Mounting 8 or 12 panels to a shipping container

[Tigerbody]

I am having some issues with mounting 12 panels on a shipping container.

One of the issues is I CANNOT use half of the top, as that has other purposes.

So, we got 20 feet or so, and the installer just has used simple hinges
to mount 3 groups of 4 each. The problem with this is it goes too much over the
20 foot design criteria.

These are KC 120's from 5 years ago.

I can imaging that mounting 8 of them in a 2 x 4 pattern will use less space.

Does anyone have any clues or pictures or both that they can impart to me?

Thanks!

Patrick in Puna Beach, Big Island of Hawai'i

[Mike90250]

Are you mounting flat, or hinged at some angle ? Flat, they can go edge to edge, but leave a inch or so, between rows for some air circulation, hot panels produce less power. If angled or tilted, you need to be aware of shade issues, the smallest bit of shade can really reduce the power of the whole array. If you mount panels so they shade each other, that's going to impact your harvest.

[Tigerbody]

Are you mounting flat, or hinged at some angle ? Flat, they can go edge to edge, but leave a inch or so, between rows for some air circulation, hot panels produce less power. If angled or tilted, you need to be aware of shade issues, the smallest bit of shade can really reduce the power of the whole array. If you mount panels so they shade each other, that's going to impact your harvest.

Right now they are hinged at around 24 degrees - for Hawai'i sun in winter.

The problem is right now they are on separate racks, so the shading makes them farther apart. I would like to rack them 2x4 or 3x4 ....

or maybe 2x6 that would overhang the container,
so how do I support that overhang?

I am not expecting more than a Cat 1 hurricane.

[Mike90250]

Right now they are hinged at around 24 degrees - for Hawai'i sun in winter.

Wow, that sounds steeper than I would have expected. What will the angles be the rest of the year ? If you can get by with 10 degrees, that will still allow for rain & dirt shedding, and less shade so you can pack them closer.

[Tigerbody]

This angle is what every installer does over here.

We are at 44 degree latitude, so need to shoot at the Sun

Wow, that sounds steeper than I would have expected. What will the angles be the rest of the year ? If you can get by with 10 degrees, that will still allow for rain & dirt shedding, and less shade so you can pack them closer.

I dont want to do a anything different than what is common here,
and every degree helps at some point.

I also need to make it so I can get the summer angle, which, of course,
is more than overhead on the summer solstice.

[Tigerbody]

opps -

Opps, Latitude is 19.7 N on big Island of Hawaii.

I will check more closely.

I am 4 miles away from an active Lava flow,
so everything could change.

[Tigerbody]

Not pointed south

So, the installer aligned the panels with the container,
not true south. This is about 20 degrees south east.

Is this going to be a problem?

I am only seeing around 1080 Watts during the peak of the day,
for 12 Kyocera KC 120, which to me calcs to 1440 Watts during
peak sunlight.

[Mike90250]

So, the installer aligned the panels with the container,
not true south. This is about 20 degrees south east.

Is this going to be a problem?

I am only seeing around 1080 Watts during the peak of the day,
for 12 Kyocera KC 120, which to me calcs to 1440 Watts during
peak sunlight.

Well, if you have a tendency to get thunderstorms (clouds) in the afternoons, it may work out after all.

[russ]

1440*0,77 = 1108

You probably have good sun and seem right on the mark or close to it.

[Tigerbody]

What is the 0.77 factor about?

1440*0,77 = 1108

You probably have good sun and seem right on the mark or close to it.

[Sunking]

What is the 0.77 factor about?

The absolute best efficiency using MPPT controller harvest energy and using every bit of it on a daily use. Not realistic, 50% is more realistic.

[Tigerbody]

The absolute best efficiency using MPPT controller harvest energy and using every bit of it on a daily use. Not realistic, 50% is more realistic.

So, are you saying that I am doing REAL well with an output of 1100 Watts?

Is it possible to get all 120 Watts out of these cells?

Mahalo

http://www.solarpaneltalk.com/images/smilies/blabla.gif

[russ]

The 120 watts (STC) is a lab test number at 25

[Mike90250]

The absolute best efficiency using MPPT controller harvest energy and using every bit of it on a daily use. Not realistic, 50% is more realistic.

Just to clairify a bit, this 50% I belive, is from PV panel, charging batteries, using power at night, and the recharge, with all the losses along the way.
Charger losses, 3%
inverter losses, 5%
battery recharge loss, 20%
PV with real sun & heat losses. 20%
ends up being very close to 50% losses.