# Dave Cloud's Dolphin EV



## Snakub (Sep 8, 2008)

Just wondered what everyone here thought of this EV since I saw it on evalbum I have been wondering about it ever since http://www.evalbum.com/3242

200 miles range lead acid WOW 
Would it be more efficient to have one motor on the rear end rather than two on each wheel?


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## Ziggythewiz (May 16, 2010)

Highly doubtful. The amount of power needed seems much higher than 33 lb batteries could hold. Not that that area is very clear though.

Also, at the time it was written, it had 156 miles on it, so obviously the 200 mile range wasn't verified.

Typically multiple motors on multiple battery packs and controllers will be less efficient, because they are running at half the voltage and greater weight.


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## samwichse (Jan 28, 2012)

Seems like 1980 lbs of lead might give you 200 miles in range with a very low drag design.


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## Snakub (Sep 8, 2008)

Still even though each battery only weighs 33 lbs there are 60 of them that's 10 strings of 6 33 lb 12 volt battery that's probably 50 amp hour that's 500 amps hours with a very low aerodynamic drag coefficient. I think he has only one controller but like you said one motor would be more efficient. I wonder how he adapted each motor to the wheels?


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## Ziggythewiz (May 16, 2010)

Still only 3 kWh, which is double I've run with a range around 20, even at double the efficiency that would give 80ish miles.

A thread about it on ecomodder makes it sound like the furthest it went was 80, and could have done 10 more. It also sounds like the 162 Wh/m was when running 1/2 or 1/3 of those batteries. I suppose you could calculate 200 if you use the unloaded efficiency, the fully loaded capacity, and assume lead gives you 100% of rating.


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## The Toecutter (May 30, 2010)

Ziggy, you should read that entire thread. There is a lot of valuable information and links leading to further information present. The evalbum entry is not up to date with the reality of Dave Cloud's achievements with this project or the information made available on ecomodder and elsewhere.

I'll post some pieces.

For one thing, it really can do 200 miles range at freeway speeds:



> To see how far he could drive the car, he and a friend drove it from his home to Bellingham and back, twice. The first drive was hampered by rainy weather and qwackers pulling in front of him and then, inexplicably slowing down. Last Sunday, he succeeded in making the entire trip -- at freeway speeds -- without interference and finally depleted the battery at 201 miles.


http://www.evworld.com/article.cfm?storyid=1887

Also, the vehicle is hardly optimized for efficiency. Dave Cloud explains:



> When I say 130-140 WH/mi that is at a constant rate cruising at 65 mph on the flat. When I said 177 WH/mi over the first 171 mi of my trip, it was an average that included several stops and starts that were as high as 1000 wh/mi for the first mile of a restart. The reason for the high wh/mi on the starts is because the motor is really inefficient taking off from a stop when it is geared for 71 mph on the top end because there is not a transmission (if I had a transmission I could probably drive it in a manor to reduce that number). The original 192-wh/mi figure was an average over the whole trip, including starts and stops and a conversion from amp hours to watt hours that was not accurate, it did not account for large voltage sags towards the end of my run. I have two amp hour meters set on amp hours not watt hours because I do all my battery testing in amp hours, in order to more accurately gauge differences between battery weights. Therefore I am more familiar with amp hours, verse watt-hours.
> 
> Another thing I would like to clarify is that my goal was to build a vehicle that can go 200 miles on a single charge with a speed of 60-65 mph for 85% of the miles, for under $3,000. I accomplished this goal. Because of my $3,000 limitation I made a lot of compromises in the chassis design hoping that the aerodynamics of the vehicle would make up for those inefficiencies. Inefficiencies such as front wheel bearings that rumble, back tires that are 10 years old and misshapen, single speed dual series motors (that were $100), no re-gen and inexpensive Curtis controllers.


http://ecomodder.com/forum/showthread.php/ultimate-aerodynamic-car-dave-clouds-dolphin-13142-11.html



It is real. You can talk to Dave Cloud for details; his phone number is in the eco modder link. In fact, if you do a little number crunching, the theoretical results closely match Dave Clouds claimed results, when you make harsher than normal assumptions for rolling resistance, wheel bearing losses, ect. and account for the high motor amp accelerations at low rpm.

