[McRat]

Greetings,

My background is that of a hobbyist hotrodder and racer. I've raced cars, bikes, and trucks, both on pavement and in the dirt (and salt). Both gas and diesel. I'm best known in the diesel world. Life begins at 50psi boost.

I'm trying to get an education on what it takes to build an electric car.

I started to build a 1000w watt solar car, but that is only for playing on dry lakebeds.

What looks more promising is a LiFeO4? electric car or motorcycle. I'm going LiFeO4 for safety, as I read they are safer to charge.

Questions:

1. Are LiFeO4's safer than Li-ion?
2. If cost is not a problem, what is the best high-discharge-rate battery technology? Duration of WOT is about 45 seconds.
3. Are R/C plane LiFeO4's OK to use?
4. Is there a good book written recently on racing electric technology?
5. What kind of electric motors are the racers using?
6. If you were to build something with 500HP for 45 seconds where would you be shopping?

Thanks in advance for any and all input.

Pat McSwain

[Woodsmith]

Welcome to the forum, Pat.

Have you any photos of the solar car?

There will be lots of info here about the performance and hotrod side of things here, some in build and some complete.

[McRat]

Originally Posted by Woodsmith

Welcome to the forum, Pat.

Have you any photos of the solar car?

There will be lots of info here about the performance and hotrod side of things here, some in build and some complete.

It's at the pencil and bar napkin stage. We have the solar panels, controllers, and throttle. It's going to be VERY primitive. Not something for highway use. We have 10 x 100w of 18vdc x 5.5a semi-flexible panels. We were going to make it aerodynamic, but that would require more time and technology than we have available. It must be crazy lightweight, yet inexpensive. $2500 limit on spending, and when we are done, we hook it into the grid and make electricity for the house.

Basically the "flexible" panels weren't very flexible. Think .250" thick poly carbonate as far as flex goes. The other technology of flex panels is only 1/2 as efficient per sq meter.

[Ziggythewiz]

Originally Posted by McRat

Questions:

1. Are LiFeO4's safer than Li-ion?
2. If cost is not a problem, what is the best high-discharge-rate battery technology? Duration of WOT is about 45 seconds.
3. Are R/C plane LiFeO4's OK to use?
4. Is there a good book written recently on racing electric technology?
5. What kind of electric motors are the racers using?
6. If you were to build something with 500HP for 45 seconds where would you be shopping?

Welcome! I'm particularly interested in your solar car.

1. Yes
2. RCs frequently have the best C rates due to lower AH. Other than those Headways are the best I'm aware of.
3. If done properly, sure.
4. If it's in a book, it's outdated.
5. Usually dual Warp 9s, 11s, or similar.
6. Evnetics, netgain, and Headway

[mk4gti]

Check out xof1.com ... Inspiring stuff!

[McRat]

Originally Posted by Ziggythewiz

Welcome! I'm particularly interested in your solar car.

1. Yes
2. RCs frequently have the best C rates due to lower AH. Other than those Headways are the best I'm aware of.
3. If done properly, sure.
4. If it's in a book, it's outdated.
5. Usually dual Warp 9s, 11s, or similar.
6. Evnetics, netgain, and Headway

The problem with a solar car is HP. You get about 150w per square yard with "available" cells. So a car 6ft wide x 12 ft long can only make about 1.5 HP to the ground under the best conditions. That would not move a modern car more than 1 mph. So it has to be uber light, and you need to make it bigger. We are starting with 4' x 12' of panel area for our 1000w. But I believe the answer is going to be a skelton trailer that is lightweight, large, and flat, and can hold 2000 more watts. of power. Now it should go over 30 mph. How much? Dunno. But 3 hp can certainly move a light object a good clip given enough running space. The goal is 60mph without spending hundreds of thousands or millions of dollars like the others projects have. Think of it as a wind surfer that works with no wind.

Thanks for the info!

[McRat]

Sidebar - The fastest average speed a single person bicycle has gone on level ground in two directions without drafting is 83 mph.

Which is far faster than any solar-only car has ever went. It was built by one guy, not a engineering college or General Motors.

So a "racing" solar car will not make as much HP as a man pedalling a bike.

[Ziggythewiz]

Not as much peak HP, but I bet the solar can put out more HP long term. Solar planes can stay in the air night and day, I'd like to see a man do that flapping his little wings, or even on a bike