effectiveness of solar & wind - Page 11

LaLeLu · #**101** (**permalink**) 03-20-2007

Quote:

Originally Posted by camaraderie

LeLaLu...
I own a solarstik and I have personal, first hand knowledge of getting 8+ amps per hour out of it.
Since the owner of solar stick says it puts out 6 amps and you claim 8 I think you might need to adjust your measuring devices. I am NOT disparaging the product only claiming that CONTINOUS output of greater than 8.3 amps is impossible for a 100 watt panel. (100 watts= 12V x 8.3amps!!) and that therefore claims of 80-100 amp hours a day are ridiculous...especially since there are losses in the system and the owner says 6 amps is the average output INTO the batteries after regulation.
Sorry... I'm glad you are happy with the product but again...the laws of the universe don't get altered just cause somebody mounts a couple of panels on a rotating adjustable mount.

I think that you are not factoring in the "smart" charge controller into your calculations. The charge controller has three displays: battery level, solar panel output and charge controller output. The charge controller output is generally higher than the solar panel output. It has something to do with the controller converting the power so that your batteries can accept it. (This was explained to me, but went in one ear and out the other). Anyway, I don't want to argue with you - my point was that I have personally, consistantly (in the short time we have had it installed) generated 80 - 100 amps per day. If it pleases you, I will take a picture of my charge controller as it hits 8 or above and post that for you. By the way, the charge controller is made by Blue Sky, which, as far as I know, has no affiliation with SolarStik.

For anyone else who is reading this post, if you are interested in the product, talk to someone who has one. I think that there is going to be an article coming up in Practical Sailor on it in the near future. (That's what the SolarStik people said at the boat show - I don't know what month it will be out, so watch for it.)

tomaz_423 · #**102** (**permalink**) 03-20-2007

I thought Conchy and Tookewl are one person anyway.

And Cam: TOOKEWL never said WITHOUT ADJUSTMENT - just without adjustment each hour.
As I read it I understood it like "few times a day would be good enough".
Simple math: sinus value of the sun attack angle to the paness is one of the the factors reducing the output. This means (look at sin curve values) that adjusting few times a day will give you 80 to 95 percent of what you could get if you would be adjusting all the time.
Sin(90)=1 this means 100% of sun rays hits the solar panel
sin(80)=0.99 this means 99% of sun rays hits the solar panel
sin(70)=0.94 this means 94% of sun rays hits the solar panel
sin(60)=0.87
sin(50)=0.76 would be 76%, but at this angle the protective glass starts mirroring some rays away
sin(40)=0.54
sin(30)=0.5
sin(20)=0.34
sin(10)=0.17 this means only 17% would hit the surface, but most is refleced away ba the glass.

So, 30 degree off sun (which is 2 hours) is not a big loss. If you adjust to get 90 degrees in two hours than you must adjust every 4 hours and get more than 95% theorethical gain.
But please: this in math, not real life. Real life includes: clouds, boat swinging at anchor, shaddows from masts, booms, trees etc, forgeting to adjust, dust on panels, ....

camaraderie · #**103** (**permalink**) 03-20-2007

Susan...you obviously don't understand OHM's law very well and that is NOT a slam.Here's the deal.... As I said...the MAXIMUM output at 12V for a 100Watt solar panel is 8.33amps. This can't happen on your panels since they are rated at 17V so their maximum amp output is 5.88 amps at THAT voltage in direct sunlight.
The Bluesky is a great device that makes sure their is a good interface between your 17V panels and your 12V battery so that the MAXIMUM amperage is not lost. This means that the blue sky has the potential to get you CLOSE to the theoretical maximum of 8.33amps at 12V being delivered into your batteries. So...I don't doubt that you CAN see 8amps input on your panel at PEAK.
The other problem with maintaining this even if you could somehow maintain 8AMPS being delivered to your batteries is that your batteries will not accept 8 amps as they begin to edge over 80% charged. But that is a whole nother discussion. The point is that even IF you are able to get 8 amp instantaneous readings...you'd have to maintain that reading for 10 hours a day to get 80 amp/hours into your batteries. That is patently ridiculous unless you are near the equator in a cloudless sky with someone constantly tweaking the panels from 8AM to tropical sunset at 6PM.
So...hopefully that explains why you are TRUTHFUL when you say you see 8 amps and I am truthful when I say you cant get 80 a/h into your batteries per day. I am prepared to eat my words here if Practical Sailor says anything different.

