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I have a bunch of Christmas light that work with three AA batteries, and I was wondering what would be the best to turn them on and off using my smartphone. Any ideas? I was thinking on an ESP32 but I am not sure if the batteries will last much time...
I have many decorations in my house that contain battery-powered LEDs (wreaths, garlands, signs). I'd like to be able to turn these on/off with my phone or smart assistant. Years ago, there was a company selling AA batteries that contained a wifi module that allowed you to turn the power on/off, but they disappeared.
Are there any solutions on the market for this? Basically, battery-operated smart remote-control relays that can easily be incorporated into standalone decorations (wifi, Bluetooth, Zwave, Zig bee, whatever)
I'd even settle for a programmable battery-powered relay that could be wired in to a battery circuit, so that I could have all the decorations coordinated to turn on/off at the same time
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.
The other answer is correct. For this kind of power, a 12V SLA is the only practical battery based solution, while a generator of some kind (a stand alone or a car) is the other solution. Old car batteries could be used, instead of buying new ones. Old batteries won't start a car, but can easily power this.
That said, you should look into a more efficient setup. Depending on the lights, there may be a diode full wave bridge rectifier that converts the AC to DC. If the lights have a small bulge near the power connector it likely does. You could measure the voltage at one of the bulbs.
If this is the case, you could use a simpler step-up boost regulator, instead of a bigger inverter. No need to invert to AC just to rectify it again.
You could also use LED strings instead of incandescent if you haven't already switched. Less power needed.
Finally, you could bring the voltage down a bit. At 100V, it should still light, just dimmer. Depends on what you think is acceptable. But it would cut out say 40W from your five string setup. Like buy 4 get 1 free deal.