Adding a solar panel


May 30, 2021
Catalina C310 Seattle
Greetings all!

We just purchased Serenade, a 2004 C310, hull number 260. We are excited about our new boat and as always with boats, we have many questions.

For this post, the subject is adding a solar panel because we will moor on a ball, not at a marina.

We have AGM batteries, house and starting. I am not sure of brand or amperage, that research remains.

While moored, we will leave the bilge pump on. While cruising the auto pilot and refrigerator will draw the most current.

My question, has anyone installed a solar panel on the Bimini? If so, how many watts, what brand, did you use a controller, and how is the system wired to both banks of batteries?

Thank you to anyone answering this post. One of the reasons we chose the C310 is the active and very helpful website.


Stephen Nielsen
West Seattle
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Dec 15, 2006
Catalina Catlina 310 Campbell River BC
Yes I have 2 65 watt panels on the dodger and 2 100 watt panels on a arch I built. With these we can run everything and charge the batteries during the day. The batteries are 4 6 volt fld 1 agm starter and 1 12 volt agm trolling motor battery. I also use a victron battery isolator so I can charge the trolling battery and house with out these batteries seeing each other. Time on the hook 1-2 weeks and we don't need to start the motor.

Tom J

Sep 30, 2008
Catalina 310 Quincy, MA
I have two 165 watt panels mounted on the davits of my C310, but for your bimini, a flexible 100 watt panel would work well. I have that panel mounted on the curved roof of my RV. The panel and controller and cables are sold as a kit by Hamilton Ferris. The panel can be ordered with snaps for the bimini installation.
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Nov 18, 2010
Catalina 310 Hingham, MA
We started with 2 100 watt semiflex panels in 2014. That wasn't really enough. The boat was pretty bare at the time with not much more than factory equipment. in 2016 we added 2 50 watt panels to the bimini and 2 100 watt semiflex panels to the lifelines a solar wings. That was enough and we were now energy independent.

In 2018 I replaced the semiflex solar wings with hard panels. Those two hard panels produced more than the 500 watts of semiflex panels. We changed out these panels to add a watermaker.

In 2019 we went to lithium batteries, added an arch by Atlantic Towers and put a 295 watt hard panel on the arch. The arch also lifts the dingy. The 295 watt panel alone produces more power than all the previous setups combined.

What I have found is higher voltage panels produce more power. And not just a watt for watt but they start producing usable amperage earlier in the day and stay productive longer. At 6:30 most mornings I'm showing zero net amps (meaning the solar is already covering my house loads). by 7:30 I'm already taking in more that 7 amps. With the same footprint as my 295 watt panel I could now get a 375 watt panel and probably eliminate the solar wings.

We are looking at getting a bigger boat and the first thing I will do to that boat is put an Atlantic Towers Arch-in-a-Box on and then two large solar panels.

Good luck and fair winds,

Feb 26, 2004
Catalina 34 224 Maple Bay, BC, Canada
If so, how many watts, what brand, did you use a controller, and how is the system wired to both banks of batteries?
SJN, welcome and congratulations on your new boat. As you spend more time here, you'll find a lot of help is available. Smitty's blog is a very good place to start to learn about electrical systems for boats, I highly recommend you spending time reading about the work he has done, because he goes into a lot of detail about the why of what he did.
Two other resources you should spend time with about boat electrical systems are Maine Sail's excellent website and my collection of links, many of which go to his site and his posts on this fine forum.

Marine How To - DIY for Boaters - Marine How To

Electrical Systems 101 Electrical Systems 101
Dec 28, 2015
Laser, Hunter H30 Cherubini Tacoma
Getting your agms charged back to 100% on return to your moorage will be your big challenge with the consideration of getting the minimum recommended voltage for the batteries from the charger. Keeping below the minimums impacts battery lifespan. Given our weather, I’d go as big as you can with panels that are the most efficient ( rigid over flexible) and a quality, efficient controller. I’d also consider putting a large, external alt on it if it doesn’t have one to get as much bulk charging into them so when you moore it, the panels have less work/time needed to get to float. Once the battery is at float you could use a tiny panel but it’s getting there that is the challenge after a deep discharge from a multi day trip. I have. 2 125watt panels/ charger , 255amphr agm and a 70amp alt and ext regulator and still believe I will never get to true 100% state of charge while off of the dock and I bet I motor about 65% of the time when on on a multiple day trip. I’ll be dependent on my shore power/charger to get back to true 100% on return. You won’t have that luxury. Read up on Mainsails articles on agm charging and how long they actually take. Mount the panels as far back as possible to keep out of the shadows of the boom/sail as much as possible. It’s amazing how impactful that is. I mounted mine on the cross bar of my davits and made them so I can pivot them forward and back then on anchor. It really helps in the mornings when the sun is low.
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May 30, 2021
Catalina C310 Seattle
Thank you for your helpful replies. You have successfully started my journey to Solar.
Oct 3, 2011
Anam Cara Catalina 310 Hull #155 155 Lake Erie/Catawba Island
Welcome, echoing what others have said this is a great source of Help, Just Ask and you get it!