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mcharbs55

- 13

- 1

I am having a hard time deciding the size of a solar array to boil water for a school project. Before putting any thought into the subject I simply thought that I would just take the wattage of the panels and add them up since they are added in both series or parallel and then select an element close to that wattage. Apparently this is not the case.

I am trying to do my calculations for a regular household element that is rated for 1500W at 120vac with panel specifications as 31.5V and 8.89A. My calculations go as follows:

With 5 panels connected in series=157.5V, 8.89A

Element Resistance: 120^2/1500= 9.6ohms

Element Power: 157.5^2/9.6= 2,583.98W

Element Current Draw: 2,583.98/9.6= sqrt269.16= 16.41A *This value cannot be supplied*

How would I go about calculating the voltage drop caused by the current draw being higher than the panels are capable of handling?

regular vdrop calculation would be: IR= (8.89)(9.6)=85.34V

if the power is recalculated with the new voltage of 72.16V I get a wattage of 542.4W. This seems way too low...also, performing this vdrop calculation does not seem to make sense in this scenario. If it is correct, then why are panels that are rated to supply 1400W providing a value so small? Would rearranging the panels make any difference (1 in parallel and 4 in series)?

Thanks for any help you can provide.