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  1. Join Date
    May 2013
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    5
    #31
    Quote Originally Posted by 12vdc View Post
    ^ Wrong

    If you series the batteries it will produce 24 volts.
    Yes, the batteries are in parallel during jump start (+ to + and - to -). The series connection refers to the connection of the starter(load) and battery(source).

    While this is the case, I am not certain if this is why some call this a series connection. Maybe nakasanayan na lang din.

    Regarding jump start procedure, wouldn't it be safer to connect negative first? I believe the body is connected to ground(negative terminal of battery). If one were to connect the positive terminals first and somehow touch both car bodies without insulation the person would complete the circuit, possibly causing the current to pass through the person. As opposed to when we connect negative to negative first, where there is very little chance of accidentally connecting the positive terminals because of the relatively lesser exposed metal connected to them. Of course, this is based purely on electrical theory and I'm very open to correction. Wisest would be to follow what is stated in the user manual of your vehicle.

    As for jumper cable current rating, I'd go for at least double what your starter is rated.

  2. Join Date
    Jun 2012
    Posts
    1,490
    #32
    In a sense, may be true if the mechanic is careless.

    On the other hand, connecting the positive first, by the same careless mechanic and accidentally connected the negative of the jumper to a circuit more negative than the positive but more positive than the negative, then think about what will happen.

  3. Join Date
    Jun 2012
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    1,490
    #33
    Quote Originally Posted by alexverzosa View Post
    Yes, the batteries are in parallel during jump start (+ to + and - to -). The series connection refers to the connection of the starter(load) and battery(source).

    While this is the case, I am not certain if this is why some call this a series connection. Maybe nakasanayan na lang din.

    Regarding jump start procedure, wouldn't it be safer to connect negative first? I believe the body is connected to ground(negative terminal of battery). If one were to connect the positive terminals first and somehow touch both car bodies without insulation the person would complete the circuit, possibly causing the current to pass through the person. As opposed to when we connect negative to negative first, where there is very little chance of accidentally connecting the positive terminals because of the relatively lesser exposed metal connected to them. Of course, this is based purely on electrical theory and I'm very open to correction. Wisest would be to follow what is stated in the user manual of your vehicle.

    As for jumper cable current rating, I'd go for at least double what your starter is rated.
    Correct.
    During jumpstart, you are not connecting two batteries but a load so you can not say it is "parallel".

  4. Join Date
    Nov 2009
    Posts
    3,340
    #34
    Quote Originally Posted by alexverzosa View Post
    Yes, the batteries are in parallel during jump start (+ to + and - to -). The series connection refers to the connection of the starter(load) and battery(source).

    While this is the case, I am not certain if this is why some call this a series connection. Maybe nakasanayan na lang din.

    Regarding jump start procedure, wouldn't it be safer to connect negative first? I believe the body is connected to ground(negative terminal of battery). If one were to connect the positive terminals first and somehow touch both car bodies without insulation the person would complete the circuit, possibly causing the current to pass through the person. As opposed to when we connect negative to negative first, where there is very little chance of accidentally connecting the positive terminals because of the relatively lesser exposed metal connected to them. Of course, this is based purely on electrical theory and I'm very open to correction. Wisest would be to follow what is stated in the user manual of your vehicle.

    As for jumper cable current rating, I'd go for at least double what your starter is rated.
    Maybe the term was coined from early training on basic electricity like how to connect a light bulb of a flashlight using 2pcs size D batteries in series. Even if you put the starter (load) to the battery (source) it will still be in parallel.

    For DC system, positive first for safety. Chassis having the larger surface area(surroundings) is electrically negative. For AC system esp unbalanced transmission, lage grounding at neutral side ang una for safety.

    When buying jumper cable, inspect the quality of wires and how good the clamps and the crimping. The finer/heavier the strands on the same wire gauge means it could carry much current than those having larger strands.. Those in the market mostly are overrated so id suggest get the highest rating as possible just to be sure. Another is, during jump starting if you are unsure how good the car's chassis ground, id suggest clamp it directly to the negative terminal. I tried jump-starting L300 using Gauge 12 3C royal cord bolting it directly to the clamps. Considering diesel takes time to heat the heater and have larger starter motor, i would assume even a 150Amps cable would do the job for a gas engine.

  5. Join Date
    Mar 2008
    Posts
    49,434
    #35
    [QUOTE=alexverzosa;2179839]Yes, the batteries are in parallel during jump start (+ to + and - to -). The series connection refers to the connection of the starter(load) and battery(source).

    While this is the case, I am not certain if this is why some call this a series connection. Maybe nakasanayan na lang din.

    because they did not know any better..?
    besides, it is easier to say series than it is to say parallel..

  6. Join Date
    Jun 2012
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    1,490
    #36
    Quote Originally Posted by 12vdc View Post
    Maybe the term was coined from early training on basic electricity like how to connect a light bulb of a flashlight using 2pcs size D batteries in series. Even if you put the starter (load) to the battery (source) it will still be in parallel.
    Thevenin's Theorem states:

    Any linear electrical network with voltage and current sources and resistances can be replaced at terminals A-B by an equivalent voltage source Vth "in series connection" with an equivalent resistance Rth.

  7. Join Date
    Mar 2008
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    49,434
    #37
    Quote Originally Posted by confused shoes View Post
    Thevenin's Theorem states:

    Any linear electrical network with voltage and current sources and resistances can be replaced at terminals A-B by an equivalent voltage source Vth "in series connection" with an equivalent resistance Rth.
    i think it means, you connect the other car's battery in series with the starter of the car with dead battery, and, necessarily, in parallel with the dead battery.

  8. Join Date
    Jun 2012
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    1,490
    #38
    Quote Originally Posted by dr. d View Post
    i think it means, you connect the other car's battery in series with the starter of the car with dead battery, and, necessarily, in parallel with the dead battery.
    Correct dr.d.
    In this case, the dead battery is already a load (no longer a source) and is receiving current from the live battery.

  9. Join Date
    Nov 2009
    Posts
    3,340
    #39
    Quote Originally Posted by confused shoes View Post
    Thevenin's Theorem states:

    Any linear electrical network with voltage and current sources and resistances can be replaced at terminals A-B by an equivalent voltage source Vth "in series connection" with an equivalent resistance Rth.
    That is true when you consider the wires as part of the resistance.

    But Kirchhoff's law states " in parallel circuit the total current is the sum of the currents through the individual components"

  10. Join Date
    Oct 2011
    Posts
    26,770
    #40
    Kung ang dead battery ay considered na load edi magiging simple series circuit yan. But could we consider the dead battery as a load? Baterya or source supple un eh mahina lang nga voltage.

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