sulphuric acid vapor during charging

cosmicray Registered Users Posts: 24 ✭✭
I've noticed that I get a fine amount of sulphuric acid vapor deposited on the top surface of my GC-2 batteries during normal charging. The dampness was confirmed to contain sulphuric acid by neutralizing it an old tooth brush and some baking soda.

Is this deposited sulphuric acid meaningful in relation to what is still in the cells ? Over time do I need to consider adding some to make up for the loss ? The batteries are being charged outdoors, under an awning, so the vapor is not concentrating indoors. Batteries are about 2 years old.



  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    That dampness becomes conductive and can be a parasitic load on the batteries.  As to whether you lose enough electrolyte to have a significant effect on battery capacity, I'm not sure. 

    Forum member @blackcherry04 has pointed out that you can aim the vents on your battery caps to avoid putting the spray on your terminal lugs.

    I use WaterMiser caps on my batteries and they really do work to keep the sulfuric acid in the battery.

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    It's not really "vapor".  It's mist from the gas bubbles popping. Each time one pops, a little drop of electrolyte mix is launched.  Once in a while, it gets out through the vent hold and lands on the top of the battery case, or underside of the battery box lid......  over years, it might amount to a tablespoon full.  I've never heard of needing to add more acid to compensate for it.
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  • Mangas
    Mangas Solar Expert Posts: 547 ✭✭✭✭
    Water Misers here too.  Definitely reduced my watering schedule to 3 or 4 times a year.  I use the shorter caps on the Trojan L 16 REBs'.

    Droplets on some of the caps never seemed to effect my SG levels or battery life.

    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
  • Johann
    Johann Solar Expert Posts: 245 ✭✭✭
    Is it common to see sulfur deposits on the outside of GC-2 batteries or is it a sign from overcharging those batteries?

  • cosmicray
    cosmicray Registered Users Posts: 24 ✭✭
    Johann said:
    Is it common to see sulfur deposits on the outside of GC-2 batteries or is it a sign from overcharging those batteries?

    From what I saw in the used pile, back when I was buying batteries, I think it is. Most of the actual golf-cart owners probably expect to replace them every X years, and don't pay that much attention to the accumulation of deposits/crud. It would be an interesting experiment to take some baking soda along, and see how many of those junked batteries fizz when a little is applied.