Question Solar panel selection

[Hoshi]

I have been reading the list of solar info that was provided here. One question I do have is the addition cost of Obsidian roof mounted Panels worth the cost?

 

[Kevin D Pem]

I have been reading the list of solar info that was provided here. One question I do have is the addition cost of Obsidian roof mounted Panels worth the cost?

The best way to answer that is with a statement I received the first time I got some solar.

"there are only two kinds of solar panel. Those that are mounted and those that are broken"

In my years full timing my observation is he was correct.

 

[Hoshi]

The best way to answer that is with a statement I received the first time I got some solar.

"there are only two kinds of solar panel. Those that are mounted and those that are broken"

In my years full timing my observation is he was correct.

well, they are mounted I am just not sure about the different qualities of panels? Humor an old woman.

 

[Kevin D Pem]

"A" panels are grid grade panels. "B" grade panels are off grid panels because of quality. Efficiency increases may be available and is used by manufacturers to sell panels. Lets look at efficiency:

One square meter of surface gets 1000 watts of sun energy. The amount of energy converted by the panel is a percent of that power. It is that percent of power that is stated when we look at panels. That said the area you give up on a roof is based on that value. This of course does not include the area lost to frame structure. If the panel is a grade "A" panel it has a 20 year guaranty to produce no less than 80% of the original value.

For most of us We will have space left on the roof after we have all the panel we want. What this says is we really should not be concerned about efficiency because we still have space on our roofs.

Because On grid solar panels must meet a set standard to be used on grid("A") any panel that meets that standard is for the most part equivalent. You may see a difference in cell alignment but that is where it ends.

for mobile use frame build is important but only on a very poorly built coach. For heat transfer the panels should have a space of no less than 2" under them. More is better.

The best money spent is on an MPPT controller as the losses for the other cheap PWM controllers are large.

Battery type is also important. AGM have less resistance than flooded making them charge faster(less loss of power from the panel). I will make the point that in the north where freezing weather is the norm much of the year, Lithium is a bad idea on a working solar system in a house that is not kept above 32 deg Fahrenheit at all times during the daylight hours.

I upgrade all wire for solar. If awg 10 wire is good enough I use awg 6. any loss or heat of any amount that is measurable is loss of energy.

I hope this helps. If it is more than you asked for, I am sorry. If you understand what you are trying to achieve it is easier to make choices that fit.

 

[Hoshi]

"A" panels are grid grade panels. "B" grade panels are off grid panels because of quality. Efficiency increases may be available and is used by manufacturers to sell panels. Lets look at efficiency:

One square meter of surface gets 1000 watts of sun energy. The amount of energy converted by the panel is a percent of that power. It is that percent of power that is stated when we look at panels. That said the area you give up on a roof is based on that value. This of course does not include the area lost to frame structure. If the panel is a grade "A" panel it has a 20 year guaranty to produce no less than 80% of the original value.

For most of us We will have space left on the roof after we have all the panel we want. What this says is we really should not be concerned about efficiency because we still have space on our roofs.

Because On grid solar panels must meet a set standard to be used on grid("A") any panel that meets that standard is for the most part equivalent. You may see a difference in cell alignment but that is where it ends.

for mobile use frame build is important but only on a very poorly built coach. For heat transfer the panels should have a space of no less than 2" under them. More is better.

The best money spent is on an MPPT controller as the losses for the other cheap PWM controllers are large.

Battery type is also important. AGM have less resistance than flooded making them charge faster(less loss of power from the panel). I will make the point that in the north where freezing weather is the norm much of the year, Lithium is a bad idea on a working solar system in a house that is not kept above 32 deg Fahrenheit at all times during the daylight hours.

I upgrade all wire for solar. If awg 10 wire is good enough I use awg 6. any loss or heat of any amount that is measurable is loss of energy.

I hope this helps. If it is more than you asked for, I am sorry. If you understand what you are trying to achieve it is easier to make choices that fit.

THAK YOU, THIS ACTUALLY HELPS A LOT.

 

[Calsun]

I recently added a Grape 190W panel for $218 and a Renogy 100W panel that cost $104 Much cheaper than the Zamp panels with the same output and same durability. I bought the feet separately and AMsolar sells some for different panel frames, 35mm or 40mm. I already had two Zamp 100W Obsidian panels and they provide no advantages over the Renogy panels that cost a fourth as much.

