Solar System Design

[IStream]

Okay, so it's time to add some solar to my boat. For various reasons, I've ruled out rigid panels and am very attracted to the Renogy 100W flexible units. At 1/5th the price of the Solbians, I figure I can give them a shot and if they crap out after four or five years, I'll still have gotten my money's worth. I've got enough room on my sailboat's hard dodger for eight of the Renogy 100W panels and plan to install four in a T configuration with two panels forward and flanking the centerline and two panels aft and oriented athwartship, beyond the end of the boom. I generally have my boom pulled to the side when not sailing so it won't be directly over the spine of the T either. Nevertheless, it's likely that at least one of the panels will be shaded by the rigging for at least part of each day, so I need a system configuration that'll minimize the negative impact of shading of one or two of the panels at a time.

I was originally planning to use separate Genasun MPPT controllers for each panel to address the shading issue but they don't have a 100W controller so you have to buy their 140W controllers at $170 each, which quickly adds up. Alternatively, for about $530 I can get a Morningstar 60A MPPT controller which will give me room to expand with more panels in the future at no additional cost. In addition, it can be networked and monitored via my laptop, which a nice-to-have feature. If I go the Morningstar route, I figured I'd wire the panels in parallel with Schottky diodes to address the shading issue, albeit at the loss of a fraction of a volt from each panel at all times.

FYI, my house bank consists of 800AH of Lifeline AGMs (inherited from the previous owner), I'm charging with a Balmar-regulated 140A Delco frame alternator off the engine and a Magnum MSH3012M inverter/charger while at the dock. I seldom let the bank get below 70% SOC and usually have an opportunity to get back to 100% within a week. The objective of adding solar is to buy more time on the hook without having the run the engine.

Any opinions on the alternative solutions or the system plan as a whole are welcome!

Thanks.

 

[Maine Sail]

The Renogy panels do have an attractive price but I won't personally install them. All the Solbian knock off panels come out of the same sleazy factory in Shenzhen. This sleazy factory hides behind about 5 or 6, maybe more, front companies that all claim to be "the manufacturer." This is simply how the Chinese do business and why it is so tough to go after them for patent infringement... It is also how companies like Renogy or Grape etc. can all claim to be the manufacturer but it is pure BS.. Call them Grape, Renogy, Shine etc. they are really all the same product.

We have seen many of them not putting out anywhere close to their rating. The performance warranty is also very lacking (on one brand there is none, workmanship and materials only for 5 years).

The best advice I can give is to A/B test all the panels BEFORE you install them. They should all have near identical performance. If not keep sending them back until you get a matched set. Look at both current and voltage when you test them. Best to build an easel and set them on it on a clear day so all A/B's are comparable.

If you do that and they last a few years you got a good deal. DO NOT buy these panels and not test them!!!!

DO NOT bend these panels anywhere near the 30 degrees they suggest you can!!!!!

There should be no need for diodes in a parallel set up. They should also have bypass diodes in the j-box but I believe only have two..

The Morningstar is a good choice..

 

[IStream]

Thanks, Maine, good advice. I'll get some 100W load resistors and test them thoroughly before acceptance. I noticed that Amazon sells them for $20 more than Renogy's "sale" price but if panel consistency is a problem, it's probably worth it for their no-hassle returns and 2-day prime shipping on the initial order and/or any replacements that may be needed.

BTW, I'm more interested in their low profile than their flexibility. I don't need more than 5 degrees of bend to conform to the dodger and they'll essentially be permanently installed.

 

[Bob846]

IStream, you never mentioned the amp/hours you draw in a typical 24 hour period or coming from Seattle, if you plan to use the boat primarily in the summer (long days) or winter (very short days - I used to live in Portland OR). 800w of solar is pretty hefty. I have a combined wattage of 340 this yields about 20 amps at the noon. Shading is big issue so the more you can reduce shading of any one panel, the better. I use rigid panels (BP Solar) and so far no complaints (at 7 years old). Don't get fooled into "marine use". All panels should be able to stand up to outdoor exposure. Mounting is big deal; especially offshore so robust mounts are key. I'm a proponent of BlueSky Energy Inc's. controllers as they are well built and quite efficient. Plan your wiring accordingly to minimize voltage drop. I run each panel through a fuse block so it's easy to isolate a panel should the need arise. A good battery monitor is also key to understanding your requirements and monitoring the batteries. I find my biggest draw is refrigeration.
Best of luck with your design and installation.

