Solar Power Shed Project

[patrick_g]

Griz, I think I understand the question. IF a itsy bitsy glass bead on the end type diode got bird doo on it would the tracker lose its mind?

Don't build it that way for that very reason!

If you put a few square inches (maybe a 1/2x2-3 inch) translucent screen with the diode positioned to "see" the screen then a fleck of doo doo on the screen obscures a small fraction of the diodes illumination and it doesn't make much difference. If you hypothesize a "mud storm" (Brief rain during a dust storm) or some such then most optical trackers would suffer a failure. If you use an IR diode and an absorbent screen (at visible and near IR wavelelngths) then the diode would actually be reading the temperature of the absorbent screen like a non contact IR thermometer. If one of the screens began to be shadowed its temp woould go down constituting an error signal which would cause the controller to slowly drive toward rebalancing the detectors. The IR aproach is not nearly so bothered by a fleck of debis and might work failry well (recall you only have to be within several degrees not spot on) even with bird do on one screen.

Thre is no optical sensor that can withstand an arbitrarily heavy deposit of material on a sensor. I suppose you could have a reservoir of windshield washing liquid (not easily frozen) periodically sprayed on the sensors. IT wouldn't be perfect but it woiuld be better.

Alternatively you can adjust the tracker's positioin to maximize the area of the shadow cast by the panel. This will have sufficient accuracy to get you within a few degrees and is resistant to bird doo. An optical sensor (maybe IR) would be aimed at right angles to the plane of the panel and be on the back side aimed away from the sun. I can see how a super simple circuit could drive panel mount to minimize the light sensed by the sensor.

Minimum light in the sample of the albedo woud be when the shadow of the panel was at its max and that is when it is aimed the best at the sun.

Pat

I can see how a system based on minimizing the energy collected from the albedo

 

[patrick_g]

Griz, I think I understand the question. IF a itsy bitsy glass bead on the end type diode got bird doo on it would the tracker lose its mind?

Don't build it that way for that very reason!

If you put a few square inches (maybe a 1/2x2-3 inch) translucent screen with the diode positioned to "see" the screen then a fleck of doo doo on the screen obscures a small fraction of the diodes illumination and it doesn't make much difference. If you hypothesize a "mud storm" (Brief rain during a dust storm) or some such then most optical trackers would suffer a failure. If you use an IR diode and an absorbent screen (at visible and near IR wavelelngths) then the diode would actually be reading the temperature of the absorbent screen like a non contact IR thermometer. If one of the screens began to be shadowed its temp would go down constituting an error signal which would cause the controller to slowly drive toward rebalancing the detectors. The IR aproach is not nearly so bothered by a fleck of debis and might work failry well (recall you only have to be within several degrees not spot on) even with bird do on one screen.

Thre is no optical sensor that can withstand an arbitrarily heavy deposit of material on a sensor. I suppose you could have a reservoir of windshield washing liquid (not easily frozen) periodically sprayed on the sensors. IT wouldn't be perfect but it woiuld be better.

Alternatively you can adjust the tracker's positioin to maximize the area of the shadow cast by the panel. This will have sufficient accuracy to get you within a few degrees and is resistant to bird doo (but noting is mud dauber resistant!). An optical sensor (probably do not want IR since recently shadowed but previoiusly strongly illuminated dirt will still be highly emissive of IR) would be aimed at right angles to the plane of the panel and be on the back side aimed away from the sun. I can see how a super simple circuit could drive the mount to minimize the light sensed by the sensor.

Minimum light in the sample of the albedo woud be when the shadow of the panel was at its max and that is when it is aimed the best at the sun.

Pat

 

[Rob-D]

It depends on how sensitive the set up is. Worst case, you're a little off dead center.

Pat,
You make me laugh!
I wanted to adapt a Weber carb to my old VW Rabbit back in the seventies and laid out a plate that I brought to a machine shop. The guy charged me 50 bucks and drilled it wrong.

I went out and bought a lathe and learned how to do it myself. That was thirty years ago and I've never regretted it.

 

[patrick_g]

The guy charged me 50 bucks and drilled it wrong.

I went out and bought a lathe and learned how to do it myself. That was thirty years ago and I've never regretted it.

I guess I'm just too dense. I don't get it. I would have bought a drill press to drill holes.

