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Robert Bruninga posted about this on yahoo's technical group, and I got permission to share the link:

http://web.usna.navy.mil/~bruninga/APRS-SPHEV.html

So now, I am scattering it around the Prius internet universe. Take a peek at what he's done.

DAS

I want one and it would actually work in NM. Don't know how many places in the US it would work well. Desert Southwest and CA maybe.

--des

Hi Doug:

___I am not a fan of solar paneled and powered Prius’ for a number of reasons but take some shots at my ideas when you get the time to reply.

___If Bob says he is inputting 800 Wh on a typical MD day, I truly hope he is seeing that amount of power going into the spare Pb-Acids daily - year round. This is a good thing of course. 800 Wh is good for ~ 4.5 miles while hypermiling and maybe 3 for the rest. Another good thing imho.

___Now for the not so good. A small group of Pb-Acid’s running deep discharges will kill their cap in less then 500 cycles. They may last with a cap over 70% for a little over a year given the average daily commute driving back and forth to work 200 days/year plus the non-commute back and forth to the grocery store, HW store, movies and video rental joint etc. when not commuting. Next is the amortized cost for the panels.

___All in, the panels and replaced Pb-Acids to move the Prius ~ 750 extra miles/year via EV or heavily assisted ICE-On costs upwards of $7,500 over 10 years and 150,000 miles. That “free” 750 miles per year costs $1.00/mile by my calc’s and that is simply and unfortunately an outrageous amount of $’s after purchasing one of the most fuel efficient vehicles on the planet to begin with :(

___Good Luck

___Wayne

What needs to happen is the cost of solar panels to come down... way down. Which hopefully they will soon. When that happens it would be beneficial to just install them on your house as opposed to your car to not only recharge your car when your home, but also your house. I used to think solar panels on cars were cool... but it just doesn't make much sense when you really think about it.

Blake, how about on the fire trucks? Larger area and you could always harvest something from the fires you have to go put out? ;)

What I need to do is come up with a stirling engine that can withstand the intense heat of fires to run a generator... I bet that would produce loads of energy! ;)

What I need to do is come up with a stirling engine that can withstand the intense heat of fires to run a generator... I bet that would produce loads of energy! ;)

Now there's an idea. How about an extensible rod for conducting the heat? Then you can adjust the intensity at the engine itself by moving it closer or further away from the flames?

Back OT, the Aptera uses Solar Cells on its roof to power the climate controls inside (mostly low power fans, I think) -- that seems a reasonable use of the roof area of a vehicle but as you say, the price of the tech has to drop quite a bit. By that time I'll just cover every available surface at home to generate as much as I can. Living off the grid would be ever so nice!!

Speaking of stirling engines, I know that currently SES has the solar dishes with stirling engines, but I was wondering if there might be a simpler type of collector that would work. Create a stirling engine where the hot end is an evacuated tube solar collector.

Evacuated tube collectors are able to create hot water even in very high lattitudes, and don't require solar tracking. In fact, such a generator might even be *more* efficient in higher lattitudes due to a greater temperature gradient.

Has anyone heard of someone trying this? Sadly I'm not an engineer, or I'd probably try to build one on my own.

Dave

A while back I was looking into a mini solar array to charge my block heater at work. And that's when I was introduced to........the limitations of solar power. :). I'll take a grid Prius instead. :)

Having said that, how cool is this?

"Field events, emergencies, or just watching the kids soccer match (with the Prius electric A/C)... "

So he can sit in his car with the solar panels providing sufficient SOC to run the AC alone? Or to put it another way, USING THE SUN TO COOL HIMSELF FROM THE SUN...........take that sun ;)

A while back I was looking into a mini solar array to charge my block heater at work.

Interesting! Isn't a block heater just a resistive heating element? No need for inverter, you should be able to dump the DC straight into the plug on the block heater.

Though who's to say a 10 watt panel could hope to keep a block even above ambient... maybe with sufficient insulation it could help maintain the temps for the commute home.