 

[IStream]

Hi Bob,

Thanks for the input. I am in Seattle and sail mainly in the summer but I really like to go out in the spring and fall when there are far fewer crowds. The 800W design is really just for the zombie apocalypse. I don't think I'll ever go above 400W and may end up shortening my hard dodger anyway, so 400W is a pretty hard limit unless I get creative with panel placement elsewhere. If I'm careful, I use about 150AH per 24 hr period when I'm on the hook but that can easily jump to 250AH if I go balls-out on the power consumption.

The big issue is when I don't want to run the engine for more than a day, both because I'm not charging the batteries and also because I can't use it to chill the holding plates in my fridge (via the engine driven compressor) and I run out of hot water. I can run my 110VAC fridge compressor off my inverter but that's pretty inefficient and I can get hot water via my diesel hydronic heater, which adds circ pump and fan loads. It's these circumstances that get me to 250AH/day consumption.

My goal is to spend two days on the hook in the shoulder seasons and three days in the summer without running the engine and without using more than 300AH net so my 800AH house bank stays well above 50%, even as it ages. That means I need to generate about 150AH per day in the summer and about 100AH per day in the spring/fall. Assuming a 400W system that produces 200W on average for six hours a day in the shoulder seasons, I get my 100AH and if I can get 250W on average for 8 hours a day in the summer, I'm covered there too.

As for mounting, I'm attracted to the flex panels mainly because my boom sweeps over my hard dodger with only about an inch of clearance when it's horizontal. I don't want to compromise sailing performance in heavy air by lifting the boom and/or risk damage to rigid panels that stand proud of the dodger inch or two.

 

[IStream]

UPDATE: Maine, you were right as usual.

I ordered a pair of Renogy 100W flexible panels on Black Friday and another pair the following week, both via Amazon. The first pair were fulfilled by Amazon via the Renogy warehouse in KY. They arrived with the brass grommets somewhat tarnished and the protective peel-off film tightly adhered to the surface of the panels. Clearly, they'd been sitting around for some time. The second pair were fulfilled directly by Renogy out of their CA warehouse and were much fresher, with bright grommets and protective film that came off easily. The second pair were within the specified 3% of each other in Voc and Icc. Compared to these, one of the first pair had a Voc that was down by 50% and the other was down by 25%. They're going back to Amazon tomorrow.

I plan to install the first two in parallel and will keep trying to get a well-matched second pair. Once I do, I plan to add one panel from the second pair in series with one panel from the first pair on each of the left and right sides of my hard dodger. That way, each series pair should have similar performance. I've got a 25 foot wire run from the panels to the controller and running each side in series will keep me below 1% voltage drop with my 8 gauge wiring. The Morningstar MPPT penalizes me with about a 1% efficiency drop going to a series parallel configuration vs. all parallel but I save about 3% in voltage drop.

 

[gettinthere]

Any comment on the Go Power semi flexible panels sold by Defender?

http://www.defender.com/product.jsp?path=-1&id=2485729&cartId=5962291

Two 100 watt semiflexible panels and a 30 amp PWM controller for under a grand.

 

[Chief RA]

gittinthere: MPPT controller, not PWM. Go on Amazon, you can get what you want for lots less than a grand! Chief

 

[mitiempo]

Any comment on the Go Power semi flexible panels sold by Defender?

http://www.defender.com/product.jsp?path=-1&id=2485729&cartId=5962291

Two 100 watt semiflexible panels and a 30 amp PWM controller for under a grand.

I sell the Go-Power panels and their controllers. Their controllers are good but they only have PWM. The panels have proven to be good quality and their customer service/warranty is excellent. I have only had 2 issues over the last year or so. One panel had an intermittent negative wire connection and it was promptly replaced. The other problem was with 2 panels on a bimini. The panels were laced together and one grommet pulled out in a gale, leading to the destruction of both panels. Go Power (Carmanah) replaced both panels after seeing pictures and shipped the new panels to the customer in California free of charge - from Canada.

I buy the panels from Carmanah - owner of Go Power - and they are located about 1/2 a mile from the store. I but a la carte panels and controllers rather than kits. Most panels are sold with Genasun MPPT controllers.

MPPT should give you a 15% to 20% increase in output over PWM.

Genasun does not have a controller large enough for 2 100 watt panels. Some customers have bought a controller for each panel which can have some benefit. Others have purchased Morningstar MPPT controllers.

 

[gettinthere]

Mitiempo
I dont understand why, at defender, the kit I listed with the pwm controller is cheaper than buying just two 100w panels. Any insight there?

I do not want to buy this sort of stuff from amazon. I want a known dealer to back me up if there are issues.

