AC/DC Setup with On Board Charger and Solar Panel

[Coolbud01]

Greetings,

I'm trying to picture how I should go about setting up my charging system with an additional solar panel to provide power both while in the dock and out on the water.

My current setup is a 24' Invader V250 with one cranking battery and one house battery with a 1/2/ALL selector switch between them and no charger. There is no isolator between the two batteries and the single altenator. There is shore power available but with no genset. No AC-powered equipment will be needed while on the water, however I want to continuously run a small DC fan and the stereo for 8+ hours.

1. Will a 5A on-board dual-bank battery charger be enough to charge both batteries while on shore power, while having the DC fan and the stereo on? (sleeping on the boat overnight while at the dock)

2. Will a 3.5A solar panel (no regulator) be enough to operate the stereo and DC fan for 8+ hours while on the water while providing some charge to both batteries, assuming strong sunlight? Do I need to add a diode for a small panel like that?

3. How and where do I wire up both the on-board charger and solar panel? I understand how to hook up one or the other individually, but are there any problems with having both? Will a switch be needed between the two?

Thanks in advance - let me know if any additional information is needed.

-Tobias

 

[Coolbud01]

Re: AC/DC Setup with On Board Charger and Solar Panel

Update to question #2: I found a 100W/16.5V/6A panel for a few bucks more. Will either of the two work?

 

[Silvertip]

Re: AC/DC Setup with On Board Charger and Solar Panel

I hope you are quoting 3.5 and 6 AMPS correctly and not 3.5 and 6 WATTS. If the numbers you indicate are correct, with either of the two panels you need a charge controller. Solar panels cannot power anything by themselves. They need to first store the energy they develop in a battery bank. The battery bank then delivers the power to the accessories. Whether you can run 8+ hours on one battery depends on the current draw of the accessories you must run. Besides the stereo and fan, you also have interior lights, bilge pumps, nav/anchor lights and whatever else operates from the battery bank. I seriously doubt even a 6A panel will keep up with demand.

 

[Coolbud01]

Re: AC/DC Setup with On Board Charger and Solar Panel

Silvertip,

Thank you for the reply. Yes, they are 3.5 AMP and 6 AMP panels respectively. I know that the 6 AMP panel comes with a regulator and from there it goes to the battery bank on the boat. I picture the larger panel (I'm leaning towards purchasing that one, if this thread pans out) being able to provide a small charge to the house battery on the boat while the stereo and the DC fan pull power from that same battery. I'm sure that if I ran those few accessories continuously then I would eventually kill the house battery. But with the additional 6A charge from the solar panel, would it be enough to maintain that small of a load for 8ish hours with good sun then plug in the shore power to recharge the house battery with the on-board recharger?

With my envisioned setup, would I end up wearing out my wet-cell batteries with that kind of discharge cycle?

Is there a better setup for what I'm envisioning?

Thanks again,

Tobias

 

[Silvertip]

Re: AC/DC Setup with On Board Charger and Solar Panel

Away from 120 volts AC shore power you are limited to a Genset, solar, or a large battery bank. Solar does you no good overnight. It can only deliver 6.5 amps in full sun. That's 6.5 amps/hour with no losses. We can't answer your questions because we don't know what the current draw is for the accessories you plan to run. The current draw is usually provided on the equiment label. Add them up. If the total is more than 6.5 amps the panel cannot keep up. I personally feel solar panels are a waste of money on a power boat. The alternator on your boats engine (an I/O for example) is 60 amps or higher. Start the engine, set it for a slightly fast idle and use the switch to top off that battery if you need to -- that's what the switch is for.

 

[Boatist]

Re: AC/DC Setup with On Board Charger and Solar Panel

I agree, solar panels normally only good for maintaining a battery when it has no load. also solar panel only puts out max power if is is pointed directly at the sun. If it is on top of a top or deck it will only put out full power if the sun is straight up. In the morning and evening it will not put out much.

Also a fan can draw 1 amp to 20 amps. Stereo can draw 100 amps for a high power stereo with sub wooffers, or very low amps with a small radio on earphones.

I have not seen a solar panel work well on a boat as they are hardly ever pointed directly at the sun.

 

[Coolbud01]

Re: AC/DC Setup with On Board Charger and Solar Panel

All,

Thanks for the replies and the suggestions. I'm now thinking that with two new batteries (one for cranking and one deep-cycle for house) and an isolator between them and the altenator, I should be good for a day on the water as long as I start the engine every few hours and top off the charge. Any recommendations on chargers? I still want to have the boat plugged into shore power and be able to use my DC system without draining the batteries, perhaps even charge them while using various accessories. The AC system isn't used for much, just a few outlets downstairs and the electric portion of the stove. Everything else is 12V.

Thanks again for the knowledge,

Tobias

 

[Star]

Re: AC/DC Setup with On Board Charger and Solar Panel

THANK YOU FOR ALL OF THE INTELLGENT ANSWERS!!! I am so tired of these baseless dreams to power their lives from the sun. Optimistically a battery charges at a rate of 70% efficency. The cost and weight of a real functioning system with controller is out of sight for most of us.