effectiveness of solar & wind

[camaraderie]

Yeah...you can mitigate the damage getting 180 degrees but that is not possible on most sailboats. You may have a different situation and it is still 8hp of pull on a small engine. The other way is to extend the shaft of the pulley block forward into another bearing (mounted to the hull no the engine) to relieve about 1/2 of the load. (note:this was advice to ME from Don Casey when I was looking at this issue...don't wanna seem like I am the authority on this and he is due the credit for the advice.)
FWIW he guaranteed me I would have bearing problems if I simply used a 200A single alternator to double pulleys.
So...I guess you do what you can to mitigate the damage if you really need the amps....and again...this my not even be an issue once you get into larger engines with beefier bearings than the under 100HP stuff we generally discuss on here.

[Cruisingdad]

Other than the fact that it is not good for your main, I think the biggest issue would be the 8hp loss. If you are in a strong current, that could be a problem on many boats.

[sailaway21]

Cam,
If I may? I do not think the problem is that the alternators are not 180 degrees opposed. After all, look inside virtually any auto. The alternator, air pump, a/c compressor are not equilateraly opposed. I think, from your other comment, that the problem is more one of finding a very secure way to mount the second alternator. If it flexes, you're gonna schwanz it. Stock components on the block have attachment points right in the casting. I would posit that the install is not impossible, but merely very difficult without the aid of a machine shop and professional fabricator.

[sailaway21]

I was more than a little serious about the battery in the keel idea. I think a good chemical engineer and a tool and die maker could have a field day with the idea.

Here's another one. We've all seen the keel on Giu's boat, and been sworn to secrecy about same. Imagine that the bulb was hollowed out longitudinally. One could mount a venturi tube with an impeller in there. Viola!, a water generator. And yes, properly designed the debri could be kept out.

[camaraderie]

Sailaway...I agree about the need for a machine shop/mechanic. The difference between the items you mention and a 100 amp alternator is that you are looking at a 4HP takeoff on those bearings...much more force than an A/C. Either way though as you say...not very practical.

[sailaway21]

Actually A/C will knock off about seven HP on a four cylinder engine under load. Alternators are not as bad as generators or A/C because they, well, alternate.

[Idiens]

Looking at the Yanmar twin alternator installation, it looks pretty robust to me. Instead of a second alternator an Aircon pump can be fitted, and I bet that can pull a bit of hp too.
However, my idea was to get the most from the typical 30 minutes engine running out of harbour and 30 minutes running back in. Mostly, the full 200A would not be taken, so the hp loss to the propellor would not be so significant. If hp loss were a problem, there are ways to trick the alternators into thinking the batteries were full(er) and not pump 200 A or any at all. Then there is only the friction loss from the installation.

[PBzeer]

With my new alternator (70 amp on a 13 hp motor), and external regulator, part of the installation was a 3 position toggle switch. This allows use of the external, internal, or freewheel. Even with the built in ramp up time for the alternator to kick in, I've found in colder weather, that I needed to switch to freewheel on startup, until the engine had warmed up. It came in the most handily though when I was traversing a lock with a very swift opposing current.

[Cruisingdad]

Hello All,

Been out enjoying Spring Break and testing out the new systems. At the risk of sounding like a schoolboy who just got back from Xmas (and bragging about his toys), let me tell you about the panels: Awesome!!!

I basically kept my batteries floating or full the entire time without the need for any outside electrical generation. Saturday, which was partially sunny during peak charging, I still put out 176 amps for the day. The day before I am not sure because they filled the batts and went into standby.

There are only two issues I should mention. The first I have brought up before: Making a passage. With the Chartplotter running, radar, autopilopt, microwave, etc... I will seriously dig into my batts. Somewhere close to 200/day is probably realistic, unless you really use a lot of conservation. Thus, underway, my batts will slowly deplete even with the panels. Second, Hot water may become an issue. I did not (and have not) planned that into my budget. We always ended up having to run the main or genny before to generate electricity (and would in turn generate hot water too). Going for days without running them will deplete your hot water. I have some ideas about this, but before I go into anything too drastic, I will wait and see how the warmer weather reduces hot water use. It was quite cold this weekend (well, for Texas). Anyone trying to be completely off the grid should be aware of that.

I made a point to try and remember many of the exact numbers for this discussion (which I subsequently forgot about happy hour everyday), but I would generate about 3-4 amps shortly after after sun up. By 930 that number was 6-8 amps. It quickly jumped exponentially from there. By 1130-200, we were putting out well into the low 30s. In overcast, our output dropped about 20-30%, but would jump back up as the sun broke through the clouds.

I have not changed my electrical budget for the panels from 150 ah/day. However, I can see it is quite possible (and likely) I may exceed my budget. I am hopeful that the wind generator will pick up any slack the solars cannot. I should have those answers for everyone soon.

- CD

[Idiens]

Sounds great CD - what are the dimensions and weight of those panels again?