How to Determine the Off Grid Solar Battery You Need
Off grid batteries can be flooded type that you will have to maintain with distilled water. They are less expensive than the sealed AGM type and can last the same amount of time.
For higher battery cycles, use 6 volt deep cycle batteries for best results.
Crown is an American Mfg battery company and has the highest battery cycles compared to Interstate, Trojan, US Battery and Exide.
For Off Grid Solar Battery – 12 volt good, 6 volt better, 2 volt best.
Traditionally, solar batteries or battery back up batteries are flooded, the kind you have to water.
AGM and Gel are preferred because they are maintenance free and they recharge much quicker. But the cost is usually prohibitive. But while supplies last, we stock a maintenance free AGM deep cycle off grid solar battery at a price of $125 ea*
Battery Cable for Sale for Off Grid Solar Battery
If you need to power your house with an off-grid solar system but cannot connect to the grid, then you will need to build an off grid solar battery bank to run your house. Don’t fear, batteries last a long time, require a little maintainence and are cheaper in the long run than paying local utility companies.
The goal when designing an off grid solar battery bank is to have a battery bank that is big enough to supply all your needs for a few cloudy days but also small enough to be charged by the panels.
Here We Go!
- What Size Inverter?
Choose an inverter that can handle the peak load or maximum wattage of your home. This can be calculated by adding up the wattage of the appliances and devices that can be ran at the same time. Count everything from microwaves and lights to computers and even clocks. The sum of all power consuming devices will tell you which size inverter you will need. Example: A room with two 60 watt light bulbs, one 300 watt pc = 120 + 300 = 420 watts
- Daily Energy Use
How much energy used in a day? How long or how much time does each device run (hours) during the day? Multiply the wattage of each device by the hours it runs to equal the # of watt-hours per day. Now, add all the watt-hours to get total of daily energy use in watts. This rough estimate will more than likely to be low, so adjust by multiplying the value by 1.5. This is called adjusting for system loses and will account for decreasing performance when temperature increases. Example: Two 60 watt light bulbs run for 5 hours per day and the computer runs for 2 hours per day.
Math – 120 x 5 + 300 x 2 = 1200 watt-hours. 1200 x 1.5 = 1800 watt-hours per day
- Days of Autonomy
Means how many days of energy do you want to store in your battery bank. Generally this is anywhere from 2 to 5 days.
- Battery Bank Capacity in Amp Hours or AH
Take the watt-hours per day and multiply by the number of days of autonomy you elected. Example if you want the batteries to last 3 days, then 1800 watt-hours per day or 1.8 kwh (kilowatt hours per day) can be written as 1.8 kwh x 3 days x 2. We multiply by 2 because batteries can only be discharged to 50%.
So, from the example above, we use 1.8 kwh and want the batteries to last 3 day and need to multiply by 2. 1.8 x 3 x 2 = 10.8 kwh, this is the energy we need from the batteries. Convert this to Amp Hour AH by dividing by the total system voltage the inverter and battery bank will run on. This can be 12v (usually RV and Marine systems) 24v or 48v for commercial application. If we choose 48v the minimum AH capacity is then 10800 / 48 = 225 ah
- If you looked at a Trojan 6v T-105 AH rating at 20 HR you would see it is 225 AH. Therefore two 6v T-105 wired in series would be 225 AH.
Choose the 6 volt off grid solar battery size that works best for you application. The larger higher amp hour L16 batteries are more economical for the $ to ah ratio but can be too large or heavy for every application.
The three battery brands we sell for renewable energy are Trojan , Rolls and US Battery. All three battery manufactures have superior quality and last a long time with proper maintenance.
Renewable Energy Battery