Solar Power

[teejayevans]

Originally Posted by cat49

What are some of the average amount of amps you can expect from a solar panel setup? I am thinking 780watt solar systems.....the ones from talco electronics, they have 390watt kits X 2 equals 780 watts they say they can generate 96-120amp/hrs per day....is this realistic? on the low side? on the high side? for cruising in the tropics. i want to try to get as much electricity from solar as possible.

On a clear 11 hour day, my 186 watt panels will give me 60 ah IF I make the effort to adjust the panels during the day to try to prevent shadowing and try to stay oriented to the sun. 2 are mounted and 2 are loose that I move around. Output goes something like this:
1st hr: 1 ah
2nd hr: 3 ah
3rd hr: 5 ah
4th hr: 8 ah
generally I rarely have them all aligned, so I top out between 8-9 amps, sometimes get 10+, if batteries are charged, then the some the ah get wasted later in the day.
If you are lazy or fix mount your panels, your output will be much lower.
Tom

[Cotemar]

vbrent,

Solar panels last for 25 years. No Solar Panel companies do marine environment life testing, because it’s to expensive and the market is very small, so they do not warranty for marine use.

SunPower as most other solar panel makers do not have marine installers. Marine solar installs are a DYI project. Not very hard to do. All the info you need is in the Controller manual for wiring and setup.

Mark

[Mark Johnson]

I've never heard of IQ panels, but of the commonly available low V panels, (meaning, not for direct High V grid connection), Single crystal (= made from slices of a single crystal rather than chopped up pieces of crystal), polycrystalline, and amphorous, The panel with the most power for it's size, is by far the single crystal type. It is also the most expensive. A good power to size ratio is WELL worth it on a boat, where space is so precious.

The flexible roll up panels seem neat, but have to be HUGE to equal a single crystal panel, and the flexible thin panels have less than half the lifespan.

The best place to look for good solar panels, is not necessarily the marine catalogs, but back to the land, "off the grid cabin" catalogs. M.

[Cotemar]

For a Cat solar panel system you need the most watts in the smallest, lightest panel.

Read all the spec's you can find.

SunPower was by far the only panels I could find that meet that Most power in the smallest lightest panel criteria

[schoonerdog]

You're working this backwards. First, figure out your daily electrical draw. Refrigeration and freezer will by far be most of that. In the tropics, 5amp refrig cycling 1/3rd of the time would be around 80 amp hours per day. Once you do have this, then multiply the amp hours per day needed by four and that will give you a good ballpark for the total watts of solar panels you would need. We've got a similar system to the one you want to build, ours is 700 watts and provides enough power for lots of lights and a 110 liter freezer and 130 liter refrigerator. Remember, you need to plan the entire system as well. An outback mx60 couldn't really have more than 800 watts of solar panels. And to use that I needed to install two runs of 8 ga wire between the panels and the charger. Cats have very long wire runs compared with monos. It's easy to say "I've got the space for X number of solar panels" but when you look at the wiring needs, the limits of the MPPT charging systems, voltage limits (you don't want to go too high), there is definitely an upper limit to solar panel systems on boats. BTW, your battery bank size is dictated by your amp hours that you consume and the period between charging cycles. So my solar panel system allows me to actually reduce my battery size, as it only needs to provide power at night. A regular battery bank charged by a generator would need to provide power for at least 24 hours between charging cycles.

[schoonerdog]

BTW, I get in full sun around 35 amps for I'd say from 10am to 2pm during the peak hours in summer.

[cat49]

who sells the sunpower E19 panels...i looked at the specs they look pretty good.

[BjarneK]

I have no personal experience with these, but Sanyo apparently makes some quite efficient panels: SANYO :: HIT Power and HIT Double :: HIT Power. The HIT Power 205 claims 17.7% module efficiency.

[noelex 77]

Originally Posted by Mark Johnson

T
Our 280W of solar panel power total, from 4 panels, well separated, and one usually a bit shaded... Give us a max of about 60 Amp/Hours per day on a REALLY good day.

