Amps are big.

Discussion in 'Off-Topic Members Lounge' started by flippineck, Oct 29, 2016.

  1. flippineck

    flippineck

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    Having spent an evening soldering 12 off, 20W 12V halogen lightbulbs together to create a 'dummy load' to simulate something behind a battery charger eating up the energy supplied by solar panels, I was quite suprised.

    Rigged them up as six strings of two each series string, all connected in parrallel.

    I expected that applying 24V from my new bench PSU, might result in a few amps flowing and an array of moderately lit bulbs.

    As it was, the bulbs started lighting up at a pretty low volts level and by the time I'd cranked it up to 24V, I had nearly 10A flowing and the fixture I'd rigged up to hold the lamps was starting to go on fire.

    The PSU's rated to happily supply 10A but I was starting to feel like I was in welding territory!

    There's a lot more punch in an amp than I thought.
     
    flippineck, Oct 29, 2016
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  2. flippineck

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Well... Each bulb requires 20/12A = 5/3A = 1 2/3A, so each string will be 1.667A times 6 strings, that's 10A.
     
    (*steve*), Oct 30, 2016
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  3. flippineck

    flippineck

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    Yes the maths should have been obvious to me I guess.. If there's 10A on offer then the bulbs will take it! Just pleased that my PSU survived the ordeal. Pity I've already left averagely good ebay feedback!

    Next time I won't use a plywood frame-thing to hold the bulbs. What was I thinking..

    This is the PSU in case anyone needs a recommendation for a really easy to use, rugged bench supply that seems capable of surviving abuse .. not the seller I used but same type

    www.ebay.co.uk/itm/142045067116
     
    flippineck, Oct 30, 2016
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