GORV - Digital Magazine Issue #8 | Page 12

LET THERE BE LIGHT! THERE’S NO SHORTAGE OF BULLDUST SURROUNDING RV SOLAR. ENGINEER COLLYN RIVERS SORTS FACT FROM FALLACY. WORDS: COLLYN RIVERS | MYTH 1 All solar modules are much the same so buy the cheapest you can (per watt). REALITY Not all solar modules are the same. This applies not just to output but also to quality. There are less than 50 solar cell makers, of which only 40 or so also manufacture complete solar modules. 12 gorv.com.au All others buy the cells (often of low output). A typical 12 volt solar module has 36 cells (72 internal connections). A vast number of Asian assemblers use cheap labour to solder them all manually, with varying degrees of expertise. These are marketed under any number of names or, as eBay shows, often none at all. The best solar modules are (in 2017) 18%-19% efficient. Those cheaper are 10%-15%. Vendors claim more, but that is of individual cells, not 36 soldered together with connection and other losses. Expect to pay about $2 per watt. MYTH 2 A 120 watt solar module will produce at least 120 watts in a typical RV installation given a typical Australian sunny day.