Electric Motorcyle Issue?!!??!?

Question

I'll be using 4 lead acid deep cycle batteries that put out 875 CCA and 205 amps continuous and so forth but the motor only uses 133 amps and 48 volts, just want to know if the controller should be rated at 300 amps, 400 amps, 550 amps? I'm wanting to get a curtis controller off ebay and found all three but which one!???

Answer 1

In my opinion, any one of those would work fine. The main difference is in the level of performance you want out of this bike. A higher amp controller will give you let you climb hills faster, and give faster acceleration in general. The top speed is the same unless you go to a higher voltage. The trade off is, when you are running more amps through your motor & cables, they will heat up and fail if the motor doesn't have some means of cooling (usually a blower forcing air through it) and the cables  need to be thicker.

If you have mostly flat land where you live, and an easy-going driving style, a 300A controller would be fine.

Once you are up to speed, you'll probably draw less than 200 amps cruising on flat land.

Definitely install a good ammeter and keep an eye on your motor amps. You might want to avoid several-mile uphill climbs and similar situations that will draw a lot of amps for extended amounts of time. If you draw 500A for more than about 2 minutes at a time, it's very likely that stuff will start burning up. If you anticipate a lot of hill climbs, you should  have a blower forcing air through the motor, and a good heatsink/fan combo for the controller as well.

A 48v controller is appropriate for your system. The engineers at Curtis know that a fully charged 48v pack is more than 48v and they have built in the appropriate tolerance for over-voltage. The controller also is capable of feeding more current to the motor than it draws from the batteries, so even if it's giving 400 amps to the motor, it will be pulling much less than that amount of current from the batteries. If you want to have the option to add more batteries and run a higher voltage system, you could get something like a Curtis 1209B or an Alltrax 7245... both of those are rated from 48v-72v so you can run it on 48v now, and add more batteries later if you want to have a higher top speed. Those controllers are a lot more expensive than a regular 48v one, and also physically larger and heavier.

Answer 2

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Answer 3

The controller is only a conduit of energy to the motor so if the rate matches or exceeds the amps the number to choice is one just higher. The controller will feed only want is needed to the motor. That means the motor will not run more amps than what it is rated for so don't worry, just cover the difference between the two devices.

Spartawo...

Answer 4

Controller voltage rating should be at least 25% more than peak voltage from the charged batteries.  So batteries are really 13v x4 = 52v + 25% would be 65V.

Controller current rating should be minimum 3 times the motor continuous current rating.  peak on a motor is normal 2x continuous, and the extra is for instantaneous and safety margin.

3 x 133 = 400 amps.

so for long term reliability your controller for this motor should be rated at 65v or more and 400 amps or more.