I'd like to lay hands on a Diesel Rabbit P/U in good condition for a fair price!

Pat

 

[Rob-D]

Pat, it required a couple of blind holes that I couldn't do at the time so I brought it to the machine shop.

Never mind the diesel Rabbit. I'd like the Audi 1.2 Turbo diesel that gets 80 to 90 mpg! Actually VW is making one too. The German's say the TD is a much better fuel saver then the hybrid. I'm inclined to agree. What's the value of a Prius with 100k miles on it? Not much in my book. I hear that lots 2000 Insights are coming in with bad batteries now regardless of what Honda says about battery life. They discontinued the Insight in Sept. I don't know if they are using the same batteries in the Civic.

I called Audi and they said not to expect it here because of polution laws. Don't get me started on that one!

Well back to solar panels..........

 

[patrick_g]

Rob, I don't know about Honda hybrids except I didn't want one after seeing and testing a Prius. We didn't get the Prius just as a mileage thing. We like the car, really like it, more than most cars we have had or tested. I put a lot of confidence in Consumers Reports and when they reported VW quality taking a downhill turn in recent years I shied away. Otherwise we might have a TDI in the garage.

I personally buy into the philosophy or theory of the hybrid and believe a diesel-electric would be a great choice. It could be even a better choice if the batteries would support greater distances between recharging. Then lots of short local errand trips might not require running the engine and the electricty to recharge is even cheaper than fuel (gas or diesel.) Gas here is about $2.07 or so and diesel is $2.45 or so (on road taxed.) I think it is weird that diesel is way more since it is simpler to produce but what can you do?

Since we weren't just looking for the best mileage but had to satisfy several other factors as well I think the Prius came closer to fitting our requirements than any car we tested (lots of cars.) Did I mention that we just love it? We would probably be just as happy with it if it were just gas or diesel powered and not hybrid.

I know you have expressed a pretty negative view (don't know why) but there are a lot of folks out there who want a Prius. Toyota converted factories doing other vehicles to 24-7 Prius production over a year ago and they can't catch up with demand. Our dealer has called us twice and sent one letter in the last year trying to buy our Prius back at a premium over book and offering us a sweet deal on a new vehicle (not a Prius.) They want to resell it to folks willing to pay a premium for a used one.

We have had it for over 2 years and have been super pleased. I'm sure there is a $ level at which I would let it go but it is very unlikely anyone would pay my price. We have almost 6 years left on the battery warranty which seems to be something that folks tend to coment on and worry about.

The battery is groups of cells strapped together so if a cell did go bad you don't replace the whole thing just the group with the failed cell. We have bumper to bumper 100K waranty on the rest of the car and so far less than 25K miles so we are averaging about 10K milles a year. By the time it is 10 years old (we have 100K) and the batt is out of warranty should I care about resale value? Who knows what sort of batt technology might be available by then. Or maybe hydrogen cars will be practical and cheap. Maybe cold fusion will be used in small home power generators.

Pat

 

[Rob-D]

Pat,
It’s not that I’m against the Prius, I love Toyotas and have had more than one.

The problem is Hybrids in general, I’m just not sold on them. Also in the mountains we need 4WD. My driveway is over six hundred feet with a moderate uphill rise. The Prius is just to low and getting caught in storms and white outs would leave us stranded on the road in situations where the 4WD would and has gotten us home and through it.

I talked to the Toyota dealer here last September he said I could have one in six weeks. If I needed a second car I might have gone for it but the thought of never needing a battery warranty or the added complexity of Hybrids to get the same mileage as a TD really bites me hard. I know the poor repair reputation the VW has but even looking past that my state won’t allow VW diesels here.

I know Toyota repair records are great but the parts are a fortune if you ever do need a repair and we all do at some point or another. The cost of a new muffler/tail pipe on my old 4WD Corolla was so expensive I wound up MIG welding one out of SS so I wouldn’t have to be bothered with it again. Finally everything else under the car rusted in our salty winter roads and I gave up the ghost and let it go. My friend did the same with hers.

