Only Solar

[GordMay]

Solar Conference
Solar Power 2006 ~ October 16 - 19 at San Jose, Ca, Convention Centre
The Solar Electric Power Association (SEPA) and the Solar Energy Industries Association (SEIA) invite you to join us at Solar Power 2006 to find out what's new under the sun in the areas of solar technology, energy policy, and market opportunity.
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More Information: http://www.solarpowerconference.com/

[rtbates]

I totally agree with all you say about limiting power requirements and solar. My only disagreement is in losing the inboard diesel. I'd never toss Seraph's little 1GM for an outboard. Having that diesel is what,IMHO, turns a boat into a tiny ship. Besides with my Cape Dory's overhangs I'd have the OB prop in the air half the time coming over swells. I do appreciate that nice big storage area you now have! Glad it's working for you.

[rebel heart]

I had a 75w panel on an Ericson 32, and it worked out really well. Got 4.5 - 5.5 amps out of it with the sun shining just right.

It all comes down to how much power you need to replace, so don't get mad at solar because it can't generate enough juice to make up for your over budget electrical needs.

[Lancerbye]

I would like to put in solar panels, but the efficiency will have to increase before I will find them a viable power source in the Pacific North West( Canadian Portion). Not quite enough sun. For now I rely on high output alternators when motorsailing and a 12KW quiet and efficient Diesel Generator when not. I also have two 4D AGM house batteries which will run a 2500 watt inverter for a fair while. In the process of changing Cabin lighting to LED to save on power.

[Charlesc]

Originally Posted by CSY Man

My 33' cutter rigged sloop have two 75 watt solar panels over the bimini top. Would not want to be without 'em:

They put out about 40 to 50 amps per day, enough to drive the compressor for the fridge/freezer...The Sun-Gods are cooling my beer for free..

I also installed 1 panel over the bimin.

1- 130watt panel and charge controler = 7.3 AH which runs my ice box kit at 4 amps.

[Sandero]

Speaking of high output alternators... such as 100 or 125 amp... What sort of output do they actually put out for others? I have a 125 on a MaxCharge612 and I never have seen more than 48amps.

I am told the alt output will depend on the engine RPM, of course. and the max output would be at something like 6000 rpms of the alternator ir I recal correctly and that would mean the engine is running very high RPMs in my case. Max RPMs is about 3000, but I never see more than 2800, perhaps because of the prop or whatever... and I normally motor at 2000 or so so it is 2/3 of the max speed and so I must be getting only a 2/3 opf the max possible output from the alternator.

This doesn't even consider slippage and belt tension issues.

Then of course the is the temp sensors which may also limit output. In the hot months the batts may get quite warm and pumping a lot og amps raises up the temp and that in turn cuts the alternator output back so the batts don't melt or explode I suppose.

How many amps do you see from these high output alternators under NORMAL charging conditions?

jef
sv shiva

[hellosailor]

Jef-
If you have a real 100A alternator, and it is connected to a real marine type (external) regulator, AND it is belted up properly with the right size pulley, matched to your cruising RPM...Yes, it can put out 100A.

The fine print: Most alternators are rated for peak output--and they can't sustain it. Look for a "continuous output" rating. Also, most alternators are smart enough to start cutting back when they overheat. In a car or truck, there's plenty of wind blowing through past the alternator. In a boat, a true heavy duty alternator will be using dual cooling fans--one in front, one behind. And, often using oversized diode array and heat sink castings, because heat kills.

Then there's the speed thing. Many alternator makers won't show you their output curves. Delco and ACDelco will. Some models, like the ACDelco CS130D (PDF somewhere in the ACDelco site) are designed to put out 45A at 1600 shaft RPM--and their full 100Amps closer to 6000 shaft rpm--and they'll run all day at 18,000 shaft RPM. They can literally run all day at 3x the speed which is required for full rated output.

So if you are designing an electrical system, and you know your engine will be turning 3200rpm for cruising, you can specify a pully on the alternator that will run the alternator at full output (6000 shaft rpm) when your engine is only turning at 1500 rpm. And, even at "full battle speed" with the engine pushing 4500 rpm the alternator can still run all day without any harm, without having to cut back power.

I mention that particular alternator because it has incredible specs, it was used in full sized cars and light trucks. MOST of the alternators on the market are not like that. They may need 5000 shaft RPM to produce full power, and by 10,000 they are burning out. And of course, those specs are in automotive use with automotive airflow cooling them.<G>

Like everything else, building a robust alternator that can handle a wide range costs money--and most buyers can't understand it.

