Flexible Solar Panels

Sue Clancy · November 30, 2016, 01:47:41 PM

I took the liberty of posting an article to the tech wiki about our experience installing flexible solar panels this summer on the bimini of our 1987 Mark 1.

Totally worth the money which has already paid for itself in saved transient slip fees. - Total cost $680.05

Of course it helps that I was able to do all the sewing modifications to the bimini which I had made myself during the winter of 2014.

http://c34.org/wikiwp/?rdp_we_resource=http%3A%2F%2Fc34.org%2Fwiki%2Findex.php%3Ftitle%3DFlexible_solar_panels

Paulus · November 30, 2016, 01:53:07 PM

Nice write up. I am on my 4th season with my solar panel. We spend 3 months living on the boat and rarely stay in a marina.
Paul

kwaltersmi · December 01, 2016, 05:30:51 AM

Very nice write up. I'd love to have a similar set up on MkI. We currently get by using a portable (non-mounted) rollable 14w panel from PowerFilm, but we don't run the fridge while away from the dock (unless motoring) so it really just tops off the batteries from using lights at night. Your set up is much nicer, but I can highly recommend the PowerFilm flexible panels. Ours has been working great for 4 years with no issues. Here's my original write-up on the PowerFilm panel.

DaveBMusik · December 01, 2016, 07:50:52 AM

Thanks for this! I've been struggling with this decision for a year. To put regular panels on my davits or flexible on my bimini.
Does your bimini have the center bow and did you just go right across it? I couldn't tell from your pic.

Thanks!

Sue Clancy · December 01, 2016, 07:57:02 AM

Does your bimini have the center bow and did you just go right across it?

- Yes we have a center bow and we did go right across it. Initially based on our setup, the bimini had a pretty steep peak at the center bow and it was causing the panels to not lay flat. We were able to adjust the bimini so that the center bow did not stick up so high by adjusting a bunch of the fittings to change the angles. This may not work for everyone as it may cause too much tension on the bimini zippers. We did pull out some stitching on one corner as a result and I have had to resew that zipper end.

DaveBMusik · December 01, 2016, 10:58:37 AM

Quote from: Sue Clancy on December 01, 2016, 07:57:02 AM
Does your bimini have the center bow and did you just go right across it?

- Yes we have a center bow and we did go right across it. Initially based on our setup, the bimini had a pretty steep peak at the center bow and it was causing the panels to not lay flat. We were able to adjust the bimini so that the center bow did not stick up so high by adjusting a bunch of the fittings to change the angles. This may not work for everyone as it may cause too much tension on the bimini zippers. We did pull out some stitching on one corner as a result and I have had to resew that zipper end.

I've toyed with the idea of putting some kind of a stiffener under the flex panels but I worry about heat build up. How has shading been on the bimini?

I do have davits and they would probably have less shade and could be angled to the sun. The expense is a bit more, I worry that being the furthest item astern could be problematic and they are not exactly a "traditional" look...

Sue Clancy · December 01, 2016, 11:08:04 AM

I've toyed with the idea of putting some kind of a stiffener under the flex panels but I worry about heat build up. How has shading been on the bimini?

In terms of a stiffener, that would not really solve the issue. The problem is the area needs to be as close to flat as possible or you won't be able to hold them flat to secure them to the bimini. In terms of shading, there is not really anything except maybe the line of the backstay at certain angles that is an issue and we did not find that to be an issue in the heart of the summer.

Honestly though if we had davits installed, we probably would have opted for a rigid panel across the davits. Fairly easy to install, cheaper for the panel itself and you can get more AMPS from the solid panels. Also, in the winter (not sure where you are) you could leave the rigid panel up charging the batteries on the hard.

We are actually in the midst of selling our C34 and the new boat we have purchased has 4 - 100W rigid panels on it. One is on the davits - the others are on a solid arch. They are left up all winter and we are able to monitor the batteries via a remote monitoring tool. As of this moment (2:06 PM EST on a cloudy day after 2 solid days of rain, the batteries are at 14.08V.

csimmerling · December 03, 2016, 06:11:24 AM

I bought a 100w flexible panel and laid it on the deck in front of the mast and behind the hatch (corners tied to hand rails). It's a great solution for us.

Paulus · December 13, 2016, 08:05:12 AM

I have the same system but did not put a on/off switch in the system. Did you put this between the panel and controller or between the controller and battery? When I installed my panel, the feedback from this site was that I did not need to disconnect the solar panel when plugged into shore power. Interested in your thoughts.
Paul

Stu Jackson · December 13, 2016, 09:10:33 AM

Quote from: Paulus on December 13, 2016, 08:05:12 AM
I have the same system but did not put a on/off switch in the system. Did you put this between the panel and controller or between the controller and battery? When I installed my panel, the feedback from this site was that I did not need to disconnect the solar panel when plugged into shore power. Interested in your thoughts.