It may be worth checking they are all working. With 330w solar a good day for us would be 150AHrs. A few days ago we had 75AHrs and that’s in the middle of winter in Europe That’s seems about double the output watt for watt that you are getting.
The photos show the locations of the panels on your boat are a bit prone to shading, as you mention, which may be the cause, but it still seems a low output. (I assume you are referring to the solar panel output (at 12v), not the maximum your batteries will take which is more to do with consumption)

[Cotemar]

cat49,

I purchased my SunPower panels from www.Munroelectric.com in Boston Massachusetts.
They shipped them directly to my home in Connecticut.

Contact Jeff Higgins jeffh@munroelectric.com direct line 508-536-2149

http://www.munroelectric.com/silvereclipse/index.jsp?path=solar_products&prev=solar&altLM=sol ar

Mark

[Mark Johnson]

Noelex,

Interesting point!

I was not talking about A/H measured at the panels. I was talking about A/H that were in fact put back into the batteries. This is measured accurately with our Link 10 battery monitor. (It counts the amps going in or out with a shunt in the - wire, right at the batteries.) Since we normally take our batteries from 100% charged, down to only 90% charged every day, and are basically topping off the last 10% with solar panels, the batteries are in the range where they can only accept a charge more slowly. This is why many people may choose to only bring their batteries back from a morning low of 60% charged, to 90% charged every day. The (wet) battery will accept the charge better in this range. It could be that if we tried the above range of charging, we would find that our A/H per day output, is actually better than I stated. Since our two Trojan L-14 batteries are around $500, we are going for battery lifespan, more than recharging efficiency. Along with our "Hydrocaps", we only add water 4 times a year, and expect a > 10 lifespan, used this way.

The original L-16s were a victim of my own complacency! The "Hydrocaps" work SO well, that I forgot the batteries altogether, and after about 6 months, they did run dry. So, they never wore out, I killed them! This is when we down sized from L-16s to L-14s. (From 380 A/H to About 340 A/H) My practice now is to add water on the first day of each season. It makes it easier to remember. If I used a deeper cycle and big alternator, my battery water monitoring would have to be several times what we now do.

Yes, we do usually have one panel with a dark shadow. The one on the back cabin top is under the boom! The one on the back rack, (110w), usually puts out the same amount of amps as the other three combined. It is bigger, in a better location, and tilts. (We have separate Amp meters on them to read their output.)

They are about 14 years old and getting cosmetic flaws, but the output is about the same as day one. I think the "just topping off" thing that we do, is the explanation.

Oh yes, I have said this many times elsewhere, but we have watched our amp meeters as it became overcast, and find that ANY light makes them work. A cloudy, sunless day, but REALLY bright, (like you need sunglasses), is almost as good as direct sunlight! Even the illumination of our LED anchor light creates a tiny bit of power.

Mark

The L-14 batteries in the photo, are before their Hydrocaps,each of which look like a large mushroom.

[Velma]

So can someone summerize please, must be my slow thinking Frozen Canadian mind....

Velma

[Southern Star]

Velma, Watts divided by Volts will give you AMPs. Hence, with a 12 V system, panels totallying 360 Watts can theroretically produce 30 Amp/hrs of charge. Theoretically because: 1. Your panels cannot be shaded. 2. these figures are calculated with the sun at an optimal angle (essentially, 4 or perhaps 5 hours mid-day). 3. the panels must be angled perfectly into the sun at all times. 4. There are internal losses through regulation, etc.

The numbers being quoted are from practical experience and are pretty much consistent, bearing in mind differences in geography, weather and mounting type and location on each boat.

Brad

[Mark Johnson]

The Watts divided by volts would not be figured at the boat's V, but the panel's. Just read the specs or lable on the back, for the panel's voltage. Most Panels are 17,18 or 19V.

Our 280 Watts total of solar panel (= all 4 together), with 14 years of age on them, figuring the wire, diode, and charge controler losses, with usually one panel shaded... and "A/H charged" meaning "how much actually went into my batteries"... We get 55 to 60AH on a really good day! 50 on an average day, and 35 A/H on a really dark cloudy day.

Mark

[Southern Star]

Thanks Mark for the clarification. My results with 240 watts (3 X 80 Watt Kyocera panels mounted between the davits and essentially unshaded) run about 45 to 70 A/H depending upon the amount of sunlight. I am going to add 2 more 100 Watt panels, but as these will be mounted on the bimini, they will be much more susceptible to shade and hence less effective. Still, not bad for something reliable, silent and relatively cheap.

Brad