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Battery powered 120V light bulb Answered

I'm trying to build a steam-punk costume and wanted to use a motorcycle battery to power several edison squirrel cage style bulbs. Fortunately these blubs look better if they are dimmed, but what I'm having a problem with is a schematic and what type of transformer to use.



3 years ago

running on 1/10th their rated V? I think they'll be quite dim, and waaay below rated amps. You may need an inverter to to get some substantial voltage.


8 years ago

You don't need a transformer to use power a bulb with DC.

The question is, do you need a resistor to stop the bulbs blowing from the high current a motorbike battery can deliver?

Anybody know what current such a bulb can take?

I don't know much but I do know that

Watts = Amps x Volts

so technically a average bulb takes 60-100 watts so

60= Amps x 120


100= Amps x 120



60= Amps x 12


100= Amps x 12


He's not talking about old-style filament bulbs, but "several edison squirrel cage style bulbs" that are running dimmed.


8 years ago

The filament of a 120V bulb should glow with a much lower voltage. How much glow will depend on the bulb and the voltage used. A 12V battery might be exactly right for your project.

The bulbs should be wired in parallel to the battery, so they all "see" 12 volts.

If brighter is better, you might need a pair of batteries (in series) to get to 24V...

Transformers won't work with DC. Much more complex electronics (inverter) would be required to boost the battery voltage, and safety would become an issue.

Actually, a motorcycle battery can provide significant current--not high enough voltage for electrocution, but high enough current that a "short" would burn you, or could light a costume on fire.