Skip to main content

Lead Acid Battery Charger Circuit Diagram


Except for use as a normal Battery Charger, this circuit is perfect to 'constant-charge' a 12-Volt Lead-Acid Battery, like the one in your flight box, and keep it in optimum charged condition. This circuit is not recommended for GEL-TYPE batteries since it draws to much current. The above circuit is a precision voltage source, and contains a temperature sensor with a negative temperature coλficient. Meaning, whenever the surrounding or battery temperature increases the voltage will automatically decrease. Temperature coλficient for this circuit is -8mV per °Celcius. A normal transistor (Q1) is used as a temperature sensor. This Battery Charger is centered around the LM350 integrated, 3-amp, adjustable stabilizer IC. Output voltage can be adjusted with P1 between 13.5 and 14.5 volt.

Lead Acid Battery Charger Circuit Diagram

Lead Acid Battery Charger Circuit DiagramT2 was added to prevent battery discharge via R1 if no power present. P1 can adjust the output voltage between 13.5 and 14.5 volts. R4's value can be adjusted to accommodate a bit larger or smaller window. D1 is a large power-diode, 100V PRV @ 3 amp. Bigger is best but I don't recommend going smaller. The LM350's 'adjust' pin will try to keep the voltage drop between its pin and the output pin at a constant value of 1.25V. So there is a constant current flow through R1. Q1 act here as a temperature sensor with the help of components P1/R3/R4 who more or less control the base of Q1. Since the emitter/base connection of Q1, just like any other semiconductor, contains a temperature coλficient of -2mV/°C, the output voltage will also show a negative temperature coλficient.

Battery Charger 1 That one is only a factor of 4 larger, because of the variation of the emitter/basis of Q1 multiplied by the division factor of P1/R3/R4. Which results in approximately -8mV/°C. To prevent that sensor Q1 is warmed up by its own current draw, I recommend adding a cooling rib of sorts. (If you wish to compensate for the battery-temperature itself, then Q1 should be mounted as close on the battery as possible) The red led (D2) indicates the presence of input power.Depending on what type of transistor you use for Q1, the pads on the circuit board may not fit exactly (in case of the BD140).

Labels:

Comments

Post a Comment

Popular posts from this blog

A basic Arduino Solar PV Monitor

I have just recently had solar pv installed, mainly to future proof my energy costs, I do not expect it to be like drilling for oil in my back garden, however the return looks to be encouraging. The install gives you another single unit meter, from this you will see the total amount the panels produce, but that is about it. I wanted to know how much the production was as it was happening, I discovered the light blinks on the front of the meter will flash 1000 times for each kWh of electricity which passes through. The rate of the flashing of the LED tells you how much power is currently passing through the meter. [ ]
Post a Comment
Read more

Build a Key Operated Gate Locking System Circuit

This simple key-operated gate locking system allows only those persons who know the preset code to open the gate. The code is to be entered from the keypad within the preset time to operate the motor fitted in the gate. If anyone trying to open the gate presses a wrong key in the keypad, the system is disabled and, at the same time, sounds an alarm to alert you of an unauthorized entry. Figs 1 and 2 show the block and circuit diagrams of the key-operated code locking system, respectively. Connect points A, B, C, D, E, F and ground of the circuit to the respective points of the keypad. Keys S7, S16, S14 and S3 are used here for code entry, and the remaining keys are used for disabling the system. It is very important to press the keys in that order to form the code. To start the motor of the gate, press switches S7, S16, S14 and S3 sequentially. If the keys are pressed in a different order from the preset order, the system will lock automatically and the motor will not start. Fig. 1: Bl...
Post a Comment
Read more

Apple releases TV spot for new iPods

Apple has just released a fun commercial to showcase its new line of iPod players and the various colours they come in. The TV spot titled ‘Bounce’, has a bunch of colourful iPod touch, iPod nano and iPod shuffles er…bouncing to music. With all that colour and dancing and bouncing, you may forget that Apple’s latest gen line of iPods has some other awesome features. For instance, the fifth gen iPod touch comes with Siri, 4-inch retina display and an A5 chipset. Maybe the next ad will showcase some of these features with less bouncing.link
Post a Comment
Read more