Adding a solar panel

[dsherburn]

I'm adding a 100watt solar panel to my R23. All I really need is some "on anchor" supplemental charge so I can keep the refrigerator going and an anchor light on.

If I'm plugged into shore power and the solar charger is connected to the batteries do I need to worry about back feeding the solar charger? In other words, will the voltage from the on-board shore power battery charger negatively impact the solar charger?

 

[scross]

You will need an appropriately sized solar controller installed between the solar panel and the batteries. Along with several fuses and correct gauge wiring. With the proper installation you do not need to worry about the solar panel when hooked up to shore power.
That said, when my boat is on shore power in my driveway during the off season, I do turn off the solar panel at the switch I installed between the solar panel and the solar controller.
See this thread for information on installing a solar panel.
viewtopic.php?f=24&t=9821&hilit=DIY+rack+solar#p67789

PS: Why only a 100 Watt panel? Mounting size constraints? If I was going through the effort to install new solar I’d go with at least a 190 Watt panel.

 

[dsherburn]

Thank you! Yes the 4 stage PWM solar controller with fusing and disconnects are part of the install. I just wanted to insure the battery charger wouldn't back feed and harm the solar controller.
ds

 

[Cutwater28GG]

I just installed a duo 340w panel. Huge difference. I’m loving the duo aspect. If a part of the panel is shaded I still get half output and not none. It was a q cells 340 duo from platt.com

 

[knotflying]

I just installed a duo 340w panel. Huge difference. I’m loving the duo aspect. If a part of the panel is shaded I still get half output and not none. It was a q cells 340 duo from platt.com

Were you able to use all the existing mounting hardware? did you also change your controller?

 

[Cutwater28GG]

swapped to a victron 100/30 MPPT controller. so much better as I now have a remote battery sensor so the correct voltage is delivered to the batteries after cable loses. Also the bluetooth app is fab

also added a switch between the panel and the controller which was missing in my sunsaver duo setup. Also added a 30 amp fuse after the controller to protect the wiring.

with half the panel shaded from the radar I still produce almost 10amps... at the correct voltage at the batteries

the other thing the new controller gave me was a much more aligned charging profile for the batteries I use.

I use the Universal AGM's and Im pretty sure I have been under charging them since new with both the shorepower, alternator and sunsaver.

the alternator is putting out 14.1 volts which I dont think is high enough to fully charge the batteries.

this is the panel I used

https://platt.com/platt-electric-su...PEAK-DUO-BLK-G6-340/product.aspx?zpid=1458239

I used the same 4 mounts on the rails. I just carefully drilled some new mounting holes in the frame of the new panel to match the bolts. didnt have to move the rails as a result but could mount the panel further forward.

had to add MC4 connectors to the existing cables going through the roof to connect to the panel as pretty much all new panels use these now. but I was saved from having to run new wires through the roof: my least favorite idea. I cant really go bigger than this panel because the cabling would start to get undersized for the power
make sure you have the right crimper for this task.

 

[dsherburn]

scross: (Vicky Foley/Al Thomas)-I never answered your question as to why only 100 watts. I have a new R23 and am trying to minimize electrical draw at anchor. I purchased a 100 watt "kit" from Renogy that included the panel, cables, and mounting brackets. I mounted the panel to the sport bars with the Sea Dogs mounts. I will "temporarily" run the cables to the PWM controller mounted near the batteries. Until I figure out what I want I'm trying not to drill any holes in the new boat. The panel I have from Renogy is the typical polycrystalline panel in an aluminum frame. While not horribly heavy, it's a small boat and I'm considering the semi flexible panels I can mount on the canvas as an alternative. I'll get this wired up and evaluate. If I decide on different panels; no loss as I have the aluminum framed panels ear marked for my daughters camper. I was worried the shore power charger may back feed the controller and mess it up. I purchased (fusing) and a small Blue Sea disconnect switch for the PWM module.
Cheers!
Dan

 

[scross]

Dan, the larger rigid 190 watt panels are about 6-8” wider and 15-18” longer than the 100 watt Renology panel. That may give you a sense on how much room you have on the sports rack.
The bigger panel fit with plenty of room to spare on our R-25 Classic. We have a Yakama Rocket Box on the starboard side of the sports rack and I wanted enough room to make sure it wasn’t shading the solar panel. It doesn’t except when we are pointed north for the first hour of sunlight in the morning.
It’s always nerve racking drilling holes through the fiberglass but being as the solar wiring comes through at one of the highest points in the boat plus goes through a “waterproof” Blue Sea Systems Clamshell made it less stressful.
Photos in my album of the install.

 

[dsherburn]

Thank you for all the detailed replies. Being my R23 didn't come with the solar option, where do you think the factory wire route would be from the panel (on the sport rack) to the controller (mounted near my batteries)?