As mentioned, this will be my first project with an Arduino and after researching a bit I decided to join a forum to help me get started.
Project consists of controlling a 20amp dc power source that is supplied from either the output of a solar battery bank or a power supply on AC mains. High level functionality would be;
Use the battery bank as a source until the voltage drops to say 12.1 vdc or banklow().
Then after a few milliseconds, switch over to the power supply until the battery bank voltage becomes say 13.1 or bankcharged() and after a delay switch back to the battery bank.
Quick questions;
Would the Nana be a good choice for the platform as well as preparing me for more complex projects?
Will the Arduino pins be able to handle the coil of a 20amp 5v relay to switch load or should I go with ssr’r?
I am really looking forward to getting into this as I have a few projects in mind from controlling a greenhouse heating system (solar hot air panels, ground heat recovery, humidity, etc) to automating my security system.
Anyone? :
I followed the guidelines of correctly posting a question, or is the question too basic for this group. The level of knowledge here seems to be on the high end so maybe I will come back once I get more experienced.
There's nothing wrong or too basic about your questions - I'm a little surprised that your post slipped through the cracks without a reply - unfortunate timing perhaps.
A Nano is fine for your project and could do much more complex things. Unless size is an issue, an Uno is a common Arduino to start out with though, primarily because most shields are designed to fit it. Just start with something cheap in case you accidentally let out the magic smoke.
Don't worry about the Nano standing you in good stead for later projects yet. Just get your basic project going, plus whatever enhancements you come up with on the way. Then you'll know enough to evaluate whether your future ideas need more capable hardware.
An arduino can easily switch relays as long as the current required is low enough (less than 20 mA). There are loads of relay boards that are arduino compatible - I'm looking at one right now on my desk that has a pair of Songle relays that would work for you. Check Sparkfun or Adafruit or your supplier of choice.
Those voltage dividers look plausible, but I'll defer to the folks who know what they're talking about when it comes to electronics.
For a ready to use item those voltage dividers would be fine.
Being 5 to 1, it’s going to output 2.42 volts at banklow and 2.62 volts at bankhigh.
Arduino analog.read(pin)reports back to the program a value from 0-1023 based on voltage present from 0-5 volts as default. So 2.5 volts would read as 511 or 512.
If ultra low power consumption is a concern, I would use a “Normally Open” micro relay in-line with the supply voltage to the divider so that too monitor the voltage you activate the relay, wait few milliseconds, read voltage, then turn off the relay again.
