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Re: [hreg] FW: solar lawnmowers

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  • James Ferrill
    Right. On the sci.chem.electrochem.battery newsgroup a number of months ago, we had a big thread going on to hash out the myth. The best that anyone came up
    Message 1 of 5 , Jun 2, 2000
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      Right. On the sci.chem.electrochem.battery newsgroup a number of months ago,
      we had a big thread going on to hash out the myth. The best that anyone came
      up with was back after the turn of the century, batteries were made of wooden
      boxes lined with tar paper. If you set this on a concrete floor and the
      battery leaked a little (which was fairly common), a conductive path would be
      set up that would drain the battery. Concrete reacts really well with battery
      acid. I still know people who won't put a battery on the floor unless it's
      setting on a piece of wood because of that myth.

      James


      "Kevin L. Conlin" wrote:

      > The myth about batteries and concrete is that by leaving them directly on
      > top of a concrete floor, the concrete "drains" the charge out of the
      > battery. This hasn't been true since WW2, but a lot of people still swear
      > by it since their father or grandfather drilled it into their heads. None
      > of them can ever explain why this will happen, since it normally rests on
      > conductive metal in a car, but they will adamantly swear it's true.
      >
      > ----- Original Message -----
      > From: s askew <rsaskew@...>
      > To: <hreg@egroups.com>
      > Sent: Friday, June 02, 2000 10:49 AM
      > Subject: Re: [hreg] FW: solar lawnmowers
      >
      > > I am not sure what the myth about batteries and concrete is, but
      > > from my experience a battery that leaks at all will begin to eat
      > > the concrete. I now store batteries in a plastic tub and have
      > > added some baking soda at the bottom hoping to neutralize any
      > > acid that does leak.
    • Kevin L. Conlin
      Hi James, Your theory on the self discharge is correct, however the mechanism was a little different. The actual reason, according to my battery expert, is as
      Message 2 of 5 , Jun 3, 2000
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        Hi James,

        Your theory on the self discharge is correct, however the mechanism was a
        little different. The actual reason, according to my battery expert, is as
        follows.

        Before and during WW2 battery manufacturers made the battery cases out of a
        hard rubber material called ebonite. After the Japanese took over the
        rubber plantations of southeast asia and the Pacific islands, rubber came in
        short supply. In order to stretch their limited supply, the battery
        manufacturers started mixing small bits of flax and cotton in with the
        ebonite to act as a filler and conserve the rubber. These impregnated
        fibers were slightly conductive electrically. When a battery was left on
        concrete, the change in temp from night to day, and the batteries' high
        thermal mass would cause condensation under the battery, wicking up from the
        concrete. The conductive fibers in the cells would cause a slight short
        circuit between the cells in the battery, draining it. This was compounded
        by the fact that the batteries were not built as well as today's batteries,
        and they tended to self discharge faster anyway. The combination of self
        discharge and short circuits between the cells made the battery go dead very
        quickly. Thus, a battery stored for several weeks or months on a concrete
        floor would be completely dead, and ruined because of the resulting
        sulfation. After WW2, all the battery manufacturers converted to plastic
        cases, and the problem went away, forever, however the myth hasn't.

        I have to attribute this information to Foster Faerman at Tideland Signal,
        who knows more about lead acid batteries than anyone else I know. His
        father used to own a small battery manufacturing plant, and he literally
        grew up in the battery business. When I asked him about the myth many years
        ago, he reeled off the explanation quickly and succinctly, and it makes
        perfect sense to me. So there you have it, that's my explanation, but I
        liked your deductive reasoning as well. I wonder if anyone else can add to
        the unraveling of this myth.

        Best regards, Kevin PS How's the Solar Clubhouse coming? Will
        it be ready in time for football season?
        ----- Original Message -----
        From: James Ferrill <jferrill@...>
        To: <hreg@egroups.com>
        Sent: Friday, June 02, 2000 9:04 PM
        Subject: Re: [hreg] FW: solar lawnmowers


        > Right. On the sci.chem.electrochem.battery newsgroup a number of months
        ago,
        > we had a big thread going on to hash out the myth. The best that anyone
        came
        > up with was back after the turn of the century, batteries were made of
        wooden
        > boxes lined with tar paper. If you set this on a concrete floor and the
        > battery leaked a little (which was fairly common), a conductive path would
        be
        > set up that would drain the battery. Concrete reacts really well with
        battery
        > acid. I still know people who won't put a battery on the floor unless it's
        > setting on a piece of wood because of that myth.
        >
        > James
        >
        >
        > "Kevin L. Conlin" wrote:
        >
        > > The myth about batteries and concrete is that by leaving them directly
        on
        > > top of a concrete floor, the concrete "drains" the charge out of the
        > > battery. This hasn't been true since WW2, but a lot of people still
        swear
        > > by it since their father or grandfather drilled it into their heads.
        None
        > > of them can ever explain why this will happen, since it normally rests
        on
        > > conductive metal in a car, but they will adamantly swear it's true.
        > >
        > > ----- Original Message -----
        > > From: s askew <rsaskew@...>
        > > To: <hreg@egroups.com>
        > > Sent: Friday, June 02, 2000 10:49 AM
        > > Subject: Re: [hreg] FW: solar lawnmowers
        > >
        > > > I am not sure what the myth about batteries and concrete is, but
        > > > from my experience a battery that leaks at all will begin to eat
        > > > the concrete. I now store batteries in a plastic tub and have
        > > > added some baking soda at the bottom hoping to neutralize any
        > > > acid that does leak.
        >
        >
        > ------------------------------------------------------------------------
        > Best friends, most artistic, class clown Find 'em here:
        > http://click.egroups.com/1/4054/0/_/58590/_/960004984/
        > ------------------------------------------------------------------------
        >
        >
      • James Ferrill
        ... That s a really good explaination. We ought to collect those into a book. One guy in that newsgroup made up a bogus explaination that postulated that there
        Message 3 of 5 , Jun 3, 2000
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          "Kevin L. Conlin" wrote:

          > Your theory on the self discharge is correct, however the mechanism was a
          > little different. The actual reason, according to my battery expert, is as
          > follows.

          That's a really good explaination. We ought to collect those into a book. One
          guy in that newsgroup made up a bogus explaination that postulated that there
          were concrete mites and acid mites that multiplied into battery-draining
          colonies when batteries were put on concrete. It wasn't true, but the way he
          told it was hilarious! :-)

          > Best regards, Kevin PS How's the Solar Clubhouse coming? Will it
          > be ready in time for football season?

          Things have been going well. I start a new job Monday, so I'll be able to
          continue buying solar toys :-) I finished the battery cabinet Tuesday, put it in
          the shed, and vented it to the outside. It has one 24V string of 4 golf cart
          batteries @ 220 AH installed and connected to the bus bar system. I'll probably
          put in another set tomorrow if I can find enough good ones at Sams.
          Unfortunately, they back-ordered my charge controller, so I'm going to get
          another one so I can move the project along. It's supposed to be raining anyway
          for a few days, so I'll have to wait to mount the panels.

          James
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