This project started because I wanted a Li-ion charging circuit with more flexibility than afforded by other do-it-yourself circuits, but at less cost than the programmable computerized chargers. The goal from the beginning was to design, build, test and share a charger that was able to charge Li-ion cells of any size and with any number of them in parallel to a predictable and repeatable
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state of charge without any trickle charging. Furthermore, the design needed to be as simple as possible; with a minimum parts count, reasonable cost, and ease of contruction to allow it to be built by an amateur (such as myself). On the advice of Silverfox, I contacted MrAl about this project, and he worked with me for months carefully considering many options and designs, all tested by him virtually on his computer, until we arrived at a design that adequately met the project goals. I then built and tested the charger with much help from MrAl. This is the result. This charger has a unique feature among Li-ion chargers. It has a variable shut-off current to allow the user to terminate charging at a specified current level. This allows the user to not only charge cells to the desired state of charge, but also to charge many cells of the same capacity at once in parallel. Many chargers charge cells in series, which can cause cells to become unbalanced and even overcharged. Overcharging a Li-ion cell is one of the most dangerous things you can do with one. By placing them in parallel, they are able to equalize. Note that cells with open circuit voltages differing by more than about 0. 5 Volts should NOT be connected in parallel, but should instead be charged individually. Some chargers are made to sense a certain shut off current which makes them suitable for charging cells with a certain range of capacities. Charging larger...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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