Energy monitor

A student team is designing a energy monitor for a sustainable living situation; including solar panels, hydro power and battery stacks. I would like to have an open-ended conversation on the aspects of this system:

This project will be realized and implemented as a small part of an art installation in the east coast of the United States. It will not be operated by people with knowledge of Arduino, and to expect them to have significant computer or hard/software skills would be wrong. The actual monitoring of the system is not the main objective of this thread; what I would like to get out of this is advice on the user interface, specifically for the non technical population (artists, not engineers, will be operating this). It needs to be easy and ready to read and operate, so easy that an 8 year old could understand it. All comments, suggestions, and criticisms are welcomed, especially if I have been too vague.

Thank you for reading

Interesting. So what I get out of the description, people will read the numbers and see how their power supply compares to their power usage, and power stored (in batteries?). Then be able to make adjustments to the usage, to ensure a continued availability of power. If I am not close, please tell us in similar terms the goal. Thanks

You got it. Only thing I would add is the energy produced through solar panels and a small hydro power system. So, energy produced, energy stored, energy use, and possible predictions (such as, "if you continue to use to use this much power, batteries will be depleted in x amount of days").

Thanks for reading and replying

Well, if they want to estimate for the next few days, they should be able to enter weather forecasts, such as % sunshine, and winds. EG, if the next two days are forecast to be mostly cloudy, and winds at 4 mph, would be a bit different than a forecast of the next two days sunny, with winds at 18 mph.

How big of an electrical system will this be, or is it mostly theory ?

It won't be theoretical in the end, but I don't have those figures right now. When I do I will be sure to post them.

Thanks again

Hello again,

I have a some information about the system. There are two 290w solar panels, charge controller (waiting on specs), four 12v batteries, and a 1100-Watt Power Inverter. As far as electronics/appliances go, there will be a water pump, water analyzer, DC lighting, up to 3 laptops, cellphones, and possibly a wireless hotspot. This is not a grid tied system, these people NEED to know when levels are low and consumption is high. There are many possible solutions for this. IDEAS?? QUESTIONS?? zmoze

The most important thing to do is to decide on an energy budget. The solar panels will provide a certain amount of energy, and this must be stored in the batteries for when the sun isn't shining. Obviously you can't use more energy than that.

You need to go through EVERY electrical appliance and calculate the number of watt-hours it will consume (watts times (run time in hours)). Usually this is done on a daily (24 hour) basis, so you would come up with units of watt-hours per day.

You need to know how many watt-hours the batteries will store (usually given in ampere-hours or Ah, then multiply by the battery voltage). This is all you can draw during the dark, keeping in mind certain rules for battery care. For example, don't discharge lead-acid batteries below 10 volts/battery.

Then you need to know how many hours/day the sun will be shining, multiply that by the total panel wattage. If you can optimize the panel orientation during the day, you'll get a lot more energy than if the panels are fixed.

You need a power monitor on the batteries and panel.

There is lots more information on line!

Very helpful jremington, thank you. Any ideas on displays, LCD, TFT, LED array? Other than the classic displaying of numbers and what not. Something different maybe, this system must function well, but is a part of an art exhibit, so aesthetics are important.


You can design the user interface on a computer using some software like Visual Basic, Processing or Python. The software will send data to the energy monitoring system through the serial port and the data coming from the monitoring system will be displayed on the computer screen in the form of graphs or graphs. If you want the whole system to be independent of a computer then you can use a touch screen along with a SD card to create a nice looking user interface on the Arduino itself, you can switch to bigger Arduino Mega or use multiple Arduino UNOs with the Software Serial Library if the number of pins is limiting the things that you can do.

How big are the batteries and how are they wired. (series or parallel). A 1100 watt Inverter can pull close to 100 amps from a 12V battery and this will rapidly deplete the battery. You need some idea of how much energy is going to be consumed each day.

So, power usage does not include any, air conditioning, refrigerator, TV, fans? What do you think will be the most energy hog? The water pump is used for what, and how much usage? Are the 4 batteries, like trolling motor batteries, or what? We are to assume the DC lighting is LED? We are to assume the laptops and hotspot will be turned off shortly after dark (over night)? Yes, as suggested earlier, if you have laptops, a good readout would be through the laptop. If on low power status, you can schedule the hotspot and laptops to one half hour around noon. With laptops and hotspot, you can get forecasts for weather for the next couple days, and add that info into the calculations.