Being such a heavy car with a messed up alignment and poor tire choice(due to budgetary considerations), having direct drive takes a huge toll on efficiency in stop and go driving. If, OTOH, it were set up to shift the two motors electronically between series and parallel, or just used one single large motor where high current's weren't as lossy(WarP 11 HV, Kostov, ect), its gains in efficiency would be substantial.

With the off the shelf CALB LiFePO4 batteries on the market today, and a decent drive setup, and fixing the tire and chassis/alignment issues plaguing that car, it could break multiple world records at once with a sub $50,000 budget for additional components, and hold those records for a long time. A car with that low drag could reach ~200 mph on around 200 horsepower, and under the assumption that it is street legal, it would undeniably set a record at Bonneville in what would be a category for street EVs. Put in three Netgain Impulse 9"s(Limit all three to a modest 170V/450A in series, and allow 800A each with all three in parallel, where they will produce ~150 lb-ft each, and combined peak around 220 hp at 5500 rpm redline with 170V/450A limit on each), a 192V pack of CALB 3.2V 400AH cells(60 in series for 1892 lbs, 76.8 kWh), a Soliton 1, and a custom single-speed ratio geared for 200 mph at 5500 rpm, then drive it to the salt flats without any need to put it on a trailer, and see what it does... My guess would be 0-60 mph ~8 seconds, a top speed of 200 mph, and a 750 mile range at 65 mph.

750 miles per charge is not out of the realm of possibility with an equal weight in LiFePO4 in that car versus the lead currently in it combined with further improvements to efficiency; the LiFePO4 batteries I am referring to aren't even close to being the ones on the with the highest wh/kg rating... compare the wh/kg of the batteries in Wayland's Insight. Imagine 1900 lbs of _those_ in the dolphin... can you say 1,000+ miles range? Recharge time would not even be an issue at all. *drool*


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## Ziggythewiz (May 16, 2010)

The Toecutter said:


> Ziggy, you should read that entire thread.


Sorry, that's a long thread.

I tend to believe math more than some blog post. To get that many miles at that rate, those batteries are putting out 50 ah each, which would be a 0 peukert 100% DOD lead battery used mismatched surply battery.

And the car is pretty highly customized already.


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## DIYguy (Sep 18, 2008)

I dunno, but that seems like an awful lot of weight for that vehicle. ? ? Could it really carry a 2000 lbs of battery? Just sayin'. I've had 1600 lbs of lead in a half ton truck and I had to add a leaf spring . . oh, and it had 4 wheels... lol


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## MN Driver (Sep 29, 2009)

I like the design and I believe the results. I drive a 1st Gen Honda Insight and have driven 1500 miles on Interstate highways off of a hair under 20 gallons of gas, started with a full tank drove to the Detroit, MI and around in the area to do what I was there for, filled up on gas and drove all the way home, stopping in Madison, WI on the way back to Minneapolis, MN. The Dolphin is more aerodynamic than my car though. Weight doesn't matter much when you are going a steady speed on a freeway without stopping, hills will slow you down on the way up but the way down will recover the energy and rolling resistance isn't that much higher. I've driven over the GVWR of my car with a buddy and when he drove my car at 85mph we still managed 55mpg that tank going that speed even with the extra weight.

I'll be adding 400 pounds of LiFePO4(20kwh) to my Insight and am expecting 100 miles or better. There is a person on Ecomodder who added a boattail to the rear of his Insight and it increased efficiency quite well. I won't do the same since I want a car that blends in as an unmodified vehicle(no 'Electric' stickers or anything) and would be concerned over crash liability with a body modification.

Ziggythewiz, if you are drawing power for 200 miles, that is 3+ hours and its mostly steady state cruising, there won't be nearly as much peukert as a standard lead-acid conversion.


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## Ziggythewiz (May 16, 2010)

MN Driver said:


> Ziggythewiz, if you are drawing power for 200 miles, that is 3+ hours and its mostly steady state cruising, there won't be nearly as much peukert as standard lead-acid conversion.


More than at the 20 hr rate. Anything above 0 and it isn't possible.


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