Using a 2 watt coleman battery maintainer to keep batteries alive when not in use.

rp3703rp3703 Posts: 111Registered Users ✭✭

Just for peace of mind, I’m trying to figure out if these coleman battery maintainers will keep my batteries alive through a Northern Ontario winter. I paired my 6V 215 AH batteries to make them 12V and attached a maintainer to each pair. The maintainers state they can deliver 15V @ 133 mAmps. Other than that, I can find no other info on them. Is it possible to make a good estimate of the viability of them keeping the batteries alive?

1860 W (6) Rensola JC310M, Classic 150, [email protected] (8) Deka DSGC15 FLA's, Victron Phoenix Multi 24/2500 Inverter
Powering-20.5 CuFt. Fridge, 1 HP Submersible water pump, UV, Washing Machine, Gas Dryer, Gas Stove, Lights and Receptacles
Off Grid Cottage on lake in Northern Ontario 46˚N 

Comments

  • mcgivormcgivor Posts: 2,299Solar Expert ✭✭✭✭✭
    Northern Ontario winters are generally cold so self dischargeing would be of little concern if fully charged, left disconnected in an unheated space. Leaving something connected, in your absence could fail in undesirable ways. When fully charged a flooded lead acid battery will not freeze until -70°C, upon returning fully charge before use. Attached pdf provides information 
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 

  • EstragonEstragon Posts: 2,920Registered Users ✭✭✭✭✭
    With no controller between the panel and battery, I'd be a bit concerned there may be nothing preventing the batteries from keeping the panel warm. Maybe there's a blocking diode stopping higher voltage batteries from discharging into a lower voltage panel, but I wouldn't count on it without testing.

    In a Northern Ontario winter, the batteries will be pretty cool most of the time, and have lower self-discharge. With no loads and fully charged, they should be fine from ~Oct-May.
    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
  • 706jim706jim Posts: 216Solar Expert ✭✭✭
    Another voice saying just leave them alone over the winter.
    Island cottage solar system with 1400 watts of panels, Trace DR1524 MSW inverter, Trace C40 PWM controller 8 Trojan L16's. My 25th year.
  • rp3703rp3703 Posts: 111Registered Users ✭✭
    In case it was not obvious, I was asking whether this would work after the fact. I left my batteries like this at the end of last season and now I'm freaking out that they will be dead or after hearing from you guys, exploded with battery acid running all over the floor.
    1860 W (6) Rensola JC310M, Classic 150, [email protected] (8) Deka DSGC15 FLA's, Victron Phoenix Multi 24/2500 Inverter
    Powering-20.5 CuFt. Fridge, 1 HP Submersible water pump, UV, Washing Machine, Gas Dryer, Gas Stove, Lights and Receptacles
    Off Grid Cottage on lake in Northern Ontario 46˚N 
  • mike95490mike95490 Posts: 7,952Solar Expert ✭✭✭✭
    I've got a battery maintainer, and it has a red LED that lights when charging.  It could be wired for forward/indicator and reverse/blocking, not sure if LED specs can handle 15Vrev bias
    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 ,

  • BB.BB. Posts: 28,034Super Moderators, Administrators admin
    edited June 13 #7
    I have had very good with Battery Minders

    https://www.amazon.com/BatteryMINDer-Model-2012-Maintainer-Motorcycles/dp/B005EKY1EM

    On car batteries (that are rarely driven). Regular chargers and cheap float chargers would cause long term loss of water.

    When the charger reads full you can move to the next set of batteries (1 or so days of charging). Reconnect every 30 days of 70f or 20c. If batteries are very cold (near or below freezing) then very low self discharge.

    Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mcgivormcgivor Posts: 2,299Solar Expert ✭✭✭✭✭
    edited June 13 #8
    rp3703 said:
    In case it was not obvious, I was asking whether this would work after the fact. I left my batteries like this at the end of last season and now I'm freaking out that they will be dead or after hearing from you guys, exploded with battery acid running all over the floor.
    Hopefully no damage has occurred, the charger, according to specifications, can provide 2W under optimum conditions, being that the winter sun would be weak and of short duration, optimum conditions are unlikely, so if it could manage 50% output for 2 hours the voltage would likely remain well below 15V. Hope everything is fine.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 

  • EstragonEstragon Posts: 2,920Registered Users ✭✭✭✭✭
    edited June 13 #9
    > @rp3703 said:
    > In case it was not obvious, I was asking whether this would work after the fact. I left my batteries like this at the end of last season and now I'm freaking out that they will be dead or after hearing from you guys, exploded with battery acid running all over the floor.

    Most likely, the batteries are fine. If not, all you can do is make contingency plans. Freaking out won't make any difference to the batteries.

    Earlier advice about leaving batteries alone for the winter was based on a ~Oct to May period when it's cool/cold. As it usually does, it warmed up in early May, with a few days near 30°C since, so having a maintainer may not be a bad idea.
    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
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