I redid the electrical system for some friends a few years ago, and convinced them to spend the $100 that a local machinist wanted to make up a custom pulley, optimized so that full engine speed was still inside of what the alternator could run at--but just barely. The result was that we could charge batteries in HALF the time they previously had, using the same spec alternator (another Delco) but with the pulley matched to what the alternator and engine needed--not what some boatbuilder had handy on the shelf.

Battery temp sensors have nothing to do with the alternator output per se, they're just telling the regulator to stop killing the batteries. The alternator itself needs to be smart enough to throttle back when IT is overheating. Some are, some aren't. You have to pull teeth to get some of the data on this stuff.

So...spec the system and all the parts right, and you can get full spec coming out of them all. But that's not sexy enough to sell parts.< G >

[Sandero]

I returned to the boat this weekend and the both banks were completely topped up (link20 flashing). The alternator is an AmpTech which is a marine rated unit on a Balmar MaxCharge612.

I measured my flywheel which is 12" &#177; &#216; and the alternator pulley is 3" &#177; &#216; the engine speed range is typically 800 RPMs for idle and 2000 RPMs for cruising. If I am not mistaken the alternartor is turning 4x the engine RMPs or min 3,200 to 8,000 for crusing RPMs. I run the frig compressor at 1,500 rpms which would be 6,000 RPMs for the alternator.

I still think the solar charging confuses the alternator smart regulator. When there is sunlight the Link is reading 13v which I believe is the raised voltage from the solar panels via the regulator. The Link does not see the state of the batts but of the "system".

For example, when your alternator is in bulk the link will read 14.4 volts. That may be the charge at the batts, but the minute I turn the engine off the true state of the batts will be reflected and it could be 12.2 or 12 .5 depending on how deeply they are discharged. However if the solar panels are connected the MaxCharge 612 will see 13+ because solar regulator is trying to charge the batts and that is the voltage it uses to get the amps in. How can the smart regulator see the state of the batts when the solar panels are charging the batts?

What say you?

jef
sv shiva

[hellosailor]

Jef, I think you're on the right track, too many cooks spoil the soup. I'm starting to appreciate the concept of one MPPT controller with multiple inputs, designed so the left hand understands what the right is up to. I can't see any way that multiple separate regulators can avoid pranking each other, so to speak.

In your case, it might mean adding in a relay cutout, so that the solar panels are cut out when the alternator is running, allowing the more powerful alternator to work at maximum.

[senormechanico]

Originally Posted by hellosailor

Jef, I think you're on the right track, too many cooks spoil the soup. I'm starting to appreciate the concept of one MPPT controller with multiple inputs, designed so the left hand understands what the right is up to. I can't see any way that multiple separate regulators can avoid pranking each other, so to speak.

In your case, it might mean adding in a relay cutout, so that the solar panels are cut out when the alternator is running, allowing the more powerful alternator to work at maximum.

Disconnecting the solar during engine operation may cause the alternator to put out more current, but I seriously doubt it would be any more than what the solar contribution would have been. Further, there would not be any point to doing so as the panel(s) are paid for and not doing anything, while you are using more fuel to run the engine to charge the batteries.

One thing overlooked so far is the size of the battery bank. A big alternator with a smart regulator charging a small (or tired out) battery bank will not stay on bulk charge for long before tapering off the current.

Steve B.

[hellosailor]

Steve-
"but I seriously doubt " Remember, we are trying to outthink nasty little silicon minds. The integral regulator in a typical alternator has at best only one criteria: What is the battery voltage?

And for those makers who have used a "one wire" installation with no sense wire to the battery, not even that. In that case the alternator just puts out power mindlessly.

But for a typical alternator with some kind of sense wire...if that sense wire sees 14+ volts coming into the sense wire, it doesn't know whether that is from the panels, or the battery, or itself. So, it throttles back right away. Probably. Without knowing what logic was being used by which parts of the charging system, I wouldn't bet on whether the solar panels were a net gain or loss while the alternator was running.

Some on now, when hasn't a wee little silicon critter missed a chance to stab one of us in the back?

[hellosailor]

Steve-
"but I seriously doubt " Remember, we are trying to outthink nasty little silicon minds. The integral regulator in a typical alternator has at best only one criteria: What is the battery voltage?

And for those makers who have used a "one wire" installation with no sense wire to the battery, not even that. In that case the alternator just puts out power mindlessly.

But for a typical alternator with some kind of sense wire...if that sense wire sees 14+ volts coming into the sense wire, it doesn't know whether that is from the panels, or the battery, or itself. So, it throttles back right away. Probably. Without knowing what logic was being used by which parts of the charging system, I wouldn't bet on whether the solar panels were a net gain or loss while the alternator was running.

