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120v dc charger

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  • 21-07-2014 3:43pm
    #1
    pedronomix
    Closed Accounts Posts: 997 ✭✭✭


    anyone any idea where I could get my hands on a cheap one of these only need up to 1 amp.

    cheers

    Pedro


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    #2
    adrian92
    Registered Users Posts: 566 ✭✭✭adrian92


    Just curious about the application for this? Is the 120v battery made up, for instance, by a number of low voltage batteries in series?


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    #3
    pedronomix
    Closed Accounts Posts: 997 ✭✭✭pedronomix


    adrian92 wrote: »
    Just curious about the application for this? Is the 120v battery made up, for instance, by a number of low voltage batteries in series?


    Yip 102 NiMh cells !! I just need to get them up to 110V to allow installed charger to take over.. I now only have 42v and need north of 100V!!


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    #4
    Sir Arthur Daley
    Closed Accounts Posts: 6,720 ✭✭✭Sir Arthur Daley


    Do these batteries have to be rechargeable?


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    #5
    pedronomix
    Closed Accounts Posts: 997 ✭✭✭pedronomix


    Sir Arthur Daley wrote: »
    Do these batteries have to be rechargeable?

    I am looking for a charging solution, not batteries.. they are NiMh cells.


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    #6
    Sir Arthur Daley
    Closed Accounts Posts: 6,720 ✭✭✭Sir Arthur Daley


    pedronomix wrote: »
    I am looking for a charging solution, not batteries.. they are NiMh cells.

    Nimh cells are batteries are they not?


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    #7
    pedronomix
    Closed Accounts Posts: 997 ✭✭✭pedronomix


    Sir Arthur Daley wrote: »
    Nimh cells are batteries are they not?

    They are, I have them.. what is it you have to offer on the topic of charging them? Anything?


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    #8
    Sir Arthur Daley
    Closed Accounts Posts: 6,720 ✭✭✭Sir Arthur Daley


    pedronomix wrote: »
    They are, I have them.. what is it you have to offer on the topic of charging them? Anything?

    In post 3 you said you need them yet now you say have them so have you acquired them since that post?


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    #9
    pedronomix
    Closed Accounts Posts: 997 ✭✭✭pedronomix


    Cognitive issue Dear Boy, read all the posts slowly from the top, if you get lost read them again in sequence. 102 cells answer in Post #3 refers to question posed in Post #2.


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    #10
    adrian92
    Registered Users Posts: 566 ✭✭✭adrian92


    Would it be an option to arrange a number of batteries , in parallel, to make up, say 12volt x 10 in parallel and charge using a 12v charger? (total charging current supplied would, in this case, be 10A not 1 A.)


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    #11
    Sir Arthur Daley
    Closed Accounts Posts: 6,720 ✭✭✭Sir Arthur Daley


    Im sorry, i took the understanding that you wanted to make up 120 volts with batteries. Anyway my decipher of it was wrong. My bad.


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    #12
    pedronomix
    Closed Accounts Posts: 997 ✭✭✭pedronomix


    Sir Arthur Daley wrote: »
    Im sorry, i took the understanding that you wanted to make up 120 volts with batteries. Anyway my decipher of it was wrong. My bad.

    Gracious! :)


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    #13
    pedronomix
    Closed Accounts Posts: 997 ✭✭✭pedronomix


    adrian92 wrote: »
    Would it be an option to arrange a number of batteries , in parallel, to make up, say 12volt x 10 in parallel and charge using a 12v charger? (total charging current supplied would, in this case, be 10A not 1 A.)

    It would be seriously dangerous to the cells to try to charge them at 10A...max max 1.O but 500mA would be much more preferable.


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    #14
    adrian92
    Registered Users Posts: 566 ✭✭✭adrian92


    I meant the current supplied by the charger, in my example, would be the sum of the 10 seperate currents to each of the 12 battery units. (e.g 1A/12volt battery pack).-just an example)


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    #15
    pedronomix
    Closed Accounts Posts: 997 ✭✭✭pedronomix


    Such a solution could be a major problem technically, ideally a 0-150v supply with current controlled to 0.5-max 1.0Amps. Fully charged this cell pack has 3.5Kw, plenty to stop your heart or perhaps even kill you.


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    #16
    adrian92
    Registered Users Posts: 566 ✭✭✭adrian92


    Why is that; would it be difficult to wire them (temporarily) into a number of 12 volt packs; connect the 12v packs in parallel and use a 12v charger?

    (out of curiosity I was wondering what is thwe appliction for a 120v DC supply??)


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    #17
    Chet T16
    Registered Users Posts: 2,320 ✭✭✭Chet T16


    adrian92 wrote: »
    Why is that; would it be difficult to wire them (temporarily) into a number of 12 volt packs; connect the 12v packs in parallel and use a 12v charger?

    (out of curiosity I was wondering what is thwe appliction for a 120v DC supply??)

    You would need to ensure equal current to each battery pack as the internal resistances will probably be different.

