PWM VS MPPT TROPICS

[FlyingCloud1937]

Originally Posted by Pelagic

Thanks to all for this Series/Parallel discussion in order to maximize the benefits of a MPPT controller.

Just a newbie on Solar but I suspect the best wiring solution is often dependent on the balance between the equipment and installation factors.

Colemj’s 4 x 120W Kyoceras each have a Voc of 21.5V
As Mark surmised... a drop in voltage in low light supported his Series solution to keep juice flowing into 12v battery bank? (float at about 13.8v??)

In my case my 4 x Sunpower E20/327W units each have Voc of... 64.9V (for a 24V House bank)
96 cells and specs say 3 bypass diodes
I am also using the Outback 80 amp with 150VDC Max


1.....Will the MPPT perform better if it is seeing 129.8Voc as opposed to 64.9V for 24V delivery?

Unlike Colemj….I will have partial shading.

2......If so is it still worth testing in 2 sets of series, while at Marina?
Or
3......Just set up with 4 in parallel as previously advised?

Thanks for your guidance..

http://global.sunpowercorp.com/cs/Sa...&ssbinary=true

TESTING implies Scientific.

To be scientific you have to control for all variables.

On a boat no one can control for all variables, because on day 2, test 2 all variables have changed.

The bat state of charge can, and will change the results.

The cloud cover on a clear day will vary.

In the end a 1x2, or a 2x1 or a 2x3, or a 3x2 can produce results that will be arguable. It just depends on the solar day, and all of the variables....including bat.SOC.

Lloyd

[Pelagic]

Normally that would be so… but this time of year in Subic we are blessed with endless sunshine.

The vessels orientation remains the same so on board shading would be consistent.

Also… because we are not living on board at the moment… I can set up a standard dummy load and SOC at daybreak to test the performance.

While not truly scientific… after a few weeks it should identify a trend

[FlyingCloud1937]

Originally Posted by Pelagic

Normally that would be so… but this time of year in Subic we are blessed with endless sunshine.

The vessels orientation remains the same so on board shading would be consistent.

Also… because we are not living on board at the moment… I can set up a standard dummy load and SOC at daybreak to test the performance.

While not truly scientific… after a few weeks it should identify a trend

just for giggles...what would happen???

if you moved aboard,,,,

then decided to go for a mooring buoy, instead of dockside.

now what would happen, if the weather changes day by day?

Where would the science come from?

Lloyd

[sailinglegend]

If you have shade then you will need to add extra bypass diodes across the output of each of your panels to bypass any shaded panels in the series array. I suspect the bypass diodes you have built in will only bypass the shaded cells within each panel.

Colemj’s panels have no shade so he doesn't talk about extra bypass diodes.

This I think is where there has been a lot of confusion in this thread - but please correct me if I am wrong.

[s/v Jedi]

Originally Posted by Pelagic

Thanks to all for this Series/Parallel discussion in order to maximize the benefits of a MPPT controller.

Just a newbie on Solar but I suspect the best wiring solution is often dependent on the balance between the equipment and installation factors.

Colemj’s 4 x 120W Kyoceras each have a Voc of 21.5V
As Mark surmised... a drop in voltage in low light supported his Series solution to keep juice flowing into 12v battery bank? (float at about 13.8v??)

In my case my 4 x Sunpower E20/327W units each have Voc of... 64.9V (for a 24V House bank)
96 cells and specs say 3 bypass diodes
I am also using the Outback 80 amp with 150VDC Max

1.....Will the MPPT perform better if it is seeing 129.8Voc as opposed to 64.9V for 24V delivery?

Unlike Colemj….I will have partial shading.

2......If so is it still worth testing in 2 sets of series, while at Marina?
Or
3......Just set up with 4 in parallel as previously advised?

Thanks for your guidance..

http://global.sunpowercorp.com/cs/Sa...&ssbinary=true

I have the same Outback controller in the 60A version. It will collect statistics incl. the number of kWh delivered per day. The way to test is to run a couple of day then change array setup and run another couple of days and compare trend in kWh.

FlyingCloud is into science but you are not, you just want the best working setup for you. There is no need to know exact kWh for same light input, just which setup delivers more power.

[colemj]

Originally Posted by s/v Jedi

I have the same Outback controller in the 60A version. It will collect statistics incl. the number of kWh delivered per day. The way to test is to run a couple of day then change array setup and run another couple of days and compare trend in kWh.

