Marine Electronics Forum

solar charger

Old 09-22-2020, 06:27 PM
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Default solar charger

Forgive me if this is beating a dead horse but the searching ive done i couldnt find the answer i was looking for. Hoping someone here can help me out, looking to add a solar charger to my batteries but cant seem to find one for multiple batteries. Can multiple leads be run from the single battery port on the controller or does there need to be a panel and controller for each battery. I feel a 120w panel would be more than enough for maintaining 3 batteries.
Old 09-22-2020, 06:57 PM
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generally they are all one battery bank. generally only one bank (house) needs to be charged because the engine batteries should not be draining.

are you trying to store it for many months? or why do you feel the need to change every battery.

if there are VSR's or ACRs between batteries then you only need to connect the solar to one anyways. depends how the boat is wired.

Last edited by smac999; 09-22-2020 at 07:05 PM.
Old 09-22-2020, 07:02 PM
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How is your battery system setup now? You have three individual batteries doing there own thing on the boat? What type and size are they? What boat?

they make solar controllers with dual battery outputs. I haven’t seen three outputs before, but also never searched for them.

you could also go the ACR/VSR/combiner route between the batteries so you can have your alternator charge all three while running and then when docked/moored, your solar system can take over. That way all you need is a single controller. Sterling Power even makes a combiner which has super low power draw and is programmable. Great fit for solar.

You have some options.
Old 09-23-2020, 12:25 PM
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I have 3 brand new optima blue tops. Boat is new to me so im still trying to figure it all out but i believe the batts on the starboard side are the starting batteries and the port are a house and gene start.

My reasoning for wanting this was because we ran out a fuel recently due to being mislead on capacity and got stranded for a day. By the time we tried getting some fuel from another tank that wasnt feeding originally, after trying to start the engines so much they were completely drained. Eventually got a tow but basically im just paranoid now about not having enough juice.

I havent seen any multi bank solar chargers, didnt know if i was just missing something.
Old 09-23-2020, 02:04 PM
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The juice you should be worried running out of is your fuel.

what boat is this?
Old 09-23-2020, 02:22 PM
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Well now that i know i have about half the fuel as i should that juice wont be a problem anymore.

35 contender sc
Old 09-23-2020, 06:03 PM
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This is what I installed on my boat mid summer. I got the 20 amp unit with display. Shoot Tom a email if you have any questions, he was great. I have a sunpower 110 watt panel on my hardtop. It maintains one 8d starting battery and two group 31 deep cycle house batteries. 12 volt wired parallel. One lead to start battery, the other to the house bank. You can set the percentage of charge. Mine is set 50 /50. Boat lives on a mooring, I can run my live well all day now without have to start up my main engine to charge. I install this myself in a afternoon and cost me about $500 all said and done.
Old 09-23-2020, 06:53 PM
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I have been using a T-Top mounted, semi-flexible panel set-up since 2009. Currently I have two panels to charge 3 batteries. I use two dual battery charge controllers and have two monitors. I built a bracket out of angle aluminum and 1/4" starboard for the monitors.

Over the past 11 years I have replaced:
  • two panels
  • 1 charge controller
  • 1 monitor
Generally, panels average $120 (Amazon & EBay). The charge controllers and monitors typically cost $30 (Amazon & EBay) for a set.

How do my batteries hold up? I just replaced all three with a new set in May. I use Duracell AGMs from Sam's Club. These average $150 each. The old ones all tested at better than 12v when I pulled them out. They are being used by friends on other boats. The last time I purchased batteries was April 2008 about a year before I first set-up my solar system.

Old 09-25-2020, 01:11 PM
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To help with replenishing your fuel system you could install momentary switch to drive a priming fuel pump, rather than battery supply to drive starter to (lot less currant draw) prime system. Same principal is used on 99% of automobiles manufactured today. Use fuse (s) in circuit directly off of battery not through ignition system, as pump could kick back when disconnecting. (magnetic discharge)
Old 09-26-2020, 05:05 AM
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