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Off Grid Power Calculations for Wind or solar systems

Hello Friends. I know a lot of you are always wondering, about power calculations,  From the size battery bank you will need for and off grid system,  I will be posting Different Calculators you can use for you ever day needs, for installing and off grid system.

I will have charts for Battery’s, Solar, Wind, Inverters, Charge Controllers, Fuzzes, Breakers, and also determine wire sizes for the application they are used in.   As times goes I will be posting videos on YouTube of a solar install with Grid support, as a back up system,  and as my system builds to and off grid system, using Quality products.   Safety is a Number 1 priority , to protect your investment.

So Fell free to use the links to pages with Calculator, and graphs and more as I post them.

Here is a link to some power Calculations For KVA to KW, to KW to Horse power. POWER CALCULATIONS

Below are some nice charts created by Chris,  AKA Justin Case. On his YouTube channel. There is a link in the left side bar to great YouTube channels.  His is top notch there we be more added but his channel I have learned a lot.  I have a lot of respect for Chris, He is completely off grid,  He has over 400 videos on How To’s, Reviews, and much much more.

What Chris has done here is made it easy to determine the size battery bank you need with first Chart he has created. Of you are wanting to go off grid and you know what power you are going to be using, The easy way to do that is look at y our power bill for a month were you use the most KW  in that month.  Lets say you have a month were you use 3,000 KW now divide that by 30 days. That’s 100 KW per day. now divide that by 24 hours witch will give you about 4.16 KWH.    Now you may not use 4.16 KWH each hour. you might use more one hour and less the next, all depends on your loads at the time.  Now you will also want to see were can you reduce you usage’s IE high energy efficient appliance’s lighting and so forth

So if in one day you use 100 KW’s Witch is a lot of power.  but to power your home for just one hour, you would need a battery bank with at least 350AH for 12 volts 175 AH for 24 volts and 87 AH for 48 volts.   and if you want to run your home for 1 full day to.  now take the AH’s you need and multiply buy 24 to run your home for 24 hours with no sun to recharge the battery bank.    IE for  12 volt system you will need 8,400 AH battery bank  24 volt systems 4,200 AH, and for 48 volt battery bank 2,088 AH,  So if you want to save money on the battery bank you need to first decrease you power needs and only use heavy demanding loads when you have full sun to off set you battery bank and your power usage. other wise you will lose power though out the night.   This is just for one day with out any son.  and if you wanted to go a week just think about what size battery bank you would need using 100 KW per day. So you would want to reduce that as much as possible. Many people can go days on 1000 AH battery bank, Your learn to be energy conservative  and move your loads around when you have the most power production.

I have seen YouTube video after YouTube video were people have taken there battery bank as dead as you can get it. You never really want to take you Battery bank below 70% Reason is Batteries have so many cycles. when you drop you battery bank down to 50% or less that in one duty cycle for a battery. Below 50% your frying you battery’s,  This duty cycle and percent of charge also effect your AH. Something else you want to determine when buying a battery bank for your off grid or battery back up system.

Below are Two Charts Justin Created for E-solar    Also a Great company. That supports Chris’s YouTube channel. 


Justin Case chartsEstimated













The next two Charts are just sections of the above two charts So you can get a side by side view of Watts to Amps so you can determine  what size Battery bank you need for your power consumption and a state of charge so you can see at a glance the state of charge of your Battery bank.

First one is for a 24 volt Battery bank system

24vdc Volts and Amps Chart






















The last chart just like the one above but for the 48 volt battery bank systems.

48vdc batter SOC only

24vdc Volts and Amps Chart