This is how we made our decision. Our Morningstar records 72 days of detailed information. I ran the panels all in parallel for 3 weeks and then in series/parallel for 3 weeks and compared the data. The weather and boat positioning during these 6 weeks changed daily, but from the perspective of a 3 week average, the two test periods were comparable environments.

Our panels do experience some shading. Depending on boat position, there can be partial shading of one panel in a series string by the radome, and most days, one of the series strings is not active at all during the early morning and late evening because the boom blocks it (we mostly face northish this time of year).

Mark

[Bluewaters2812]

Forgive me for being a thicket but can anyone tell me which controller/how many I would need if we fitted 3 x 245watt Kyocera solar panels?

[noelex 77]

Originally Posted by Ship2210

Forgive me for being a thicket but can anyone tell me which controller/how many I would need if we fitted 3 x 245watt Kyocera solar panels?

With 735w you are in the "big league" and need a good controler.
The Outback 60 is arguably the best. You are close to its maximium capacity so the slightly larger Outback80 may be a better choice because it will give you some room for expansion in the future.
The other alternative is the Midnite controllers. These are very similar to the Outback but have got some great new features such as upgradable software, but they don't have the proven reliability of the Outback.

[Bluewaters2812]

Originally Posted by noelex 77

With 735w you are in the "big league" and need a good controler.
The Outback 60 is arguably the best. You are close to its maximium capacity so the slightly larger Outback80 may be a better choice because it will give you some room for expansion in the future.
The other alternative is the Midnite controllers. These are very similar to the Outback but have got some great new features such as upgradable software, but they don't have the proven reliability of the Outback.

Thanks for that response, its exactly the sort of response I needed.

[colemj]

The Morningstar Tristar 60 is also a very good controller for your application.

Mark

[Bluewaters2812]

Originally Posted by colemj

The Morningstar Tristar 60 is also a very good controller for your application.

Mark

Thanks, I'll have a look at the Morningstar Tristar 60 too. The Outback Flexmax 80 does seem to be a good option to look at.

[Emmalina]

I currently run 1200w of panels from a very nice chinese company sinosolar. Using 2 Morningstar MPPT chargers. Power abounds all day and they start getting active about 40 mins after sunrise. What I like about the Mppt chargers is they will take panel voltages up to 150v VOC so eliminates the great thick wiring. PS these guys do a 300w mono panel that is 2mm thick and weighs 9kg AND is semi flexible. I always calculate to get about 50% of my panel output worst scenario. Just my 9 bobs worth .....

[Bluewaters2812]

Originally Posted by Emmalina

I currently run 1200w of panels from a very nice chinese company sinosolar. Using 2 Morningstar MPPT chargers. Power abounds all day and they start getting active about 40 mins after sunrise. What I like about the Mppt chargers is they will take panel voltages up to 150v VOC so eliminates the great thick wiring. PS these guys do a 300w mono panel that is 2mm thick and weighs 9kg AND is semi flexible. I always calculate to get about 50% of my panel output worst scenario. Just my 9 bobs worth .....

Thanks for your response. Am I right in thinking that 1200 watts of panels must surely provide for all your energy needs each day? Its making me wonder whether 735 watts will be enough, although I must admit that I am also considering adding a wind generator too. Perhaps if I added a 4th panel, taking my panel supply to 980 watts I wouldn't need a wind generator? That way, if I assumed a 2:1 wastage ratio through the inverter I should expect in the region of 490 watts per day? Any thoughts folks?

[deckofficer]

Originally Posted by Emmalina

I currently run 1200w of panels from a very nice chinese company sinosolar. Using 2 Morningstar MPPT chargers. Power abounds all day and they start getting active about 40 mins after sunrise. What I like about the Mppt chargers is they will take panel voltages up to 150v VOC so eliminates the great thick wiring. PS these guys do a 300w mono panel that is 2mm thick and weighs 9kg AND is semi flexible. I always calculate to get about 50% of my panel output worst scenario. Just my 9 bobs worth .....

Do you have a link to that 300 watt 9 kg panel? I couldn't find it on a google search.

[Emmalina]

Don't know if Sinosolar retail to be honest
I bought a pallete of panels as samples
www.sinosolar.com I think it is