Complete Solar Power Systems
By David Dell
We first installed a solar power system on our beach side home in Puerto Armuelles 4 years ago.
If you decide to go off-the-grid, there are some caveats you should be aware of.
Firstly, Solar is not a direct replacement for your existing utility company electric supply. For example, if, at the moment, you have several 220 Volt air conditioners that are running day and night, then solar is not for you. If you think solar will save you bundles of cash in the short term, then you will have to think again. The cost of solar has come down but it is still not a cheap alternative.
So why anyone would want solar?
In Volcan, where we live part of the week, the power goes off almost every single day. Even with battery back-up you still have those annoying times when you are in the middle of a Netflix movie and then, just at that critical moment – the lights go out.
Even more annoying is being at the beach on a hot and humid evening when the lights go out and of course – the fans stop. If you have ever suffered through such a sweaty, sleepless night, then you realise how important a fan can be. After 17 years or so in the tropics I find that yes, I can live without air conditioning – but I cannot live without a fan.
REVERSE EXTRACTION FANS.
In our beach home I have developed a simple system to keep us cool at night when sleeping. Simply place a standard 12 inch bathroom extractor fan in the wall above your bed. The trick is to install it in REVERSE. So instead of sucking warm air out of the room, it blows cool outside air in.
Before midnight on most nights my dear wife will turn to me and say “Dear, I’m cold, please turn the fan off.”
Enough said.
So how does solar work and what do I need?
Solar panels are covered with photovoltaic cells. When sunlight hits these cells the photons of sunlight are converted into electricity. This is direct current electricity (DC) the same as you would get from a 9 volt battery. Now to use that in your home you will need to convert that DC into AC (alternating current) the same 110 volts electricity you get from a three pin plug. For that you will need an INVERTER. Simply put this changes DC into useable AC.
To graphically illustrate this see diagram above.
First sunlight hits the solar panel. Then a CONTROLLER regulates the DC power and sends it into a battery. Then the INVERTER converts that battery DC into 110 volts AC and sends it to your 3 pin plug.
HOW MANY PANELS AND BATTERIES DO I NEED?
I will make this as simple as possible. What is your budget? How much can you afford?
A basic system will give you about 1,500 to 2,000 watts. What (excuse the pun) does that run? Well, we have that system right now and we run several large ceiling fans (day and night) a small fridge, a computer, a 36 inch TV and DVD player, A 4 camera security system, a water pump for our well (maybe an hour a day) and at night we have 2, 300 watt LED security lights and 5 smaller perimeter LED lights. - and yes (as noted above) we run a reverse extraction fan.
We have six panels of 260 watts and six TROJAN gel batteries. The panels cost $345 each and the batteries are $349 each. The 60 amps controller cost $670, the INVERTER about $400
Note: we did use other American made batteries that were cheaper – but eventually they all failed. Also, there are cheaper panels but the ones we buy have a 20 year guarantee.
Refrigeration:
Unless you have a large solar system you will not be able to have a decent sized fridge.
THE SOLUTION:
A propane gas fridge is wonderful. A Canadian company called UNIQUE can be found on the web.
They are more expensive but the one we have can switch from propane to electric. So when you do get city power, its a doddle.
Another essential piece of equipment is a battery monitor.
We use this VICTRON battery monitor it gives lots of information about state of charge, power useage, and it provides an alarm to warn if the power is getting low.
You will need a battery monitor.
CAN I USE POWER TOOLS?
Yes, In the day you have excess power. I have even used an angle grinder and electric drills (around midday and only for short periods).
At night we only consume about 25%. Normally, never a problem as the panels bring us back up to 100% around midday.
However, during the rainy season you may have consecutive days with little or no sunshine.
This year we had almost a week of rain and cloud and for the first time our 4 panels system never fully charged our batteries. Each day our total power became less and less. We were in danger of having a shut down - so we bought 2 extra panels for just such contingencies.
So far, despite many overcast days - we still manage to reach 100% of charge.
Buy peace of mind - buy extra panels.
If you have any questions about our solar system,
email me and I will try my best to help: David Dell