Ok so all this talk about solar effecency had taken over my curiosity. What the MPPT controller manufacturers state on why those chargers are more efficient with partatl shading and cloudy days make sense in an electrical theory way. But we all know theory and real life can be different. So I could not stand it anymore and will be doing some testing. So I ended up buying these.
I know it will be more effecent then the charger than I have now. So not a complete waste of money. I also purchased the Bluetooth module for improved setup and monitoring. I really only needed the 75/10 since that will accept 145W input. (3 50W panels will never be 100% efficient.) However the 75/15 was only $5 more. I felt that was cheep for %50 more head room.
The manual states the most efficient set up is 2 12v panels in series. I will test with the 2 panels I have already installed and a 3rd one to see what the difference is. The positive thing if I go with the 3rd panel is I will not have to upgrade my wire. Since I will be increasing voltage and not current. I may have time this sunday to install and test with the 2 panels already installed.
chargers are more efficient with partatl shading and cloudy days make sense in an electrical theory way
Well sort of no matter how you rig it PWM MPPT SERIES or PARALLEL shade and cload kill solar output, period your MPPT might be 30% more efficient but 30% of squat is still squat .
The manual states the most efficient set up is 2 12v panels in series
That will be for two panels for the rated output i.e 2 x 125W panels for the 15A
You only have 50W panels so at about 2.75A max per panel string all three for 36V at 8.25A as that controller is rated for 75V and 15A. Leaving one panel of automatically cuts your output by 33% regardless of cloud or shade.
I may have time this sunday to install and test with the 2 panels already installed.
Cool, interested to see what you find out and think.
Well sort of no matter how you rig it PWM MPPT SERIES or PARALLEL shade and cloud kill solar output, period your MPPT might be 30% more efficient but 30% of squat is still squat .
Yeah, While I like everything mounted permanent that can be, thats the reason I am a fan of portable panels for smaller boats. Move them as the sun moves and leave them stowed on day trips and when not in use. Can get by with much less panel that way vs an inefficiently mounted permanent one. I find that just the shade from standing rigging as you change tacks can turn a 100w panel into a 5w panel.
Ok so I left work early to get some things done before our Wednesday night race. Was able to get the controller temp installed. About the only data I have now is the radio and instruments have a load of around 2.5 amp. With the clouds and later in the day the solar array was only taking up about 1 amp of that, total load was -1.5. When I installed the new controller it shifted the total load to -.5 was getting about another 1 amp of output? Panels still in parallel. Jury is still out on function of the new one but once I learn it hopefully it will be better
grady wrote:Ok so I left work early to get some things done before our Wednesday night race. Was able to get the controller temp installed. About the only data I have now is the radio and instruments have a load of around 2.5 amp. With the clouds and later in the day the solar array was only taking up about 1 amp of that, total load was -1.5. When I installed the new controller it shifted the total load to -.5 was getting about another 1 amp of output?
Sounds like it to me, though a short delay in the switch-over could mean the solar irradiance had increased already. But I'm watching intently as I've been thinking about adding a small, temporary panel myself, one that would strapped to something like the cabin roof while at the dock/mooring, and be removed for sailing. And that bluetooth monitoring capability is pretty interesting. Keep us posted.
Last edited by Tomfoolery on Thu Apr 20, 2017 7:29 am, edited 1 time in total.
Your thoughts? So this controller has a programmable load output. What would you do think is a cool/useful feature?
A, Set output up to come on at sun set off at sunrise. Hook that up to nav, anchor lights so you can turn them on and they they come on and off automatically.
B, Set it to come on at battery full charge voltage. Hook that up to circulation, ventilation fan. That way when battery is chargeed it circulates and ventilated the cabin with excess solar power.
grady wrote:A, Set output up to come on at sun set off at sunrise. Hook that up to nav, anchor lights so you can turn them on and they they come on and off automatically.
Anchor, but not nav lights. Don't want them coming on when not underway.
grady wrote:B, Set it to come on at battery full charge voltage. Hook that up to circulation, ventilation fan. That way when battery is chargeed it circulates and ventilated the cabin with excess solar power.
I prefer passive ventilation. Since adding some vents and ports, I never get 'boat smell' below decks, in the driveway or at the dock, and that's with the hatches closed. If I need more, because I'm on the boat, then I pop open the big hatch as well as the companionway. If I need direct breeze, I have 12V fans, and a small but powerful 120V fan, which is useful especially when I'm inside working on something and need the air stream. But passive is my preference for all other times.
Your thoughts? So this controller has a programmable load output. What would you do think is a cool/useful feature?
C, any other ideas?
I could not think of a timer use, so set it to "on" and ran my switch panel loads through it. (they are low draw) The app (before I went to a mounted display) then functions as a load monitor tracking power in/out of the batteries 24/7 as well. I find it convenient to see all 3 parameters on 1 screen, power in from the panels, power being used by devices, net power in/out of the batteries.
I have a vicrton BMV702 battery monitor I now rarely look at except for accurate amp hour count since the solar display shows everything at once.
grady wrote:A, Set output up to come on at sun set off at sunrise. Hook that up to nav, anchor lights so you can turn them on and they they come on and off automatically.
