Electronics Engineering

18650 - This is the most common standard for a Li-Ion battery (or Cell in correct technical terms).  In your Laptop, usually multiple 18650 cells are connected in series to provide a higher voltage.  A 2-cell battery (Multiple cells connected together is technically called a battery), will have 2 cells in series and produce 7.2 to 7.4 Volts. The Power Bank that we talked about in my earlier post usually comprises or 1 or more 18650 cells - But these are connected in parallel. There are wild claims regarding the capacity of power banks and 18650 cells as well. So lets make it clear here - The Size of a 18650 cell is 18x65mm.  In that space there is little room for wild swings in capacity - The Chemistry is nearly the same.  So we have real capacities ranging from 2,000mAH to 3,100mAH. Cell capacities are Colour coded (You can check the details in one of the links below).  The Purple Colour Cell manufactured by Samsung is one very commonly available battery...

You have bought a power bank and are wondering if it really measures up to the advertised Capacity? Check with this Power Meter. You can connect it to any USB Power Source like your Power Bank. It will Show you the Output Voltage of the Power Bank - This should be 5V On the USB Female side you connect your Load. You can then see the Current that the Device Consumes. Leave it on for a while and it can give you an indication of the Power Consumed.  This is also the Power delivered by the source (Could be your Power Bank) It measures Voltage & Current - Power = Voltage x Current (For DC Voltages like this one) The Total Energy that can be delivered by your Power Bank = The Capacity of your Power Bank. Energy (Or Capacity) is the ability for the Power Bank to give X Watts for T Time before it runs out of juice. Hence TIME is the factor that comes into play to measure the Total Energy that can be delivered by your Power Bank or The Capacity of your Power Bank Capa...

Having developed small led lights I wanted to set up my own home lighting with some of these. From that experience I want to put this information up here for someone who wishes to use slar pv for his home. Start with the load - How many lights will you use - In my case each Light is either 1.5 watts or 2.5 watts. Let us take the total load in watts as X. You may want to use this load for Y hours a day. Calculate the Solar Panel required with a simple formula: Panel required = 2*(X*Y/6) for regions between the two tropics and = 2*(X*Y/5) for regions away from the two tropics. Notice that the difference is the figure 5 in place of 6 - you may take anything in between for regions closer to the tropics. The Panel size that you arrive at in step 3 is to be rounded off to the nearest available Panel. Remember we are talking here of 12 Volts Panels which usually have 36 cells in series. Let us say you arrive at Panel size of A watts. This is the size you will use. Now about the Battery: ...