Sanyo double hit panels inverter sizing

solar roller · December 2009

Scenario
Sanyo Double HIT 195w panels that will be mounted on a canopy type racking on the edge of a water bank.

These panels I’ve read are capable of producing 130% of their face plate.

If I plan on installing 25 panels creating around 4875w (based on the 195w panel x 25 face plate rating) I should use 5000w inverter?

If the stars align and the system produces 130% of the face plate that would yield up to 6337.5w as a system (4875 x 1.30).

Questions
1. Is the 130% production like hitting the lottery with so many random factors allowing for that to happen?

2. What inverter should I use a 5000w inverter and when the stars align I will be donating 1400obo watts or so or oversize the inverter to a 6000w risking the efficiency of the inverter to possibly gain the ROI with the extra 1400obo watts if the 130% GAIN IS FEASIABLE?

newenergy · December 2009

Re: Sanyo double hit panels inverter sizing

Under what circumstances do they produce 130% of nameplate? Most of the time they will be producing less and there are losses in the conversion to AC and the inverters are rated in AC output.

The inverter manufacturers have string sizing software that will show you the projected outputs under different circumstances.

25 of these panels is well within the specs for a 5000W inverter.

BB. · December 2009

Re: Sanyo double hit panels inverter sizing

On average, your peak power (on good days) will be around 77% of name plate rating or:

77% * 4875 watts = 3,754 watts typical peak.

Your actual peak (cold weather, edge of cloud event can be somewhere around 4,200 watts (based one what I see with my GT system).

Can you see higher--perhaps when snow is on the ground and reflection from from the snow field (plus cold weather) could get it higher...

You will not damage the inverter. It is designed to limit to its maximum power ratings.

I would not feel bad limiting the inverter to a 4,000 watt model. The amount of time your system will operate > 4,000 watts will be pretty limited (few hand fulls of days a year for less than an hour?).

Maybe somebody with logging on their systems can give you a better answer.

-Bill

solar roller · December 2009

Re: Sanyo double hit panels inverter sizing

You guys are a wealth of knowledge and so very helpful, thanks.

What had me concerned was the below info that i found on (http://www.ecodirect.com/Sanyo-HIP-195DA3-195-Watt-40-Volt-p/sanyo-hip-195da3.htm):

"IMPORTANT HITR Double bifacial solar panel's Rated Power (Pmax)1 is measured at Standard Test Conditions (STC). STC does not include power produced from the backside bifacial effect of the panels. Bifacial panels may produce up to 130% of their STC rating, dependent upon installation design and location albedo - the site's reflectance rate. Use caution when selection, calculation and sizing system components to account for the increase in power."

So in conclusion from your knowledge the above statement should be taken with a grain of salt.

This system will be installed on the bank of a large pond, which i thought could be an ideal placement for the bottom side of the panels to recieve maxium light, that could allow the sun light to reflect off of the water to the backside of the panels.

Again that for you knowledge.

BB. · December 2009

Re: Sanyo double hit panels inverter sizing

I would try a test... Solar cells when shorted by an Amp Meter are a very good tool to measure solar radiation (watts per sq ft/meter).

Take any solar cell/panel over to your site during the middle of the day. Connect it to your amp meter and point it at the sun (cover the back if it accepts solar energy from the rear face--we only want to measure energy from the front). Measure the current. Now, point its back face (covered/shaded if needed) to the sun and measure the current from reflected light.

Now, what are the two currents. If the rear facing current is 30% of the sun facing current--then I would consider their claims when used at your site to be plausible.

Obviously, if you could do the same test with a real HIT panel would be neat. Set panel up with amp meter at site, then cover the rear with cardboard and see what happens. If you are going to be installing a large array--it would be worth the effort.

Remember, the larger array, the more shading there is. The closer the panels are to the ground/mounting surface (such as roof mount), the more shading too.

Even with a small panel, you can simulate a larger array + shadows by holding your reverse facing array closer the ground/roof surface when doing the measurements.

A single panel on a pole in the middle of a snow field is probably going to behave different than a 200 sq ft array mounted 5" over a asphalt shingle roof.

-Bill

Solar Guppy · December 2009

Re: Sanyo double hit panels inverter sizing

Maybe if its on a 30ft pole it might get more energy output, but you have to have reflected sunlight ( like mirrors ) and in 99.99999% of the installations that's not going to happen

Further, if you considering the Sanyos based on this marketing hype, your paying a huge premium that in real world means nothing.

Bang for the buck, look at the Evergreen modules, you'll get 30% more for your money per watt basis, possible more depending if you consider seconds

solar roller · December 2009

Re: Sanyo double hit panels inverter sizing

Bill I will definitely try your test and post the results. It will be next year sometime. This racking system will be a custom canopy along the water’s edge about 7’ tall designed to have the least amount of obstructions to the backside of the panels.

Again thanks

BB. · December 2009

Re: Sanyo double hit panels inverter sizing

I always wondered how well one of those panels collected light from behind.

Take an array, and put a couple of 2x4 boards across the face of all of the panels--and I would expect a 50% or worse hit in array output from shading in full sun.

The HIT modules have to be mounted somehow--so they are going to have structures at the rear (cross pieces and vertical mounting posts) for a standard mounting system (unless you use some sort of expensive architectural mounts that holds the panels from the sides like window glass and a clear span with only edge supports). [ps: I see from your post just before mine that this was a canopy installation and rear obstructions will be minimized]

In the end, like Solar Guppy says... Look at the panel + mounting prices per watt. If you can get good quality panels and mounting that is 30% less than the Sanyo HIT pricing--then it is an obvious win for the less expensive array.

