winter recommendations

well, It has been a while since I have posted any cries for help, and in fact things ran smoothly for the duration of the summer for my first solar installation on my Travel trailer. now we have parked the trailer for the season, and I am wondering how my batteries will fair over the winter. the modules aren't in the best location for full power production, but I'd say they get at least 3-4hrs of direct sunlight a day, which seems to be keeping the battery bank state of charge around 12.8v. does anyone have any suggestions for maintaining batteries in the off season?

Comments

  • BB.BB. Super Moderators Posts: 26,867 admin
    Re: winter recommendations

    Keep them fully charged and check the water once a month or so until you figure out how often you need to check.

    Monitor the float voltage--if your controller has a float setting.

    If you are not using any power, and your controller does not have a float setting or adjustment--you can probably just turn on the solar charger one day per week to keep the batteries topped off and avoid overcharging (which may be your bigger problem at this time).

    Without searching your previous posts--knowing the battery type, total AH/voltage rating, and controller brand/model would probably get you a more exact answer.... i.e., if these are flooded cell batteries, you still want to equalize them once per month or so to keep the electrolyte well mixed, if your area freezes--how cold does it get--flooded cell batteries that are near dead freeze very easily--AGM's are not susceptible to freeze damage at all--but you need dto avoid charging while any battery type is frozen, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: winter recommendations

    these are sound recommendations thank you. I guess at this point I should avoid leaving the charger on full time like I have been. What I have are two AGM 220 AH deka batteries, and the charge controller is a mppt bluesky
    3024di. As for the climate here in Montana, things will definately be dropping below zero through out the winter, so If it has been wicked cold out, I should hold off on charging until things warm up a bit?

    -and I am hoping to use some power probably just by running an extension cord from the inverter to our cabin, twould be a shame to use all coal power, when I have free juice from the sun...
  • icarusicarus Solar Expert Posts: 5,090 ✭✭✭✭
    Re: winter recommendations

    Assume you have a good charge controller, and you have no phantom loads, you will be fine. I have one system that sits alone for 7 months, through the winter. The batteries just sit there fully charged, and even thought they get to -40 once in a while, they are fine after 10 years.

    As Bill says, check the water if you can, and if you can check the cells with a hydrometer every month or so. A Dead cell can kill the whole string, depending on how long it is left on the string,

    Tony
  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: winter recommendations
    ...two AGM 220 AH deka batteries, and the charge controller is a mppt bluesky 3024di.
    The batteries are sealed AGM models, so the electrolyte level can't be checked, nor should they be equalized in the conventional sense. If they're just going to sit and be maintained by the PV array and controller, then I recommend you set the target absorption- and float voltages (ref 77 F) at the lower end of the ranges suggested by East Penn (Deka and MK).

    See: http://www.eastpenn-deka.com/assets/base/0139.pdf

    All of this assumes that the controller has a remote batetry temp sensor attached to the battery bank.

    HTH,
    Jim / crewzer
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: winter recommendations

    as crewzer said and once everything is right with proper voltages set and a bts it is fine to leave it on all of the time as the controller won't let anything bad happen to the batteries assuming there's no loads on the batteries. if no sun for awhile, it will be ok as agms will hold their own longer than standard lead acid batteries as their self-discharge rates are lower and being more efficient they charge up slightly faster too. only problem may be snow on the pvs longer than you'd like, but as said the batteries have a lower self-discharge rate.
  • mike95490mike95490 Solar Expert Posts: 7,307 ✭✭✭✭
    Re: winter recommendations
    solsauce wrote: »
    well, It has been a while since I have posted any cries for help, and in fact things ran smoothly for the duration of the summer for my first solar installation on my Travel trailer. now we have parked the trailer for the season, and I am wondering how my batteries will fair over the winter. the modules aren't in the best location for full power production, but I'd say they get at least 3-4hrs of direct sunlight a day, which seems to be keeping the battery bank state of charge around 12.8v. does anyone have any suggestions for maintaining batteries in the off season?

    IF you have no loads on the batteries, you should be fine, as long as your charger does not overcharge the batteries. Fully charged flooded cells (and AGM I suppose) won't freeze till they are about - 77F, I think thats when tires break off the rims.
    http://jgdarden.com/batteryfaq/carfaq4.htm#freeze_points
    If they are true AGM's 3-4 hours of sun, per week, should be enough, if there are no loads.
    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

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