An off grid solar electric system is perfect for people whose home is far from the utility grid. It is also a perfect system for those who desire true energy independence and are willing to live in an energy efficient and mindful way. Island Solar specialize in off grid solar electric systems in the Caribbean.
It is important to understand a few key points if you would like to live completely off grid. The most important is understanding that the more power you use, the more a solar system designed to meet those power requirements will cost.
If you want a “battery backup” type system and not true off grid, we would want to have an idea of the clients annual electrical usage/ consumption. This information is in graph form on your most recent BPL electrical bill. Also let us know if your building has the heavy consumers like air conditions and water heaters.
1)When we design an off grid system, we need to know how much power you need each and every day. We will design your off grid system specifically for the way you use power to ensure reliable and long lasting electricity for you and your family. If you are interested in a true off grid system, where there is no available BPL power, once you’ve read to the bottom of this page, click on the link for a “Load Evaluation Form” This form is what we need to determine your power needs for a truly off grid system.
2)Off grid systems (and battery backup) require batteries. Batteries add considerable cost to a solar system and you can expect, without exception, to get what you pay for. Cheap batteries will have you replacing those heavy batteries all too soon. An off grid type solar electric system is the most expensive alternative, but also very rewarding for our customers. Learning to live in an off grid home is very satisfying but requires paying attention to your power usage. Batteries themselves require care and maintenance. Battery maintenance is easy, just not something most people are used to doing. Island Solar includes a laminated battery care sheet for each customer to place on their battery box. This ensures the best maintenance and therefore the longest life for your battery bank. The life of your batteries is directly related to how well those batteries are cared for.
3) There are different types of batteries. Please stay away from “deep cycle marine” type batteries. These will not serve you well as they are not true deep cycle and therefore not well suited to an off grid home.
FLA batteries- Flooded lead acid batteries are the most often used type and give you the most “bang for your buck”[. They can take deep discharges of up to 80% without suffering damage. The life span can be from five to twelve years, depending on the battery used, how well it was maintained and how many cycles of discharge and at what depth of discharge they experienced. A properly sized battery bank is essential to long battery life.
AGM– An absorbed glass mat battery is another battery option. They use a lead paste sandwiched between fiberglass plates. These are true “maintenance free” batteries, although it is still important to have tight and clean connections and cables. This type of battery can only be drawn down to a maximum of 50% of its rated storage capacity. They are also close to 75% more in cost than a FLA battery, with about the same expected life with proper care and use.
Lithium Ion– Examples of this type of battery would be the Tesla Powerwall2. While a viable alternative, they are difficult to buy right now. Other examples of lithium type batteries would be the LG Chem battery, Panasonic’s lithium battery and Sony also makes a type of lithium battery. All of these require battery management systems and can be drawn down to as much as 95% of their rated storage. They are pricey per watt of storage and should be matched with the correct electronics battery management system, usually built into an inverter. A good example is the Pika Energy (https://www.pika-energy.com/) systems which Island Solar installs which combine grid tied inverters with an available battery backup for critical loads. This is not true “off grid”, but does supply power when the grid goes down to a designated sub panel for loads like your refrigerator, water pump, lighting, a small ac split, etc. Lithium technology batteries are getting to be a better and we recommend at least looking at this technology!
Flow Batteries- These are still in the experimental stages, but show great promise. Currently they are about 20% more in cost than a lithium type battery, but can be drawn down 100% and can be expected to last about ten years.
Island Solar has many, many successfully installed off grid system here in the Bahamas and we can help you avoid the pitfalls of inexperienced installers learning on your hard earned money. We live with what we sell and stand behind it!
The first step for designing a true off grid home is for the customer to complete our load evaluation form. Click on the link below to access and print out the form. Each person/family uses electricity differently. This load form is the first step to energy independence and becoming aware of your power needs. Our design will only be as accurate as your load form is, so remember to include all your appliances, air conditioning, lighting, water pump, and every other electrical appliance in your home. When you have completed the form, simply email or mail it to us and we can start the design process.