Homemade lead acid batteries



  • Deveak_KaizenDeveak_Kaizen Posts: 12Registered Users ✭✭
    Its kind of expensive in the US if you buy "battery acid" from auto stores, its pretty cheap if you buy in bulk from chemical suppliers.
    Some sell it by the ton for under 300 bucks. So pretty close to 2 bucks a gallon. Most likely your paying so much because of hazard shipping and environmental laws. While its messy, with some preparation you could filter and concentrate battery acid from car batteries.
  • mcgivormcgivor Posts: 2,062Solar Expert ✭✭✭✭
    edited March 18 #33
    @BjornM said, I know what you mean. Almost every single component for a DIY battery is hard to find in Sweden. Didn't use to be like that when I was a kid, but now everything is considered dangerous for people or the environment. I have no good source for sulfuric acid yet. Ironically it is one of the cheapest chemical substances in the world. When I lived in Thailand, you could buy it for $2 per gallon.

    The current price in Thailand is 10 Bhat per 620 ml beer bottle ~6 per US gallon, so still around  $2 at current exchange rates, probably much cheaper if purchased in bulk 
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • clockmanfranclockmanfran Posts: 22Registered Users ✭✭
    edited March 19 #34

    Battery Acid for our particular batteries would be Sulphuirc Acid, 1 to 15 ratio to De-ionised water/distilled water.

    I use a 80% sulphuric acid and can be readily obtained in  500ml bottles in Europe with out to many issues.   So 500ml would make about 7.5 litres, (about 1.5 us gallons). .....  See pic of bottle in my Fume cabinet, with the label disappearing from just the fumes alone.

    I think that this homemade battery topic may be raising false hopes regards getting batteries cheap, and now its getting technical and in the Dangerous Acid discussion area. Perhaps another more technical Forum may be better appointed.   Depends on the Mods here?

    Safety protection at all times.

    PLEASE PLEASE remember, NEVER NEVER NEVER ADD water to the NEAT Sulphuric ACID solution.

    ADD the Sulphiric Acid to the water very carefully and slowly, and let it disperse within the water. Even so when adding correctly in just one go, in one spot on the water, the solution gets very hot very quick, and spits and spatters.

    Don't mess with neat sulphuric acid it does permanent damage to our fleshy bodies.

    Everything is possible, just give me Time.

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  • BjornMBjornM Posts: 8Registered Users ✭✭
    edited March 25 #35
    Since the Plante method of forming lead sponge at the electrodes is so time consuming, how about make the electrodes really thin so the process can be faster?

    Lead has low structural integrity, and would easily fall apart when very thin. Instead, lead coated copper foil could be used. This foil could be sandwiched with very thin polypropylene felt, and rolled up into a cylindrical shape. Each layer around 3 mm thick.

    From a research article:

    "The conditions for copper corrosion were investigated with regard to its use as the negative grid material in high performance lead‐acid batteries with gelled electrolyte. The experiments on copper sheets show that only under very extreme conditions, when there is a thin electrolyte film on the surface and no lead coating over a distance of more than about 3 mm, copper dissolution can occur. In this case, substantial potential shifts in the thin electrolyte film, resulting in a much more positive potential at that part of the electrode, were measured. With a properly lead‐coated copper grid there will be virtually no copper corrosion even under starved electrolyte conditions."


    EDIT: Rewritten for clarity.
    Off grid in a small cottage in western Sweden.
  • Deveak_KaizenDeveak_Kaizen Posts: 12Registered Users ✭✭
    Neato! So you can use copper to strengthen the grid or plate? You can order fumed silica online. A rubber cork could be used as a over pressure valve. Not sure if a real 1-2 psi plastic one way valve could be had. The copper and pure lead would certainly mean a low resistance battery.  You could probably do a plante plate with an inner copper grid for strength. Eventually it will be exposed but by that time the plate would be pretty compromised anyways.
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