battery watering confusion

After 6 years I am now in the process of replacing my battery bank of 16 Trojan T-105's with DEKA batteries. I have religously watered the Trojan batteries and maintained them, and I am well pleased with them. I always brought the water up to the bottom of the fill well in accordance with the instructions of Trojans web site.

When I purchased the DEKA batteries, I was told NOT to bring the water up to the bottom of the fill well prior to charging but fill them only after a full charge has been performed. I am a little hesitant not to put distilled water in the batteries prior to charging.

Which method is correct, fill or not fill. :confused::confused:

Comments

  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: battery watering confusion

    as I was told, add water to cover the plate tops, charge, and after they cool, top off. When charging hard, the batteries heat up, fluid expands, and a freshly topped cell may overflow. New ones may not have as much spare space inside.
    YMMV.

    and you have unmixed acid & water, and needs a bit more charge to "stir" the mix ??
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  • Mangas
    Mangas Solar Expert Posts: 547 ✭✭✭✭
    Re: battery watering confusion

    I use a simple Plewes auto battery filler. Works great, no mess and doesn't overfill them. I remove water miser caps before using the filler.

    I keep a spare.
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF Custom House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    Re: battery watering confusion

    The primary reason is to prevent overflow when topped off in a partial charge state.

    Another issue is upsetting the uniform recharging of the plates. Added water at the top will create a 'supercharger' for the plate area at the top of the battery. Recharging involves the lead-sulfate (discharged) plate looking for water to converter back to sulfuric acid and leaving pure lead back in the plate. The lower part of the plate subject to higher acid concentration becomes the super-charger to the top section of the plate where the water is.

    In extreme case, this can put a very high recharge current density into a small area at top of plate, damaging plate or the separator between the plates resulting in higher battery leakage or battery failure.

    This is most likely after refilling when water is very low, near or beyond where top of plate is exposed. In this situation, add water in small amounts and physically rock battery (if possible) to mix up electrolyte before adding more water.