What About 'these' Solar Panels ?

[gscriba]

I'm a bit confused when it comes to 24 volt vs 12 volt panels. My plan as it stands is to wire in series (after reading all the posts regarding the series vs parallel debate). I would like to mount minimum 2, but more likely 4 panels. In a 12 volt system, which is most advantagous of the following:

Solar Panel 125 Watt 12 Volt Polycrystalline Silicon PV

or

Solar Panel 125 Watt 24 Volt Polycrystalline Silicon PV

using a Morningstar TriStar 45 MPPT?

[Nicholson58]

If you want to connect in series you need to be sure that panel(s) are not partly shaded, even by small objects. Series is regularly done in power stations sited in the open. Boat panels are most often wired in parallel. If your panels do not have diodes internal you will probably need to have them external. This prevents the shaded panel from getting overheated by the unshaded panel trying to force current the wrong way through the panel. Your charge controler should prevent back current from the batteries when the sun is down. Make sure your charge controler is rated both for the amps and for the open circuit voltage.

If your boat is 12 volts and your panels are nominal 12 volts you can use a PWM type charger. You will not get much benefit from an MPPT unless the panel voltage is significantly above your battery voltage. (likewise if the panels are 24 and the boat is 24)

I encourage you to follow my link in post 65 to Handy Bob. His blog is well worth the read before you design your system. Particularly interesting are the photos showing how only a very small shadow puts a wrench in the system. Bob is big on Morningstar PWM and MPPT charge controlers. I've read a lot of data on various manufacturer's products. I tend to like their stuff too based on the specs and manuals.

In our case, we needed big power. My 3 panels are 220 watts; 54 volts open circuit and the boat is 24 VDC. This requires MPPT to control the charging feed to the batteries. I will be wired parallel.

[Ram]

Search Results :

Wow German made $1 a watt for any size !

[NorthPacific]

Good Advice Nic58I

encourage you to follow my link in post 65 to Handy Bob. His blog is well worth the read before you design your system. Particularly interesting are the photos showing how only a very small shadow puts a wrench in the system. Bob is big on Morningstar PWM and MPPT charge controlers. I've read a lot of data on various manufacturer's products. I tend to like their stuff too based on the specs and manuals.

[NorthPacific]

Shaded Panels.

to avoid shade patches could panels be positioned to catch reflected light from the ocean?

[Nicholson58]

Originally Posted by NorthPacific

Shaded Panels.

to avoid shade patches could panels be positioned to catch reflected light from the ocean?

It can only help. some panels are more capable of utilizing wider spans of wavelengths as well and so will do better in overcast than others. It is a technique in winter when the sun is low in the north to try to catch reflected light from the snow. The thing is though that light tends to penetrate water when the incidence angle is above critical. The reflected light will blind you but the energy is probably not as great as one might think.

Generally, you only assume output of about 50% of name-plate due to poor angle & shade. Make sure panels have sectional bypass diodes and operate in parallel.

[NorthPacific]

Ok, so not a completely dumb idea, but not the medical break-through. I will give it a go and see what difference I get. Bob's blog is very good. I wrote a brief note and he responded, with encouragement. Seems both genuine and knowledgeable.

Think I am beginning to understand the do's and don'ts. Like everything about a cruising boat nothing is simple.

[Nicholson58]

Originally Posted by NorthPacific

Ok, so not a completely dumb idea, but not the medical break-through. I will give it a go and see what difference I get. Bob's blog is very good. I wrote a brief note and he responded, with encouragement. Seems both genuine and knowledgeable.

Think I am beginning to understand the do's and don'ts. Like everything about a cruising boat nothing is simple.

The tech part of things is a bit of a hurdle. I'm a PE and have designed machinery and complex control systems for 35 years. I'm still somewhere low on the learning curve where it comes to much of this. Just keep on banging your head. and some stuff makes it in.

[NorthPacific]

I can relate to that. 16 months to finish. The only problem is the list of to dos gets longer and ever more complex. Hopefully the snow will soon melt and we can start sticking the bits together.

We do for fun right?

[juneausailin]

Demeter, curious... Where did you get the articulating mounts? That's exactly what I'm looking for...

Originally Posted by SV Demeter

Just an update on the UL Solar panels that I started this thread on. I finally installed (4) of the 100 watt panels on my boat on articulating mounts on my railing. The photos below show the panel set up but the railing wasnt finished. I have them wired in a series/parallel set up with the two on each side in series. Saturday was mostly sunny but with a few big clouds quickly moving through. In the bright sunlight with the panels up but not aimed at all I was seeing 25amps coming out of the Outback Flexmaxx 60 controller. Im very happy with these panels so far and they appear to be made well but time will tell. I paid $245 each for the panels from the maunfacturers website.

[impi]

We are cruising the world with our Catamaran and have various sources of power - undoubtedly my Balmars are the best 'charging' investment I ever made, second my solar panels and third the Genset.
We have 50 amps out put on 5 Kyocera 135 solar panels wired with THICK good quality wiring over short distance runs and wired through a 50 amp MPTT controller. Of course the 'tilt' makes a big difference and also light ... generally we bargain on getting 40 amps per hour to the batteries in FAIR light conditions
I must admit I wish I'd put a 6th panel on the back ...
Happy sailing guys and hope to see you on the water some time!

[SV Demeter]

Originally Posted by juneausailin

Demeter, curious... Where did you get the articulating mounts? That's exactly what I'm looking for...

I had them made by a fabricator who happens to also be a friend. He is in Annapolis- Rhode River Fabrication 410-2279-0210 his name is Pete Appell.

[SV Demeter]

Originally Posted by impi

We are cruising the world with our Catamaran and have various sources of power - undoubtedly my Balmars are the best 'charging' investment I ever made, second my solar panels and third the Genset.
We have 50 amps out put on 5 Kyocera 135 solar panels wired with THICK good quality wiring over short distance runs and wired through a 50 amp MPTT controller. Of course the 'tilt' makes a big difference and also light ... generally we bargain on getting 40 amps per hour to the batteries in FAIR light conditions
I must admit I wish I'd put a 6th panel on the back ...
Happy sailing guys and hope to see you on the water some time!

Good lord how much juice are you using in 24 hours that 675 watts of solar cant keep up and you have to rely on alternators? Im excited about 400 watts based on our daily consumption of 90 amp hours...

[Tropic Cat]

Originally Posted by SV Demeter

So BP and Kyocera get good marks. Any other brands come with good comments? Not really into squirting silicone an would prefer decent MC connections.

BP bought the old Siemans solar division. I have a 20 year old Siemans panel on the stern of my boat. The only glitch was when I was struck by lightning. One of the diodes blew in the panel. Took me 15 minutes to change it and good to go ever since.

This is an older design, and is about 1 inch thick in a rigid aluminum frame

[downunder]

Originally Posted by SV Demeter

Good lord how much juice are you using in 24 hours that 675 watts of solar cant keep up and you have to rely on alternators? Im excited about 400 watts based on our daily consumption of 90 amp hours...

If you were setting up a catamaran today and it has room why not put on 1000W of solar. At $1.00 to $1.20 per watt why not- pretty cheap power.