120W Solar Panel on Hybrid Car Roof only gives 200 more miles per year.

rollandelliottrollandelliott Posts: 755Solar Expert ✭✭
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Company estimates 120W solar roof panels give you 200 more miles per year, saving you a mere 6 gallons of gas.

I had this "great" idea of buying a 144watt uni-solar panel and mounting it ontop of my car roof, but for the life of me couldn't figgure out any practical usage? I'm sure strangers would ask me if my car was solar powered!?!? that might get annoying after a while.

I guess if you go camping a lot you could hook up a couple of extra batteries in the trunk and run a fan or led light, radio, etc.

Any other practical uses of having 144watts of solar on a car roof?

Comments

  • CariboocootCariboocoot Posts: 17,615Banned ✭✭
    Re: 120W Solar Panel on Hybrid Car Roof only gives 200 more miles per year.

    Why would anyone expect any different? One horsepower is 746 Watts. There's not that much room on the roof of the average vehicle.

    Maybe I should do that to replace the alternator that just died on the 4Runner. Let's see, it needs to put out 100 Amps @ 12 Volts so ... 1200 Watts of panel ... uh ... I need to extend the length by about 15 feet to make up for something that occasionally draws maybe 2 HP.

    There's the problem.
  • rollandelliottrollandelliott Posts: 755Solar Expert ✭✭
    Re: 120W Solar Panel on Hybrid Car Roof only gives 200 more miles per year.

    It's been my experience that the general public think solar panels are much MUCH more powerfull than they are. I frequently get comments about what am I powering with all my solar panels? When I tell them only about half of my elelctric bill they are surprised.

    I guess the point is, since the solar panels ontop of the car produce such little power what would be a more effective use of them? fans, extra lights, radio? Splurge and buy a battery bank enough to power fridge or microwave? Just curious what possible uses of portable solar are. Hope to get some creative ideas.
  • CariboocootCariboocoot Posts: 17,615Banned ✭✭
    Re: 120W Solar Panel on Hybrid Car Roof only gives 200 more miles per year.

    The only practical application I can think of is to keep the battery topped up when the vehicle sits for an extended time. Today's cars have quite a bit of parasitic loads (running on-board computers for instance). Some manufacturers ship cars with little panels attached for that very reason. Otherwise it's a farce.

    You are spot-on about people's expectations. Possibly half the off-grid problems are caused by this.
  • icarusicarus Posts: 5,108Solar Expert ✭✭✭✭
    Re: 120W Solar Panel on Hybrid Car Roof only gives 200 more miles per year.

    The newest generatio Pruis use a roof panel to power the HVAC while parked. Not a bad idea, but not a very efficient use of PV in the net. Like everything else, there are "optics" involved.

    Tony
  • WindsunWindsun Posts: 1,164Solar Expert ✭✭
    Re: 120W Solar Panel on Hybrid Car Roof only gives 200 more miles per year.
    icarus wrote: »
    The newest generatio Pruis use a roof panel to power the HVAC while parked. Not a bad idea, but not a very efficient use of PV in the net. Like everything else, there are "optics" involved.

    Tony

    Those things are more of an "eye-candy" overpriced option than anything else. One brand I looked at, the solar vent fan option was over $400 - and consisted basically of a 6 watt panel and a small DC computer fan, which you can buy for around $30-$40 total max. And they don't really work all that well. I set up a test with a spare 60 watt panel and a 14 watt 12VDC computer fan in my Explorer, and it only reduced the inside temp of the car about 10 degrees.

    There will never be a totally solar powered car unless you can repeal the laws of physics, or the sun starts putting out about 10x as much light (which might cause some other minor problems...).
  • bill von novakbill von novak Posts: 806Solar Expert ✭✭✭✭
    Re: 120W Solar Panel on Hybrid Car Roof only gives 200 more miles per year.
    Maybe I should do that to replace the alternator that just died on the 4Runner. Let's see, it needs to put out 100 Amps @ 12 Volts so ... 1200 Watts of panel ... uh ...

    I doubt your car regularly uses 1200 watts of accessory power! Unless you have a VERY large sound system . . .