 

[Chief RA]

Amazon backs their sales and provides the best prices. I have bought many thousands of dollars worth of items and exchanged/returned when needed. Kits with PWM are cheap because they are trying to move the PWM controllers because sold separately they sell poorly now.
Chief, EE,FCC lic#1890

 

[Maine Sail]

Any comment on the Go Power semi flexible panels sold by Defender?

http://www.defender.com/product.jsp?path=-1&id=2485729&cartId=5962291

Two 100 watt semiflexible panels and a 30 amp PWM controller for under a grand.

I have no experience with Go Power but from what I understand all the cheap Chinese semi flexible panels all come out of the same factory in China then get re-labeled as Shine, Grape, Renogy, Go Power etc. etc. etc..... This means you should pick the panel by how the company re-selling them stands behind the product and what their written warranty is.

I know Go Power is a pretty reputable company but DO check the performance of each panel in an A/B side by side test. (See IStream's report above) The performance of these panels can be highly variable because most of them are using non "A Grade" cells to keep the pricing down........

 

[Chief RA]

Renogy sells their own products even when ordered THROUGH Amazon. I just checked. Chief

 

[gettinthere]

Hmmmm
Renogy offers 5 year material and workmanship warantee. Most panels offer some specific sort of output guarantee.

 

[Maine Sail]

Renogy sells their own products even when ordered THROUGH Amazon. I just checked. Chief

"Their own products" is a bit misleading. Renogy is little more than what I call a sticker company. A sticker company operates by slapping their logo/sticker on a panel or product that is also sold to multiple other re-sellers from the same factory.. The key with any Chinese sticker company is how well they stand behind the product they are putting their sticker on. In my experience Renogy does a decent job at this but not stellar...

Having been working with a few Chinese manufacturers, on a product I am trying to develop, I can tell you the way they do business, in electronics, is very, very odd. Tracking down the actual manufacturer is very, very difficult as they like to front or cloak the actual manufacturer with anywhere from 3 to 20 store front marketing brands all "claiming" to be the manufacturer.

This way companies like Go Power, Renogy, Grape and others can all claim they are the "manufacturer" of the product when they are not. They are told they are but this is really not true if you were to dig deeply into it.

It is actually a brilliant way to get more product onto the street but where they fall flat is in the lack of ability to make minor tweaks that would physically separate the product aesthetics & performance wise from the ones they sell to others to slap a sticker on.

Books will be written about how the Chinese market and get electronics to market and their shell company games.....

Still, the best way to buy these products is though a company that stands behind them, Go Power, Renogy, eMarine etc., and not off eBay. Then, when you test the product, and it fails to perform, you simply ship them back for a replacement until you get one that does perform...

 

[Chief RA]

Maine Sail: My point is Amazon likely does not stock these as they are not shipped from an Amazon warehouse as was previously alluded. As far as marketing and business concepts: I agree with your analogy of Chinese subterfuge. I am an ex Yamaha dealer with BS in Business as well. Never taught Business classes but certified for several of them!
Happy New Year! Chief

 

[mitiempo]

Mitiempo
I dont understand why, at defender, the kit I listed with the pwm controller is cheaper than buying just two 100w panels. Any insight there?

What are the prices?

 

[Maine Sail]

Maine Sail: My point is Amazon likely does not stock these as they are not shipped from an Amazon warehouse as was previously alluded. As far as marketing and business concepts: I agree with your analogy of Chinese subterfuge. I am an ex Yamaha dealer with BS in Business as well. Never taught Business classes but certified for several of them!
Happy New Year! Chief

The 100W semi flexible Renogy is an FBA (fulfilled by Amazon) product. This means they are in-stock in the Amazon warehouse and that they also qualify for Amazon Prime shipping.. Some items on Amazon ship direct from Renogy and some are FBA..

As an Amazon Prime junkie, and Prime abuser, I appreciate FBA products...

 

[gettinthere]

Mitiempo

The whole kit with 2 panels and pwm controller was about $930. Buying two 100w panels and no controller was about $950...give or take $10 as I recall.

 

[weinie]

The 100W semi flexible Renogy is an FBA (fulfilled by Amazon) product. This means they are in-stock in the Amazon warehouse and that they also qualify for Amazon Prime shipping.. Some items on Amazon ship direct from Renogy and some are FBA..

As an Amazon Prime junkie, and Prime abuser, I appreciate FBA products...

As always, thanks for the info.
I may pull the trigger on the 50 watt version on amazon.
Its only about 2 x 2 feet. I imagine I could just install a quick connect fitting wired to a controller near the batteries and just slap the panel on the deck when I leave the boat each time.

That should be sufficient to keep the batteries (3 x 80AH) topped off without evening having to permanently mount a whole unit.

The price is right and if it doesn't work, it's not a huge investment.