I have a garage in a building, along with about 30 other people. We have all had electricity in our garages, but we didn't have to pay for it - people who lived in that building paid for it. However, about a few months back our electricity was cut out from our garages, because someone supposedly had some big electricity draining equipment in their garage and people in the building decided they will not pay for it. Now I have to come up with a way to get light in my garage.

I thought of using a car battery, and some 12V light bulbs. However, I want to see how convenient that will be. I want to calculate for how long I will be able to use the light before recharging the battery.

I have no idea how to calculate this, so I would really appreciate if anyone could help.

Let's imagine I have a car battery of X Amper-hours and Y light bulbs (12V bulbs) that each lights with Z Watts. What is the formula to calculate how long I will be able to use those bulbs before I empty my battery?

watts = volts times amps. Divide the watts by 12 volts to get the amps. Even a small light will be enough in a big, dark garage to keep from running into the car and finding the keyhole.

Keep up your good work in automotive. I am covered up with HVAC stuff.

Thank you very much, labman!

I'd actually need some better lighting in the garage, because I use it as a storage place for my engine I plan on rebuilding, and I need some lighting to work on the engine.

Looks like I could keep a 40W bulb working for almost 11 hours... that's a lot longer than I expected!

Thanks again!

May want to try to find some 12 volt flouresent lights for larger light needs.