Setting up solar panels, need advice.

[caguy]

I am installing a couple of solar panels on the C27 with a 12v system. I have two group 27 batteries on the boat hooked up with a master switch. I would like to charge both batteries.
Should I hook up the + lead to the center post on the master switch and leave the switch on the 1 and 2 setting? Is there an advantage to running on one battery at a time? Does discharging one battery at a time last longer than both at the same time?
I assume that in setting up the solar cells I wire them parallel and not in series. Am I correct? Just want to make sure.
I'll have the admiral on board all next week and there is no room for a fubar.

 

[zeehag]

my ericson has a breaker switch just for solar panels and i can turn em on and off as i so choose...works great. i charge both banks at same time.

 

[Sumner]

Frank do you have specs on the panels and controller? Voltage, amps? Controller type?

We use and charge with both batteries and panels in parallel and also have a single double pole switch that takes the panels and charge controller out of the circuit. The switch breaks the circuit on each side of the controller. Not absolutely needed, the Blue Sky tech recommended it to me.

Sum

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[caguy]

Zee, I was thinking about you the othe day. Oddly enough it came up when I was looking for information on the solar cells. I came across an extensive article on a female solo cruiser (Rebecca Burg). Thought you might enjoy it.

http://www.artoffshore.com/solosailorgirl.html

 

[zeehag]

ty for the linky---she is an interesting soul....cute lil boat , too--looks like a bayfield....

 

[Bill Roosa]

A single large battery bank will cycle each battery less which increases the number of cycles you will get from them. It also leaves you with no back up soooo.... I always run on both and if I see the situation developing that will leave me with not enough power to start the engine (in the morning usually) I reduce power consumption and switch to 1 or 2 so the other is backup.
If you want to charge both batteries all the time AND want to only discharge a single battery (or both) you are out of luck unless you want to add some additional components (diodes, solenoids, switches etc)
Honestly I would wire the solar panels (in parallel if they are 12+ volts each) to the Common output of the three way. It is simple, allows you to charge/discharge an individual or both batteries and requires no additional components.
I should warn you that you are not going to get a big boost in battery life while you are on the boat and using the electrical appliances unless you have a very large set of panels. solar does great after you reduce the load to balance production- consumption - storage.
There is a spread sheet in the downloads section that can help you figure out the loads - production - storage values.

 

[Mike B1026]

You may want to check this controller out. I have one and have had several customers that bought them:


http://www.morningstarcorp.com/en/sun-saver-duo

It will charge both batteries at the same time plus you can configure the way it charges and even for different types of batteries.

 

[jviss]

A single large battery bank will cycle each battery less which increases the number of cycles you will get from them.

I don't understand what your are trying to say with that. Perhaps you mean that you'd discharge the batts less deeply on each cycle, which might prolong life?

Honestly I would wire the solar panels (in parallel if they are 12+ volts each) to the Common output of the three way.

Are you saying wire the panels directly (and permanently) without a charge controller?

I don't get idea of connecting the panels to the common. This would mean with the switch set to off that the panels would be driving the loads without the batter, potentially presenting an over-voltage condition. If the switch is left on, at night the panel could discharge the batteries.

 

[jepomer]

If you have two separate battery banks, you would want to keep both charging. Connect one solar panel to one bank. Connect the other solar panel to the second bank. This way both banks will charge.

Unless the solar panels are small wattage (less than 15 watts), you will need a charge controller for each panel. The low cost ones will be okay for simply topping off the batteries if you are away most of the week. The MPPT is the best method. The PWM is acceptable alternative.

Read this article (http://www.pbase.com/mainecruising/solar_panel) for more useful understanding.

 

[caguy]

Thanks for all of the info. I found some good videos on pwm and may use that in the future to save on electricity.
I checked the wattage on the two solar panels I am using an the produce about 15 to 20 watts each. I have them hooked up to the old battery that I just replaced to see how they perform. Yesterday they charged from 11.94v to 12.25.
I left them hooked up over night to see if they have a diode built in.
As far a cycling is concerned I will probably just leave them connected the whole time.
I will set them on the cabin roof just forward of the mast after I get moored.

What guage wire should I use to run from the front deck to the master switch its about 12'?

 

[rardiH36]

I am not sure that I understand the reason why you just don't wire one solar panel to one battery and the other to the other... solar charge directly to the battery before the AB switch. That way when you are off the boat and the switch is in the off position, each battery will charge independently. From what I have read, a 20w panel is large enough that a charge controller is needed. Panels will generally output 18V in full sun. Too much for a battery unless the panel is just a very small 5-7 watt type. I've been having good success for the past few years with one 20W panel feeding into a dual battery charge controller which meters the charging independently to each of my two group 27 batteries. Since you have two panels, then you could get two single controllers instead.

http://www.amazon.com/HQRP-Duo-Batt...026389&sr=8-11&keywords=duo+charge+controller.

