Monday, 13 August 2012 17:00

Our Solar System – Part 1

Part 1 – System Overview

As most of you know, we get all of our electrical power from our solar power system. In the blog Our Solar Power I describe a system that is completely “hands off’ automatic if you want to use it that way. I choose not to.

I’ve never had any experience with solar energy before now. When the system was installed I received a pile of literature, user manuals, and an hour of instruction. For me the instructions when right in one ear and out the other. It takes me a while to absorb information that is so unfamiliar.

As you gradually get used to working with solar power you become more familiar with how each component works. The components for us are broken down into the following categories: solar panels, battery charger, inverter, batteries and Trimetric monitor.

There isn’t much to do with the panels. Keep them clean and free of snow in the winter. Adjust the tilt twice a year for maximum exposure to the sun. The sun is high in the sky in the summer and low towards the horizon in the winter. The sun stirs up the little electrons in the panels which creates electricity which is then sent to the charger.

The charger receives electricity from the panels and maximizes that power in terms of efficiency to charge the batteries. Once it is set up it is virtually hands free.

The panels make electricity which then goes to a charger which maximizes the power and sends it to the batteries where it is stored for future use. The larger the battery bank, the more storage capacity you have. This is where our power comes from when the sun is gone at night or on a cloudy day. We have enough storage capacity for about three days. Once my batteries get down to about 60% capacity the generator will come on to charge them back up if the sun isn’t shining.

Batteries need to be maintained at all times. I keep the terminals clean, the water filled up in the cells and the batteries equalized once a month. There are a lot of opinions on how often to equalize batteries. My warranty requires that you do it once a month. Equalizing batteries is a controlled overcharge for a given length of time to desulphate or kind of like a self cleansing. It also causes all of the cells to become equal. For instance if you have one weak cell it will cause the whole system to be less powerful than it should be. By “equalizing” that weak cell will be brought up to the same level as the other cells and your system will be as strong as it can be.

The inverter is programmed to do a lot of things. It is talking to the charge controller, the batteries, and the AC panel all of the time. It coordinates all of those along with your backup generator when necessary. It is the Manager of the whole solar power system. One of the most important jobs an inverter does is to convert the battery DC (direct current) to AC (alternating current). Solar panel and battery power are DC.

Most homes are wired for AC. Ours is too. The inverter sends the converted DC power to our AC panel. From that point on our house operates just like yours for electricity. We use the same appliances and light bulbs as everyone else. Once an inverter is programmed to do what you want it to, it is also hands free.

Inside our house we have a Monitor of what our system is doing all of the time. It tells us how much power there is to use, how much we are using, and how much is left. It is only a monitor. It doesn’t manage or operate anything but is a necessary source of information you can use to manage your system if you choose to.

Part 2 next week – Managing the System

Ed and Laurie Essex live off grid in the Okanogan Highlands of Washington State where they operate their website  and Off Grid works.