Joule Thief

[Poit]

Hey guys,

Ive been thinking lately, if a JT is good at using up all the energy in a battery for say, a LED torch. Can a JT be used in a device that uses a lot more power, say, a electric scooter? like this one http://www.bestscooterbuys.com/evo800.html (I own two of these!! great fun!!)

It is a 36 volt system (3x 12v 12amp sla batteries) @ 800watts.... currently the scooter will go at full speed (35km/h) for about an hour before the battery is "flat".... but if a JT was built, like... a BIG JT was built... couldn't I in theory get a lot more use out of the scooter?

I would really love some input here, because I don't know a hell of a lot about electronics, its a hobby that I never really got all that good at

Would it be as simple as getting a very large transistor, very large toroid, and a very large resistor? or is there a better way?

Thanks for your time in reading this... look forward to peoples responses.

Pete

[Pirate88179]

Poit:

Interesting idea but I am not sure if it will work or not.  You are dealing with a good sized DC motor in that scooter.  If it would work, I believe you are correct about scaling up the JT, big time.

One way to possibly test your idea might be to get a similar, very small DC motor that will run on like 2 volts or so, and first run it straight from a battery of known charge, time how long it runs.  Then, run the same motor from the same sized charged battery using a JT circuit and see if it runs longer.

That is all I can think of to try.  The pulses in the JT fool our eyes making us think the light is on all the time when in fact it can actually be off as much, if not more, than on depending upon the duty cycle.  I am just not sure how the electric motor would react to these pulses...in fact, sending it AC or pulsed DC it may not run at all.

It would be a good experiment to try then we would know.

Bill

[Poit]

Poit:

Interesting idea but I am not sure if it will work or not.  You are dealing with a good sized DC motor in that scooter.  If it would work, I believe you are correct about scaling up the JT, big time.

One way to possibly test your idea might be to get a similar, very small DC motor that will run on like 2 volts or so, and first run it straight from a battery of known charge, time how long it runs.  Then, run the same motor from the same sized charged battery using a JT circuit and see if it runs longer.

That is all I can think of to try.  The pulses in the JT fool our eyes making us think the light is on all the time when in fact it can actually be off as much, if not more, than on depending upon the duty cycle.  I am just not sure how the electric motor would react to these pulses...in fact, sending it AC or pulsed DC it may not run at all.

It would be a good experiment to try then we would know.

Bill

awesome idea.. ill do that now (the test that is)

[resonanceman]

Hey guys,

Ive been thinking lately, if a JT is good at using up all the energy in a battery for say, a LED torch. Can a JT be used in a device that uses a lot more power, say, a electric scooter? like this one http://www.bestscooterbuys.com/evo800.html (I own two of these!! great fun!!)

It is a 36 volt system (3x 12v 12amp sla batteries) @ 800watts.... currently the scooter will go at full speed (35km/h) for about an hour before the battery is "flat".... but if a JT was built, like... a BIG JT was built... couldn't I in theory get a lot more use out of the scooter?

I would really love some input here, because I don't know a hell of a lot about electronics, its a hobby that I never really got all that good at

Would it be as simple as getting a very large transistor, very large toroid, and a very large resistor? or is there a better way?

Thanks for your time in reading this... look forward to peoples responses.

Pete

Poit

I am pretty sure it will be a while before anyone makes a JT big enough to directly  power a scooter.
However.........a normal JT might  be a good thing for a scooter anyway.
A JT can be used to charge a battery ...  charging  a battery with a JT conditions the battery kind of like  a bedin motor  will condition a battery.   Once conditioned the battery may  hold  a few % more power....... and it will recharge faster .
Now if  you wanted to add some solar cells to your scooter.......you could  use the JT to trickle  charge  the battery even while  you are riding it........and if you park  it in the sun  it will charge a little ......and I mean a little.... I charge a 14 AH SLA battery  with a JT ......if I discharge the battery alot  it takes days to  recharge.

gary

Edit

I have been working on making a much stronger JT without using a hard to obtain toroid .  Once I come up  with a good design  maybe some more options  for your scooter will be available.

[kooler]

 i made me a jt train one jt run a jt running a jt..
i know you guys done this before.. but i wanted to try it..

http://www.youtube.com/watch?v=HN3F_nQCBRE

robbie