Solar LED Road Stud Reflectors for safety (reserve, work, companies)

[jimmy lao]

Can we use environmental technology to save lives, money, and the environmental costs of replacing totaled automobiles?
Yes. We can do it with those little reflector bumps in roads.
Now, most countries have begun installing Solar Smart Studs on some of their darker stretches of road. The solar studs have a little solar panel in them, along with an LED light and traditional reflecting surface.
Drivers on the retrofitted roads enjoy 10 times more visibility (90 meters to 900 meters) with the new in-road lights.
As a result, drivers have 10 times more notice to adjust to changes in road direction. In some scenarios, the lights can replace overhead street lamps, completely eliminating the need for the roads to be on the electric grid.
The lights last about ten years, and after that they are just as useful as the old studs used to be. Preliminary tests in England have shown a 70% decrease in nighttime accidents.

[harry chickpea]

What a stupid idea. First, no battery is going to last ten years under those conditions. NiCads and NiMH have a cycling capacity of about 1000 charges and discharges. THat means 3 years tops before a battery changeout. Second, reflectors are in one of the harshest environments, where they are subject to abrasion, road salt and sand, snowplow blades, agricultural impliments, and so on. Third, during the winter in the snow states, not only will they not get enough sun to recharge and last the entire night, but they will be covered over exactly when they are needed most, in snowfall conditions.

This is NOT by any stretch an ecologically sound idea. It places hard to recycle chemicals in the roads, takes a tremendous amount of energy to make and install, and has little benefit. What it DOES do is make someone money and raise taxes.

[f_m]

Not sure why this is in business, but it has been brought up in another category.

http://www.city-data.com/forum/new-m...rs-safety.html

If they use low brightness (as compared to bright enough to be seen in daylight) then battery life can be very long, and it won't take much to make them visible when it's dark.

[harry chickpea]

I'm sorry, but the physics of batteries makes a ten year self-enclosed solar stud an impossibility. Period. That report was in 2007. Go to the area in a couple of years and see what the reality is.

Most people are functionally illiterate when it comes to electricity and battery chemistry. Companies like this prey on that innocence.

[f_m]

Originally Posted by harry chickpea

I'm sorry, but the physics of batteries makes a ten year self-enclosed solar stud an impossibility. Period. That report was in 2007. Go to the area in a couple of years and see what the reality is.

Most people are functionally illiterate when it comes to electricity and battery chemistry. Companies like this prey on that innocence.

But why does Toyota say their Prius batteries (NiMH) last the practical life of the vehicle? It seems many last a while (their warranty is 8 years or 100k so they expect it to last at least that long). While not the exactly the same, these solar powered lights may or may not work depending on the design of the charge and discharge. I had figured that proper and slow charge and discharge (using pulse width modulation to maintain a reasonably bright light but minimize power consumption) would minimize the charge/discharge number of cycles. Their spec indicates it is slow, ~20 nights of use on a single charge. So charging is only needed about every 1.5 months. Yes, it would be interesting to see it they still works after a number of years, but if they last as long as Prius batteries then it would work.

FAQ detail

[harry chickpea]

The answer to your question gets very involved. The Prius has an on-board charging system. Depending on the state of the batteries and the conditions, the software controlling the IC engine can be optimized to prevent any severe strain on the battery, and limit discharge to acceptable levels. In essence, the battery lives a pampered life and never has to run through a complete discharge recharge cycle. In some ways, it acts more like a capacitor or short term storage device than a true battery. On top of that, the "practical life" of a Prius for the first owner is likely to be somewhere between three and five years, as technology changes and styles change.

Compare that to a solar stud placed on a tree-lined road in a northern climate, where clouds, snow, road dirt, and even the side of a mountain can prevent a full charge. When I lived in Vermont, we had one winter where the sun did not come out from mid-November until there was a brief appearance in March. It then returned to hiding until sometime in April. With daylight occurring sometime around 9 AM and night starting at about 3:30 PM, the reserve is nowhere near enough to give the batteries a chance.

[f_m]

Originally Posted by harry chickpea

The answer to your question gets very involved. The Prius has an on-board charging system. Depending on the state of the batteries and the conditions, the software controlling the IC engine can be optimized to prevent any severe strain on the battery, and limit discharge to acceptable levels. In essence, the battery lives a pampered life and never has to run through a complete discharge recharge cycle. In some ways, it acts more like a capacitor or short term storage device than a true battery. On top of that, the "practical life" of a Prius for the first owner is likely to be somewhere between three and five years, as technology changes and styles change.