Hi All:

___The Prius’ EBH is supposedly a 400W device. The peak output of the solar array is 215W per Bob’s description. Not enough juice to heat the car and certainly not enough to cool it either although it would help :(

___Good Luck

___Wayne

By posting this link, I in no way am suggesting that either aspect represents a cost-effective modification to Prius. I just appreciate what RB has done here. It speaks both to his skills and dedication, and to the amenability of this hybrid vehicle platform to many interesting modifications.

He is not the first to have done similar, but we can learn something from each different design, and he has made an excellent exposition on the web page.

Covering the upper horizontal surfaces of Prius do not make it a Sunraycer, for several obvious reasons. But having the ability to get 100-ish watts from the sky wherever you can drive the thing is an extension of capability. It complements the Prius' inherent ability to act as a 1 or 10kw (depending on how many wires you cut) mobile power source via gasoline. If it is un-beautiful, perhaps that is just the thing to stimulate PV people to improve their designs. I see a lot of overlap between Prius 'modifiers' and pioneers in other fields.

A bunch of added lead bricks is anathema to most hypermilers, but they are cheap and rugged and (as I said before) will rule the EV road for quite a while in terms of population. He might kill them off early (by taking the bricks below 10.5 volts) and he might not. Let's wait and see. In the meantime there is a small part of the Prius operating envelope where more amp-hours can substantially improve FE as demonstrated by the late Andy Roberts.

For the same money, one can accomplish more personal CO2 reductions, in others ways that are already well known. So choose as you will. Personally it does not inhibit me from 'looking at the menu'.

RB may offer kits or components later, but not via a .mil web site.

DAS

Obviously it is an expensive little toy!! And not an all that practical one (it sounds reasonable here--desert Southwest (but they wouldn't make a commercial car that way anyway), even IF the cost of these numbers went down substantially).

With solar on the house, and a plug in the garage, that would be the best, imo.

I also would want to be off the grid... (or maybe car to grid!!!)
BTW, I know someone who lives off the grid. But is powered with Propane. Yikes. Makes PNM (local utility) almost a friendly company.




--des

Obviously it is an expensive little toy!! And not an all that practical one (it sounds reasonable here--desert Southwest (but they wouldn't make a commercial car that way anyway), even IF the cost of these numbers went down substantially).


It's an EXPERIMENT. Cost effectiveness rules do not apply. If something is learned, we all eventually benefit.

Go for it, man!!

Hi Doug and Doc:

___I didn’t mean to run amok on Bob’s setup but am just frustrated with the whole lot of auto manufacturers and the stunts they pull as of late. Toyota’s 62 mph pure glide capability appears to only be an ECU flash away and that extra NiMH for < $1K OEM for 4 – 5 miles of AER would make my heart swoon.

http://www.cleanmpg.com/photos/data/501/Toyota_Prius-II_OEM_PHEV.jpg

___Good Luck

___Wayne

"Toyota’s 62 mph pure glide capability appears to only be an ECU flash away" Yeah funny thing about that. Mathematically, it should have come along with the NHW20's electric motor redline increase. Toyota kinda sorta forgot to change it.

Actually there exist at least two other explanations. They were waiting to see how well 'the planetaries' would hold up, or they wanted to hold back a feature for an eventual longer glider.

DAS

It's an EXPERIMENT. Cost effectiveness rules do not apply. If something is learned, we all eventually benefit.

Go for it, man!!

I know that.

I also don't think "expensive toy" is a bad thing. For instance, the Tesla Roadster is a WAY expensive toy, but who knows? The rich people buy it and maybe someday they make a car that is affordable to many more people. They have plans somewhere down the line for a quite affordable car. I wouldn't feel bad if they knocked the big 3 off totally.
Also the PHEV are mostly in the "expensive toy" categories, but they may someday be affordable.

So I agree.

Also they are working on a highly efficient inexpensive (spray on) plastic solar paint that collects UV light vs visible light-- but them on a car (they are very light), and it doesn't matter if you live in a cloudy state or a sunny one. So there is a possible long term benefit in the real world.

--des

I have always been a fan of solar on cars... but as with most things ... it depends on your point of view.



___I am not a fan of solar paneled and powered Prius’ for a number of reasons but take some shots at my ideas when you get the time to reply.


Those are the pretty much standard arguments people bring up about solar power on a car.



