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Load Bank Video Update

murankar

Moderator
Staff member
Armed Forces
I did this video in one take and no editing. I was excited to see that my first 2 packs made it and that one of the features actually worked. Anyhow take a watch its about 15 minutes long.



 

murankar

Moderator
Staff member
Armed Forces
So far. Almost done with the build. Exciting for me for sure. This project is well outside my knowledge base.
 

Tony

Administrator
Staff member
It is starting to look really good! It's still early, but why are you using rheostats rather than a constant resistor setup for setting the cell voltages? I would think once you know what ohm resistors to put in there that it wont' change. Again, still early, only had one cup of coffee so far.
 

murankar

Moderator
Staff member
Armed Forces
The arduino for what ever reason will not pragmatically calibrate. There is noise in the circuit thread causing at least three cells to not read zero. I want it to read zero while not being used.

Then after running some tests earlier even if the arduino reads zero, the cells are off in voltage a when compared to my volt meter. Soon want the display to be really close or dead on.

The end state is to see if a cell is dead or is dead and to have it shut down the discharge circuit.
 

Tony

Administrator
Staff member
Hm, sounds like you need some capacitors or something somewhere to filter out the noise.
 

murankar

Moderator
Staff member
Armed Forces
More than likely. I have 3 cells that zero out and three that don't.

Its going to be trial and error to get it right. I don't know enough about capacitors. I know what They do and what they are used for but that's about it. What I don't know how to size one for the application.
 

Tony

Administrator
Staff member
For your application, I would think a 100-500µf for the specific voltage you are running would be plenty. Not a lot of current going though that board unless you need to put them on the main power line lol.
 

Tony

Administrator
Staff member
Something like a 10v 100µf cap I think would work. Very small. I'm sure there is a better one out there.
 

murankar

Moderator
Staff member
Armed Forces
I don't need mains, just the balance lead.

Do capacitors put out a constant voltage or can they fluctuate biased on input voltage?

Reasoning is because the voltage divider puts out a voltage relative to input voltage. I need that output voltage to be variable.
 

Tony

Administrator
Staff member
They will only store what they are supplied with. Just like the caps on an ESC that make the plug spark when you first plug it in, then they absorb some of the current demand while also smoothing out the current and reducing noise in the line.
 

Tony

Administrator
Staff member
If you are worried about when the voltage in the line goes down, you can always put a small resistor across the leads to help drain it faster. Most high voltage electronics such as PSU's where high voltage comes in and low voltage comes out have drain resistors on the caps so the caps don't try to kill you when you open up the case.
 

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