Some on now, when hasn't a wee little silicon critter missed a chance to stab one of us in the back?

[sv_makai]

Sorry about the slow response, been off working on Makai. I agree with GordMay. Solar panels are not the best thing for a boat, but the other choices aren’t that great either. But our goal was to be able to sit indefinitely without having to run a genset for anything and not live like we are in a cave.

The link and the remote display for the solar charger SB50 (50amp version) are somewhat redundant. That is why I would not spend the money for a dedicated display if I already had a separate battery monitor. The link doesn’t control the solar panel charging just provides a display. The overall controlling is done at the solar charger box by the system setup. After that it is automatic, with the exception of equalizing. A button the charge controller turns that function on and off. The dedicated display panel is neat for a while as it can tell you what the input and output amps/volts are directly from the controller. Except for setting the system up is was of little use and the money could have been spent elsewhere.

Makai caries the 4 Kyocera 120s permanently fixed to the bimini top. Because they are laying on the bimini they are at a slight angle running from the outside of the boat in. Are peak amperage is 32-34 daily. It has hard to provide an average as the 680amp battery bank was almost always on float by 10-1030 every morning. Even cloudy days still generated 15-20amps peak.

The normal process was to use the battery power all night, get up talk on the SSB, make coffee with the drip coffee maker, etc. As soon as it starts to get light around 0600 ish the panels would actually start to generate some usable current. Around 1030 the batteries were floating. At this point we would turn the watermaker on for a couple hours and charge anything that needs it. Usually stopping about 1200.This basically diverts the excess amps that are available but not being used t charge the battery banks to operate other devices without draining the bank. Usually by 3PM we would be floating again. With a goal of always being fully charged as the sun goes down.

As with most things more solar is better if you have the space or can afford. I actually designed our system to be able to upgrade the total watts/amps with out having to rewire. Just add a second charge controller. I am going to remove the 120’s and put up the 4-200 watt grid tie panels. They are not much larger in foot print with more output.

But that is just us

[GordMay]

Originally Posted by sv_makai

... I agree with GordMay. Solar panels are not the best thing for a boat, but the other choices aren’t that great either.

I think is Bil referring to my post:

Because Photo-Voltaic solar modules produce the most power when they are pointed directly at the unshaded sun, a boat is not an ideal site for a solar panel.

The optimum orientation of a PV module is determined by the sun’s inclination (tilt angle above horizontal), and it’s azimuth (angle clockwise from true north).

On a boat, it’s generally impracticable to avoid the deleterious effects of poor azimuth angle (1) and shading (2) effects; which leaves cruisers only one easily controllable criteria - Tilt Angle (inclination).

*1. The optimum axis value is an azimuth angle of 180̊ (south-facing) for locations in the northern hemisphere, and 0̊ (north-facing) for locations in the southern hemisphere. This normally maximizes energy production. For the northern hemisphere, increasing the azimuth angle favors afternoon energy production, while decreasing the azimuth angle favors morning energy production. The opposite is true for the southern hemisphere.

*2. Partial shadowing of a module should be avoided at all costs as the effect is a disproportionate reduction in power output. The cells in a module are in long series strings, where the current passing through each cell is the same, the effective output is thus determined by the cell with the lowest output.

For a fixed installation, a tilt angle equal to (or within 15 deg. of) the ship’s Latitude normally maximizes average annual energy production. Increasing the tilt angle (steeper) favors energy production in the winter, while decreasing the tilt angle (flatter) favors energy production in the summer.

If you have the ability to adjust your module’s inclination, the following tilt angles can increase you output by up to 30%.

Ship’s Location (Latitude N or S) ~ Tilt Angle (above horizontal)
0 - 10 degrees ~ 10 Degrees
11 - 20 degrees ~ Lat + 5 degrees
21 - 45 degrees ~ Lat + 10 degrees
46 - 65 degrees ~ Lat + 15 degrees

[rleslie]

Bil,

I find it very interesting that you are able to run a watermaker and keep up with your other daily uage with just 4-120w panels. That's great!!!! In my view, silent energy production is certainly worth the extra cost.

We have 2-120w panels run through a MPPT and even without a watermaker, find that we need to run the generator every third day. I usually adjust the panels twice daily if aboard....once mid-morning and again late afternoon.

I have mixed feeling about the Honda genset. Using it requires a larger charger and for us the noise is really annoying. But, when we're on the hook and need charging fast, nothing beats it.

Roger