___All in, the panels and replaced Pb-Acids to move the Prius ~ 750 extra miles/year via EV or heavily assisted ICE-On costs upwards of $7,500 over 10 years and 150,000 miles. That “free” 750 miles per year costs $1.00/mile by my calc’s and that is simply and unfortunately an outrageous amount of $’s after purchasing one of the most fuel efficient vehicles on the planet to begin with :(



the linked site lists $2,500 for his Solar panels and $500 for the PHEV LEAD Acid battery pack ... so I am not sure where you got the $7,500 number from???

At $3,000 for the project Solar panels do not stop working in 10 years either.... You might have got that 10 year number from thinking that the solar panels would be thrown away with the car???? but it makes more sense to keep on using the solar panels for all they are worth.... I did not see him listing his specific type manufacture and model of solar panel but there are several solar panels that have been in service for over 20 years with less than a 10% reduction in their power output.... so over 50 years is very doable for a useful service life from some solar panels ... now this will depend on the type of solar cell used.

Without knowing exactly what kind he has... I assume closer to a 25 Year Solar cell service life... but could be over 50 years....


___If Bob says he is inputting 800 Wh on a typical MD day, I truly hope he is seeing that amount of power going into the spare Pb-Acids daily - year round. This is a good thing of course. 800 Wh is good for ~ 4.5 miles while hypermiling and maybe 3 for the rest. Another good thing imho.


800 Wh per day he is reporting as an average ... x365 = 29.2 KWh of solar energy per year.... for I expect 25 years... but even at 10 years that is ... x10 = 292 KWh of solar powered electricity ... x25 = 730 KWh at 25 years.... 200 Wh per Mile is a common number for EVs ... I do not know off the top of my head what the Wh per mile number is for a prius in EV mode.... but at 200 Wh that is 1,460 Miles of EV mode for a 10 year and 3,650 Miles of EV mode for 25 years....

A prius without additional Electric power normally gets around 50 MPG depending on driver and route etc.... so 29.2 Gallons of gas offset by 10 years .... 73 gallons of gas offset by 25 years....

As for the cost....

it is about what you want to spend your money on...

a $50 average cable TV bill for the next 10 years will cost you ~$6,000 ... at what point in watching TV do you get that $ back??? the answer .... never....

or you could spend half the TV cost at the reported ~$3,000 to use ~29.2 less Gallons of gas in 10 years....

If you make more money than you need to live... they rest just goes to raise your standard of living ... how you choose to spend your extra money is up to you... by a $3,000 TV spend $100 per month of TV Shows ... by a $40,000 car.... by a $500,000 home... I don't think any of these choices are "bad" or "wrong" they are your choices... you earned the money....

If lowering your Gasoline use is even 1/2 as important to you as your Cable TV shows you do things like this to reduce your gasoline use...

just my 2 bits....

the linked site lists $2,500 for his Solar panels and $500 for the PHEV LEAD Acid battery pack ... so I am not sure where you got the $7,500 number from???


The extra $4500 was calculated in because of the (reasonable) assumption that the batteries would need to be replaced yearly with that kind of heavy deep cycling. Even "deep cycle" lead acid batteries really don't hold up all that well to continual flattening and the capacity will drop shockingly fast.

His point was that this set up does not give as much benefit as other methods of saving fuel and that it is also less durable than other methods. If you were to replace the lead acids with LiON tech incorporating some battery management algorithms you might get better longevity but at that point you may as well just go straight to a plug in setup and use a much large solar array in a fixed location that can provide much more power than the very small surface area available on a car.

You are entirely correct about the usefulness/durability of solar cells, but this application does not seem worth the expenditure?

Hi Iamian:
I have always been a fan of solar on cars... but as with most things ... it depends on your point of view.

the linked site lists $2,500 for his Solar panels and $500 for the PHEV LEAD Acid battery pack ... so I am not sure where you got the $7,500 number from???___What Sean said. It is the “yearly replacement” of Pb-Acids at $500 a pop that throws the numbers in the garbage.

