prius portable solar panel

[djphill]

If i were to leave a solar panel on the dashboard when i park, would i collect any energy. If so, if it were plugged into the cigarette lighter would it help the mpg at all.

[efusco]

Originally Posted by djphill

If i were to leave a solar panel on the dashboard when i park, would i collect any energy. If so, if it were plugged into the cigarette lighter would it help the mpg at all.

1) Yes
2) No...unless you modify the cig lighter/power point...and even then it's pretty questionable.

elaborated...
1) Sure, a solar panel will collect some energy..but about the biggest you're going to fit there is about a 5W and most that are sold for cars are about 1.8W...so it'll collect energy, but not a lot relative to the Traction battery.

2) Both front power points are disengaged when the car is turned off. The lower one under the dash can be pretty easily modified to be 'always on'. But even so the energy will go only to the smaller 12v battery. While that can be nice to keep it topped up, esp. when the car will be parked for a long time it is unlikely to make any measurable impact on fuel economy. I have one of those 1.8W panels and sometimes connect it directly to my 12v battery (with alligator clips) when I leave the car parked for over a week at the airport.

[djphill]

I was also planning on using a small solar panel to charge my cellphone and ipod.

[qbee42]

Originally Posted by djphill

I was also planning on using a small solar panel to charge my cellphone and ipod.

That makes more sense.

To expand on Evan's comments, it's not an easy process to charge the HV traction battery in a Prius. I could build a solar charger that would work with the HV battery, but it would take me several days of design work, a lot of expensive parts, and then would only make a tiny, tiny difference in the level of charge. If you really want to do that, put the panels on your house where they can be big enough to make a difference.

Portable panels are great for small appliances and topping off 12V systems, so I like your second idea.

Tom

[dwreed3rd]

What about a folding solar panel windshield shade to trickle charge the 12v? Some assembly required! (modification).

[efusco]

Originally Posted by dwreed3rd

What about a folding solar panel windshield shade to trickle charge the 12v?

It's a cool idea, but would be expensive and probably would be larger than necessary for the job. Why not a convenient $25 1.8W panel available anywhere?

[David Beale]

Solar panels of this type are about 10-15% efficient. If you want to shade the windshield with one it would probably be inside (they are expensive and you don't want it walking away!). So the panel would still heat up the interior of the car with 85-90% of the effect of the unshaded sun.
It -would- be able to keep the 12V battery charged, keeping in mind the 12V battery is probably fully charged when you shut the car down. You -could- trickle charge something else as well. Panels that small would put out up to about 200 mA - you loose a lot of energy through the windshield, and assuming you park the car facing due south or wherever the sun is most of the time you are parked. It drops off fast when you are not facing the sun.

It's a neat idea, just not very practical. The panels that go on the Prius roof are better, but only a little. They are expensive and provide only marginal power, and it goes to the 12V system, which doesn't need it!

[dwreed3rd]

David, Thanks! I particularly get the point that the panel would absorb the heat into the car instead of reflecting it back out the windshield, defeating the main purpose of using it in the first palce. Good thinking.

[Stefx]

How about this idea:

Go in a big parking lot, ask a friend to be at the wheel. Get out and push the car as hard as you can. You can probably have a 200W output for 20-30mins, you'd charge the traction battery. This would be a lot more useful than a little solar panel, and you'd lose weight, therefore improving your mpg further.

[carz89]

Originally Posted by Stefx

How about this idea:

Go in a big parking lot, ask a friend to be at the wheel. Get out and push the car as hard as you can. You can probably have a 200W output for 20-30mins, you'd charge the traction battery. This would be a lot more useful than a little solar panel, and you'd lose weight, therefore improving your mpg further.

Awesome! Classic! I must try it and measure the charging current with my scangauge.

Taking the math one step further, 200W for 30 minutes equates to 400 watt-hours, which equates to 344 kilocalories (344 Calories in nutrition speak). Not a bad workout!