Many "dead" car batteries are actually very good ones. They can no longer provide the hundreds of anpei needed to start the car. Many "dead" sealed lead-acid batteries don't actually haveIt is no longer possible to reliably provide dead batteries with the hundreds of watts of power needed to keep the computer running in a power-off state. A few years ago, I decided to add another small solar panel to my collection on top of my house. I have 5 and 10 watts. The new one is 20 watts. It is dedicated to providing emergency power supplies for lighting, small fans and other miscellaneous items. Small low voltage equipment. I need a battery for this setting as it needs to be able to provide power 24 hours a day. I decided not. The dead car battery will be perfect, as it will require less than half an amp of maximum load to power in any long period of time. There is a big difference between 200-600 amps and half amps. The battery in the photo was replaced when it stopped starting my car. I can charge the battery with a solar panel with a linear regulator. The cost of a linear regulator is usually less than a dollar. I decided to use the charging controllers as they can charge the battery more efficiently using the available power supply. When you use the charging controller, you get more running time at night. There are cheaper charging controllers but after reading a few of them I chose this one. Currently 20 W solar panels (9-24-12) $52. 99 plus freight for Ul-solar. ComI did some extensive testing to make sure I knew how well the system worked during a long outage. I was running this fan 24 hours a day a few weeks ago. The system works well. Since then, I have been using LED lighting on the terrace for two consecutive years and 24 hours. The fan in this photo is the 10 "12 V 5 W 2 speed fan Wal-Mart is clearing. They are still selling, but the season is over. I have three or four. The TheLED board has 16 LEDs. The battery did not even try to power this tin1 Watt load. This is a nice 12 volt battery powered clip I made with a 120 volt light. The 12 volt led board is connected in series with a 33 ohm resistor with four Type 20 mA LEDs. So this lamp can output 20 mA at 12: 00. 5 V (1/4 W ). There is an RCA plug on the back of the motherboard that plugs into the RCA jack inside the lamp. If I want to turn on or use a different LEDs, I can unplug this board and insert a different board. I also made a desk lamp with a fully enclosed battery. I decided to turn green with these lights and other low voltage devices I made, so I bought a 5 watt solar panel a few years ago. We don't use chimneys because we have birds (they are sensitive to smoke) so I put the solar panels on top of the chimney. As the current is too low, I ran from the panel to the garage with a cat 5 cable. Because all I need to do is charge my other UN. About twice a month (as needed) I made a battery charging board with a linear regulator. This is a 15 volt regulator. The battery never reached 15 volts. When the battery is about 12 v I will charge it and I will charge it to about 12 V. 5 volts. I check two lights every few weeks. They run for a long time. The 7 Amp hour battery is a bit excessive for a load of 20 mA. It’s great. Two lamps are used every day. About every 6 weeks or so, one of them will be charged. The battery is kept above 11. 5 volts make them last longer. The charging board also has a 12 volt regulator so I can run the 12 volt unit directly from the solar panel. So you have it. You can run whatever you want from these nationsCar battery without electricityIf you buy a 12 V to 120 V Inverter, you can power many 120 V devices. In addition, you can run any device with a plug that can be plugged into the car cigarette lighter Jack. You can prepare some quick and convenient camping at home when there is a power outage, 5 watts for less than $50. 00 or install a 20 watt power supply for more than $100. 00. If you want to be very simple and cheap, can I suggest you do this for very simple emergency LED lighting :-------------------------------------------------------------------------------------------------Update and Information: Technical information for Sunguard charging controller :------------------------------------------------------------------------------------------------------------Led for Beginners: it is a good idea to check the results after making the circuit to make sure that there is no more than 20 mA in the circuit. You can do this by measuring the voltage on the current limiting resistor through the resistance value (ohm. --------------------------------Data sheets from linear regulators: Many companies produce these products. Here is the link to a 12 volt linear regulator: cost: about 18 cents. You may need a radiator in order to get the full 1. 5 amps. ------------------------------------------------------------------------------------------------------------Cheap low power fan (added 11/3/2015) Low Power 12 v fan: W, 50 cubic feet per minute, less than $11. This will apply to the regulated voltage of 12 volts as the data sheet shows the maximum of 17 Volts and some panels will exceed 18 volts. Many other fans can find it on www. mouser. Cheap Duracell battery: battery below $0. 70 etc. Watch my LED bulb video: The LED light is good but not very good. My emergency light should last 30 to 40 years. This video examines the engineering defects of most of the ready-made screws in LED bulbs. I will make a note and redesign one. See these instructions.