Solar Panels?

[iamrich]

OK -- so it's solar noon here in the Tucson area, totally clear and sunny. I took the one good panel I just bought from Eco-Worthy and ran the Voc and Isc tests. Voc is rated at 21.6, I'm measuring 24.5. Above the rating on that. Isc is measuring 10.02 amps, the rating is 11.89 amps. Is that slightly lower Isc of any concern?

Maybe adjust the angle a bit and see if it goes up. That's 245w, no? I thought they were 195w panels?

 

[AZRoadrunner]

Maybe adjust the angle a bit and see if it goes up. That's 245w, no? I thought they were 195w panels?

They're 195 watt panels. I angled the panel up and down and slightly side to side to max out the readings.

 

[unsubscribed]

If you buy a Victon Multiplus, you can set it to charge your batteries based on voltage or SOC settings. I use a timer to limit when the Mulitplus gets AC power in. So basically, I'm "time shifting." The timer disconnects the Mutiliplus in the morning, and reconnects it after peak APS hours. (8 o'clock pm.) This way, the solar panels run my equipment and charge up my batteries during the day, and if there's a need to top the batteries off at night, then the Multiplus kicks in.

Mine is only a 3 kW inverter (not 5 kW). Unless you buy their 48 V inverter. (But then it's only 230VAC out.)

 

[unsubscribed]

I don't think that you can really know how a panel is performing until you hook it up to a (good) mppt and load it. For whatever reasons, I rarely see Vmp on my REC's. Nevertheless, as I posted above, they have produced more than their rated 330 W. (And that was without them being aimed at the sun! (Roof limitations.))

 

[Q-Dog]

If you buy a Victon Multiplus, you can set it to charge your batteries based on voltage or SOC settings. I use a timer to limit when the Mulitplus gets AC power in. So basically, I'm "time shifting." The timer disconnects the Mutiliplus in the morning, and reconnects it after peak APS hours. (8 o'clock pm.) This way, the solar panels run my equipment and charge up my batteries during the day, and if there's a need to top the batteries off at night, then the Multiplus kicks in. It's only a 3KW inverter... unless you buy their 48 V inverter. (But then it's only 230VAC out.)

I am doing the same thing with mine. It has had to charge from the grid 2 times the last 7 or 8 days because of low sun.

 

[unsubscribed]

So, based on the posts here, I just checked SanTan's website.

Wow, 335 W for $135? That's half of what I paid for REC's n half cells.

This deal seems too good to be true. Anyone?

Hansol 355W - SanTan Solar Store

Check out our brand new Hansol 355W 72 cell monocrystalline panels! They come with the manufacturers warranty! Only $0.41/watt!

store.santansolar.com

 

[MisterSandals]

This deal seems too good to be true. Anyone?

Seems pretty standard for the Phoenix area.

Yet people still have expensive panels shipped there from around the world.

 

[AZRoadrunner]

So, based on the posts here, I just checked SanTan's website.

Wow, 335 W for $135? That's half of what I paid for REC's n half cells.

This deal seems too good to be true. Anyone?

Hansol 355W - SanTan Solar Store

Check out our brand new Hansol 355W 72 cell monocrystalline panels! They come with the manufacturers warranty! Only $0.41/watt!

store.santansolar.com

I'm not merely going to make a trip to Santan. It's going to be a friggin' pilgrimage. Just two panels like that would be more than what I really need for my project. Which is why I might consider buying four and upping the game.

 

[unsubscribed]

One thing that I noticed is the difference in the frame. The REC's have two cross bars for stability. Whereas the Hansol have none. And since the Hansol's weigh more, might twist more during installation. (And break?)

And they're not half-cuts, which I'm finding makes a big difference if any shading.

And the output isn't going to hold as long over time. Although since I'm 65, I won't be around to see 80%. So that doesn't really matter.

For the price, if one fails early, it's not much of a loss.

It's a closer drive than Flag. I might pick one up for grins.

 

[chrisski]

We already have grid-tied solar for the house -- a 5kW system installed by Sunrun.......... If the power goes out, the panels on our roof are useless because they're dedicated to grid-tie and the system shuts completely down by design in the event of a power outage.

