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Tech => Tech Help => Topic started by: somecallmemike on May 21, 2013, 09:33:46 PM

Title: Would a 24v motor be enough to move a Li-ion based 94 FZR?
Post by: somecallmemike on May 21, 2013, 09:33:46 PM

I have the opportunity to get a great deal on a 24v caterpillar motor, however I am not very savy when I comes to calculating the needed power for a motor.  I see most EV projects using a 48v motor, is this a big difference?

Title: Re: Would a 24v motor be enough to move a Li-ion based 94 FZR?
Post by: BSDThw on May 21, 2013, 10:02:23 PM

Power = Current * Voltage

Therefore, if you use 2 times the current it is theoretical the same.

The problem the more current you use the bigger the wires and connectors ... - And power loss everywhere is much more likely.

That's the main reason to use higher voltage.

Title: Re: Would a 24v motor be enough to move a Li-ion based 94 FZR?
Post by: Spoonman on May 21, 2013, 10:25:41 PM

The other reason for higher voltage is in overcoming back EMF at higher RPM.
Torque requirements aside, a 24V isn't going to spin very fast under load regardless of how much current you try and shove in there.


However - to answer the original question - yes, a 24V motor will move an FZR... just not at any particularly interesting pace.

Title: Re: Would a 24v motor be enough to move a Li-ion based 94 FZR?
Post by: skeezmour on May 21, 2013, 11:40:32 PM

You have never seen what drag racers have done with 24v/36v forklift motors then :)

Title: Re: Would a 24v motor be enough to move a Li-ion based 94 FZR?
Post by: Spoonman on May 22, 2013, 02:54:07 PM

lol - I certainly have. In fact I've TWO forktruck motors in a CBR600 chassis in my workshop as we speak.

...but they ain't running at 24 volts.  ;)

It's an unfinished project that I picked up from another fella who was playing around with EV drivetrains before building his own BMW 3-series conversion.
He never got it as far as a rideable condition, but it runs and it accelerates like a bullet - I've got drag bike aspirations for it myself but I'll not be going near it for a few years yet.

Brushed DC motors have ratings which can readily be treated more like guidlines - they'll take a helluvalotta abuse provided you advance the brushes appropriately for the desired peak revs, and don't mind them getting destroyed in jig time.

My advice is more relevent to the voltage than the motor.

Title: Re: Would a 24v motor be enough to move a Li-ion based 94 FZR?
Post by: jumpjack on November 07, 2013, 06:33:53 PM

Voltage is related to speed.
Current is related to torque.
As per my knowledge you  can reach around same km/h amount of voltage (24 V ==> 24+ km/h , 48V ==> 48+ km/h ), with around a 20% margin (48 V ==> up to 60 km/h)

Title: Re: Would a 24v motor be enough to move a Li-ion based 94 FZR?
Post by: hamr1 on November 07, 2013, 09:09:10 PM

get a 48 theres way more stuff out there for them