wajdi

modified 5 years ago

Circuit Protective for car battery with RELAY v2.1

207

03:58:07

If the sorce less then 10v or more then 14.8v crcuit will cut off. Note: Charger instead the source and the car battery instead of the low resistor (load) 

published 5 years ago

PrathikP

5 years ago

Nice job, but try to redraw the circuit neatly. Give it a try. A neatly drawn circuit is easy to analyse and pleasing to look at.

BillyT

5 years ago

The circuit works well, a couple of things though, 1. For a fixed Voltage charger for a Lead Acid Battery, the cut offs are 11.8 and 14.2 Volts. 2. As PrathikP says the circuit when neatly drawn is easier to analyse, in this case when the circuit is tidied up, it is revealed that the transistors are connected back to frount, when that is corrected the circuit still works well, check out this circuit. http://everycircuit.com/circuit/5158433526120448

wajdi

5 years ago

Thanks guys for your positive feedback, sorry for the disorder in the circuit, i had the idea so i tried it, was soo happy when worked well i shared directly, you can help me to redraw it neatly. @BillyT thanks for the correct values ;)

wajdi

5 years ago

Maybe I should command a rely to carry more current, what do you think?

BillyT

5 years ago

Wajdi, EC is good in that you can move the components around, check my cct. Also the updated circuit gives up to 5 Amps.

PrathikP

5 years ago

Billyt, if I may point out a critical error that you made: just check your NMOS and see whats amiss. You'll see it.

PrathikP

5 years ago

And here's a tip: use one single MOSFET. MOSFETs are expensive, but BJTs are not. Use to or three more BJTs in tbe control circuit to help you achieve the same thing with one MOSFET. You will know which MOSFET to get rid off when you identify the critical problem.

PrathikP

5 years ago

Here's a much simpler and improved version of the circuit http://everycircuit.com/circuit/5625743885991936 open it only after identifying the problem.

BillyT

5 years ago

PrathikP, I like your circuit the simplicity and the way youhave got it displaying, I'm not sure of the error that you are talking about unless it's the rail Versus battery voltage, I identified that problem yesterday, but was going to lead into it after looking at the BJT problems. My fix was-; http://everycircuit.com/circuit/6181083157364736

PrathikP

5 years ago

BillyT the big problem with your circuit is that the NMOS is dissipating 15.6W!!! That's a big no no. You are trying to switch a low side load using an NMOS. It's a classic mistake. Dont use that circuit. Keep the PMOS and the circuit become problem free.

wajdi

5 years ago

Thanks gays for your attention and help. PrathikP, I like your improved circuit and no need of BJTs. Like you done just we put a heat sink to the PMOS.

wajdi

5 years ago

PrathikP, your version can carry up to 7amps for 14v so up to 100w, just a good heat sink to the PMOS. Thanks again for your help. And pls share your circuit it is amazing...

PrathikP

5 years ago

@wajdi you can share the new version yourself. You have full permission.

PrathikP

5 years ago

The MOSFET in my circuit is randomly modelled. The max current rating depends on what MOSFET you use.

wajdi

5 years ago

@PrathikP i will share it with you after making test board, i will use the NMOSFET standard IRFZ44 maybe more then one on parallel mode. Then i will give you a feedback ;)

PrathikP

5 years ago

NMosfet won't work. You have to use a pmosfet

wajdi

5 years ago

@PrathikP check this: https://everycircuit.com/circuit/6150894503329792

wajdi

5 years ago

Here what i'm doing to my car dashboard https://everycircuit.com/circuit/4694156713394176

PrathikP

5 years ago

Like I said, don't use an N channel MOSFET.

PrathikP

5 years ago

As for the dimmer, you need to use a different technique. What you have done may seem to work here on EC but it actually won't. You need to use PWM or something similar.

wajdi

5 years ago

@PrathikP, the dimmer is done, installed in my car dashboard and work properly (note; my dashboard lights are LED modified long time ago). No need pwm signal ic ne555 or microcontroller. Simple way... Enjoy

wajdi

5 years ago

What about now...

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