Where you live, have you ever suffered from a power outage? In the Phoenix Valley with APS, I don't even remember power flickering once in the 10 years I've lived here. Not so in any other place I've moved.

I wonder how much longer that can last as the state continues to shut down non-green coal burning plants without opening up equivalent "green energy" replacements, with the population growing so much.

 

[unsubscribed]

Yes. The power went out for about two hours yesterday. (APS said a "major" powerline. Perhaps a traffic accident, since I don't think a construction company would be digging on a Sunday. Or the wind, since it was gusty yesterday.) I was mentally preparing to roll out the Solar Cart to power up the freezer and fridge if it persisted.

Last year, the power went out in the late summer for about 5 hours. Lightning. I did use the power cart for that.

After that, I upped to a Mutliplus, because, at the time, I was using the Giandel 2 KW (24 V) pure sine wave inverter that Will was recommending. But, to my surprise, the Giandel's cooling fans were coming on - for only a 240 W load, since it was our summer. (About 100 degrees in the garage.) I didn't have any confidence that the Giandel would be able to handle much more in the heat. Update: I should add that the Multiplus derates from 3000 W Continuous to 2400 W in heat. But at least they tell you that in their spec sheet. And even derated, it's more than the Giandel puts out. (Anyone looking for a barely used Giandel?)

And since then, I bought very quiet window AC to cool down one room in the house should the power go out in our 115 degree heat. (t's a 5000 BTU/5 Amp unit. (600 W) A reasonable load for my system. It's quiet enough that we could sleep through the night with a power failure if we have to.

Before that, about two years ago, we had an outage for two days. A substation went out. We had to drive 10 miles to another grocery store to buy dry ice to keep our food cold.

As our infrastructure ages, as the economy and politics become crazier, as our foreign enemies continue to try to hack our grid, and domestic enemies riot and break things, I think it's wise to have a smallish solar station for back up purposes. (I need to buy more panels next.)

 

[AZRoadrunner]

Where you live, have you ever suffered from a power outage? In the Phoenix Valley with APS, I don't even remember power flickering once in the 10 years I've lived here. Not so in any other place I've moved.

I wonder how much longer that can last as the state continues to shut down non-green coal burning plants without opening up equivalent "green energy" replacements, with the population growing so much.

Power outages are rare here in the Tucson area -- for now. However, I work in the power industry and behind the scenes it's overall nothing short of a volcano waiting to erupt. My consulting work takes me to power utilities all across the country and into generation plants, substations, and control centers. There are influential people and organizations in our country who seemingly have no clue what it actually takes to generate reliable, affordable electric power. They don't understand the physics or the logistics involved and they think the electric grid can run off of pink unicorn farts. As a result we, as a country, are walking on a tightrope with no more safety net and evil leprechauns are shaking the wire, trying to make us fall. I wouldn't classify myself as a "prepper"; rather, more of a realist. I'm all for "green" energy, by the way -- but the way the activists and politicians are trying to implement it is positively insane and will lead to rolling blackouts -- or worse. And on top of all that are the growing cyber security threats (that's my direct line of work) that our power utilities are having an enormous amount of difficulty keeping up with. It's a bad scene that's only masked by the fact that the lights are still on.

 

[magic8192]

Another plug for SanTan solar. I have used him and had no problems with a small order of 5 panels I placed a year ago or so.

 

[unsubscribed]

Good to hear that I'm not crazy.

Yeah, we have let our guard down, since the electrical system has worked for so well for so long. I'm not so much worried about a huge CME taking the grid down - although that's a real possibility - as I am with all the other things that you mentioned.

I don't expect to survive long term when the stuff hits the fan. (And I expect that the plan is to have it all hit the fan at the same time.) I just want to buy time. I take care of an elderly widow, and she wouldn't be able to survive more than a day or two in the Phx summer heat without air conditioning. Without power, I can boil water in the sun for preparing food. But I can't make a room cooler without solar.

If we can get buy for three weeks (and fend off raiders), the situation will change drastically after that, and we'll have to re-evaluate the situation then.

