The PIC16F870 keeps track of battery voltage as well as both charging and discharging currents. It also drives the 4 digit display, and switches the AC and load relays. The basic operation is as follows: While AC power is available, the battery voltage is constantly monitored and topped off as needed. When the AC power fails, the load relay engages the 12-volt system. This connects to lights, fans, and other 12 volt devices as needed. Should the battery voltage fall too low, the load relay is disengaged, preventing the acid batteries from being damaged by over discharging.
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Refering to the SCHEMATIC, which differs some from the LAYOUT, the planned SCR that switched power from the power rectifiers to the battery was eliminated from the design. (This left a redunant diode feeding power to the 7805). Instead, a 110 volt solid-state relay was added to the transformer primary circuit. This eliminated the rather large idling current from the scrounged transformer.
In order to measure currents up to 10 amps, .01 ohm resistors were made out of about 5 inches of #22 solid hookup wire. A simple resistor devider is used to monitor the voltage.
Since this is a Pulsed charging system (note lack of humongus filter capacitors), the battery voltage is only measured between the charge pulses. The ac connection to RC1 is used to synchronize this operation. Also, makeing a reasonable current measurement is done by summing several samples spaced over one complete charge pulse interval. In other words, the actual charge is going on only about 20 percent of the time. So taking samples over the entire interval automatically 'does the math'.
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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