I want to power Christmas lights (without a nearby power outlet) for at least 2 hours and was wondering how to go about it. The lights run on 120V AC and draw .34A per strip (about 40 watts) and I want to use 5 strips. I could buy a 12V battery and power inverter to supply 120VAC, but I would like to see if there's a cheaper or easier way.
I could rig up some AA batteries in series and parallel to supply 12V to a power inverter, but since batteries lose voltage as they drain, would I need to buy some sort of "voltage booster" to maintain the 12V? Could I even use a single portable phone charger battery (3.6V) and a voltage booster instead? Or is there some other easier way to do all of this?
Best Answer
If you want a quiet, convenient way to power your lights, your idea of using an DC/AC inverter with a conventional 12V lead-acid battery is probably the best one. You will not be able to supply 200W in a cost-effective way using either AA batteries or a miniature portable 'power bank' for cell phones.
Doing some figures, using an approximate energy density of 35 Wh/kg and a battery mass of around 20kg, this gives you a total capacity from a single automotive-sized battery of 700 Wh. You will need to verify this capacity when you choose a battery, which may be difficult since many automotive batteries do not have watt-hour or amp-hour ratings advertised. However, this means you can meet your requirement (ca. 400 Wh) with a single (fairly expensive, but reusable) battery connected to an appropriately rated inverter. Since you will be operating the battery without immediately charging it, look for a deep-cycle type battery with a discharge count rating in addition to its energy capacity rating.
Another option which is louder and requires a different investment is a hydrocarbon-fueled generator. These are available in a variety of capacities and fuel capabilities. Many options would greatly exceed your duration requirement, but would still be usable. Be aware of the exhaust of the generator and only operate it outdoors with enough ventilation.