It helps in terms of output to have the panels elevated above the roof for some amount of cooling of the cells. How much above the roof is subjective. In addition to the size of wire used it is also worth keeping the runs as short as possible. The poor installation job done by the people at the Winnebago factory put one Zamp panel to far to the rear and so need to be moved and the installer used the Zamp kit wiring and did not shorten the cable so I had and extra 8 to 12 feet of cable from the panels to the roof cap from the panels.

I do highly recommend the people at Amsolar that go out of their way to work with their customers. Another good source for solar items is RV Solar Store. A great installer for any RV is www.Offthegridrvs.com which is also a Lithionics lithium phosphate battery dealer located in Parker AZ.

 

[Kevin D Pem]

Ok @Calsun you have two different panels as far as wattage goes. You had more than one installer install them.

I failed to see a question.

But I have one. How many controllers do you have installed and of what type?

Because you have three panel brands what are the voc and mpt on the different panels?

 

[Kevin D Pem]

Oops,just noticed I was reading page 2

 

[Buly]

I need a second opinion from the electrical gurus:
Friend just gave me a nice solar panel. I did some tests, and it puts out 24V and about 0.5 Amps (think that makes 1A at 12V ?)
We boon-dock for a day or two at Harvest Host couple times in a year. My thinking is:
If I connect it directly to my 8 battery bank without charge controller, there is no chance to do any damage? Am I missing something?
It is just experimental. Not hoping to relay on it for much power
Thanks.

 

[Neal]

I need a second opinion from the electrical gurus:
Friend just gave me a nice solar panel. I did some tests, and it puts out 24V and about 0.5 Amps (think that makes 1A at 12V ?)
We boon-dock for a day or two at Harvest Host couple times in a year. My thinking is:
If I connect it directly to my 8 battery bank without charge controller, there is no chance to do any damage? Am I missing something?
It is just experimental. Not hoping to relay on it for much power
Thanks.

What are the specs on the solar panel? How many Watts?

I'm not the expert here, I defer to others such as @Chuggs but it seems to me you have a small panel and the effort it would take to connect it up will defeat the benefit. Not worth it to me.

 

[Buly]

What are the specs on the solar panel? How many Watts?

I'm not the expert here, I defer to others such as @Chuggs but it seems to me you have a small panel and the effort it would take to connect it up will defeat the benefit. Not worth it to me.

There is no spec. labels of any kind, I think it is MotoMaster Eliminator Solar Panel 15W / 1A. I told you it is experimental. I may replace the small ugly one on the front cap Newmar stuck in there? Not expecting to run my AC on it

 

[Neal]

The small panel Newmar installs typically is for chassis batteries, not house.

Again, level of effort far exceeds any gains. That small voltage will do nothing for the house batteries and the loss you'll get down the wires probably defeats it too.

With that said, I'm not sure I'll do solar on my next coach UNLESS it's stored without power. That is the one benefit. I have not seen a good ROI on solar to date other than when I was initially in a storage lot without power and I didn't want to be emptying and loading the frig each trip. If there is another coach in my future that will likely signal fulltiming and solar will not be needed. The GEN's in these coaches are great and under utilized IMHO.

 

[Rich-MLsRV]

I need a second opinion from the electrical gurus:
Friend just gave me a nice solar panel. I did some tests, and it puts out 24V and about 0.5 Amps (think that makes 1A at 12V ?)
We boon-dock for a day or two at Harvest Host couple times in a year. My thinking is:
If I connect it directly to my 8 battery bank without charge controller, there is no chance to do any damage? Am I missing something?
It is just experimental. Not hoping to relay on it for much power
Thanks.

I would be concerned connecting a 24V source to a 12V battery. The panel wants to deliver 24V. Seems you need something to step down to 12V.

You would also want a breaker of some type between the panel and battery. If the panel or wire shorts then this would cause battery to short. Not a good scenario.

 

[Buly]

I would be concerned connecting a 24V source to a 12V battery. The panel wants to deliver 24V. Seems you need something to step down to 12V.

You would also want a breaker of some type between the panel and battery. If the panel or wire shorts then this would cause battery to short. Not a good scenario.

I was trying to save The Planet, but you guys ruined it. My other option is The Aptera. We already put $100 to reserve production number. No kidding. But it is not towable