New Sunpower efficiency at 24%

[zboss]

They have increased efficiency at the cell level to 24.1% over their existing 22.8% cells.

SunPower® Solar Panel Again Raises the Bar in Efficiency - Jun 27, 2016

[woodenboats]

So what? Solar Panels are sold by nominal power measured unser standadardized conditions. A bigger efficiency cell allows for a smaller panel - going from 22.8 to 24.1% reduces panel size by less than 3%.

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[noelex 77]

Originally Posted by woodenboats

So what? Solar Panels are sold by nominal power measured unser standadardized conditions. A bigger efficiency cell allows for a smaller panel - going from 22.8 to 24.1% reduces panel size by less than 3%.

I don't think that the above maths is quite correct.

The gain is not great, but I still think it worthwhile on boats where space is a premium, especially as 22.8% is still exceptionally good.

If we take a typical boat solar array of, for example, Kyocera panels. These are about 15.5% efficient (or sometimes less). Say a 500w array made of these panels. With the same surface area of the 500w Kyocera panels, the 22.8% Sunpower panels would give us 735w. 24.1% panels would give 771w.

These are worthwhile gains, although it not clear if/when the 24.1% panels will be commercially available.

[Captain Bill]

Sunpower panels are really nice but they are only slightly smaller than other panels that are not quite as efficient. They are not so much smaller that I can put on another panel. The downside is that they cost three times as much. I priced several panels in the 300 watt range that would fit in my two 65x40 inch available spaces. LG Panels were in the $400-$450 range while Sunpowers were $1400+. I can't justify paying the Sunpower price even with their better warranty. I can replace the LG's 3 times and still not be at the cost of the Sunpowers.

[zboss]

Its not just that, its also that the voltage of the sunpower/solara panels are generally much higher. Even though they are only "slightly smaller", they start outputting useful current at a higher voltage earlier in the day and much latter into the evening. So, using your high voltage solar panel up north is much like using your solar panel down south. This also means you need smaller wires, which weigh less, are easier to install, and so forth.

All this translates to real improvements in the number of Ah a day they can be expected to provide, which means you need even less space.

If cost is the only factor than, yes, you can't beat a Kyocera panel; but for us the 4" per panel size savings is the difference between having 280 watts on our bimini or 420. Thats a major difference which in turn means I can get rid of our generator.

1.5% to 24% efficiency is a major improvement - a 6% relative improvement over the 22.5% cells and 41% better relative to 17% efficiency Kyocera cells.

[barnakiel]

Originally Posted by zboss

(...)

1.5% to 24% efficiency is a major improvement - a 6% relative improvement

(...)

Yep. 5.7% improvement exactly. The lower figure is our 'base'.

b.

[noelex 77]

Originally Posted by zboss

Its not just that, its also that the voltage of the sunpower/solara panels are generally much higher. Even though they are only "slightly smaller", they start outputting useful current at a higher voltage earlier in the day and much latter into the evening. So, using your high voltage solar panel up north is much like using your solar panel down south. This also means you need smaller wires, which weigh less, are easier to install, and so forth.

Solar cells can produce lots of volts before they can produce useful current, so high voltage panels tend to produce near identical power at the beginning and end of the day compared to lower voltage panels. The Sunpower panels do have some other characteristics that give a little more output than most other panels of identical wattage (for example, a better temperature coefficient and low light performance).

Higher voltage does help reduce the wiring size, although voltages of over 50V make me a little nervous around salt water, so there are pros and cons.

[zboss]

BIG difference between my new Solara sunpowers and my old Solbian CP140's... today I noticed that the Solaras were putting out half their rated amperage even while 1/2 shaded by the wind generator. The plain vanilla solbians would barely put out any amperage under the same conditions.

[OceanPlanet]

Originally Posted by zboss

BIG difference between my new Solara sunpowers and my old Solbian CP140's... today I noticed that the Solaras were putting out half their rated amperage even while 1/2 shaded by the wind generator. The plain vanilla solbians would barely put out any amperage under the same conditions.

Despite the lower cost of the Solbian CP's we find we sell far more Solbian SP and Solara Power-M (both with SunPower cells). For the same rated power, we see more Ah/day from the SP/P-M panels, due (as you point out) the better performance as low light angles, etc.

The new Solbian SXp panels are replacing the CP as the more economical option to SP, as the SXp seem to do better in low light & sun angles than the CP. Also seem to lose less in partial shading. Need to do more Ah testing however they are looking good.