Morningstar also makes a duo type controller if you want a brand name.

 

[caguy]

I am not sure that I understand the reason why you just don't wire one solar panel to one battery and the other to the other... solar charge directly to the battery before the AB switch. That way when you are off the boat and the switch is in the off position, each battery will charge independently. From what I have read, a 20w panel is large enough that a charge controller is needed. Panels will generally output 18V in full sun. Too much for a battery unless the panel is just a very small 5-7 watt type. I've been having good success for the past few years with one 20W panel feeding into a dual battery charge controller which meters the charging independently to each of my two group 27 batteries. Since you have two panels, then you could get two single controllers instead.http://

I thought by hooking them up in parallel that I could get more amperage out of them. I like the idea of the duo charger and the price seems right. I just ordered it.
The plan was to leave the master switch on both and turn off the swithc panel switches. I have an anchor watch app on my droid so I don't need to run the electron thirsty Garmin. I wll likely be moored this week so dragging is not an issue.

 

[Stu Jackson]

Frank, you should never wire a charging source that requires you to leave the switch on when you're away from the boat.

 

[Sumner]

Probably late since you ordered a charge controler, but?? I think you are running an outboard? If so and elect. start can you pull start it?

If so I'd run the batteries in parallel and the panels the same as then you will get the most use out of the panels and batteries. I'm not crazy about one panel for one battery and the other panel for the other battery if you can get around that. Let's say one battery gets used very little. Then the panel to that battery could of been used to charge the other one. A waste of available charging capabilities. Since your panels are so small it probably doesn't matter much, but if they were 40 watts or larger each then I would like to be using them to their full potential and also the same with the batteries. They will last longer and charge better if in one bank.

If one has a start battery and you need it (no pull start) then use a combiner (ACR)...

http://www.defender.com/product.jsp?path=-1|328|51495|299265&id=750182

... to keep the start battery charged, but when it is charged then all available charging will go into the house bank.

Again since your panels aren't very large it isn't going to make too much difference what you do, but if you plan on increasing solar then something to think about that might influence which charge controller you get now.

Have a good time on the trip ,

Sum

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[caguy]

Frank, you should never wire a charging source that requires you to leave the switch on when you're away from the boat.

With that Duo charge controller I won't have to.

Sum, I have to check the motor. It is a pull start and starts easily. I added the electric start to it and of course it has the magneto but I don't recall if it has the diodes for charging the battery. I'll have some time to screw with that stuff before the admiral gets there on Tues, although cleaning and preening before she gets there will take precedence. If I sound hen pecked it's because I am.

Checked my test battery and it is up to 13.94. I'll take that group 24 battery as a backup.

It's amazing how much work goes into a week of relaxation.

 

[Sumner]

..Sum, I have to check the motor. It is a pull start and starts easily. I added the electric start to it and of course it has the magneto but I don't recall if it has the diodes for charging the battery....

The point I was trying to make was that if you can start the outboard if for some reason the batteries died that you don't need to charge and use them separately. Keeping them and the panels together has lots of advantages.

.....It's amazing how much work goes into a week of relaxation.

Ain't it fun relaxing , we have been working on the boat for over 2 months, got 2 weeks worth of work in :cry:, and still won't get it in the water this trip and also will leave with a lot of work to do when we return. I guess that means we are really relaxing ,

Sum

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Our Endeavour 37

Our MacGregor 26-S Pages

Our Trips to Utah, Idaho, Canada, Florida

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[rardiH36]

Just to mention, look into some fuses like in your diagram. One close the the panels (which you are wiring in parallel) and one for each of the wiring between the duo charge and the batteries. I think.

 

[vtsailguy]

I am just about to start this same project.

I was wondering to myself, many of these panels come with a cigarette plug, male. Can this just plug into out cigarette female sockets that is in the boat and skip the need for messing around with any wiring?

 

[jviss]

I am just about to start this same project.

I was wondering to myself, many of these panels come with a cigarette plug, male. Can this just plug into out cigarette female sockets that is in the boat and skip the need for messing around with any wiring?

Yes, but: you should still have a controller, if for no other reason than to prevent boiling your batteries.

 

[Ron20324]

... Can this just plug into out cigarette female sockets that is in the boat and skip the need for messing around with any wiring?

Read the West Advisor.