How to build a GIGANTIC Joule theif for 288 V DC electric car?

[donx]

Hello Group, I've never taken an electronics course, I use to tinker with toys when my dad wouldn't buy the correct size batteries, and figured out electronics the old school way...

So I've seen videos of Joule thiefs and know how they work...

I am building an electric car, I will be buying Thundersky 100 amp hour cells, they are 3.2 volts each, and for my total pack I will purchase 90 units...   

90 x 3.2V @ 100 amp hour = 288V @ 100 ah,  28.8 kW battery pack...

Now here is the issue with using lithium batteries, if you ever drain them, they loose life, they are best used up until 40% is remaining... and then charge them back up.  This extends their life cycle 2000 cycles until 80%, and then 3000 cycles @ 70% then after that they become ... ?


I am going to spend thousands of dollars on these batteries has anyone ever made a joule thief that will for work for my application?  That is my question for you bright people... 

When I deplete my batteries to 50% can I turn on my joule thief circuit... or have it constantly on?  Can I charge with the joule thief connected? 

[if anybody would like to learn more about building Electric Vehicle simply go to EVTV.me, or youtube: GAVs EV]

I look forward to your responses,

Don

[Magluvin]

Hey Don

Looks great.  Is that a 9in warp motor?  You should get good power with 288v.  ;]

Im doing an 85 fiero.  Im looking to use the warp9 also.

As for the JT, if there is an advantage to using it here, that would say that the JT is OU. Cant say that it is.

One advantage may be that you can use the power that the the batteries do hold, after a long life, to possibly get the car to perform as it did when the batteries were new, but for a shorter time than without the JT. As short of a time that it takes the batteries to reach the critical drain level.

What kind of performance do you think you will get from that motor at 288v?

Thanks for showing. ;]

Mags

[donx]

To answer your question, yes that is a Warp 9, from a conversion that was recently finished.  I am using the Warp 11 HV with my conversion, waiting for the adapter plate to come.  My car weighs 5000 lbs and I am going to become the benchmark, nobody else I know has used one of those big boats that was created in 1985.

As per the JT, from wiki:

(Joule Thief) The circuit uses the self-oscillating properties of the blocking oscillator, to form an unregulated voltage boost converter. As with all power conversion technology, no energy is actually created by the circuit. Instead, the output voltage is increased at the expense of higher current draw on the input. As a result, the amount of power entering the circuit is the same as the amount leaving, minus the losses in the conversion process.

(Boost Converter)
Battery powered systems often stack cells in series to achieve higher voltage. However, sufficient stacking of cells is not possible in many high voltage applications due to lack of space. Boost converters can increase the voltage and reduce the number of cells. Two battery-powered applications that use boost converters are hybrid electric vehicles (HEV) and lighting systems.
The NHW20 model Toyota Prius HEV uses a 500 V motor. Without a boost converter, the Prius would need nearly 417 cells to power the motor. However, a Prius actually uses only 168 cells and boosts the battery voltage from 202 V to 500 V.

[e2matrix]

I think your best idea would be to check in with Thane Heins who is a member here.  Here are a couple links to give you an idea of what he is doing.  Briefly he is manipulating magnetic fields so that instead of slowing down a generator (according to Lenz's law in physics) it speeds it up.  He already has plans for how this could be used in electric cars.  Take a look here:

http://peswiki.com/index.php/Directory:Perepiteia_Generator_by_Potential_Difference_Inc

and here:

http://www.overunity.com/7530/thane-heins-perepiteia-replications/ 

Here is one of his relevant videos - http://www.youtube.com/watch?v=L3JVjbXOssQ

His member name here is CRANKYPants   

[Moab]

for what its worth big JTs are dangerous, and wont give the amperage your going to need for your DC motors. the voltage would be there but when you start pushing the kind of amps your looking at you will likely find the JT lust wont handle it for ya and youll emd up with a bunch of smoldering copper,


but hey if ya got the cash give it a try.


thats my .02