how long would a 55w bulb last on a battery?

[Pol Anorl]

im a proper tight git pikey and i wired up a long wire to an internal 12v mr16 led bulb and attached to the top of a telescopic fishing rod for fishing lighting and wired to an 18v 2000mah drill battery.
works like a lamp post

https://i.imgur.com/dAiwlkq.jpg

now its fairly bright but not super bright so baiting up is a pain, back to the question.

i was tempted to wire it to a 55w h1 but unsure on how long it would last, id need it to last a good 4 hours+

anyone know how to work out how long it would last?

55w bulb
2000mah 18v drill battery

or would 3-4 hours make the bulb too hot? itll have next to no cooling on it.
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[Major Doss]

It will last longer than a shock, and less than an offer to replace your motor.

[bamt]

It may not last long at all, as the 18V of your drill battery may kill the bulb.

But, assuming that the bulb is happy running at 18V.

Rough calculation, the bulb is 55W, so current drawn is 55/18 = 3A

Your battery is 2AH, so you'll drain it in 2/3 of an hour - 40 minutes.

There's lots of assumptions there (the bulb current will be a bit different at 18V assuming it works, because it'll be running at a hotter temperature, the battery capacity varies with discharge rate, the battery voltage varies during discharge depending upon whatever cell chemistry it has) - but it's so far off your 3-4 hours that it isn't worth trying to take them all into account.

[Pol Anorl]

Thanks, ill stick to the led bulb and possibly set up a 2nd light.
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GOOD GAME BODYGUARD: https://i.imgur.com/8WePGgf.jpg
20:30:37 Pyro.: I don't sort of like men, I take every advantage to choke on dick.
Jewlio Iglesias: You live in Liverpool - Chances are, the front door has already been kicked off the hinges