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Bad battery?????

Discussion in 'Power Electronics' started by bigone5500, Aug 10, 2014.

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  1. bigone5500

    bigone5500

    712
    120
    Apr 9, 2014
    I have a couple SLA batteries which show to have ~5.8v. I want to try to top them off with my automatic float charger which is a Schumacher battery companion. It charges at 1.5A and will maintain either 12v or 6v batteries. I have used it on this type battery before and it does a good job.

    However...

    When I connect the leads to these batteries, the indicator does not show charging. It is supposed to change to yellow when charging and green when done. It just stays green.

    I'm wondering if the battery is bad. I thought maybe there is a problem with a cell and tried to check the resistance across the terminals but could not get a reading. How can I check these batteries to know if they are bad.
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,482
    2,830
    Jan 21, 2010
    Read the voltage across the battery with the charger connected.

    Then read the voltage across the battery with a reasonable load connected (perhaps 1A or more).

    Tell us what they are.
     
  3. bigone5500

    bigone5500

    712
    120
    Apr 9, 2014
    Connected it to the flashlight it goes in and it drops to .4 - .5v.
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,482
    2,830
    Jan 21, 2010
    That's way too low for a lead acid battery. Either your load is much too large for the battery (and I'd be expecting melting wires if the battery were good) or the battery is dead.

    You didn't say what the voltage was when connected to the charger. I expect it jumps almost immediately up to the end of charge voltage.
     
    KrisBlueNZ likes this.
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