Can you Equalize Flooded 12V with Solar over a a few days?

The general consensus I read with off grid is there isn't enough sunhours to reliably EQ.

But for 12V batteries sitting on standby that get used a handful of times a year, can you simply run the EQ in mppt controller,
and then run again(re-continue) the next day? Assuming of course in between days the battery is not discharged.

My understanding is the amount of wattage/current needed is small to perform an EQ, like C/20 or less. Is this true?

ATM I have a Century 12V marine Deep cycle & the specifications seem to suggests an EQ every 3 months or so for a few hours at around 15volts+.

thanks







Comments

  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    Equalization can be continued on the next day, if needed, not loading them in the interim is a requirement , however it's best to EQ when required. By this I mean using a hydrometer to check the specific gravity of the electrolyte, if all the cells are according to specifications there is no need to perform an EQ. Lightly used batteries may require less EQ, than recomendations call for, specific gravity is the bench mark method of determining when it's actually required. Get a good quality glass type hydrometer, check the SG before making the decision as equalization is actually hard on batteries. 
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    Also consider if you have enough power to reduce stratification.

    I am available for custom hardware/firmware development

  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    edited December 2018 #4
    My understanding is the amount of wattage/current needed is small to perform an EQ, like C/20 or less. Is this true?
    Since equalizing starts with a fully charge battery, that basically won't take more than 1-2% of it's capacity at normal voltages, it usually only requires 5% of your battery capacity or less. So yes.

    You can certainly equalize on solar alone! It may be a misconception that you can't because people often use timed absorb cycles. I usually pick a couple sunny days even this time of year, when days are short and I'll try to reduce loads at night as much as possible. It's very easy when we get 2 sunny days when I spend the night in town. Then by noon my batteries are fully charged and I can start a maintenance equalizing cycle. 

    Corrective equalizing can go on for days, and in that case, a generator is a bit easier, but I've never used one with my batteries and have been dealing with it okay. 
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭

    But for 12V batteries sitting on standby that get used a handful of times a year, can you simply run the EQ in mppt controller,
    and then run again(re-continue) the next day? Assuming of course in between days the battery is not discharged.

    Used a handful of times, it's not likely they need EQ, if they have been kept de-stratified and charged.

    EQ is only done when needed
    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 ,