Battery Bank Sizing: Off Grid Solar Power System Design

altE admin i have a question plz help me out i recently installed 5 KW off grid solar system every thing is working just fine,i hired some one to do it for me so i am not an expert but i do travel alot i always have my lap top on me which always run out of charge so i thought why not built a smaller solar system that can only charge my lap top.

i have 50 watt solar panel and i just acquired a 100 watts 220Vac invertor,my lap top total power consumption is around 50-60 watts 220 Vac.i don't know plz tell me what Amp/hour battery should i use if lets say i only need my laptop to work for only 3 hours?i need one that can start charging my lap top right away during day time in emergency situation.plx guide thx.

Amy, step F: Determine total number of batteries needed. The formula should be number of parallel strings that is 2 times number of batteries in each series string.

Amy, StepD: Determine number of series strings should be changed to Determine minimum battery capacity .

hi there, can you clear something up for me.

I am trying to figure out an equation for my battery bank.

If I want to find out the amount of amps that my 140 watt tv uses, do I need to divide 140 watts by 240v ac(as this is what my inverter produces) Or do I divide 140 watts by 12v (my battery voltage). my battery bank is 115 amp hours so I want to know how long I can run the television for. thanks!

what will be the battery temperature multiplier over 25degree celcius?? will be 1. something or less??

I just say something about sizing the battery bank by array size controller max out out amp and voltage. ie...2k array, 79 amp max out put controller and 24 battery bank not up to par? (2000 79x24= 1896) by what I heard a 36v or higher voltage bank should be used? Is this correct?

Thank you very much for this very informative training.

I live in the Caribbean where we get around 5 - 6 hours of intense sun a day based on maps. I want to run a 50watt deep freezer for 8 hours a day (400 WH) using a 12v, 2000watt inverter with a PWM controller. Based on two days without sun, this video's calculation recommends a 8000 Ah battery bank yet only 119 watt solar panel! In areas such as the Caribbean, with many hours of reliable sun, can you reduce the size of the battery bank and increase the solar panels when appliances, like a fridge, are run only during peak hours like from 9am to 4pm?

I will go with 1 battery, 48 volt type: 24-85-21 charging 6 hours = 850 aph, after 20 hours = 1340 aph total KW = 64.3 that's 4 days electricity on reserve for charging EV vehicle and night-electricity with AC & pump it only cost $7000 :D

Source: http://www.rapidtables.com/calc/electric/Amp_to_kW_Calculator.htm
http://gbindustrialbattery.com/Forklift_Battery_Sizes_and_Specifications_Zone15.html
Remember if you go with those batteries, they required "distilled water" NOT TAP-WATER, batteries cells don't like calcium(

If I'm understanding your video correctly, I should never have more than two batteries in parallel? WOW! I've seen dozens of videos where battery banks have 10 or even 20 batteries in parallel. Are they all doing it wrong? I currently have a bank of 10, 12 volt batteries wired as two in series and five in parallel to get to 24 volts. Is this really a bad thing?

Thanks a lot for those very clear tutorials.
Why do you restrict your battery bank voltage to 48Vdc?
Low voltage = high current = high fire hazard or high cost (high gauge)...
I may come up with a silly idea, but I'm considering a solution enabling both power and water supply (to a water tower) from the same PV array, but using a solar pump inverter in order to preserve my batteries, the most expensive part in all this...
Pump inverters usually need a quite high DC input. We do not need to pump water like seven eleven 24h X 7 days... so the idea is to have a PV array that can be reconfigured from 2 strings of 6 panels in series (250W-60) = POWER into one string of 12 panels in series to get that high voltage = WATER. The MPPT controller shall be able to handle 300Vdc PV input, >3000W, and charge a 96V battery bank.
Voc=37.1 Vdc, %/°C = -0.32%, t°=5°C, =>Voc=39.47Vdc x 6 = 236.85Vdc
W input Max irradiance = irradiance at noon Max t° 65°
Pmax 250W %/°C = -0.47% P65° = 2,436W; 2,436W ÷ 96V= 25.4A => 30A.
I can achieve the reconfiguration with two DC Isolator Switches 4 Poles
I would not be able to do that with a 100V or 150V DC max MPPT controller, the switching POWER => WATER would be more tricky...
Some Morningstar products accept up to 600VDC PV input...

Thanks

Series strings shortens battery's life more than parallel strings. In series the possibility of overcharging independent cells inside the battery is greater, resulting in premature failing of the pack just because of one cell. Am I wrong?

how about 4____L16 batterys and a good 2000watt sine wave inverter,,,@12 volts could you run the George and small microwave,not at the same time,,,,or would 24 volts be better,,,,how many panels would I need to support a 24 volt battery bank made up of 8 ,t105 batterys,,,L16 would probably be better,,,,could you give me the numbers for each type of bank at 24 volts,,,one made up of,t105,,,,and one of L16,batterys,,,and what about charge controller,,,I can go up to 800watts I think on my pro star ps 30at 24volts,,,I have been thinking about buying another ps30,to parallel two for my,372amp hour 12volt bank I have now,,,I'll have to get,4___more,100,watt panels ,,,I'm thinking it would help with overcast days and shading,,,,later if I go to 24 volt,having 2 ,,,ps30 I'll have the capacity or ability to go up to 1600 watts of Solar I think if I'm looking it this right,,,,or I could stay at 12 volts for a while and have 800watts.....

is it a bad idea to run a George foreman grill or a small microwave on a 12 volt battery bank of I think 372amps hours,,,(4_186amp hour 6_volt golf cart batterys),for 3_5 minutes.a day???or is this honda eu2000i job???

that makes good sense to draw everything out like that and also show it to someone else who knows more than I do,,thanks for you're time,,,regards::::Bill R.................................

I just recently noticed something,,, I'm very new to Solar I studied up on all this stuff then hooked up my 4 golf cart batteries 2 strings I hooked positive and negative together on two batteries then I hooked up the other 2 batterys the same way, I then connected the first string to the second string by way of hooking up the negatives together,,,,well in all my excitement about everything I then hooked up the charge controller,,,real nice pro star ps 30 m,,,then my panels,,,made sure everything was fused and grounded,,,,got a real nice samlex pst 300,,,works great,,,well the other day I was checking the water level in the batterys and got to looking around and seen that I had forgot to hook up the the other side of the strings+pos.from one string to the other.?????I was and am hooked up across the bank diagonally it was getting 12 volts and still am,,,well after I made the correction I found my self wondering how was it able to work like that???was I only getting amps from one string???anyone know please feel free to enlighten me,the only thing connecting the strings were the_negative from one string to the other,,,,idk,whatever you do especially if you are new don't be overcome by the excitement of what you're doing take time to really look at things good and maybe get a friend for a second set of eyes to look at it too that's what I've done now,,,anyhow thought I would chime in on that

Whatever. You are just a dealer trying to pump up sales.

If you are going to teach, learn first.

Yur math is out to LUNCH in the worst way. By your numbers the actuall number of batteries you need is 4.

Battery Bank Sizing: Off Grid Solar Power System Design - Step 2

About | Information | History | Online | Facts | Discovery

Comments