A ROUGH GUIDE TO SIZING A HYBRID SYSTEM
If you are Grid Connected or have old energy bills you will see a graph with your consumption patterns, besides this, you will see on average how many kWh/day of power you are using, this is an indication of how much power you need to produce for day and night time usage. Keep in mind it does not tell you how much power you are using through the night to calculate a battery bank size. From around 4 p.m. (depending size of solar array, physical location Orientation and season of year) your solar system will not be producing much usable power, from here is when the energy that solar system has stored into a battery bank will be used following right through to the next morning also when the sun is high enough for panels to produce energy again directly for household use as well as charging depleted batteries from the evening before.
If you were to take a simple meter reading in the afternoon around 4 pm and again in the morning @ 8 am you would roughly know how many kWh/Night you need to store into a battery bank, If it’s not summer and you take a reading then you will need to calculate some AC run time also or maybe look at past summer energy bills to get an indication. Our service to you – (We could also confirm this by placing an energy monitoring system in your meter box to best size a battery bank for your home. kWh’s consumption needs to be taken into consideration with actual constant demand- (A calculation of how many amps/watts/hours all of your appliances may be drawing at any given time throughout the day)
Determining a suitable battery bank type and size will be one of the most important considerations in system selection and worst regret if you get it wrong. Some battery banks don’t work well-adding capacity at a later date. Mixing new cells with older slightly depleted cells in Off-Grid systems containing Lead Acid Gell batteries is defiantly not recommended and this is to date the most proven technology for pure Off Grid Pure Solar Systems.
Grid systems are more adaptable with newly developed Lithium technologies containing a BMS (Battery Management Systems) charging at the individual cell level, allowing each cell to charge to 100% capacity every time charging takes place provided there is enough solar or generator supply to complete a full charging cycle. In addition, most Lithium battery banks are designed to be expanded on. Grid systems also have the advantage when the battery bank reaches its cut-off limit the system will automatically supply power from the grid.
Battery banks to date are the bulk of a system cost. In another three years, we hope to see cost fall into line with the balance of solar system components. More so we would like to see a battery rebate for the solar and electric car industries.
Other considerations possible alternative energy sources like a Generator or Wind Turbine which can be used during the evening reducing battery bank size or keep the bank topped up.