Re: newbie question......How long will a 120 watt 120vac bulb run on a 60Ahr 12v
You're on the right track. However, fully discharging a battery will lead it to an early death, so it's good practice to not discharge the battery below 50% state of charge, and typically not below 80% SOC (= using just 20% of capacity) on a regular basis. Using the 50% rule and assuming a 90% inverter efficiency, you could run a 120 W 120 VAC bulb for 35 Ah x 50% / (10 A / 90%) = 17.5 Ah / 11.1 A = 1.58 hours.
This is a good example of why standard incandescent lamps should be replaced with compact fluorescent lamps (CFLs). A 14 W CFL puts out as much light as a 60 W incandescent. So, the same battery could power two 14 W CFLs instaed on one 120 W incandescent bulb for ~6.77 hours, and require a smaller (cheaper?) inverter.
Six-packs of mini-spiral CFLs are available at Home Depot for ~$10. DC CFLs are also available, but they're typically fairly expensive.
Jim / crewzer
120618: System off-line for a while...