5V UPS for Raspberry Pi: Difference between revisions

Fortunately there are UPS devices for alarm/camera systems which you can buy for few dollars from [http://www.aliexpress.com/ AliExpress], just search for ''ups 12v output'' and looks for example these rated at 35W (these are the smallest possible but still more than enough for any USB device). I was able to buy one of these in Prague in local store called [http://www.t-led.cz/ups-zdroj-12v-35w-s-nabijenim T-Led] around 20USD personally. But you can get them directly from China to anywhere in the world for around same price including shipping. The UPS power supply I bought has 110-230V AC input and two 12V outputs. One 12V output is for battery charging (0,5A) and second is for your DC-DC converter to USB (we will talk about this later). If you connect battery to UPS it would not automatically start but wait for power supply to be connected. Once power supply is connected it will start and if there is an outage it will automatically keep voltage without any downtime (tested, Raspberry Pi did not went down when I disconnected main power and it switched to battery supply). If you need a cold start (start from battery without any external power connected) there is a small button (unfortunately not external one) connected solely for this purpose.