Solar powered car: a look at the math

[MetroMPG]

Someone pointed out this very good reference to the stumbling blocks of powering a car solely by solar panels:

A Solar-Powered Car? | Do the Math

Worth a read.

[Ryland]

Having solar on your house that is grid tied tends to offset peek demand on the grid while plugging in at night tends to use power at low demand times, so while you are not using electrons that come from your solar panels that offset is well worth it and an 8 year pay back is not bad for a panel that should last 50 years!
Also the claim was a 8 year pay back at 40mpg, comparing a Nissan Versa to the Leaf is pretty fair because they are built on the same platform and can fill the same needs but only one of the Nissan Versa's gets 30/38mpg the rest get much worse and even at best that higher mpg Versa is costing $1,500 per year in fuel so you have a 5.3 year fuel pay back by powering your electric car with solar and with fuel prices always on the rise it means that you are easily paying 1/10th the per mile cost.
As I see it, the biggest reality check that he's bringing to the table is to the people who think they can put a PV panel on the roof of their car and drive forever, not the case, but if you have lead acid batteries that PV panel might trickle charge them enough that your batteries will last longer and as I figured it give an extra mile or two of range per day, 300-500 extra miles of driving per year seems like a good deal to me.

[MetroMPG]

I think the other good reality check in the analysis is that powering a significant portion of the range an electric vehicle by solar power only really works if the vehicle is designed to use very little electricity.

His examples where it's feasible are the "absurdly impractical" solar electric racers, low speed electric vehicles, and e-bikes.

All of which says in a round about way that our small number of commercially available electric vehicles are energy hogs, relatively speaking.

I'm looking forward to the day when efficiency of EV's becomes a competitive focus in that segment, as it has in the ICE segment.

[user removed]

I would use an electric motorcyle first, possible with some aero mods.

regards
Mech

[NeilBlanchard]

The Solar Taxi had about 2/3rds of the solar panels need to power it installed on a building, feeding the grid to offset the power used to charge it. The panels on the vehicle and the large trailer were only able to provide about 1/3rd of the energy used in the vehicle, so they extend the range of the battery pack somewhat.

Solartaxi - Mission

[TheEnemy]

I looked at the math for converting a small pickup a few years ago. What made it practical for me was my short commute of 10-12miles a day and the fact that we get lots of sun in the southwest.

On an efficiency standpoint the typical series wound motor gets 60-70% efficiency. A permanent magnet brushless motor gets 80-90% but at $25k+ for a 75hp they are relatively cost prohibitive.

Edit: Just looked at the warp 11 motor specs, looks like it peaks at 91% and is a series wound, so my above statement is wrong.

[spacer]

Not entirely on topic, but a rear-partial bed cover can also be a fold-out solar array, allowing for more square footage when the truck is parked... assuming no clearance issues between yourself and other vehicles/buildings/etc

[Ladogaboy]

I think that many people in the ecomodding/ev communities take information like this for granted. You should have seen the conversation I had with my dad about why hooking four alternators up (one to each wheel) wouldn't turn an electric car into a perpetual vehicle.

[MetroMPG]

I think you're right about that.

The first thought that crossed my mind when I read the article was: hey! We could just refer noobs to this when they ask why we aren't running our EV's with on board solar panels!

[Ryland]

Originally Posted by MetroMPG

His examples where it's feasible are the "absurdly impractical" solar electric racers, low speed electric vehicles, and e-bikes.

Right, I was at a presentation for the MN solar racer teams car and they were talking about how at 55mph it took 12 pounds of force to push it along, a small fraction of what a "standard" car requires, but the rules they are fallowing also spec out the angle of the drivers seat back, more or less requiring the driver to sit upright, to make the vehicle more "practical" of course it was still a ~350 pound vehicle running on $100 each LRR limited production moped tires... but in comparison to our standard vehicle on the road there is so much room for improvement!

All of which says in a round about way that our small number of commercially available electric vehicles are energy hogs, relatively speaking.

I'm looking forward to the day when efficiency of EV's becomes a competitive focus in that segment, as it has in the ICE segment.

I agree, we don't need larger batteries, we need smaller vehicles!

I also know that it's not just possible but I know first hand, people who power their electric cars off solar, two live off grid all together and one guy around here just bought a partly built EV that he's finishing up and is going to charge off his brand new PV's and the first few months that I had my electric car I was charging it at my parents house off their PVs, but whenever someone asks me why my electric car is not covered with PVs I simply explain that I don't want to put a device like that, that is designed to last 50+ years on a vehicle, because the average vehicle is designed to last 7-8 years, also solar panels need to face the sun and here the ideal angle is 45 degrees, not flat, not 10 degrees, 45 degrees, there for they should be safely mounted on a poll or on a roof where they don't have to worry about being parked inside a building or under a tree.
Even if an EV owner is not putting solar on their roof, spending on new renewable energy electrical production has over taken new fossil fuel power plants for the first time, maybe because renewable energy produced electricity has a quicker pay back? who knows, but plugging in to the grid keeps getting cleaner while gasoline burning gets dirtier and gasoline refining is still the largest single use of electricity so that electrical production is already there and we're just shifting it to powering cars directly instead of indirectly.