am planning to purchase a solar power system to power about 6no lights (but only three would be on for about 4 hrs per day), a 24" LED TV on for 12hrs per day, a home theatre on for 5 hrs per day, and a laptop for 2 hrs per day. What are the system requirements, options, specs, and if possible the estimated cost. I have contacted chloride exide and Davies and shirtliff both giving me widely varying requirements Thanks wadau
It all comes down to about 2kwh per day, that’s 60 per month and that gives you a ceiling of kshs1200 per month. Now you are willing to spend more than 500k to avoid KPLC which is cheaper? Unless you live offgrid achana na solar.
Kindly list the wattage of the devices. Eg, 3 bulbs rated at 18w for 4 hours = 216watt hours. TV rated at 30w(guesswork, use exact Watts ) for 12 hours =30 Watts 12hours =360watt hours. Do the math and finally get the total Watts consumed during the hours you’ve listed. Let’s say your consumption calculations come to 1200watt hours.
Next size your battery bank. Eg, A battery rated 200AH will give you about 2,400Watt hours(from high school physics, Power =voltage * current, 200Amps12volts =2400Wh ). Since you don’t want to discharge battery by more than 50% capacity, you’ll need another battery bringing your total available storage to 4800wh.
Well, now you have to calculate the panel size. How many hours of sun do you get? There are charts for that but for Kenya is between 5 to 8 usable sunshine. Assuming that you have 8 hours of sunshine, let’s size the panels.
4800wh /8 hours of sunshine =600 Watts an hour. You will therefore need panels that can provide 600 Watts. Let’s assume that your seller has panels rated 150watts. It means that 600 watts/150 Watts =4 panels. The assumption is that the panels will be 100% efficient which is not true, however, to be safe, you can add an extra panel to get more watts. There are tables and figures for efficiency of panels.
Well, I forgot to mention the battery bank voltage, you can have 12V, 24v or 48V. My calculations above assumed a 12v system.
There’s the charge controller that you mentioned, most folks prefer MPPT, said to be efficient than PWM.
Finally, get an inverter. Since you mentioned powering laptops, get a pure sine wave inverter instead of modified sine wave. The maximum instantaneous wattage will determine the size of your inverter. Let’s say your maximum load at any time is 600W, get an inverter that’s more than that. Remember, inverters are about 75% to 95% efficient hence need to make up for losses.
Before I forget, make sure that your cables support your maximum current otherwise you risk fires and melted cables. The crucial one is from battery to inverter. As for best battery type, I’ve no idea but people say sealed ones are better (AGM, Gel, VLR etc, do your research)
PS.
I’m self taught so my explanation might be off. I’ve never been to an electrical class. Planning to install solar end of this month. I’ve already imported MPPT charge controller and inverter from Aliexpress. I’ll buy my battery and panels from Davis and Shirtliff.
Davis & shirtliff gave me a quotation and specs which varied greatly from what chloride Exide gave and hence the OP. I think from what I have gathered here, agrees with D&S