That's what I mean, any system intended for long life must use an intelligent controller to maintain the charge at the optimal level, charge rate, and temperature dependent, etc... (this system should be smart enough to control the brightness level of the light based on the battery state, most controllers available now should do this). There are many PWM LED controllers that can adjust the duty cycle of LED's potentially as low as 90% of the comparable steady-lit power usage but still output similar brightness by the pulsing of power output in short on-off bursts not visible to the human eye. Especially, if the voltage range of the battery is much higher than the requirement. So if the initial batteries used are 10-20V (overdesigning the battery size), even though the LED's may require only 3-5V, then the battery "life" could drop down from 10-20V to 3-5V and still be usable by the system. This voltage drop could take years, but the PWM controller is still able to operate the LED's in the proper brightness range by seeing the voltage available and adjusting the pulse rate.

I know someone with a 2003 Prius still going fine, and I'm sure there are many out there. I read in Prius forums one tech attending Toyota's training said they felt the battery could last possibly up to 15 years. So between their 8 year warranty and 15 year theoretical life, 10 years for an intelligent system does not seem too impossible especially if it is overdesigned for the requirement. Doesn't mean they all will, but if my friend's can be 6 years now there are others.

Originally Posted by harry chickpea

Compare that to a solar stud placed on a tree-lined road in a northern climate, where clouds, snow, road dirt, and even the side of a mountain can prevent a full charge. When I lived in Vermont, we had one winter where the sun did not come out from mid-November until there was a brief appearance in March. It then returned to hiding until sometime in April. With daylight occurring sometime around 9 AM and night starting at about 3:30 PM, the reserve is nowhere near enough to give the batteries a chance.

I don't know if you looked at their existing list of installations, which have been for a few years, and they should have been studied by any agency wanting to spend so much money for these systems. Most of the systems were installed in the UK or northern Europe, not ideal for solar.
Astucia Case Studies

This doesn't mean that their particular system is really good without actually established evidence, but I don't see it being impossible to design such a system with overdesigned battery capacity and intelligent charger control with PWM LED lighting control.

[wheelsup]

Originally Posted by harry chickpea

Most people are functionally illiterate when it comes to electricity and battery chemistry. Companies like this prey on that innocence.

Between this post and your last on this thread it seems like you've got some pent up anger...I mean really. Functionally illiterate? That seems harsh.

Personally I'd love it if we had lights in the road if they were cost effective. I remember driving up in the hills of TN and they had lighted lane markers. Made driving thru the fog really easy. Runways have lighted edge lights as well and (the bigger ones at least) have center line lights. Makes staying on the center line a lot easier in the snow/rain/fog.

Here is a shot of the LED lane markers on the road, certainly more effective than reflectors.

They have 2 solar models, the SolarLite™ F Series marker light is flush mounted into the road, protruding just 3.5mm above the road surface, so motorcycles and even bicycles will not have any problems. A nickel metal hydride battery can fully charge in 3 hours on a sunny day and gives 240 working hours in return.


Because they are self lighting instead of requiring reflection from your headlight, the tremendously increased viewing distance increases available reaction time from 3.2 to over 30 seconds at 60 mph! Studies show reflective markers have a maximum viewing distance of 90 meters, the SolarLite can be seen, under the best conditions, from as far away as 900 meters! Projected life before replacement is 8 to 10 years

Looks like 1 3 hour charge will give 20 days at 12 hours a day of light.

[texdav]

Originally Posted by f_m

But why does Toyota say their Prius batteries (NiMH) last the practical life of the vehicle? It seems many last a while (their warranty is 8 years or 100k so they expect it to last at least that long). While not the exactly the same, these solar powered lights may or may not work depending on the design of the charge and discharge. I had figured that proper and slow charge and discharge (using pulse width modulation to maintain a reasonably bright light but minimize power consumption) would minimize the charge/discharge number of cycles. Their spec indicates it is slow, ~20 nights of use on a single charge. So charging is only needed about every 1.5 months. Yes, it would be interesting to see it they still works after a number of years, but if they last as long as Prius batteries then it would work.

FAQ detail

Well having used MIMH with bascaily the big thing weas thier lack of memory I would say that the practical life and what actually occurs with batteries is teo diffewrent things. Besides which we already have a battery disposal problem with the numbers used now.I can just see the gous on the highway replacing the batteries that go bad from shorted cell etc everyday. On dark raods its much eaier to just use reflective paints and cut the expense of those batteries and save the envionmental problems with battety disposal.

[lightspeedroadsolar]

In the U.S. LightspeedRoadSolar uses a Lithium Polymer battery which has no heavy metals and no "phantom memory". We also offer a recycle program for the batteries so that none of them wind up in landfills.

We also offer a snow-plowable model that is housed in a cast-iron shell.