Is this a start of a practical solution for charging LiFePO4 batteries in temps to -20*C

westbranchwestbranch Posts: 5,087Solar Expert ✭✭✭✭
 
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Comments

  • mike95490mike95490 Posts: 7,873Solar Expert ✭✭✭✭
    Looks like a battery with an integral thermostat & heater.   Without the heater, the battery will be damaged.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • EstragonEstragon Posts: 2,770Registered Users ✭✭✭✭
    Presumably with the heater integrated, failure might allow for a warrany claim, vs an external heater failure which wouldn't.

    The specs say max of one battery in series though, so limited to [email protected] Hopefully my L16s will hang in until less limited.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • mcgivormcgivor Posts: 2,164Solar Expert ✭✭✭✭✭
    Interestingly it says it takes 10A for 1 hour from the charger which would equate to ~130 Wh for a 12V nominal battery, the question is how many cycles of heating are required, in off-grid the charging is limited to a few hours per day, I would assume the heating is thermostatically controled, heating as needed,  if so it may self sacrifice overnight, or dose it preheat before charging. They do come at a premium cost wise, almost 4× the price of loose prysmatic cells, my particular case is at the other end of the spectrum, but given the challenge of dealing with cold, my thoughts would be along the lines of commercially available heating blankets and a control circuit perhaps using a diode to clip half the waveform to reduce current as needed. Just pondering the question of how to solve the issue and fractional divisions thereof. Nothing serious. 
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 

  • mike95490mike95490 Posts: 7,873Solar Expert ✭✭✭✭
    Since LI batteries have so little internal resistance, very little self-heating in our "solar" environment. If used for starting a car in Alaska, they can discharge (crank the engine) and then, since in the colder climes - engines are left running, it would have the time to be heated, and then charged.  On solar, it will hopefully not bleed itself dead overnight, and when charge voltage is applied in the AM, start it's heating cycle, and when warm, start charging, so you may loose an hour of harvest as it warms.    If thoughtfully insulated in the winter, it may not chill to the point where it needs heat daily.   Or throw a hot water bottle into the insulated battery box when you go to bed at night.

    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • Dave AngeliniDave Angelini Posts: 3,960Solar Expert ✭✭✭✭
    If you live there full time it is not that hard. Part time is a major mistake to use LFP, unless cost is not an issue. I have client like that and I like her for many reasons :)
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • oil pan 4oil pan 4 Posts: 739Solar Expert ✭✭✭✭
    I have charged lithium batteries at 3C and they barely put off any heat.
    You would have to charge a LiFePO4 battery the size of a forklift battery to get it to build any useable heat.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

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