Solar panels to maintain/charge a battery

[BamaAlum97]

I have seen several varieties of solar battery chargers that are intended to maintain your battery over long periods of inactivity. Does it make sense to keep one of these on your boat and set it up while out on the water to avoid draining the battery with the stereo and other accessories?

I have even seen one model that claims to charge/maintain your battery through the 12v plug and not require using clips to the battery. Would that work?

I have a single battery system and often anchor up in a cove and spend several hours swimming and lounging with the radio on...My plan would be to pull out this panel...plug it into my 12v and let it maintain the battery while I am at anchor. Worst case, I would lift the hatch and make the attachment to the battery assuming the cables were long enough. I know this probably won't charge a battery from dead...but if the battery is good to begin with, this should maintain it while I am at anchor with the engine off...correct?

Does anyone do this or something similar? Don't want to waste my money if it won't work...my plan B is to keep one of those self contained jump start units in the boat.

 

[Sharkfighter]

Re: Solar panels to maintain/charge a battery

I dont know the brand of my solar panel. Came with the boat and is hooked up to a third battery marked "Emergency". I wouldnt trust it to power all my electronics. I think it is just enough to keep batteries from going dead without use for prolonged periods not while running electronics.

I carry a jump start unit that cost like $70 if i remember (been awhile) for backup.

Rob

 

[bhammer]

Re: Solar panels to maintain/charge a battery

It'll never give you enough juice off the solar to keep it maintained while running accessories. If you are worried about a single battery, buy a jump box and keep it on board.

 

[Silvertip]

Re: Solar panels to maintain/charge a battery

A solar panel that can actually "charge" a battery while simultaneously running high current draw accessories would need to be the size your boat and cost nearly as much. The sale catalogs you see with solar panels for sale cheap are simple battery maintainers. They are good for nothing more than keeping a battery topped off during long periods of storage.

 

[Nandy]

Re: Solar panels to maintain/charge a battery

You should probably invest in a second battery. I have had 2 batteries setup in every boat that can handle the weight of the second battery. Have a cranking battery for your motor . Have a deep cycle battery for all the other electronics. This way you will have little chance of running out of power for the motor battery which is what matter the most. They sell a phase charger that you can connect between the 2 batteries. When the boat is running this charger monitors your motor battery and whet it is charged it switches to the second battery to charge that one. If either battery dies you can use the other to get you to the shore, it is a matter of moving the battery or connectors. If you want real ease then you install a battery switch. This will allow you to switch between batteries to crank your motor and even connects the 2 batteries together depending on how you wire it.
Good luck!

 

[Action]

Re: Solar panels to maintain/charge a battery

I use a 1.8W small panel that plugs into the 12V outlet, I just leave it plugged in while I am away from the lake, just keeps the battery topped up as there is an auto bilge, etc. That's about all it is good for.

 

[crazy charlie]

Re: Solar panels to maintain/charge a battery

Solar panels are good for a trickle charge to keep the battery "topped off".To accomplish what you desire ,you will need a very expensive,very large solar panel...........OR...................... a second battery. $39 at Wally world.Charlie

 

[grego]

Re: Solar panels to maintain/charge a battery

solar panels are great! when you out all day and need power. They will put out several amps,enough ,to charge a low battery. I have several, " one to starting batt,one to trolling batteries. one to wetjets. These chargers put out enough power to burn a battery if left on for a long time!!!! Not maintenance chargers! Or not the ones I have that put out 40 amps in sunlight.

 

[bhammer]

Re: Solar panels to maintain/charge a battery

put out 40 amps in sunlight.

40 amps or 40 amp hours??? Huge difference there. What ones do you have? I have seen some 3 & 4 amp panels but they cost $500 to $1000 and would be too big for most boats.

 

[Nandy]

Re: Solar panels to maintain/charge a battery

40 amps or 40 amp hours??? Huge difference there. What ones do you have? I have seen some 3 & 4 amp panels but they cost $500 to $1000 and would be too big for most boats.

Im also very interested in the tech sheet from that solar charger. Regular marine quality chargers with 2 10amp banks go for over 150.00. What is the brand/model? Im a bit skeptic....

 

[Action]

Re: Solar panels to maintain/charge a battery

solar panels are great! when you out all day and need power. They will put out several amps,enough ,to charge a low battery. I have several, " one to starting batt,one to trolling batteries. one to wetjets. These chargers put out enough power to burn a battery if left on for a long time!!!! Not maintenance chargers! Or not the ones I have that put out 40 amps in sunlight.

I have solar power at my cottage, the panels are big, 130Watts and when the sun is shinning directly on them they are taking in 4-8amps, no way is it 40amps. Most panels that would fit on a boat would not be big enough to power much, more or less they are just there to maintain the battery.

 

[jennis9]

Re: Solar panels to maintain/charge a battery

I have a small 12v one like Action mentioned. It is good for a light trickle when you have no access to a power cord. I wouldn't count on it for anything more. I have currently been using this small panel to keep the standby light from the stereo from draining the accesory battery (number 2) -- still topped off after three weeks of sitting idle.

But we also have a second battery hooked up to its own bank for our accessories.

 

[BamaAlum97]

Re: Solar panels to maintain/charge a battery

The unit I was looking at is 2.25watts...or 150mAmps. I know it is mearly a battery maintainer...I just did not know if that would maintain the battery while running the stereo.

I appreciate all of the replies.

 

[cwhite6]

Re: Solar panels to maintain/charge a battery

As an EE working in the power field, I have some doubts about the 40 amp claim. That would be enough to run a small A/C unit. Not gonna happen unless the panel is the size of a house roof. We install large ones on some control house roofs, and they are no where near as efficient as claimed by that post.

 

[Action]

Re: Solar panels to maintain/charge a battery

The unit I was looking at is 2.25watts...or 150mAmps. I know it is mearly a battery maintainer...I just did not know if that would maintain the battery while running the stereo.

I appreciate all of the replies.

You would be amazed at how long you can run a stereo on a boat, car etc before discharging the battery. You also have to keep in mind a marine battery is formulated to take many discharges, more so then a normal car battery. A stereo head unit lets say with 4 speakers is going to use a lot more watts of power and take a higher draw then the panel will provide. On your MPI motor the alternator I believe is 60 amps, so a quick ride around the lake and that is charging your battery a fair bit. As I said I use my panel only when I leave the cottage just to keep the battery topped off and because it has an auto-bilge.