Engjay

Hi Guys
i need your help with my project
i want to build up an electric kart
i got the dc motor from a treadmill
that its 1.5 hp and maximum voltage in to 180 vdc
i need now to find a dc to dc converter (how to build it or where to buy it)
buck- boost converter
to get a (12 or 24 or 36 or 48 vdc) input batriies
and want to convert it to 180vdc
i need to have a dc motor controller but i dunno where to get this stuff
and how can i start to design it ?
and what controller i need?
if you have sites or any good idea or schematic for this both circuit
plez help me

ronsimpson

I built an electric go-cart when I was a kid. I used a car starter for the motor. A headlight bright/dim switch for on/off and a car battery.
It saved the brain damage of making a 12 volt to 180 volt converter.

I know this did not help.

You might get an “inverter”. 12 volts to 110 volts. Then use 4 diodes to rectify to DC. I think you will not need a filter capacitor. The motor will not run at full power but it will run.

Nigel Goodwin

Basically what you're saying is you've got a completely useless motor for the job, and you're like to try and bodge it so you can make it work.

Simple answer, get the correct motor for the job!.

Or instead of using car batteries, use fifteen small SLA's in series to give you 180V, and you could distribute these around the chassis to give better handling.

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MrDEB

that 1.5 hp motor is too small for any real performance. Would be better off getting a kiddy electric car. may be cheaper in the long run.
Best solution is a golf cart motor or other dc motor.
I recall Popular science or mechanics had artical about using an automotive starting motor.

Hero999

Actually electric motors provide more acceleration per hp and petrol engines so 1.5hp might not be as bad as you think. The only problem seems to be the top speed is lower but gearing should be able to fix that.

I agree with Nigel, use fifteen SLAs in series to give 180V, this would be more efficient since you miss out on an extra conversion wich would loose energy.

Be careful working with 180V which is hazardous, take the following safety measures into account and you shouldn't have a problem:

• Insulate all parts of the 180V circuit, even the 0V rail!
  
• Don't use the chassis to carry current for the 180V circuit, if there's a poor connection between two parts, then one might float at a lethal voltage relative to the other.
  
• Bond all exposed metal parts to the chassis, especially those that contain live parts, e.g. the motor.
  
• If you require a lower voltage (e.g. 24V for the headlights) then use a separate battery bank. Don't be tempted to tap into the large battery bank, for a start it'll cause the batteries to discharge unevenly and if there's a loose connection in the bank, your 24V circuit could float at a much higher voltage.
  
• Connect the 0V rails of both the 24V circuit and the 180V circuit to the chassis at the same point. This will prevent the 24V circuit from floating on top of the 180V circuit if a fault occurs.
  
• Use suitable fuses on both the 24V and 180V circuits. When short circuited, lead acid batteries can explode and spray hot sulphiric acid everywhere; fuses will provent this from happening.
  
• Make sure the cable and all other components are adequately rated for the current you plan to draw.

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Nigel Goodwin

Now that's a nasty thought!

Good point!.

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Engjay

Thanks guys for Your replies
i will start as u said to
put fifteen SLAs in series
now i have 180 vdc
any good ideas ? how to build or choose a controller? for my dc motor ?
so i can controll the voltage from 0 vdc to 180vdc
i need a good controller design

blueroomelectronics

What does 15 SLA batteries weigh? What are they rated for?

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specie

Load will probably be too much for the motor.

jpanhalt

Since your motor came from a treadmill, there is usually a simple, high-voltage controller that can be plugged into the mains with it or one can be had cheaply. All you need to do is convert your 12 VDC to 110 VAC, as with an inexpensive inverter. The quality of the sine wave is not important, as the controller will rectify it first. John