    Op, how about this
    http://www.circuitspecialists.eu/power-supplies/bench-power-supplies/low-cost-single-output-bench-power-supply-csi-12001x/


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    #18
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    pedronomix wrote: »
    Such a solution could be a major problem technically, ideally a 0-150v supply with current controlled to 0.5-max 1.0Amps. Fully charged this cell pack has 3.5Kw, plenty to stop your heart or perhaps even kill you.
    The kW capability would have little to do with the ability to inducing electric shocks. If 100 batteries in series can deliver 3.5kw, they can also deliver that in any configuration.

    The all important factor is the voltage. But even at 100 volts, it would be a fair achievement to get electrocuted.


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    #19
    pedronomix
    Closed Accounts Posts: 997 ✭✭✭pedronomix


    Chet T16 wrote: »
    You would need to ensure equal current to each battery pack as the internal resistances will probably be different.

    Op, how about this
    http://www.circuitspecialists.eu/power-supplies/bench-power-supplies/low-cost-single-output-bench-power-supply-csi-12001x/


    Saw it, love it, perfect for the job but to use it once and bin it is too rich for my blood but I would pay 30 yoyos to rent one for a day!!


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    #20
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Chet T16 wrote: »
    You would need to ensure equal current to each battery pack as the internal resistances will probably be different.

    It should be OK with nimh batteries though. Nothing like as critical as lipo type ones.


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    #21
    pedronomix
    Closed Accounts Posts: 997 ✭✭✭pedronomix


    Bruthal wrote: »
    The kW capability would have little to do with the ability to inducing electric shocks. If 100 batteries in series can deliver 3.5kw, they can also deliver that in any configuration.

    The all important factor is the voltage. But even at 100 volts, it would be a fair achievement to get electrocuted.

    Massive cardiac arrest is the other way, loads of examples on the web.


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    #22
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    pedronomix wrote: »
    Saw it, love it, perfect for the job but to use it once and bin it is too rich for my blood but I would pay 30 yoyos to rent one for a day!!
    I have done similar to get a fast charger to recognise aa nimh batteries who's voltage had gone too low for the fast charger to accept them as batteries.

    What I did was got them in series and measured voltage. I have a variable power supply with amp meter. Set to same voltage as batteries. Also put multi meter reading amps in circuit. Then slowly cranked up to about 500ma. Only took a few minutes to get the batteries to enough for fast charger to recognise.

    It goes up to 15 volts and 30 amps so would do a fair few in groups I suppose.


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    #23
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    pedronomix wrote: »
    Massive cardiac arrest is the other way, loads of examples on the web.

    A car battery can deliver 2 or 3kw.

    Be doing well to be electrocuted by that.

    There will be examples of anything you can think of, somewhere on the web.


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    #24
    pedronomix
    Closed Accounts Posts: 997 ✭✭✭pedronomix


    Bruthal wrote: »
    I have done similar to get a fast charger to recognise aa nimh batteries who's voltage had gone too low for the fast charger to accept them as batteries.

    What I did was got them in series and measured voltage. I have a variable power supply with amp meter. Set to same voltage as batteries. Also put multi meter reading amps in circuit. Then slowly cranked up to about 500ma. Only took a few minutes to get the batteries to enough for fast charger to recognise.

    It goes up to 15 volts and 30 amps so would do a fair few in groups I suppose.

    Sadly a huge job in my case as they are buried in the bowel of the beast!! But you are dead on track!


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    #25
    pedronomix
    Closed Accounts Posts: 997 ✭✭✭pedronomix


    102 Nimh cells in series gives 3.75Kw at 135 V approx... not at all the same as an ability to draw big current at low (12V>) voltage.


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    #26
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    pedronomix wrote: »
    102 Nimh cells in series gives 3.75Kw at 135 V approx... not at all the same as an ability to draw big current at low (12V>) voltage.

    The point I'm making is, the 3.5kw is of little relevance.

    A person wouldn't get any worse at shock from a maggawatt 230v transformer than they would from a 1 amp fused 230v circuit, with equal contact criteria.

    But you would still want to be rather unfortunate to be electrocuted at 130 volts too. Possible yes. Very likely, no.

    At 130 volts, 30 milli amps would be 4 Watts I think. About 1/900th of the 3.5kw if you see what I'm getting at.


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    #27
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    pedronomix wrote: »
    Sadly a huge job in my case as they are buried in the bowel of the beast!! But you are dead on track!

    It worked well enough anyway. Did the same with lipo batteries but they are quickly ruined when they fall much below the voltages that their chargers recognise them.


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    #28
    pedronomix
    Closed Accounts Posts: 997 ✭✭✭pedronomix


    and how long to charge ?


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    #29
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    pedronomix wrote: »
    and how long to charge ?

    I only left for a few minutes as only needed slight charging to be recognised by the proper charger.

    If yours are at 0.4 volts and need to be at 1 volt, still shouldn't take too long, as they are nearly depleted once much below 1 volt, so doesn't take much to get them to 1v I'd say.

    Are they easily removable?


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    #30
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    110v site transformer. Diode and 110v bulb in series with batteries and ammeter might work:)


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