Figure 1 is a schematic of such an arrangement with four batteries. The diagram in Figure 2 uses one voltmeter and a two-pole multi-position rotary switch to select the battery to monitor. While accomplishing the goal of bringing the metering of batteries out of the battery compartment, this design has some safety problems. A direct connection to any point
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in the battery pack is dangerous because of the shock hazard and also because a short-circuit could result in injury or fire. The risks can be reduced by revising the design as shown in Figure 3. By placing current limiting resistors right on the battery terminals, only micro amperes are allowed to flow on the wires of the instrument, even in the case of a short circuit. Note that the meter itself is not a voltmeter but is a micro ammeter with a scale marked in Volts. If the switch is eliminated by providing separate meters for each battery, then the batteries can be compared under identical load conditions. In 1989, I installed just such a meter system in my Sebring-Vanguard Citicar. The dashboard sported eight vertical panel meters, one for each 6-Volt battery. I included trimmer potentiometers behind the dash to provide calibration of the meters. Figure 4 is the circuit diagram for one meter. These meters did an excellent job in the Citicar. It was easy to spot a weak battery and individual cell failures were immediately evident by the 2-Volt drop in the meter. I wanted to have similar metering in the Solectria Force. The dashboard appearance of the Force would suffer if I installed thirteen meters of any sort. But there is room in the instrument cluster for one small instrument. I decided to make a display which could show all 13 batteries at once in bar graph format. So the challenge was to design something that could...
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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