Understanding the Science

On Thursday, after the visit with Allen, a representative from Revolusun, our group has decided to try solar panels, instead of the water wheel solution.  After looking at our water wheel design, with our time, money and knowledge restrictions, our group has taken the step toward solar.  Before our meeting with Allen, Kyrie and I went to ask Mr. Kamalu (Physics Teacher) if he could help us figure out what was wrong with Mr. Omo’s present solar situation.  Currently Mr. Omo has a 56-watt pump, two 5 watt solar panels, a 12 volt battery and a 400 watt power inverter.  Here’s how it works:  The solar panels are arranged in a series, so together they can get up to 10 watts of power on a good day.  Now this is a very good day, without clouds, or rain and a whole lot of sunshine.  In reality because every day is not a “very good day”, the solar panels are getting more like about 6 or 7 watts.  So this power goes into the inverter.  The inverter takes the power, which is DC (Direct Current) and turns it into AC (Alternating Current).  Once the power is inverted it goes to the pump and battery.  Now here’s the tricky part, lets say that we are getting a substantial amount of power.  In this case about 50% of the power is stored in the battery and the rest goes to power the pump.  The pump needs 56 watts in order to work….yeah we have about 7 watts right now and none of that would be going to the battery….so its not working. 

Fortunately we were able to meet with Allen and Mr. Kamalu, and we figured out we need a bigger batter and bigger panels.  Our job is to calculate how many watts the solar panels need in order to give 50% to the battery and still be able to run the pump.  When doing these calculations there are many factors that need to be taken into consideration.  These include: 1) 3 days a month of rain/clouds 2) 5 hours of sun per day 3) the tilt of the solar panel 4) the voltage of the battery.  My goal is to get these calculations done by Tuesday!