The Good, the Bad, and the Ugly: Classifying SunPower solar cells

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If you see me at a trade show and notice that the company shirt I’m wearing does not fit too well around the collar, it is probably because it was bought at low cost from an outlet store by the embroiderer. The label suggests that this shirt is from a highly respected manufacturer and is of high quality, which is all true up to a point, but somehow the buttons and button-holes were mis-aligned during assembly, and so this item was sold off as a “second” or reject item in the manufacturer's outlet store.

Well, guess what? Somewhere out there is an outlet store for low grade, off-spec, SunPower® solar cells.

During manufacture, after solar cells have been tested electrically they are sorted into different “Bins” dependent on how they performed. Some will be over achievers and be put aside for research purposes, while others will simply fail miserably and be destroyed. Those remaining are the Good, the Bad, and the Ugly cells;  Good being “Prime”, Bad being “Off-Spec”, while the Ugly cells will have visual or cosmetic defects.

The Prime cells are further graded into High, Premium, and Ultra performance categories, while the Off-Spec cells are

Read more: The Good, the Bad, and the Ugly: Classifying SunPower solar cells

Marine Cooling, Refrigeration, Monitoring, And Solar Solutions

Are you a boat owner, or soon-to-be boat owner, with questions about your vessel's systems? Let us help you find those answers. For example:

    • How many amp/hours are your solar panel is putting into your battery bank? Philippi's PSM System Monitor will tell you.
    • Water-cooled vs air-cooled refrigeration, see "Which Condensing unit should I use" in Refrigeration > Planning.
    • Planning for solar panels on our boat? See "Marine Solar Panels Planning and Installation Guide in Solar > Planning.
    • Air-conditioning on your boat, while on the hook and no generator running? (Yes you can!)

If you don't see the answer to your questions in our website, blog, facebook, or twitter posts, then contact us directly. We are here for you.

Shop our catalog or click on a logo below to go directly to that product page.

Will a Battery Monitor properly show Solar, Wind, or Hydro Output?

Many boats these days have a battery or systems monitor permanently installed. Popular models include: E-Meter, Link 10, Victron BMV, Philippi BCM, etc.

With these meters, DC current is measured in and out of the battery by a device called a Shunt that is installed in the negative lead to the battery. A Shunt is simply a bar of metal with a known resistance between the two ends.

The resulting drop in current is then measured by the monitor and multiplied to give the correct current reading. The Shunt is the very last item connected to the battery negative post, and no other negative leads must be allowed to by-pass it. This is to ensure that it measures every amp of current going both in and out of the battery.

As you can see from the example below, it is possible for solar panels or a wind/hydro generator to supply power for DC loads directly, via bus bars or other connection points, without their current flowing into the battery or through the battery monitor Shunt. 

Read more: Will a Battery Monitor properly show Solar, Wind, or Hydro Output?
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