Installing serial solar panels

[DotDun]

Originally Posted by foggysail

Installing serial solar panels! I am changing my solar system and am struggling to find what I need. Sure, Alibaba has plenty of deals but then if you can get a company to supply a small quantity there is the shipping and huge tariffs.

So---- where are the places to purchase reasonably priced panels? And don't waste time with Google unless you want to get involved with home estimates and all the other crap that I personally am not interested in.

So where am I. I just tossed out my StarPro30 controller for a lot of reasons. For me, its time to go MPPT and in that quest, I just purchased and installed a Victron 150-70 controller and wonder if I messed up by not purchasing a 150-85 instead.

Panels! My current 4 polys which where advertised as 140W/panel and the best I have seen to date is about 100-110W will stay put until I get better panels. What I want are 4 each 200W mono, 36V panels. I thought of keeping my current panels but I need the real estate to increase my capacity. And in increasing my capacity, I have to be vigilant to avoid exceeding the 70 ampere limit on my new controller.

No way will I use lower voltage stuff although I would consider higher voltage panels. If I find what I am looking for, at a reasonable cost, I will operate them with two strings of series/parallel raising the operating voltage to 72V. And yes, I understand the hazards of higher voltage, I also understand the advantages of higher voltages.

Agree that shipping costs can be huge. I was able to pickup panels at Sun Electric in the Miami area. You might look for a distributor in your area.

With your controller I would go for something a little bigger than 200w (x4). You don't have to worry about the 70a limit, the controller will simply not produce higher than 70a, but no harm if your array is larger, just stay under 150v from the panels. I would consider 250w or 275w panels (x4).

[foggysail]

Originally Posted by DotDun

Agree that shipping costs can be huge. I was able to pickup panels at Sun Electric in the Miami area. You might look for a distributor in your area.

With your controller I would go for something a little bigger than 200w (x4). You don't have to worry about the 70a limit, the controller will simply not produce higher than 70a, but no harm if your array is larger, just stay under 150v from the panels. I would consider 250w or 275w panels (x4).

Thanks DotDun for your post. I should have spent greater time reading Victron's specifications. As I type, I found solar panels being offered by various vendors selling Canadian panels.

I contacted one of the vendors, Infiniti.com regarding a purchase of 4 of the Canadian #CS6K-295 monos. I almost made the purchase today. Before I do, I need clarification to resolve how the panels get shipped. And like all things in life I found myself compromising somewhat with the Vpp that is only in the upper 20's-low 30's and not a higher voltage that I was hoping for. But $178.16/panel softens hard decisions made earlier. I want to avoid having to use 00 stranded copper or such to minimize the distribution voltage losses. My plan is to use some series connections here just not sure if it will be all 4 or 2 in series parallel. In any case the Vpp will be greater than 50v meaning I can get by using reasonable wire sizes.

So I am stuck until I get the shipping issue cleared but next week should see the panels on order.

Again thanks--

Foggy

[s/v Jedi]

Sorry for only coming back to this thread so little... very busy with boat projects at the moment :-)

About the shading: yes you can get that level of difuse shading by weather conditions like described, resulting in the lower voltage. The thing is that this then affects all panels, not just one.

My comments describe practical applications on sailboats, not theoretical setups, although I fully agree with the posted theories as well. The point is that many people read these threads in order to find the info they need for their setup aboard; this is why I keep to the practical application.

About panel selection: go for the biggest, highest voltage panel you can find a good (unshaded) spot for, then select a controller that is suitable for it (or an array of those panels if enough room). Finding that right spot is the key: study candidates by observing how shadows move etc.

[Paul Elliott]

Originally Posted by s/v Jedi

About panel selection: go for the biggest, highest voltage panel you can find a good (unshaded) spot for, then select a controller that is suitable for it (or an array of those panels if enough room). Finding that right spot is the key: study candidates by observing how shadows move etc.

Recognizing that this is indeed the preferred approach, you may need (or choose) to compromise on the location, and this may affect the panel selection. In my case, I chose to put my panels on top of the dodger, under the boom. This is close to the worst location I could have found, but I did it for aesthetic reasons. Given the shadow situation, I selected three smaller (100W) panels, oriented to reduce the chance that a boom or mast shadow would hit all three panels at the same time. On the average, I probably get 2 out of three panels producing good power. It actually works pretty well, and on the hook in the tropics it provides about 99% of my energy needs.

[hellosailor]

"This is close to the worst location ... It actually works pretty well,"
Gotta agree with you, Paul. Sometimes, the reality of what we CAN do, trumps all the engineering that says what we should do.

[newhaul]

Side note the renogy 100 watt mono panels do have bypass diodes installed in them
http://vi.raptor.ebaydesc.com/ws/eBa...28361000&ver=0

[Paul Elliott]

[Oops! I read "do not", but newhaul wrote "do". Anyway, here's the proof:]

Originally Posted by newhaul

Side note the renogy 100 watt mono panels do have bypass diodes installed in them
http://vi.raptor.ebaydesc.com/ws/eBa...28361000&ver=0

My Renogy 100W panels do:



Note the unsoldered tab that should have connected the junction of the two diodes to midpoint of the two 18-cell strings. I resoldered that myself after taking this photo. Also, the diode bare leads are just clamped under the terminal strip screw plates. I don't know if this is common practice, but I would have preferred some lugs crimped and soldered to the leads.

[s/v Jedi]

It is things like the bad quality control like that unconnected tab that cause these failed field tests where it is stated that the panel doesn't have diodes or series connection doesn't work right. It is a shame but we want cheap panels and this is how it is. It's up to us to understand what we're looking at, how it is supposed to be connected and to fix it when something is wrong.

About the boom shadow: with two big panels, moving the boom to one side in the morning and the other side in the afternoon works when anchored with steady wind direction. In other places flaky wind direction, tides, currents etc. make it impossible.

[foggysail]

Originally Posted by foggysail

Thanks DotDun for your post. I should have spent greater time reading Victron's specifications. As I type, I found solar panels being offered by various vendors selling Canadian panels.

I contacted one of the vendors, Infiniti.com regarding a purchase of 4 of the Canadian #CS6K-295 monos. I almost made the purchase today. Before I do, I need clarification to resolve how the panels get shipped. And like all things in life I found myself compromising somewhat with the Vpp that is only in the upper 20's-low 30's and not a higher voltage that I was hoping for. But $178.16/panel softens hard decisions made earlier. I want to avoid having to use 00 stranded copper or such to minimize the distribution voltage losses. My plan is to use some series connections here just not sure if it will be all 4 or 2 in series parallel. In any case the Vpp will be greater than 50v meaning I can get by using reasonable wire sizes.

So I am stuck until I get the shipping issue cleared but next week should see the panels on order.

Again thanks--

Foggy

The company was Infinigi not Infinity as I posted above and when I revisited tonight to place my order, the panels were no longer listed. So back to the hunt

[snaptwo]

And an answer to your question. You can safely use standard MCB breakers ( you should use a two pole, i. e. a two wire version) as used in standard electrical distribution systems for homes, etc. These are not marine breakers and need to have some protection from salt atmosphere, however are rated for both AC and D.C. service, with the two pole versions typically offering 125VDC service. Google "MCB" ( miniature circuit breaker" and look at offerings from companies like ABB, etc. Th e data sheets are readily available to download, and indicate the D.C. ratings alongside the AC ratings. Cost effective, simple and easily obtainable, this is a safe solution as used ashore for the same purpose.