[ecat]

Hi Lukas,
i had an idea for the hovercar that could serve you or your next project.
Batteries is one thing, but charging and cassetting (no better word for now) are to be considered. I hear alot that ecars are slow (very anoying) to charge. THe new lighter batteries open the idea of cassetting them , so you can have a pack at home, at the office and at authorized centers. Like home depots do with the bbq gas propane tanks. For me , so far, the weight of gel or agms batteries was not only a problem but an advantage for ballasting (for wakesurf) , pumping water (with water pillows) , equilibrate the craft, and some other weight assisting gizmos.
PV cells are expensive but if you concentrate the sun rays with a lens or parabolic mirror, you can reduce the infrastructure cost. The sun will cook them but to cool them you may want to consider an amonia system (or CO2) using that sunlight beamheat. We use propane fridges in fishing cabins up north, no wires there ... the cold from the amonia can cool the PV cell and also air condition the car.
It comes to mind that the coolant can also heat a radiator for heating in winter.
The radiator fan can be a windturbine when the car is parked, going downhill, yes on top of the wheel regenset. I am considering that for my hovercar design , with the props, i am killing manybirds with one stone (forward propulsion, brakes, ventilation, (compost toilet, habitat) shallow water safe, regen from wind, protection from pirates at sea, even a fire extinguisher, i remove the prop and i have a saw, a drill, a grinder/sander, etc, many things not readily available with a water immersed shaft, but a must on a boat at sea.
At the end of the day, all those crafts designed to transport people are only used a fraction of the time, find another use for them. Funny enough my friend has a GM Vibe with a 115v AC outlet, he was going to buy a genset for the few power shortages we have, until i asked him if he can feed his fridge, his cpu, ... with his car ...
Keep us informed of your project, we never know.
Cheers
Mike

[Skywalker1991]

Originally Posted by ecat

I don't know if this makes sence, but i throw this at U.
I am not expert at batteries, but i know that you cannot have a bad apple in a battery pack, it will waste the others. But, from what i read, the main drawback of LiFePo batteries is it's speed. What if you have a quick battery pack at the end, the LiFePo pack would recharge on a continuous basis and the end quick ones would answer the peak demand. A bit like we do when we fill scuba divers tanks, we have what we call cascade tanks for quick fillings and the cascades are filled slowly with a little pump over night.
I also saw a Smartstart gizmo from Dometic . www.dometic.com, i don't know if it can have some application in your car. This is for ac powering the surge from air conditionning compressors in busy marinas. Air conditionning units are essential for cars in most parts of the world, heating and defrosting is also a matter in colder climates.
Are U still looking at the Emrax motors ?
I await some inputs from my friend about your quiry.
Sorry not to be more help for now.
Has there been a concept for a "no battery e-motor" yet ? Not 100% without battery mind you. There is a new "rotary" combustion motor about to be marketed, i dont know if it can run on water i.e. Hydrogen as well ... which doesn't polute very much other than the oils. So much technologies showing up...

Hi, we have decided to use the emrax motors, I also visited the company enstroj in slowenia.

Lukas, have you checked with www.ultravolt.com, or ups inverters ?

As motor controllers we will use the BAMOCARD3 from UniTek, but do you think that ultravolt could help us with chargers or something else?

Can anyone explain if there are problems when using a higher voltage for pwm?

For example if i want to have up to 190V RMS on the three phases of the motor, I would need at least 190*sqrt2=269Volts from the Batteries. But would it be a problem if I used 350V instead?

Regards,

Lukas

[ecat]

hi Lukas
My design is not for a racing car, but for an hovercraft (hovercar gizmo) . I am working out my designs more as structural and architectural aspect of things. My friend who is now in Madagascar for a year, was installing windmills in Senegal. He is a teacher in college (pre university) in charge of not only teaching electricity, but managing partneships between the working sector and the college. The college can take you to university after 2 years (if you dont flunk anything) or become a professionnal technician in 3 years (after high school), i did a little historia for you to understand the level of that teacher. THere are other advantages at university level that will develop ecolo projects, you can check with the University of Sherbrooke, i forget the exact name i can search it, they built a sailboat with high tech, if i recall correctly, i beleive Gurit supplied knowhow. Check Gurit website at least once.
All this said, my friend always says low voltage is better than high voltage, heat hence fires become a problem and very dangerous for human life. Solomons industries had developped a higher voltage motor for sail boats. Not at those (your) voltages though.
In another forum on electrical engineering, one mentionned ups capable of handling high voltages.
You may want to push the idea of a buffer (fast discharge batterie(s)) between the LiFePo4 and the motor. To bad my neighbor past away 2 years ago, he was very involved with the lithium technologies, his main concern was Hydrogen control, he repeated and repeated, beware of that Hydrogen. From what i read, LiFePo's advantage is that.
My friend has web connection problems lately, but i will transfer to you infos as i get them.
Have you looked at Plettenberg emotors ? Emrax is looking at increasing the rpm, you probably know that already. Hummm ! high rpm raises some concern for durability (windmills toasting) i would favor some transmission system. (planetary ?)
Dont forget to get your flu shot ...
haha
Cheers
Mike

[cruzangv]

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[zc47]

Originally Posted by LithiumaniacsEVRacing

We currently supply cells to other Formula Hybrid Teams.

http://www.ecedra.com/thebatteryshop.html

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