Im powering it with a 4s 3p LiFePo4 battery pack and i'm using a 10A max discharge BMS.
When I turn on the relays, the LCD display turns dim and if i attach a IR sensor on my arduino it goes dimmer and resets after the relay turns off.
I'm reading around 400mA max when the relay is turned on (powers a 12v 350mA pump) from the input (battery to arduino) wire. So that wouldnt mean my battery is short of power right?
12volt on the V-in pin of a Nano is borderline dangerous.
At that voltage you can't draw anything more than about 30mA from it's 5volt pin.
That excludes relays and the LCD backlight (not on the diagram).
Why didn't you use 12volt relays, or a 5volt buck converter instead of a linear 12volt regulator.
Leo..
so if i had a lower voltage in the v-in say 7-9v would i be able to get more current to power my components that need 5v? and is that (only being able to get 30mA max at 5v pin) the reason why my arduino resets if i plug 2 components (IR sensor, i2c 20x4 lcd display & relay) on my 5v pin? can you explain to me why that is (im new to electronics. im actually a healthcare worker and just found out about electronics =D)?
so it would be better to have 12v relays so the arduino only powers the transistor and the relay itself gets power from the input of the pcb right meaning less current draw from my arduino 5v pin right?
I'm new to electronics and had someone from fiver make the pcb for me. I just told him what components i needed and where i want them connected to my arduino. when it comes to the hardware and calculations im oblivious lol. made the wrong decision i guess. lol
Hi, sorry i'm not a native english speaker so i dont get some of the figures of speech. but do you mean i should post a wiring diagram so you guys can understand?
i actually attached a file called "coindispenser.pdf"
no. but regulator will be colder. this is only for board purposes. for any other 5V devices is an independent power supply needed. I never use onboard linear regulator.
take 5V power source and connect everything to it. Arduino too.
or dependent on what hardware you has - Relay 12V and for display and Arduino 12V-to-5V buck converter.
yes. coil devices cause a distortion on power line by switching, big capacitor can help, but buck converter is better. without display will external linear regulator enough for arduino.
You must know/understand all the power requirements of the devices to make the right choice.
Some thoughts.
1S LiFeP4 + boost or 2S LiFePo4 could work, but did you think about charging?
The Nano could power the LCD and two relays, but do you really want to use relays?
Logic level mosfets (zero current draw) are commonly used to switch pumps and solenoids.
I assume the pump/solenoid are 12volt, which makes it wise to use a 3S battery and drop to 5volt for the Arduino (5volt pin) with a buck converter instead of a linear regulator.
An RFID reader could draw 60-100mA when reading a card, and that is too much for the 3.3volt pin of a 5volt Nano, which tops at ~30mA. The RFID reader should have it's own 5>3.3volt (linear) regulator.
Leo..
damn theres so much considerations! haha. but i'm slowly understanding.
so basically, i can have a 12v (13-14v in actuality) LiFePo4 battery connected to the PCB power input and from there i have 2 paths.
to the mosfet to turn on the pump (i assume i power the gate or drain or whatever it is called with 5v through my arduino digital IO?)
from the pcb power input, i use a buck converter to power my display, arduino and IR sensor. and from the buck converter to 3v linear regulator to rfid reader.
and since the battery is 13-14 v, do i use a buck converter from pcb power input to the 2 paths i mentioned?
If the buck converter is set to 5volt... first, then you can power the nano directly on the 5volt pin, and the other devices also from that same point.
You didn't link to the RFID reader yet, but it could be wise to use a separate 3.3volt linear regulator for that if it hasn't already got one on the board. Linear is fine, because very little current and volt drop is involved if that one is also powered from 5volt.
Leo..
Hi, Wawa! do you mind checking the schematic i made? just tell me if it will work or not you dont have to explain why if not but i would really appreciate it if you do =D.
Hi, Wawa! do you mind checking the schematic i made? just tell me if it will work or not you dont have to explain why if not but i would really appreciate it if you do =D.