    Just measured the roof and hood of my Leaf, and if you covered every possible horizontal surface with solar, and you assume best commercial panel efficiency (around 17%) 6 hours of equivalent sun a day and my driving habits you could add 10 miles a day of range.
  • jaggedbenjaggedben Posts: 230Solar Expert ✭✭
    Re: 120W Solar Panel on Hybrid Car Roof only gives 200 more miles per year.
    It's been my experience that the general public think solar panels are much MUCH more powerfull than they are.

    I think a more accurate way of putting it is that most of the general public has no idea about the relative energy requirements of the common products they use. They are used to just plugging things into the wall and having them work, so the mindset becomes "if there's a plug, it will be fine." From there it's a relatively small leap to 'if there's a solar panel, it will be fine." People are very used to having things engineered for them and not having to think about the amount of energy and power required.
  • jaggedbenjaggedben Posts: 230Solar Expert ✭✭
    Re: 120W Solar Panel on Hybrid Car Roof only gives 200 more miles per year.
    The only practical application I can think of is to keep the battery topped up when the vehicle sits for an extended time.

    The OPs comments about camping are somewhat relevant. Bring a solar panel with you to a remote location, you can plug a few low power things into the power point on your car and then recharge the battery if it dies. Works pretty good as long as you plan to leave during the day.

    Of course to do this when camping you don't need the panel permanently attached to the car. In fact it's better if it's free standing so you can lean it against the car and point it toward the sun while at your campsite.
  • inetdoginetdog Posts: 3,123Solar Expert ✭✭✭✭
    Re: 120W Solar Panel on Hybrid Car Roof only gives 200 more miles per year.
    icarus wrote: »
    The newest generatio Pruis use a roof panel to power the HVAC while parked. Not a bad idea, but not a very efficient use of PV in the net. Like everything else, there are "optics" involved.

    Tony

    If you read the specifications carefully, you will see that it is not powering the HVAC. It is only running a fan to change the air to reduce the temperature rise in the closed parked car. The A/C load is far too much for the panel or the 12 volt auxiliary battery for any length of time. (The traction battery does not drive the A/C compressor.)
    SMA SB 3000, old BP panels.
  • icarusicarus Posts: 5,108Solar Expert ✭✭✭✭
    Re: 120W Solar Panel on Hybrid Car Roof only gives 200 more miles per year.

    I knew that ,, that is what I meant,, just the blower fan, not the A/C.


    Thanks for the clarification.
  • CariboocootCariboocoot Posts: 17,615Banned ✭✭
    Re: 120W Solar Panel on Hybrid Car Roof only gives 200 more miles per year.
    I doubt your car regularly uses 1200 watts of accessory power! Unless you have a VERY large sound system . . .

    This may come as a complete surprise to you, but I am well aware of that. :roll:
  • PNjunctionPNjunction Posts: 762Solar Expert ✭✭✭
    Re: 120W Solar Panel on Hybrid Car Roof only gives 200 more miles per year.
    ..Just curious what possible uses of portable solar are. Hope to get some creative ideas.

    I keep a folding panel w/cc and clips in my car since I go camping once in awhile - but the secondary purpose is for emergencies. I'm not talking doomsday, but I've been through several forced evacuations where you have 10 minutes to get out. It stays in the car since it is one less thing to think about when your mindset / adrenaline is pushing 100%, and solar power is about the last thing on your mind.

    Very simply if the car becomes my source of shelter, light, and broadcast radio news for an extended amount of time, I don't want to kill the battery or run the engine and waste fuel when it's needed for transportation. OH, and a voltmeter is also in the glove box so I can keep an eye on the SOC in hopes I don't go beyond 10% DOD. The plan is to try and not use any more than 10% of the car's sli battery in hopes of being able to start it again. There may also be other sources of sli's in abandoned vehicles etc that I could use.

    No doomsday preparations here - just simple stuff that I am glad to have already have packed in the car. I got burned on some lesser quality folding panels, and put together my own kit from PowerFilm stuff. Since I'm not trying to turn sli starting batteries into fully-blown charger setup, but just trying to keep up with maybe 10% dod, I'm not packing a huge panel - just enough to cover the drain from the radio, charge cellphones and the like and maybe intermittent use of the internal lights.
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