Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Many batteries in series (dangerous?)

  1. May 11, 2009 #1
    Is it dangerous to put, say, 100 D-cell batteries in series (the type you find in a flashlight)?
     
  2. jcsd
  3. May 11, 2009 #2

    chroot

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    That depends on your definition of "danger," I guess. It's less dangerous than typical 120V household mains, but it could still kill you.

    - Warren
     
    Last edited: May 11, 2009
  4. May 11, 2009 #3
    Their rating is about 2000 milliamp-hours, so you could light a 100-watt bulb for a few minutes. But it is dangerous to touch both ends at the same time.
     
  5. May 11, 2009 #4
    What is a reasonable limit where you don't have to worry about dying?
     
  6. May 11, 2009 #5

    chroot

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    40 volts is generally below the threshold of sensation, with dry skin. Below that, you're generally safe.

    - Warren
     
  7. May 11, 2009 #6

    RonL

    User Avatar
    Gold Member

    If the cells are ni-cads and fully charged you would have 125 volts DC, and if they are alkaline, you would have 150 volts DC, I believe both would kill a person.:frown:
     
  8. May 11, 2009 #7
    Thanks all, I will keep this in mind.

    I was googling around to find the answer to this, and as a result have another interesting but less practical question. A website claimed that if you have huge bleeding cuts on your hands, then the liquid blood could complete a circuit with much less resistance, thereby electrocuting you with as low as a 6V battery. Is this true?
     
  9. May 11, 2009 #8

    chroot

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    I don't know about electrocuting (killing) you, but it'd probably hurt like hell. Put a 9V battery on your tongue for a sample.

    - Warren
     
  10. May 11, 2009 #9
    Thats what I thought, but blood vessels travel through the heart on the way from one hand to another, so it seemed possible that it could disrupt the heartbeat rhythm.
     
  11. May 11, 2009 #10

    mgb_phys

    User Avatar
    Science Advisor
    Homework Helper

    There is also a fire and explosion risk if you short circuit them, especially if they are enclosed and so can't cool easily
     
  12. May 14, 2009 #11
    Are you actually thinking about doing this for something or are you asking this hypothetically? If so may I ask why? There might be better solutions.
     
  13. May 14, 2009 #12
    Ah the tongue voltmeter.Not to be recommended.:bugeye:
     
  14. May 17, 2009 #13
    Here people give advice on some deadly current machine and you are warning against 9V block licking? :uhh:
     
  15. May 17, 2009 #14
    Well,I like the taste of chlorine I get after eating a bag of salted peanuts and when I spark up I demonstrate the squeaky pop test for hydrogen.The biggest problem is that the tongue voltmeter is so difficult to calibrate.:wink:
     
  16. May 17, 2009 #15
    I've seen something similar done with 9V cells which clip nicely together in an end-to-end series chain of any arbitrary length.

    Seemed dangerous to me once you got above the safe ELV.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Many batteries in series (dangerous?)
  1. Batteries in Series (Replies: 5)

  2. Series battery (Replies: 39)

  3. Batteries in series (Replies: 6)

Loading...