperature was making the battery temperature sensor read low.      The sensor is attached to an inner battery cell wall with an air gap between it and the outer plastic battery shell and is below the water level.

    The battery sensor currently reads 74 degrees.      I used the temperature probe that came with a multi-meter and dipped it into the electrolyte in 4 cells.       All 4 cells are 73 degrees so the chilled water is not throwing off the battery sensor reading. 

    Cloudy morning so the batteries are just now nearing the end of absorb,    Air temperature is 87, water is 66, batteries are 74.      

    Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor

    21 SW280 panels on Schletter ground mount

    48v Rolls 6CS 27P

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  • softdown
    softdown Solar Expert Posts: 3,891 ✭✭✭✭
    #70
    Guess the battery temp might be in the 90's without the cooling apparatus. Seems pretty successful so far.

    There are dozens of variables that could be experimented with if so inclined. Impact of insulation etc. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • WaterWheel
    WaterWheel Registered Users Posts: 385 ✭✭✭
    edited September 2018 #71
    Update day 11

    Batteries have been in the same water the last 11 days with chiller running 4-6 hrs a day depending on how cloudy it's been.     Hot day today for the middle of September.

    12pm   air 91, battery 77, water 75, chiller just turned on
    3pm     air 95, battery 75, water 68, absorb ended about 2:30
    5pm     air 96, battery 73, water 64
    6pm     air 94, battery 73, water 63 chiller just turned off

    Without the chiller I'd expect to see the batteries over 100 degrees today.      As someone mentioned earlier in this thread preventing the batteries from gaining more heat than they can lose overnight is important.        Before the chilled water bath after a long spell of warm weather (over a week) I sometimes saw the batteries running 10-12 degrees warmer than the air temperature hours after absorb has ended and sometimes still above 90 degrees the next morning if we've had a week of 90+ degree days (74-80 degree nights).     So every day the batteries get a little hotter daily as the air temperatures stay roughly the same day after day until the batteries are staying 10+ degrees warmer than the air even at 5am.

    If using ice for cooling I could possibly see the need for insulation but the results with the chiller are fine without insulation, and the chiller is only using excess power during absorb and float.

    Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor

    21 SW280 panels on Schletter ground mount

    48v Rolls 6CS 27P

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  • Thick8
    Thick8 Registered Users Posts: 49 ✭✭
    #72
    I use a closed loop geothermal cooler for my PCs. I didn’t do a field installation but water bored a 35’ hole and dropped a homemade heat exchanger into it. Transferring about 1000 watts into the ground with a 12 volt 13 watt Swiftech PC pump. System water temp never gets above 78F. Will probably do something similar for my batteries.
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  • Thick8
    Thick8 Registered Users Posts: 49 ✭✭
    #73
    With both computers idling or light load (about 300 watts) the water temp is 72F. The ground water temperature is 69F year round so it could cool batteries in the summer and heat them in the winter.
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  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,166 ✭✭✭✭
    #74
    PV is still cheap and long lasting compared to batteries. When PV got really cheap, design approaches started shifting:
    Design a system for very low average daily DOD.
    Add enough PV to support some mechanical cooling for batteries and electronics in hot climates
    Get a solid 12-15 years from the battery bank.

    I always have more questions than answers. That's the nature of life.
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  • WaterWheel
    WaterWheel Registered Users Posts: 385 ✭✭✭
    #75
    Update on this water box with chiller.      About 3 weeks ago it was getting warm and I refilled the water box and set the chiller timer to kick on from 1 to 5:30.

    I'm rarely home during the day now days, the garage doors are closed allowing the garage where the batteries and chiller are to really heat up.      Outside air tempature in the low 90s this week and darn hot in the garage.     Probably over 100.       When I get home around 6:30 most days the batteries are around 74 degrees and the chilled water is about 66 degrees.

    Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor

    21 SW280 panels on Schletter ground mount

    48v Rolls 6CS 27P

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  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    #76
    > When I get home around 6:30 most days the batteries are around 74 degrees

    Just curious - what is the water and battery temperature the next morning?

    I am available for custom hardware/firmware development

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  • WaterWheel
    WaterWheel Registered Users Posts: 385 ✭✭✭
    edited May 2019 #77
    jonr,     Before I built the chilled water box my batteries would never go below 85 degrees for 3-5 months a year and bump into the 100 range by August.      

    The batteries usually drop another degree or two overnight and the water warms up so at say 8am the water is about 70 degrees and the batteries are 73 degrees.

    Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor

    21 SW280 panels on Schletter ground mount

    48v Rolls 6CS 27P

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  • WaterWheel
    WaterWheel Registered Users Posts: 385 ✭✭✭
    #78
    I have a medium sized frog living in the water bath.

    The battery box is in my garage and I haven't changed the water in a few months.      The summer heat has cooled off so I drained the water box for the winter 2 days ago.      There is still about 1/4" of water in it which will evaporate over the next few weeks.
    I'm out in the garage tonight and I hear splashing from the battery box.       It took some searching but there is a good sized frog slipping between the batteries in the shallow water.       I couldn't catch him, hopefully he'll hop out.     

    Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor

    21 SW280 panels on Schletter ground mount

    48v Rolls 6CS 27P

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  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,166 ✭✭✭✭
    #79
    Maybe he is feeling energized? (Sorry, I couldn't help myself)
    I always have more questions than answers. That's the nature of life.
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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,101 ✭✭✭✭✭
    #80
    Marc Kurth said:
    Maybe he is feeling energized? (Sorry, I couldn't help myself)
    The energizer bunny has pretty much ran his course. I vote for a new mascot.

    Found this snippet online,
    Interesting Fact: The Energizer Bunny has nothing on the Energizer Frog. Solar energy is changed to plant matter by photosynthesis. That is eaten by tadpoles that grow into frogs who keep eating and growing until something eats them. This is a very efficient transfer up the food chain of solar energy.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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  • BoFuller
    BoFuller Solar Expert Posts: 187 ✭✭✭
    #81
    Marc Kurth said:
    PV is still cheap and long lasting compared to batteries. When PV got really cheap, design approaches started shifting:
    Design a system for very low average daily DOD.
    Add enough PV to support some mechanical cooling for batteries and electronics in hot climates
    Get a solid 12-15 years from the battery bank.

    This what I had in mind when I set mine up a few years ago. In the summer I produce way more energy than I need, so I run a swamp cooler in the solar shed to keep it from getting too hot. Swamp coolers work great in AZ.
    12 Kyocera 235 panels, 3 Gyll LiFePO4 batteries (previously 16 Trojan L16 RE-B batteries), Outback 3600W 48V system, Generac 11K propane backup generator, NW AZ, off grid, 6,000 ft (system installed in April 2015)

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  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,166 ✭✭✭✭
    #82
    BoFuller said:
    Marc Kurth said:
    PV is still cheap and long lasting compared to batteries. When PV got really cheap, design approaches started shifting:
    Design a system for very low average daily DOD.
    Add enough PV to support some mechanical cooling for batteries and electronics in hot climates
    Get a solid 12-15 years from the battery bank.

    This what I had in mind when I set mine up a few years ago. In the summer I produce way more energy than I need, so I run a swamp cooler in the solar shed to keep it from getting too hot. Swamp coolers work great in AZ.
    Until the Monsoons come in August, producing an 82F wet bulb. B)

    I always have more questions than answers. That's the nature of life.
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  • BoFuller
    BoFuller Solar Expert Posts: 187 ✭✭✭
    #83
    Marc Kurth said:
    BoFuller said:
    Marc Kurth said:
    PV is still cheap and long lasting compared to batteries. When PV got really cheap, design approaches started shifting:
    Design a system for very low average daily DOD.
    Add enough PV to support some mechanical cooling for batteries and electronics in hot climates
    Get a solid 12-15 years from the battery bank.

