High efficiency solar panel - Spring 2013

If you are putting the panels on the ground mounted to a rack then size is unimportant. If you are mounting one or more to the roof of an RV then you will find that with most RV's the largest panel(s) that will fit or ones narrower than the standard residential panel which is 40" wide. You may not have room for the standard 60" panel length either.

I started with measuring my roof spaces to determine how large a panel would fit in each space without it being shaded by the TV antenna, AC shroud, roof rack, and other things protruding above the roof. When I checked out the RV solar companies that sold PV's by the individual panel and the sizes my list became a very short one. A secondary consideration is that if you are using different PV models that you match their Voc within 0.5 volts.

The most efficient panesl are those made for the commercial market, and these are not available for residential use. The best residential panels are not being sold by any of the RV solar dealers as these dealers do not qualify and the panel manufacturers don't want to sell in such small quantities to thousands of RV shops across the country and have no control over how their panels are installed and used.

Here is a simple flow chart.

Budget-->Energy Audit-->Battery bank size-->number of watts-->PWM or MPPT.

Here is a link to the rather special spreadsheet that N8GS has created to help size solar battery charging systems!

Solar spreadsheet by N8GS

harold1946 wrote:

red31 wrote:
When cost is different for the same energy ... How is the most expensive energy cost, most cost efficient? or a better ROI?

I believe you miss-understand. The higher efficiency panels produce more energy with less input. That also equates to more energy produced at lower light levels.
The Sanyo HIT technology also maintaines a higher energy output level as temperatures rise. Many panels loose as much as 60% of their output as temperatures rise.
I have seen a good number of solar installations with multiple panels of poor efficiency and dissatisfied owners. Solar panels chosen solely by cost, with little or no regard for efficiency. Then when it is found that they are not adequate they add more panels, when more efficient panels to begin with would have been the more cost effective solution.
Its pretty much a choice of the owner. More, less efficient panels at a lower cost per panel, or fewer, higher efficiency panels.

Do any of these features sound familiar? They add in thin film amorphous layers to get these wonderful attributes.

:)

Jim

At 10% peak current improvement at elevated temperature, while costing $500+ compared to others at $150, Sanyo HIT is a poor ROA.

Sanyo HIT is a good choice if a 2% greater panel surface area will cause a fit problem.

Sal

harold1946 wrote:

smkettner wrote:
^^^^ Sanyo HIT at $500+ compared to others at $150.... Yes you could just get more panels for the same price. Some days would be a wash and other days the lower price panel will produce 3x energy.

Limited roof space and cost of inverter/controller would determine optimal size.

What reference do you have that shows a lower efficiency panel that will produce 3x the power of a more efficient one of any kind?

The price example above. 3x$150 vs 1x$500.

Jim

harold1946 wrote:

smkettner wrote:
^^^^ Sanyo HIT at $500+ compared to others at $150.... Yes you could just get more panels for the same price. Some days would be a wash and other days the lower price panel will produce 3x energy.

Limited roof space and cost of inverter/controller would determine optimal size.

What reference do you have that shows a lower efficiency panel that will produce 3x the power of a more efficient one of any kind?

1x 225w = 225w $500
3x 225w = 675w $450

(ideal conditions)

Poor conditions derate the cheep panels an extra 10%? Or 60%? Your choice.

smkettner wrote:
Looks like closer to 10% typical advantage.

Bingo :)

So a panel that looses only 20% of its energy output is still 10% more efficient than one loosing 30%.
235 watts minus 10% = 211.5 watts
235 watts minus 20% = 188.0 watts.
23.5 watts lost

smkettner wrote:
^^^^ Sanyo HIT at $500+ compared to others at $150.... Yes you could just get more panels for the same price. Some days would be a wash and other days the lower price panel will produce 3x energy.

Limited roof space and cost of inverter/controller would determine optimal size.

What reference do you have that shows a lower efficiency panel that will produce 3x the power of a more efficient one of any kind?

Looks like closer to 10% typical advantage.

^^^^ Sanyo HIT at $500+ compared to others at $150.... Yes you could just get more panels for the same price. Some days would be a wash and other days the lower price panel will produce 3x energy.

Limited roof space and cost of inverter/controller would determine optimal size.