The other problem with the Prius is the city/highway mileage. If you tool around town all day that’s fine but it’s not really a commuter car. The Insight was if you could live with the ride but apparently not many people could. We’re retired and live out in the country. It’s not stop and go, which again the Prius is best at so I think the Prius fits a niche but it’s not what I’d call versatile. I’d rather have a car that I can load up for a trip like a wagon but has a good enough towing capacity so I can run a trailer on it to get cement when I need to. I don’t want a pick up truck because it’s not versatile either, the mile is REALLY bad and so is the accident avoidance just like an SUV which I wouldn't own either for that matter. Lots of people own these cars just like Hybrids.

Hybrids cost more simply because they cost more to make which brings us to repair records. All else being equal which car has a better chance of parts failures a Toyota Prius or a normally aspired Toyota with less parts to break down? I’ve trouble shot one of my Toyotas with a complex emission control system, it was a monster! I can't imagine what a hybrid problem would be like even with my engineering background.

I like the idea of saving fuel and the environment, hey I’m building an alternate energy system and designing a small electric car but I wonder how many people buying hybrids save as much fuel as I do? I ride my bike to town in the summer, use mopeds that get an honest 120 mpg or I walk.
Soon I’ll be running on hydro/solar/wind and my total energy expenditure will be much less than most people regardless of the car they drive. I think we have to look at the energy picture from the perspective of how much energy we are using with ALL of our personal consumption.

Please don't think I'm singling you out or have it in for the Prius. I believe you’re sincere about your choice and also do love the car itself but hybrids, at best, are interim vehicles. The Europeans have a much better idea about conservation. They still have their train systems and are way ahead on solar. In fact they are buying a large part of the solar panels that are being made.

 

[patrick_g]

Rob, I can't disagree in principle with anything in your post. Some differences perhaps in matter of degree but not in principle. Sure hybrids are an interim technology. How long will the interim period be? It could be 10-20 years. I'll belive in hydrogen when cold fusion is ready for my back yard electric plant or I see hydrogen fueling stations spaced so that I can drive anywhere in the USA with no worries.

I agree that there are cars with better mileage capability but I can't buy one here in the USA can I.

I don't fully agree with the Prius applicability assessment yoiu made. I know two Prius owners who are high mioleage types with lots of highway miles and both are happy as clams with their Prius. (Check the Prius thread on CBN where Gary commutes a good distance to work and back.) A friend of mine bought a Prius because he liked mine so much. He drives to Pensylvania from OKC every couple weeks and goes to Washington state at least twice a year and to South Texas a couple times a year monimum. They freely admiot they just come home to check on it, do laundry, and repack for hitting the road again. They had a comfotrtable Mercury and a van but now prefer the Prius for their trips.

We don't get the best mileage (especially in the winter) and the best tank I ver did was 52.8 a bit more than the 45-50 we typically get with my wife doing half or more of the driving. She could get bad mileage on horseback!

She loves diesels and had Mercedes TD before we moved to OK. Her ideal car would be diesel and 4x4. Probably configured as a 4-5 passenger small SUV. She loves the Prius!! If you fold the rear seats down it has cavernous cargo space and my 6'2" 245 lbs fits fine in front or back seats with more rearseat legroom than most cars we looked at. If I put the driver's seat all the way back I can hardly reach the wheel and controls. Adjusted comfortably I can get out and get in the back seat behind myself so to speak and my knees clear the seat back by a good margin. Not so in a lot of other cars. The Prius is pretty comfortable for 4 adults especially considering its size.

Ask me in aboiut 7 1/2 to 8 years what I think about maint costs and I will tell you how it went.

Pat

 

[Rob-D]

Pat,

You make some good points too and I'll take another look at the Prius. What troubles me is that I can't test drive one. Had I been able to I might have seen it in a different light.

Rob

 

[patrick_g]

Rob, I don't mean to come across with religious zeal as regards the Prius. It is surely not the best choice for everyone. It sure as heck would not forge ahead through deep snow. It has good computer traction control and computer assisted stability as well as nice anti-lock brakes but has little ground clearance and would get stopped by much snow. My VW Variant wagon would go through a lot.

Our two pickups are 4x4 and I could do pretty well with my VW beach buggy (Myers Manx type with good clearance and is highway legal) Prius is a good winter car only if the snow isn't too deep. It manuvers on ice and snow pretty darned well but would not make it in snow the other vehicles wouild make it through.

Pat