Anchor, but not nav lights. Don't want them coming on when not underway.
grady wrote:B, Set it to come on at battery full charge voltage. Hook that up to circulation, ventilation fan. That way when battery is chargeed it circulates and ventilated the cabin with excess solar power.
I prefer passive ventilation. Since adding some vents and ports, I never get 'boat smell' below decks, in the driveway or at the dock, and that's with the hatches closed. If I need more, because I'm on the boat, then I pop open the big hatch as well as the companionway. If I need direct breeze, I have 12V fans, and a small but powerful 120V fan, which is useful especially when I'm inside working on something and need the air stream. But passive is my preference for all other times.
I would use the output to power the lighting buss. That way the switches would control the lights. What would happen is you would turn you nav light switch on in the day when you left. The nav lights would come on at sun set automatically while sailing. When you were anchored that light would automatically go off when the sun rose. The only draw back is testing lights when the sun was up? Everything is LED with soldered conections so failure is low.
I am a little farther south so forced cooling is a little more desired.
Your thoughts? So this controller has a programmable load output. What would you do think is a cool/useful feature?
C, any other ideas?
I could not think of a timer use, so set it to "on" and ran my switch panel loads through it. (they are low draw) The app (before I went to a mounted display) then functions as a load monitor tracking power in/out of the batteries 24/7 as well. I find it convenient to see all 3 parameters on 1 screen, power in from the panels, power being used by devices, net power in/out of the batteries.
I have a vicrton BMV702 battery monitor I now rarely look at except for accurate amp hour count since the solar display shows everything at once.
I already have a Blue Sea systems SOC meter.
???????
Kinda leaning to circulation fans. It is alrady upper 80s here.
Was able to get out today and get some good data. The simple version is........ Wattage is wattage series paralell does not make a difference in output. It does appear to me the Victron controller is not a good controller for 12v solar panel input. The 3 days it was running with paralell panels it only had 8.5 hours of charging a day with the best output of 90Wh. I decided that series is the way to go with this controller.
I was able to get to the boat when the sun was about 3 fists at arm length above the horizon. At that time there was enough voltage at the panel to start changing. One panel in sun, one in shade. Soon after that it was charging at .7A at that time I switched the panels to series, charging went to .2A. Quickly installed bypass diodes and charging went to .7A. At that time I decided to install a 3rd panel and run in series. in my setup the best I ever can get it 2 panels in sun. One is almost always going to be shaded. I knew this when installing my panels but do not like panels hanging of the stern. Plus they catch air and slow you down.
2 panels in sun, one shaded.
One panel in shade, one panel covered with a towel.
Now the good part where this controller appears to work. Was able to monitor output at the end of the day. With the 3 panels in series the controller was able to extract energy and charg until.
The sun set.
Even with the delay in getting everything set up today the total output for the day was 200Wh. Double the previous day with 2 panels in paralell. Instead of 8:25 hours of charging I got 10:01 hours. If I would have gotten the extra charging in the morning that would be another 2 hours. (I am subtracting the 30 min I had the system disconnected upgrading.) That is an extra 4 hours a day of charging. By adding 50% more power and running in series I was able to get over 100% more output.
In conclusion, in our application I do not think series paralell makes any difference if installed correctly. Probably dependent on the controller you have. The Victron controller needs 24V input to operate. It appears to not function well with 12v panels.
I will report back with pictures of the history display from the controller after it runs a couple of days with the new panel setup.
Highlander wrote:In series u get increased Volts same amps but if one panel gets shaded u lose the total benefit of series hook-up
In parallel u get increased amps same vlt,s but if one panel get,s shaded the system still woks
is more amp,s not desirable to recharge the batt,s faster
correct me if I,m wrong ! as I,m still thinkin parallel is the better way to go ?
so I,ll wait to hear ur end results before I finally decide which way to go !
J
What this controller does is convert the higher voltage to current. They state it is in the upper %90's. It is an electronic trick capable with today's effecent components. When you look at the numbers between the 1 panel in sun and 2 panels the current is not doubled, But that is because I was covering the old panel that does not put out as much. My old panels have some UV damage in the plastic that I need to be polished out. Chinese flexible cheep panels. I am considering if I can not polish these out upgrading to better panels or making my own and intergrating them into the deck permenantly.
The 3 days this controller ran with 2 older panels in paralell the output was poor. Worse than with my bateryminder solar controller. It appears this controller works better with the higher voltage. The voltage reading it gives you is the panel voltage not the voltage it is providing the batteries.
12.75v x 2.6A = 33W that is what it is providing the battery.
33w / 24.35v =1.3A that that is all the panels were putting out.
If you ran them in paralell each panel would be putting out 12.75v and 1.3A = 16W or so.
Monday and Tuesday here has been 100% sun. Today has been 100% heavy clouds. This will be the test is to see how much energy this setup is able to extract on a cloudy day. I should make it out to the lake tomorrow and check the history.
no matter how you rig it PWM MPPT SERIES or PARALLEL shade and cload kill solar output, period your MPPT might be 30% more efficient but 30% of squat is still squat 
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