Imagine paying for a dozen eggs and only getting 10.8 eggs !
Or imagine buying a 200 watt solar panel and only getting 180 watts !
We won't mention names but many solar panel manufacturers have a warranted minimum power max rating of negative 10% or worse. In plain English what that means for example is that, when purchasing a 200 Watt panel from some other manufacturer, its minimum power max rating can be off by (negative) -10% or 20 watts !! So you could be paying for 200 Watt panel and only getting a 180 Watt panel right out of the box .....ouch !
Mitsubishi Electric solar panels are rated at an incredible -5% which is why they are in such high demand in Europe. In Germany and several other European countries, the negative 10% or more tolerance panels that are generally available in the U.S. would never make it into a European solar electric system. As much as we hate to admit it, the Europeans are about 10 years ahead of the U.S. when it come to solar electricity and they demand only the lowest negative tolerance panels on the market, it's got to be -5% or less or the Europeans don't want anything to do with it. When shopping for solar panels, always look for the lowest minimum tolerance ratings or in other words the highest warranted minimum power !
Here's a couple of negative tolerance rating for two popular competing solar panels.
Brand S. (A very popular 200 watt
panel sold by many of our Internet competitors in their pre-configured systems) According to their own
specification sheet, only 200 watts warranted minimum power.
Negative 10%.
Brand B. (A popular competitor's 170 watt panel included in the home improvement store's systems) According to their own specification sheet, only 151 watts warranted minimum power. About negative 11%.
Brand SP. (A relative newcomer to the solar industry who claims to offer higher efficiency solar panels. There latest generation 215 and 220 watt solar panels) According to their own specification sheet, only 197.8 and 202.4 watts respectively. Negative 8%.
A negative 10% tolerance rating is like buying a dozen eggs and finding a sticker on the egg carton that says "we only guarantee that this 1 dozen carton of eggs will contain 10.8 eggs !
Don't take our word for it, ask our competitors to email you a copy of their solar panel's spec sheet and look for the "warranted minimum power max" rating and see for yourself !
To be fair, because of the complex manufacturing process, no solar panel is perfect. But in our opinion 10% is just too much when there are solar panels available that have only a 5% negative tolerance.