tomaz_423 · #**104** (**permalink**) 03-20-2007

Ohh, forgot to say: It is hart for me to believe such high output for stik.
Even if you point it to the sun it is hard to get max output morning and late afternoon as the sun rays hit atmosphere at low angle so they travel long way (and looses lots of power) before they reach your stik :-)
As I did not test it I will not calim it is all wrong. I will just take certain claims with some reservation.

camaraderie · #**105** (**permalink**) 03-20-2007

Thomas...thanks for the input. I read the tookewl post differently but as you say...it does not seem possible in any case. I do not think tookewl the same person as Conchyjoe as they have different IP addresses. I assume tookewl has some interest in the product since they provide no user info and have made only one post.

Cruisingdad · #**106** (**permalink**) 03-20-2007

Is it possible that the 100W panels are indeed NOT 100W panels? What if they were 130's? This is going to sound like I am slamming their product... and I am not in any way (or accusing them of being dishonest)... but it would be a pretty slick idea to make your product look better than what it is if you say it has 100W panels but they actualy put in 130W panels. Also, very cold weather will allow a panel to put out more than rated. However, I doubt that is the temps in merrit Island, FL, as I beleive it may require something at or close to zero F.

Cam, you were in the sound business as I recall. Isn't that a little trick Alpine & Blaupunct?(sp??) used many years ago in the shows so their amps were rated to get into a low amp sound class but were in fact higher rated amps??? I don't know. My memory gets fuzzy.

LaLeLu · #**107** (**permalink**) 03-20-2007

We did an hour by hour amp reading at anchor on Sunday March 11. It was a clear, sunny, typical Florida day. Started readings at 7:30 am and last reading was done at 6:30 pm. During that time period we calculated we got 84.9 amp hours. I have the actual chicken scratch, hour by hour notes on my boat. And that's in March - I expect it will only improve as the days get longer.

camaraderie · #**108** (**permalink**) 03-20-2007

CD...no...these are not proprietary panels. They are standard 50 watters.

Oh yeah...I almost forgot...one thing not mentioned yet is AT ANCHOR where these things are designed to be used, the boat is gonna be swinging all over the place with wind/tide and current. Seems like one would have to be a slave to the panels to get anything close to max out of them.

LaLeLu · #**109** (**permalink**) 03-20-2007

Quote:

Originally Posted by camaraderie

Susan...you obviously don't understand OHM's law very well and that is NOT a slam.Here's the deal.... As I said...the MAXIMUM output at 12V for a 100Watt solar panel is 8.33amps. This can't happen on your panels since they are rated at 17V so their maximum amp output is 5.88 amps at THAT voltage in direct sunlight.
The Bluesky is a great device that makes sure their is a good interface between your 17V panels and your 12V battery so that the MAXIMUM amperage is not lost. This means that the blue sky has the potential to get you CLOSE to the theoretical maximum of 8.33amps at 12V being delivered into your batteries. So...I don't doubt that you CAN see 8amps input on your panel at PEAK.

I have personally seen it read 8.1 - with my own eyes!!!! I don't know where you are getting your numbers above (5.88) - and that is NOT a slam on you. I think your math and or logic are wrong. We get at least 6 hours of consistant readings of 8 amps. It is already reading 7.5 amps by 10am. I am not making that up - I have no reason to lie about the results I am getting. It really is just a great product, and frankly, it bothers me when I read your unfounded critisisms. I would ask you to reserve your judgment until they are tested by Practical Sailor. I have absolutely no doubt in my mind that they will meet or exceed the manufacturers claims.

sailingdog · #**110** (**permalink**) 03-20-2007

CD-

Unless they have a radically new photocell technology, they are 50 W panels. I've looked at the dimensions, and it is unlikely that they could generate 65W per panel. I have two 130W panels on my boat btw, so I have a pretty good idea of what solar panels are capable of. I've also installed a few panels, both amorphous and poly/monocrystalline types on several boats. Also, from a manufacturing viewpoint, it wouldn't pay to advertise the panels as being only 50W panels if they were actually 65W panels. The price difference between the panels is significant, and anyone who prices them would opt to buy the ones labeled 65W panels, since I seriously doubt that they could sell 65W panels at the price of 50W panels.

LaleLu-

A smart controller makes the use of the electricity coming out of the panels more efficient...but you still lose a goodly portion of what the MPPT controller reports as heat. Battery charging tends to have significant thermal losses.