    This what I had in mind when I set mine up a few years ago. In the summer I produce way more energy than I need, so I run a swamp cooler in the solar shed to keep it from getting too hot. Swamp coolers work great in AZ.
    Until the Monsoons come in August, producing an 82F wet bulb. B)

    True that. But I find here at 6,000 ft that it usually cools off quite a bit when it rains.
    And this year was really weird. We usually get 8-12 inches of rain around here in August. This year is was zero. Seems our monsoon came in May this year instead of August.
    12 Kyocera 235 panels, 3 Gyll LiFePO4 batteries (previously 16 Trojan L16 RE-B batteries), Outback 3600W 48V system, Generac 11K propane backup generator, NW AZ, off grid, 6,000 ft (system installed in April 2015)

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  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,166 ✭✭✭✭
    #84
    BoFuller said:
    Marc Kurth said:
    BoFuller said:
    Marc Kurth said:
    PV is still cheap and long lasting compared to batteries. When PV got really cheap, design approaches started shifting:
    Design a system for very low average daily DOD.
    Add enough PV to support some mechanical cooling for batteries and electronics in hot climates
    Get a solid 12-15 years from the battery bank.

    This what I had in mind when I set mine up a few years ago. In the summer I produce way more energy than I need, so I run a swamp cooler in the solar shed to keep it from getting too hot. Swamp coolers work great in AZ.
    Until the Monsoons come in August, producing an 82F wet bulb. B)

    True that. But I find here at 6,000 ft that it usually cools off quite a bit when it rains.
    And this year was really weird. We usually get 8-12 inches of rain around here in August. This year is was zero. Seems our monsoon came in May this year instead of August.

    Ah, you are above the Rim - that changes everything in a good way!
    I always have more questions than answers. That's the nature of life.
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,889 ✭✭✭✭✭✭
    #85

    Hi Marc, Bo

    Where is the rim please guys? Thx!

    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • softdown
    softdown Solar Expert Posts: 3,891 ✭✭✭✭
    #86
    My guess is the Grand Canyon. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,889 ✭✭✭✭✭✭
    #87
    I think it is in Texas where they both are from.....
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • BoFuller
    BoFuller Solar Expert Posts: 187 ✭✭✭
    #88
    Grand Canyon
    12 Kyocera 235 panels, 3 Gyll LiFePO4 batteries (previously 16 Trojan L16 RE-B batteries), Outback 3600W 48V system, Generac 11K propane backup generator, NW AZ, off grid, 6,000 ft (system installed in April 2015)

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  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,166 ✭✭✭✭
    #89
    Dave Angelini said:
    I think it is in Texas where they both are from.....

    Hi Dave and Bo,
    I incorrectly assumed that he was in a different area of Arizona, like closer to Flagstaff. I was referring to the Mogollon Rim.
    Marc


    I always have more questions than answers. That's the nature of life.
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,889 ✭✭✭✭✭✭
    #90
    Yes been to that rim. Anything like that in Tejas with lakes and mountain views?  I did some searching and the ones I found were to remote for elderly folks. The one that looks decent so far is Lake Mead near Henderson out of Vegas.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,166 ✭✭✭✭
    #91
    Dave Angelini said:
    Yes been to that rim. Anything like that in Tejas with lakes and mountain views?  I did some searching and the ones I found were to remote for elderly folks. The one that looks decent so far is Lake Mead near Henderson out of Vegas.

    Nope, this state has a whole lot of lakes and rivers in the Central to Easter section - but they are forested in flatter areas.
    West Texas is where the mountains live, but it is extremely rocky and dry, like Mead - but very, very remote. We picked this spot for lower property taxes, because they are high in Texas - driven by local schools .  Yes, great medical facilities nearby for old guys like me is important! 
    I always have more questions than answers. That's the nature of life.
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