At $3,000 for the project Solar panels do not stop working in 10 years either.... You might have got that 10 year number from thinking that the solar panels would be thrown away with the car???? but it makes more sense to keep on using the solar panels for all they are worth.... I did not see him listing his specific type manufacture and model of solar panel but there are several solar panels that have been in service for over 20 years with less than a 10% reduction in their power output.... so over 50 years is very doable for a useful service life from some solar panels ... now this will depend on the type of solar cell used.

Without knowing exactly what kind he has... I assume closer to a 25 Year Solar cell service life... but could be over 50 years....___I would not assume anything wrt life of a panel on a vehicle moving through the elements let alone VH banging away at them while driving down the road. I just do not know myself?

800 Wh per day he is reporting as an average ... x365 = 29.2 KWh of solar energy per year.... for I expect 25 years... but even at 10 years that is ... x10 = 292 KWh of solar powered electricity ... x25 = 730 KWh at 25 years.... 200 Wh per Mile is a common number for EVs ... I do not know off the top of my head what the Wh per mile number is for a prius in EV mode.... but at 200 Wh that is 1,460 Miles of EV mode for a 10 year and 3,650 Miles of EV mode for 25 years....___The calc’s in the earlier post appear reasonable at 750 EV miles for $750 per year. That is worth 15 gallons of fuel per year. There are other solutions that should/could be far less expensive on a $/mile basis is all.

As for the cost....

it is about what you want to spend your money on...

a $50 average cable TV bill for the next 10 years will cost you ~$6,000 ... at what point in watching TV do you get that $ back??? the answer .... never....

or you could spend half the TV cost at the reported ~$3,000 to use ~29.2 less Gallons of gas in 10 years....

If you make more money than you need to live... they rest just goes to raise your standard of living ... how you choose to spend your extra money is up to you... by a $3,000 TV spend $100 per month of TV Shows ... by a $40,000 car.... by a $500,000 home... I don't think any of these choices are "bad" or "wrong" they are your choices... you earned the money....

If lowering your Gasoline use is even 1/2 as important to you as your Cable TV shows you do things like this to reduce your gasoline use...

just my 2 bits....___I receive a nice benefit from the depreciable electronics I own but I do not throw away $3K on a $500 TV. I have not had Cable or Satellite for about 5 years although I wish I did ;)

___When the cel’s can pick up the juice they are rated for to fill a pack that does not need replacement, than we have an answer. You will see a lot more EV conversions on the road once that happens too. Pb-Acid for EV anything is a waste from what I see.

___A bit of history … Krousdb wired up his Prius with some advanced Pb-Acids from Eaton. The extra 100 – 150 pounds hurt his FE more then the Plug-in power gave him back so he removed them after a few short weeks :(

___Good Luck

___Wayne

Pb-Acid for EV anything is a waste from what I see.


thanks for the clarifications....

I do agree with you about the Lead Acid... but they are the cheapest batteries $ per Wh so they are usually the first ones people try in any EV project....

I am personally a bigger fan of NiMH batteries.... I like NiMH over all , more than any other battery chemistry I have read about , including Li.... Li is nice for a few things .. the Wh per Kg is a big one that attracts most people...

I don't like the shelf life of Li Technologies so far...

If you treat them the way they are treated in Hybrids, NiMH last a very very long time..... NiMH is also less environmentally harmful as far as I have read in terms of production and the battery itself.

Of course Ultra Capacitors are my #2 pick... falling behind NiMH because of the much lower Wh per pound... but Ultra Caps... have a wonder cycle efficiency... wonderful charge and discharge rates... SoC determination is easy on a Ultra Cap.... and last so long you can transplant them from car to car for most of your life.... but the much much lower Wh / Kg is a killer for most mobile applications...

I would also agree that Solar at the house is the first step and will always have a benefit with a properly set up system....

But I still like the idea of Solar on a car as well.... after the solar on the house... or if you live in an apartment and can't put it on your house just go directly to the car... The car has a surface that is being hit with sunlight anyway .... I would prefer to use it than throw it away....

And to me it is just a choice of what do I want to spend my money and/or time on.... if I have the money I can either get a lower paying job to avoid the extra money.... I can save the money... or I can spend it on things I want .... I prefer a bit of 2 and 3... save for things like retirement and for my car Plans .... :)