sealed lead acid to flooded lead acid battery

Discussion in 'The Projects Forum' started by roltex_rohit123, Apr 29, 2010.

  1. roltex_rohit123

    Thread Starter Member

    Jan 1, 2010
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    I have a sealed lead acid battery of 7.5 Ah from my computer UPS. it shows diminished performance but charges to 13.2 volts. I think the liquid inside it has evaporated. I am thinking of converting it to a flooded lead acid battery and use it for my emergency lantern. can I convert the sealed lead acid battery to a flooded one by pouring battery acid in it? then i could maintain it by adding water from time to time. is there any risk? will the battery work? I have a unrectified sourche to charge at 17 volts 1 amp which is maintained at 14.6 volts when connected to battery.
     
  2. retched

    AAC Fanatic!

    Dec 5, 2009
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    You can. The caution is when you remove the vents, to be sure to plug them to protect from spills.

    The innards of a SLA is much like a standard LA battery. The fill holes are plugged with rupture vents. You CAN remove the vents and fill the battery with water.

    You shouldn't have to add acid, just water. Use your desulfinator+charger to get the sulfates re-constituted into the electrolyte.
     
  3. SgtWookie

    Expert

    Jul 17, 2007
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    Check the manufacturer's datasheet to make sure that it is an SLA and not a gel cell.

    If it's a gel cell, you can't convert it.
     
  4. roltex_rohit123

    Thread Starter Member

    Jan 1, 2010
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    Its a battery from a UPS of my PC. and its definitely a sealed Lead Acid battery. if I just pour water to fill the cells then it would be too dilute because the is just enough acid to make it work in dry condition .so i think I should add acid so i make it to work as flooded lead acid battery.
     
  5. SgtWookie

    Expert

    Jul 17, 2007
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    If you change the specific gravity of the battery, it won't work properly.

    Hard to say how much water may have evaporated. You could try adding just enough distilled water to cover the plates, and then a little acid. Charge the cell. Keep reading the specific gravity while you are desulphating it. If the specific gravity at some point exceeds about 1.26, you will need to add more distilled water.

    If you simply add acid, you may wind up with electrolyte that is much too high in specific gravity after the lead sulphate has been dissolved back into the solution.

    Monitoring the specific gravity is really the only way you can get an idea of where you are, and where you need to go.
     
  6. retched

    AAC Fanatic!

    Dec 5, 2009
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    Adding acid is VERY rare. I work with hard used LA batteries every day, and I have never had to add acid in the course of standard use. If you spilled a new battery, maybe.

    But if the water evaporated, the electrolite would become very acidic and become sulfate rather quickly. Add distilled water and put on charge.

    I would use a pulse charger, and as SgtWookie said, check the specific gravity before charging and after your inital overnight charge.
     
  7. roltex_rohit123

    Thread Starter Member

    Jan 1, 2010
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    0
    I dont have anything to check the specific gravity of the acid. the battery has never spilled a drop since it was in my UPS cabinet. Once I added water to it but then it didnt help much. I think there has been a lot of sulphation inside. so i want to convert it to a flooded battery like car battery. I would add the special acid we get in our garages which is adjusted to the battery acid previously. it will not change the gravity in the cell and also dissolve the sulphate. then I would take pulse charging for some days. and also desulphate it for some days. the solution would be just right in a few days.
     
    Last edited: Apr 29, 2010
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