Objective: Today I power my tools (drill, circular-saw, reciprocal saw etc.) in my shed by running a power line from my house. I wish to install solar power panels on my shed; however, before I do so, I wish to make sure everything is theoretically and practically correct.
Prototype: My thoughts and calculation:
- A circular saw needs the most power compared to other tools (~13 amps); hence I used it for my baseline worst-case scenario. i.e. the circular saw needs 13 amps * 120 volts = 1,560 watts
- With a 12v DC battery, 1560 watts would imply that I would need 130 amps
- A normal car battery at full charge stores about 48 amp-hours
- This implies that a fully charged car battery would run my circular-saw for about 48 amp-hours / 130 amps = 0.36 hours = 0.36 * 60 ~ 22 minutes
- I plan on converting the 12v DC to 120-volt AC using a standard OTS inverter (~$20)
- Is my (sizing) calculation correct?
- Is my prototype’s design reasonable?
- Any suggestions?