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Topic: Power a 12V water pump by a 12V battery through a relay (Read 2972 times) previous topic - next topic

AntroxEv

Show us what 'you' expect will be the final schematic for this project.

Make sure you show all your connections.

The initial idea was proposed in the schematic below.

Currently I have only two power supplies, one could be a parallel configuration of GP23A batteries,
or one  Sealed Lead Acid Battery 12V 2.3Ah.
I was going to use the last one that should have enough capacity to power arduino per two weeks and the water pump.

My question is:
Can I remove the jumper but still use the 5V from Arduino by creating two different circuits on the breadboard?
I also have transistors and diode to do that. I would go for a similar schematic than the Project 10 of the starter kit with the addition of the relay.

I will try to realize that during the week. I hope to do not be so far from the final configuration.
thanks




Let's see the actual wiring.
That relay board has 5V relays, not 12V.
Make sure the relay jumper is removed.
Add a reversed biased kickback diode across the motor.

You need the diode to snub out inductive switching spikes.

[/quote]

larryd

If you are going to power the motor and Arduino from the 12V battery, suggest you forget the relay board and just use a MOSFET circuit as seen below.



EDIT:
An IRL3705N would also be a good MOSFET you could use.

Always use the devices data sheet to confirm lead identification.





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AntroxEv

EDIT:
An IRL3705N would also be a good MOSFET you could use.

Always use the devices data sheet to confirm lead identification.






I tried to use the IRF520 mosfet instead of the relay. I set up the same configuration of the Starter kit Project 10.
It seems working fine. Unfortunately, I have to make this project working from tomorrow.
I think I can give up to use the relay because of the lack of a third source to power the coils.

Having said that, now I have to go back to the energy consumption problem.
I have two possible choices:
1) use a 12V lead battery 2.3Ah to power both arduino and the pumps. In that case, I think I still have the problem to isolate the pump from arduino (maybe a diode?)
2) Use the 12V lead battery 2.3Ah to power arduino only while using one or more GP23A 38 mAh to power the pump. If I am using this second option, maybe I have to connect to the breadboard several GP23A in parallel in order to have the same voltage but more capacity

Any idea or comments on something that I could be wrong?


larryd

An IRF540 is not a logic level MOSFET, an IRL540 is logic level.

You can check to see if the IRF540 is indeed working properly by checking the voltage from the drain to source.  Use a DVM set to DC volts.

What do you measure when the pump is running?


You may not need isolation between the Arduino and pump circuit if it appears things are functioning as you want.

The circuit offered to you in post #31 will probably be all you need to use.





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AntroxEv

Sorry for my long absence.
Practically I did not use the relay and try the configuration with the MOSFET given in the starter kit..
Everything was working well (as with the relay) until I tried to power both arduino and water pump with the same 12V battery.

I killed it. The ATmega328P is fried I guess.



I attached a photo of the schematic I think fried the board.  The configuration is similar to the starter kit project 09 but as I said, I use the battery to power both Arduino and the pump.

I remember the pump start working badly before pushing the button and a continuous feeble noise was coming out. I disconnected everything but Arduino was dead (power is working but no anymore chance to upload sketches).
Could you please tell me what went wrong in my schematic?

Cheers

larryd



If things were wired as in your schematic, you should have been okay.

However, the resistors in post #31 should have been included in your circuit.

Your actual wiring may not have been the way you show things in the image :(  i.e. wiring error.

You may have had a wire accidentally short on something.

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wvmarle

Indeed... miswire the MOSFET and you can get 12V into your Arduino pin. That would explain the symptoms.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

Paul__B

OTOH you have quite likely simply blown the regulator.

Define "fried"?

Does it accept an upload of the "blink" test program when disconnected from your circuit and connected by the USB to the PC?

AntroxEv

OTOH you have quite likely simply blown the regulator.

Define "fried"?

Does it accept an upload of the "blink" test program when disconnected from your circuit and connected by the USB to the PC?

Nope. Unfortunately I am not able to upload any sketch into the board. I have also tried to use the sketch already uploaded in the processor but either arduino does not receive any input or it does not send any output.
The board is powered since the led is on.

I could test the "fried" arduino with the new one as a tutorial I have seen online as last resort or do you have a better recommendation?

wvmarle

I could test the "fried" arduino with the new one as a tutorial I have seen online as last resort or do you have a better recommendation?
Give it a ceremonial burial and grab a new one.

Or just toss it in the trash can and grab a new, if you're not into ceremonial burials.

Anyway, don't bother too much with the broken one. These boards are cheap, not worth trying to fix it.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

AntroxEv

Indeed... miswire the MOSFET and you can get 12V into your Arduino pin. That would explain the symptoms.
The MOSFET was wired well. I worked step by step starting from the project 9 of the starter kit and it was working fine.
Then I replaced the DC motor with my water pump and the 9V battery with a 12 V battery.Again it was working.

Finally I moved the 12V battery from the power bus on the right to the left one. From that power bus I connect VIn and the ground of arduino. On the same power bus I use a jump wire to link the + of the left bus to the + of the right bus.

I attached the pic of Project 9:




If it is a wiring problem, it would be in the jumper wire from the breadbord to arduino or from the left to right bus

AntroxEv

Give it a ceremonial burial and grab a new one.

Or just toss it in the trash can and grab a new, if you're not into ceremonial burials.

Anyway, don't bother too much with the broken one. These boards are cheap, not worth trying to fix it.
Yes but I hope to do not have to change 3-4 arduino per years : )

larryd

One last time, add R1 and R2 (see post 31) to the MOSFET circuit.

If you are still using the IRF520, this is not recommended, it is not a logic level transistor.

If you insist on using the IRF520, suggest you use circuit 'E1' below, R5 could be lowered to 1k.





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AntroxEv

Hi Larryd,
you offered me good tips that I will follow. Thanks for that.
I do not have a IRL3705N  or IRL540 yet. I will buy them.

Now I was more interested to understand what break my arduino to avoid to repeat the error again.
I am curious to to repeat the first steps to see if anything else is damaged (e.g the mosfet I used).
There is a topic on this page about someone that had a problem with the IRF520 and 12V as I did.
Maybe that was the problem?

After that, I wonder which configuration between yours with the mosfet or the first one with the relay will consume less current.


larryd

It is quite impossible to know what went wrong :( .

However, when the Arduino is first turned on, I/O pins are set to input which is floating.

When the gate of your MOSFET is floating, the transistor is not turned on or off.

Depending on the transistor, this is not a good situation, your transistor may have been damaged, then the Arduino got damaged.

This is why we have the 10k resistor going to GND as in the image on post #31, it makes the gate LOW at Arduino power up time.

But it might be more likely you accidentally shorted something.



Good luck not following the suggestions you are offered.


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