Sunday, 22 October 2017

My small solar power system

This is the first part of a series of blog posts that will cover how I've set up a small solar electricity system, that generates and stores solar energy, and how I monitor and control it.  

I should be very clear at the outset, I'm no expert, and am not qualified in this field - I've just read a bit and have built my own system.  I take precautions as best I can, but if you're contemplating doing anything like this yourself, make sure you know what you're doing as you can get a shock that could hurt you, or especially if you're using an inverter to generate mains electricity, you could get at shock sufficient to kill you.

I'm doing this small scale - it's a hobby, and I generate some electricity that I use to power all my usb devices (phones, tablets and cameras) all summer.  I also store the electricity and power my living room TV.

It's the sort of system that would be useful in a caravan/camper van or on a boat.

So what have I got ?

2 x 100 Watt Panels2 x 250 Watt Panels

2 x Epsolar Tracer A (30A)

Approx. 200Ah Lead Acid Batteries
(24V configuration)
Approx 3kWh Lipo powerwall
(7S configuration)

A busbar for connecting storage
and chargers
A Big Red Button for killing the Load

A number of sonoff switchesA raspberry Pi

I used to have more lead acid batteries but I'm slowly transitioning away from them, and my system was originally a 12V one, but now is configured as a 24V system.

I've been building a 3kWh powerwall with lithium polymer batteries - some are reused laptop cells, and others are new ones.

By themselves, the solar charge controllers can do an awful lot, but with the addition of a small computer such as a RPi and sonoffs they become much more flexible.

Elsewhere in this blog I've already covered how to add software to the RPi to obtain, store and display the data from your EPSolar Tracer A charge controllers.

To display what your system is doing and that gives output like this

What I'll be covering in the next series of posts is more to do with what you can measure and control once you've got this data, and a little more hardware, and how you can integrate your solar data with other sensors and actuators.

I'll be using node-red to do this, it's a simple interface for controlling things.  We'll start off by making small flows, but once you get going the complexity of your control can build to meet your needs.  It produces really crisp and clean dashboards, controls and graphs, you can make small ones for phones

Or larger dashboards for PC or tablets

But you can also leave node-red running in the background, and have it monitor, and turn things on and off as necessary without any input from you.

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