I would hard pressed to believe a 130% output based on reflected light from a normal install that is not done over a field of mirrors/snow. But, I have not done the testing either.

-Bill

RCinFLA · December 2009

Re: Sanyo double hit panels inverter sizing

Did not see where you are located. Winter cold will get you more output. If there is snow on the ground might even help for back illumination.

Look up the temp coefficient for your panels. In summer heat typical power drop is 15% to 20% from the 25 deg C rated power spec temp when panels are cooking at 120-140 deg F temps.

Hope you don't get disappointed come July-August.

Windsun · December 2009

Re: Sanyo double hit panels inverter sizing

We don't sell a lot of the Sanyo double face, because they are so expensive per watt compared to most other panels. But in our limited experience, you will be very lucky to get more than a 5% increase from any reflectance.

BB. · December 2009

Re: Sanyo double hit panels inverter sizing

Solar Roller's IP comes back as from Louisiana.

Another issue is that New Orleans Louisiana comes back with not very good solar hours per day--even compared with San Francisco California. I would guess the marine layer and humidity really reduce the amount of sunlight:

Here is 1 kW of solar panels for New Orleans (rest are defaults):

"Station Identification"
"City:","New_Orleans"
"State:","Louisiana"
"Lat (deg N):", 29.98
"Long (deg W):", 90.25
"Elev (m): ", 3
"PV System Specifications"
"DC Rating:"," 1.0 kW"
"DC to AC Derate Factor:"," 0.770"
"AC Rating:"," 0.8 kW"
"Array Type: Fixed Tilt"
"Array Tilt:"," 30.0"
"Array Azimuth:","180.0"

"Energy Specifications"
"Cost of Electricity:"," 8.1 cents/kWh"

"Results"
"Month", "Solar Radiation (kWh/m^2/day)", "AC Energy (kWh)", "Energy Value ($)"
1, 3.49, 80, 6.48
2, 4.84, 100, 8.10
3, 5.09, 113, 9.15
4, 5.60, 117, 9.48
5, 5.75, 122, 9.88
6, 5.64, 112, 9.07
7, 5.51, 114, 9.23
8, 5.35, 112, 9.07
9, 5.18, 105, 8.51
10, 5.39, 117, 9.48
11, 4.50, 98, 7.94
12, 3.86, 88, 7.13
"Year", 5.02, 1277, 103.44

And for San Francisco:

"Station Identification"
"City:","San_Francisco"
"State:","California"
"Lat (deg N):", 37.62
"Long (deg W):", 122.38
"Elev (m): ", 5
"PV System Specifications"
"DC Rating:"," 1.0 kW"
"DC to AC Derate Factor:"," 0.770"
"AC Rating:"," 0.8 kW"
"Array Type: Fixed Tilt"
"Array Tilt:"," 37.6"
"Array Azimuth:","180.0"

"Energy Specifications"
"Cost of Electricity:","12.5 cents/kWh"

"Results"
"Month", "Solar Radiation (kWh/m^2/day)", "AC Energy (kWh)", "Energy Value ($)"
1, 3.62, 82, 10.25
2, 4.59, 95, 11.88
3, 5.22, 120, 15.00
4, 6.11, 134, 16.75
5, 6.36, 144, 18.00
6, 6.47, 141, 17.62
7, 7.01, 157, 19.62
8, 6.67, 149, 18.62
9, 6.62, 142, 17.75
10, 5.41, 121, 15.12
11, 3.87, 84, 10.50
12, 3.35, 77, 9.62
"Year", 5.45, 1446, 180.75

Add in the fact that New Orleans seems to have very cheap electric rates--It is hard to see that solar PV Grid Tied systems would have much traction.

-Bill

solar roller · December 2009

Re: Sanyo double hit panels inverter sizing

I' am in New Orleans, i pay .14 cents/kwh.

The state gives us an additional 50% credit/REBATE against our state taxes plus the 30% fedral incentives. That is why it makes $ense

Windsun · December 2009

Re: Sanyo double hit panels inverter sizing

solar roller wrote: »

I' am in New Orleans, i pay .14 cents/kwh.

The state gives us an additional 50% credit/REBATE against our state taxes plus the 30% fedral incentives. That is why it makes $ense

It makes sense if you owe that much in taxes, but those are usually tax credits, so you only get the benefit if your taxes are high enough.

dwh · December 2009

Re: Sanyo double hit panels inverter sizing

As for reflectance - he does say the install will be next to a lake, so that could possibly have a noticeable impact on the back-side photon absorption.

Assuming it does, then (for the engineers); What would be the potential increase from MPPT and also the potential peaks from edge of cloud events?

A simple 30% as the marketing describes?

Solar Guppy · December 2009

Re: Sanyo double hit panels inverter sizing

I don't think its even remotely possible water could reflect 30% of the irradance onto the backside of panels ... in all cases the water is flat and the sun would be sending photons towards the panels and reflections would be in the opposite direction

Now mirrors or possibly a snow covered hill behind an array might get something onto some of the panels, but I doubt it would be any measurable increase on daily harvest, possible a few minutes of increase but that's nothing for the daily total

Its just marketing to sell a product and it looks like based on the OP posting, they fall for it

niel · December 2009

Re: Sanyo double hit panels inverter sizing

dwh,
you said, "A simple 30% as the marketing describes?"
that is an up to type thing as it is more around 10% typically and also would depend on battery soc for a charged battery doesn't get a boost. what ever is being fed to the mppt controller is what the cc has to work with to act upon. remember that mppt recovers a portion of power that was normally lost to a standard pwm and is conditional in that and how much.

general,
if there's that much reflected to the back of the pvs then turn them around as they're facing the wrong way.:p:roll:

Sanyo double hit panels inverter sizing

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