Solar Panels Brands - does it matter?

The point of my comparison is that the 24V panel price is offsetting the higher MPPT controller costs and it appears to be a continuing trend with the added benefit of a more efficient controller.

Yes. Now imagine that you have 64 sq.ft total space available that breaks into several small areas so you can't put 3x270W.

In fact this was my situation. But then I started looking at installations of others and now have options for installing 3x270W panels.

Not that much wind pressure. LOL

I bought a couple or Sharp 250 watt, 24 volt panels. They are 65" x 32" and weigh about 40 pounds each. The aluminum frame is fairly heavy for a panel, but not heavy enough for my application. I will be building an aluminum frame underneath the factory frame to make it strong enough for my application. They certainly seem to be decent panels but my application requires the to withstand more wind pressure.

CA Traveler wrote:

2x270W = 540W, 45 MPPT, $832 and 35 sq ft
6x140W = 840W, 60 PWM, $1035 and 64 sq ft
3x270W = 810W, 60 MPPT, $1034 and 53 sq ft

Yes. Now imagine that you have 64 sq.ft total space available that breaks into several small areas so you can't put 3x270W. So you have to go with either 2x270W or 6x140W, and the latter will result in more watts. This what I've been trying to tell - the shape of available space may dictate the choice of panel size. 6*140W will also have a lower per watt cost than 2*270W. Just an example...

The panels for a given setup all need to be closely matches unless multiple controllers are used

Yes. The OP should better get all the panels at the same time, rather than "upgrading" later. In the past the panels cost $6 per watt and people could not afford enough wattage, so they were buying one panel, then another, and it was mismatched, and the efficiency was lower. But now panels are cheap, 10 times cheaper.

JiminDenver wrote:
Wow do I like that 270w panel. It's the same size as my 220w mono and at least 10 lb lighter.

I would be wary of panels too light, especially with relatively new brands. There can be a lighter aluminum frame or thinner glass. Though 37 lbs is not "too light", it's more like a "normal". My (pretty old brand) 245W Poly weighs 39 lbs, and all their panels from 220W to 250W have the same size and weight. I guess with higher wattage panels they just leave smaller margins between the cells and around the perimeter.

Some panels have a flimsy frame with single-wall vertical side, while others have a double-walled side. The material is usually thin, less than 1/16", so the frame profile does matter.

Wow do I like that 270w panel. It's the same size as my 220w mono and at least 10 lb lighter. I bet I could get three, maybe four on the roof. The controller and battery bank to match wouldn't be cheap. Come to think of it, if I had a bank that big I wouldn't need the solar. lol

One size panel and controller doesn’t fit all so it’s good to have choices. In my travels I’ve seen at least a dozen installations where the panels were mounted many inches above the roof to eliminate shadows from everything on the roof except antennas. But if the installation is close to the roof then most rigs will have shadows to consider regardless on panel size.

The 140W 12V panel on Solar Blvd is 59”x26”, 30 lb and cost $139.00
The 270W 24V panel on Solar Blvd is 65”x39”, 37 lb and cost $202.50

Using MS controllers on the Solar Blvd site:
4x140W = 560W, 45 PMW, $602 and 43 sq ft
2x270W = 540W, 45 MPPT, $832 and 35 sq ft
6x140W = 840W, 60 PWM, $1035 and 64 sq ft
3x270W = 810W, 60 MPPT, $1034 and 53 sq ft

The panels for a given setup all need to be closely matches unless multiple controllers are used which can be an advantage for 12V panels.

This points out that 24V panels have advantages and the downside may be minimal.

69 Avion I sent you a PM.

steveexplorer wrote:
...the 24v panels are the cheapest way to get lots of wattage with the smallest footprint.

You won't have the cheapest cost, the smallest footprint, and lots of wattage at the same time. Very rarely you can fill all the available space with 24 panels so that no space is wasted and there is no shading. Smaller panels will fill the space better so there will be more wattage, but the cost will be higher.

270W panel is a monster. It takes 2 people to lift and mount it on the roof.

If you can live off 540W AND if you can fit 2*270W 24V panels, go for it. Don's spreadsheet will tell you, more or less, whether your needs are within 540W. This will be cheaper than many small panels but you could likely get more wattage with many small panels.

It is easier (cheaper) to do things right from the beginning. 24 panels with MPPT controller need to be closely matched, for better efficiency. So if you think that you need 2*270W, buy both panels right now. For 540W you don't need 60A controller, 45A is enough.

I don't think there is such a thing as a cheap contractor :), in any trade. Especially in RV solar where they are trying to make it look like a sort of a black magic. RV shops are particularly useless in this respect. But there is a List of completed projects. Look at Mr. Wizard's installation, for example. Few aluminum angles for mounting brackets, a screw in the panel side, a couple of screws in the foot of the bracket.

Thanks Don for your suggestions and for the links. Very helpful.

Another issue. I do not currently have the knowledge or experience to do the installation. Do people know of good modestly priced installers that they have had good experience with? I am in northern California, and can connect with installers around San Francisco, Oakland, San Jose, Santa Rosa, Sacramento, ....