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Amps are big.

flippineck

Sep 8, 2013
358
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Sep 8, 2013
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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.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
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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.
 

flippineck

Sep 8, 2013
358
Joined
Sep 8, 2013
Messages
358
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
 
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