 

[unsubscribed]

I estimate it generates about 8wk a day (maybe more),

FYI, I harvested 3.7 kWh yesterday during the equinox in sunny Phoenix. That's using two 330 W panels, baking a bit in the sun (80 degrees F outside) and not aimed correctly. (Peak power yesterday only 530 W. (Continuous sun.))

Using my figures and mutliplying up for your array, I calculate you would be making 12 kW a day if you are similarly situated. More if aimed correctly.

 

[AZRoadrunner]

FYI, I harvested 3.7 kWh yesterday during the equinox in sunny Phoenix. That's using two 330 W panels, baking a bit in the sun (80 degrees F outside) and not aimed correctly. (Peak power yesterday only 530 W. (Continuous sun.))

Using my figures and mutliplying up for your array, I calculate you would be making 12 kW a day if you are similarly situated. More if aimed correctly.

A question to make sure my thinking is straight. My goal is to build a relatively robust power cart for occasional and emergency household use. It will have 200Ah of 12v power storage (two 100Ah Battle Borns in parallel). My goal is not to go off-grid totally, but to be able to solar charge the batteries as fast as possible so that I can build a second power cart and potentially have one in use while another is charging. Like you, buying time. I'm also in my 60s and it's just my wife and I at home. We have a 3kW quiet Honda generator that could easily run our portable A/C unit and the refrigerator. So -- my solar project is all about having plenty of power to run the small potatoes for a while.

Someone on Craigslist is selling new 395-watt panels for $195 each. In rough numbers -- connected in series, four of those panels would deliver approximately 200 volts at 10 amps (not what I want, and a Victron 250/100 would cost over $900). Connected in parallel, however, the panels would deliver 50 volts at 40 amps, which is within the limits of a much less expensive Victron 100/50, and the Battle Borns have a maximum charge rate of 50 amps -- so the Victron would be theoretically dumping all the power into the batteries at a fairly rapid rate.

Have I got the math straight on this? I may also head out to Santan anyway, but am using those 395 watt panels as an example. Craigslist can be iffy.

 

[Ols]

I "hate" to suggest these panels, because if Will mentions them, they will sell out like SOK batteries did.

330 Watts for just over $200. (5% discount for first order.) Blows the doors off the silly 100 W panels that I was buying when I first got into solar.

I've seen two produce 687 Watts this month on a partly cloudy day (so they had cooled down before the sun come again) in Phoenx, AZ.

I've seen them produce 450 Watts on a cloudy day here!

REC Solar N-PEAK Series 330 Watt Monocrystalline Solar Module

Note: This panel is discontinued, Please look at the other REC panels we offer. Please email us or give us a call if you would like help finding an alternative.

www.solar-electric.com

No sales tax. (Something about Arizona not taxing solar stuff.)

The only "down" side, is that they are expensive to ship ($120 for the first) because they have to go by truck.

But if you live in AZ (or nearby) just drive up to Flagstaff to get them.

(@AZRoadrunner : If you drive up there, I would like to buy two more. I'm near I-17.)

pmikep, sorry for the silly question looked on the site solar-electric.com could not find what voltage those panels are 12v or 24v

 

[Forbisher]

Someone on Craigslist is selling new 395-watt panels for $195 each. In rough numbers -- connected in series, four of those panels would deliver approximately 200 volts at 10 amps (not what I want, and a Victron 250/100 would cost over $900). Connected in parallel, however, the panels would deliver 50 volts at 40 amps, which is within the limits of a much less expensive Victron 100/50, and the Battle Borns have a maximum charge rate of 50 amps -- so the Victron would be theoretically dumping all the power into the batteries at a fairly rapid rate.

Have I got the math straight on this? I may also head out to Santan anyway, but am using those 395 watt panels as an example. Craigslist can be iffy.

