New Solar Panels

[Lance Jones]

Woo-hoo! Scored two 40 watt panels at the Miami Boat Show. That will give me a total of 120 Watts when I install them along with my current 2 x 20 watts. Now my question. I'm not an electrical guru. Is this an adequate amount of wattage to charge me batteries while on the hook? We traditionally don't use a whole lot of juice while on the hook especially since I've converted to all LED interior and nav lights. I guess our biggest draw is either our fans or TV.

[Rick Johnson]

Lance,  When I had a single 100w panel it could not keep my battery bank charged while I was using my normal lights and the refrigerator.  I added 2 BP 40w panels ($155 each) and now the batteries stay topped off as long as the days are sunny.  My 180w vs your 120w, my guess would be "ya need more power!"  But obviously, it all depends on how much power you use and how sunny it is...

Don't forget the diodes...

Cheers,

Rick

[Lance Jones]

Thanks Rick! Diodes included btw. I plan on getting mo powa as time goes on.

[Stu Jackson]

Now my question. I'm not an electrical guru. Is this an adequate amount of wattage to charge me batteries while on the hook?

Lance, congratulations on your new panels.

In answer to your question, we have no clue.  No one can answer that question but you.

I suggest, without being an electrician, that you can do simple math, so why not try doing an energy budget.  The way to do that, with a simple form, is right here:  http://c34.org/bbs/index.php/topic,3976.0.html  West Marine has one, too:  http://www.westmarine.com/Images/wa/Elecbugt.pdf

You put in what you use, including the size of your battery bank, and add in what your charging sources put back in to find the answer.

If you need to know what your solar panels can input, either check the instruction manuals you got with them (my old UniSolar panel had a great calculator for that) or go to the West Marine Advisors and see what they have to say about solar panel input.  Here: http://www.westmarine.com/webapp/wcs/stores/servlet/westadvisor/10001/-1/10001/Solar-Power.htm

Steve Dolling also wrote about his solar panel regulator.  Do you have one?

Here's an earlier solar story:  http://c34.org/bbs/index.php/topic,5137.0.html

[Lance Jones]

Thanks Stu!

[cmainprize]

Hi Lance
FYI, I had a single 130 watt panel on my old C30.  All lights were LED, but the fridge was always cold and even made ice.  I never plugged the boat in unless we need 120 volt power.  The panel ensured we always went to bed with full batteries and it seemed whatever power we consumed during the night was put back in to batteries before lunch.  I can only think of the rare occasion when we ran the engine to charge the batteries after sitting on the hook for three or four days if was very cloudy or late in the season (low sun).

Our C34 has two 125 watt panels and a bigger battery bank, but the kids like to watch movies at night and they are in the fridge all day

[Ron Hill]

Lance : With that many Watts solar power, you'd better consider a solar V-Regulator.

When it gets cloudy, I just pull out my little Honda and don't have a problem.  It's much more prudent to run that $800 engine than it is to run that $9000 engine - which BTW doesn't really like to run at a fast idle.      A thought

[prh77]

Ron;

      I could not agree with you more. With all the $ that is put into high output alternators and high tech regulators, and all the questions about belt alignment and tension, not to mention the issues of carbon build up and cylinder glazing due to runnining our engines at 1700 rpm to charge the house bank.......give me my Honda generator.

[Ron Hill]

Guys : Don't want to give the reader the wrong impression.  
The expensive hi output Alternator and the Voltage regulator pay for themselves when you do what most of us usually do - just stay on the hook overnight.  When you start the engine in the AM, pull the anchor and motor out to where you can hoist the sails - those expensive charging items have done their job and the batteries are fairly well up to charge.  OEM chargers wouldn't even be close to getting the batteries back up to charge.  
It's when you decide to stay on the hook another day or two, is when the Honda does it's job (Sun or NO Sun).