Solar panel wiring questions

Zetta

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Joined
Jan 1, 2024
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5
Hi everyone. I don’t know if and where this question may have been asked before but this group looked like a good place to start.

I don’t have 110v power at my boat lift so I would like to install a solar panel to recharge my single 12v deep cycle boat lift battery and my two 12v deep cycle trolling batteries which are wired in series to give me 24v.

Is there a way to wire a panel and controller so it is smart enough to charge all of the three batteries without risk of over charging any of them?

Thanks in advance!!!
 

mike_i

Ensign
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Jun 28, 2017
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939
Unless you install several high wattage panels and they're mounted perfectly you will unlikely need to be concerned about over charging. Sounds like you have a large amount of battery capacity. Read about solar charge controllers.
 
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ESGWheel

Chief Petty Officer
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Aug 29, 2015
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465
As suggested, here is a recommended starting point for reading about controller’s link. And while mostly about need one vs. not, the author says he is an ABYC Certified Marine Electrical Systems Specialist. He may be open to answering questions such as yours. I have not (yet) had a reason to reach out to him so unsure if this is simply an old site or if he is still active.
 

tpenfield

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Staff member
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Jul 18, 2011
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18,036
Hi everyone. I don’t know if and where this question may have been asked before but this group looked like a good place to start.

I don’t have 110v power at my boat lift so I would like to install a solar panel to recharge my single 12v deep cycle boat lift battery and my two 12v deep cycle trolling batteries which are wired in series to give me 24v.

Is there a way to wire a panel and controller so it is smart enough to charge all of the three batteries without risk of over charging any of them?

Thanks in advance!!!
Did you ask this question on the DIY Solar Forum? Seems familiar.
 

KD4UPL

Senior Chief Petty Officer
Joined
Feb 13, 2010
Messages
667
It would be far simpler, easier, and likely cheaper to have a seperate panel and controller for each battery.
There are some controllers with a main output and a secondary output of lower capacity. I don't know of a 3 output controller or one that will output 2 different voltages at the same time.
 

cyclops222

Lieutenant Junior Grade
Joined
Mar 21, 2024
Messages
1,232
A separate Photo Cell panel for each battery is most efficient and safer. Then recharging is faster. A correct sized fuse or circuit breaker is required for each Photo Cell.
Or a small quiet motor generator can be rigged up if you want / need every day, fully charged batteries.
 

Zetta

Recruit
Joined
Jan 1, 2024
Messages
5
Thanks for the replies and sorry about not responding. I forgot to click the box to receive notice when anyone replied to my thread.

Looks like I have some reading to do and I will check out @nola mike.

Thanks again
 

nola mike

Vice Admiral
Joined
Apr 22, 2009
Messages
5,350
My setup was simple, and I'm far from an expert. I just used a separate panel/controller for each of my motors. If you just wanted one controller, I would install a battery switch in the boat that would switch the trolling motors from series-->parallel when I wanted to charge. I don't know enough about 24v charging, but think you'd need either a 24v panel or 2 12v panels in series, and then 2 separate controllers for the 2 banks of batteries. I like my first idea though.
 

nola mike

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Apr 22, 2009
Messages
5,350
Wow, so I'm the wrong guy to take advice from. Got back from a ride this evening and couldn't get the lift up. Took me an embarrassingly long time to diagnose a dead battery. Ended up bringing out another battery and jumper cables. Sounds easier than it was ;) . This has probably not been charging for a couple of weeks. Hooray, another project for tomorrow.
 
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