Your maths is off.
4 395 watt panels is 1580w
1580w into a 12V battery is 131A

A 50A Victron is only good for about 700w of panels at 14V

2 12V 100Ah BB in parallel can be charged at 100A which is 0.5C

 

[Forbisher]

pmikep, sorry for the silly question looked on the site solar-electric.com could not find what voltage those panels are 12v or 24v

Just look for the panel specs even on so called 12V or 24V panels.
Voc
Vmp
Imp
Isc
Forget about calling panels 12V or 24V if you are using a MPPT scc.
12v or 24v is referring to battery voltage catergories for PWM scc.

 

[iamrich]

FYI, I harvested 3.7 kWh yesterday during the equinox in sunny Phoenix. That's using two 330 W panels, baking a bit in the sun (80 degrees F outside) and not aimed correctly. (Peak power yesterday only 530 W. (Continuous sun.))

Using my figures and mutliplying up for your array, I calculate you would be making 12 kW a day if you are similarly situated. More if aimed correctly.

I always derate everything I mention. I am only using 9 panels (2250w array) and it starts putting out power at 9am right now and goes until 6:30pm (at least it did yesterday), but these are used panels, facing more East than South, and almost flat (10 degrees). The good news is that I have room for 27 more, but that is way down the road (after the house is built if at all).

I intend to have at least 10kw of panels by the time I am done, maybe more. My house (when built) is going to have a large roof facing directly south (the back of the house).

 

[AZRoadrunner]

Your maths is off.
4 395 watt panels is 1580w
1580w into a 12V battery is 131A

A 50A Victron is only good for about 700w of panels at 14V

2 12V 100Ah BB in parallel can be charged at 100A which is 0.5C

Dangit! I suspected my math was out of whack. I think I'll have to just go back to my original simpler system -- two 195-watt panels. That's 390 (theoretical) watts into 12 volts, which is 32.5 amps. That's a (theoretical) 6.25 hour charge into 200Ah of batteries. I can live with that. If I understand correctly, then -- an optional additional 195-watt panel would raise the maximum amps to 48.75 and reduce the charge time to a little over 4 hours. A Victron 100/50 would handle that?

 

[unsubscribed]

So @Forbisher has brought to light an interesting fact about the Victron MPPT's, which I found a bit disappointing after I shelled out for a 150/35.

(I bough the Victron 150 V unit after maxing out my Rich Solar 20 unit, which would go into shutdown if my then array (five 100 W panels in series) over voltaged. (Which it did. It would hit 105 volts in the morning, before current started loading it down.) Now, it turns out that I'm running my two REC's in parallel, at only 37 Vmax and I could have saved money by not buying the Victron. (Although the Rich Solar would be at its max 20 Amps with what I have now, leaving no room for expansion. (I never forsaw that I should have bought the Rich 40 unit.) Although the Victron unit is better. (Although whether it's $200 better is questionable.)

I had thought (and it was MY fault for not reading their data sheet more closely) that my Victon 150/35 could handle 4.5 kW. (150 V x 30 A.)

But no - my MPPT can only handle 1000 W (in a 24 V system.) And as Forbisher pointed out, even less for a 12 v system.

So my first piece of advice for @AZRoadrunner is to go with a 24 v system. More efficient all around. And if you tell BB that you're going to run two of their 100 A in series, they will "match" them for you.

Now, if I were to take my 4 BattleBorns and wire them in series (for 48 V), then my MPPT can handle 1400 W (I think it is.) But Victron doesn't make a Multiplus that takes 48 V and puts out 120 VAC. And I would have to put more panels on the roof in a series/parallel connection. Which I don't have room for.

 

[AZRoadrunner]

Good points, @pmikep. At this point, however, I already have a 12v/2kW inverter/charger and the Victron 100/50 100/30 is also on-hand -- which, looking at the specs again, is rated for 440W at 12 volts. I'll have 390 watts between the two panels and, as you've steered me towards, the Victron I have cannot handle a third panel. I'm learning....stuck at 12 volts for now, but learning....

 

[MisterSandals]

Victron 100/50 is also on-hand -- which, looking at the specs again, is rated for 440W at 12 volts.

The specs say that? I ask because 50a x 12v = 600w.

 

[AZRoadrunner]

The specs say that? I ask because 50a x 12v = 600w.

Typo on my part. I meant 100/30. Correcting the posting!