Paul,

All systems I am aware of require the solar to be disconnected from the controller FIRST. What you suggest in putting a switch between the controller and the battery could indeed fry the controller. There should be a fuse at the battery. You can put a switch between the controller and the panel, since most controllers require disconnecting the panel first anyway. There is no reason to disconnect the panel when any other charging sources are present. I recommend reading your controller manual again.

Sue Clancy · December 13, 2016, 10:16:34 AM

QuoteI have the same system but did not put a on/off switch in the system. Did you put this between the panel and controller or between the controller and battery? When I installed my panel, the feedback from this site was that I did not need to disconnect the solar panel when plugged into shore power. Interested in your thoughts.

Our switch is between the controller and the battery. It is a circuit breaker switch which acts as a fuse to protect the battery from the whole system.

mainesail · December 13, 2016, 10:17:00 AM

Couple of thoughts on semi-flexible installs.

#1 They should not cross a bimini bow. Doing so can lead to micro-cracking of the cells, then hot spots then holes in the bimini.

#2 They should not be walked on unless specifically designed for this

#3 Cheap MC4 connector fail at an alarming rate in the marine environment. I have had to trouble shoot numerous installations where the cheap Chinese MC4's had failed to pass current. I have also seen multiple cheap MC4 connectors literally crack in half. You want premium quality MC4's such as Multi-Contact branded MC4's. Alt-E stock the Multi-Contact brand. Multi-Contact invented the MC4 hence the "MC" in the name. Amphenol (Helios) also makes excellent MC4's but you need a very expensive tool to crimp them.

#4 If you are not buying premium semi-flexible panels using "A" grade Sun Power cells, such as Solara, Gioco or Solbian, please, please, please test your panels when you get them to confirm performance. An OCV test and a short circuit test will be necessary. I find about 4 to 5 out of every 10 cheap knock off semi-flex panels fail to meet spec. Test them and send them back until they perform.

#5 When using Velcro be very sure the lapel does not over hang any portion of the cell.

#6 When lifting or moving these be very careful supporting them. I was with a customer when he tried to pick his 100W panel up with his thumb on top and fingers pressing the bottom of the cell. You guessed it the crack the cell made was audible. Bye, bye panel....

#7 Remember these are "semi" flexible. The more you bend them the sooner they will be destroyed. Most of the cheap knock offs out of China land here riddled with micro-cracking of the cells already.

#8 While Renogy seems to stand behind their products they are nothing more than a "sticker" brand. What I mean by this is they simply source their products from China and put their sticker on it. I have seen Renogy panels with the identical model number & specs not even made by the same factory. Much of the Renogy stuff has proven to be absolute horse dung from their controllers catching fire, to semi-flexible panels developing hot spots & burning though canvas to failing MC4's & panels simply not meeting spec..

The solar market right now is kind of where LED lighting was a few years ago, in a state of scammery.

Paulus · December 13, 2016, 11:25:02 AM

Stu,
I was not suggesting an on/off switch. I thought from reading Sue's write up that she had a on/off switch, did not realize it was a circuit breaker. My system does have a fuse between the controller and battery and must disconnect the panel first. I have this taped to my controller. I am on my 4th season here in Michigan and run it year around. Thanks for the reminder Stu. You gave this same advice when I was installing it.

Concerning #4 from mainsail's comments: SunPower makes various cell's depending on the target market. Is there any way of knowing which solar cell you are getting? Most of the specs on solar panels just say "sun power cells". They are not equal.
Paul

John Langford · December 18, 2016, 05:29:41 PM

Question for Mainesail
Do you have brand recommendations for hard solar panels? I was looking at a Renogy "suitcase" package made up of two hinged 50 watt hard panels with supports that I would use on the foredeck of my Catalina 34 when in an anchorage. The price is right and the reviews from users seem positive but I would prefer to buy quality panels.

Noah · December 19, 2016, 09:01:09 AM

I am by no means an expert on solar panels other than i have 36 of them on my home!

However. I am an expert in marketing and if the sales literature says "sun power cells" that could mean ANYTHING that allegedly harnesses power from the sun. "SunPower" (rendered as one word) is a registered trademark of SunPower). They are a respected brand name solar panel/equipment maker. Their equipment is designed in the US and made overseas. There are lots of knock-offs and imposters out there.