Prepared to Formulate An Off Grid Solar Energy System
Alright..let's say you added up all of your demand as 25kwh or 25000 watts per day. Next you have to find out what number of 'peak' hours of sunlight your location receives every month. You can find charts that can assist you with that right here. Then you use the correct peak sunlight and use that to split into the daily wattage use. Let's figure acquire 5 hours of peak sun. 25000 watts / 5 peak hours = 5000 watts per hour. This would mean that you need to be able to a 5000 watt (5kw) off grid power inverter. Basing your need on only 'peak' Sun/hours enables any possible inefficiencies may be present, as obviously sunlight is shedding daylight for more than just 5 hours.
You will absolutely want to have some way to online backup your stand alone solar system, so you can relax knowing you will have a continuous supply of power when the Sun goes down and on cloudy days. Batteries are certainly the most utilized for this purpose, in particular, 'deep cycle' batteries. Regular car type batteries are not well suited for an extremely application. These identical forms of batteries are used in a similar manner in conjunction with wind/turbine power systems. There are calculators out there over the internet that can help you in sizing up your battery bank, but it certainly is nice to know the old fashioned way (with our brain!).
As an example we will base the battery needs to allow for emergency/nighttime energy of 48 hours, or two days. It's not really that in order to find figure out; possess our daily element (25kwh) 25,000 watts; now we just double that sum to (50kwh) 50,000 watts; divide this by a 96vdc set up (best for this application) and we thought of total amp/hour (Ah) need of 520Ah; now we need to double this figure (to cover depth of charge at 50%) to be 1040Ah. Deep cycle batteries should just be discharged to 50% of its total rating to prolong its life. Most regularly, residential systems use 12v batteries, so we make use of some zero maintenance Trojan Deep Cycle Batteries model# 6D-AGM 200Ah. We need a total battery bank size of 1040Ah divided by each battery size of 200Ah to get 5.2 batteries; round this figure up to (6) batteries (never round down). This battery bank will all equate to (8) 12v batteries wired in series to get the 96vdc needed by (6) batteries wired in parallel to receive the 1042Ah needed. Just end up requiring a total of (48) 12v 200Ah solar batteries for this project. The correct terminology for this is 6 strings of 8 batteries.
The solar modules needed are sized much like the batteries. Take the 5kw system we came up with and go from there. Find some top rated quality panels you can discover and just take their wattage rating and divide that amount into the total required wattage of 5000 watts. The charge controller in this example would be one rated at 96vdc by 60amp (these can handle up to ten.7Kw).
As was mentioned earlier, there are calculators on the to help you through this whole process; however, even programs can mess by means of you. We always employ both methods to ascertain we have correct way figures. Batteries can easily cost similar to what your solar array, so you need to sure and set things right the first your time!