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I just finished wiring up my EV (Mitsubishi Expo, Warp 9, Logisys controller). It just barely moves (a few inches). The batteries are low (they have been sitting for sveral months), but the voltage stays at about 90 volts and only drops a couple of volts when I open the throttle. The car and motor have been sitting for about a year. I tested the system by engaging the motor with 36 volts a few days ago, without any pre-charge resistor. Could I have burned out the controller allready?
 

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We would have to know more about your EV to venture a guess. What is the pack voltage and type? How is the controller currently programmed? How did you connect 36 volts to the motor and what else was connected to the motor when you did that?
 

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Update; Two of the batteries were bad. I don't understand how the voltage could sag only a little, and the amps could go to nearly nothing (maybe the controller reduced the load faster than the sample rate of my meter(?)). I made it around the block, but by the time I got home, the car was doing about 5 MPH, and this with batteries at about 75% SOC. Also, the moror smelled of buring insulation... Is this smell normal for a new motor?
 

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4/9/11 update The burning smell turned out to be the frozen front brake caliper. With a fan on the controller, it is now only getting warm. I can still only do about 30 MPH. I put voltmeters on the motor and on the battery pack, and I'm getting just about exactly 1/2 the voltage at the motor. Batteries (undser load read 130 volts, voltage at motor 65 volts... system: 13) 12volt AGM group 27 batteries, Logisys controller, Warp 9 motor.
 

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Some pictures or links to more info about your build would be helpful. Here are some other things you could try but just speculating. Also, how many amps are being pulled off your 132V battery pack (13 * 12V) to maintain 30mph?

It is normal for the voltage on a series motor to be considerably less than the battery voltage is. So I wouldn't be worried about that.

Are the other 3 brakes seized too? :)

Do you know if your throttle assembly is working right? If you have a throttle pot (like the curtis PB-9) is it not opening all the way? This would limit your throttle just like a misadjusted carburetor linkage would on a gas engine.

Does the controller have a proper heat sink (not just the fan)? If it does not it may overheat internally very quickly and start limiting power to save itself. It should have either a 1/4" or thicker aluminum plate with at least 2 to 3 times the surface area of the base of the controller on either side, OR better yet a finned heat sink with a footprint the same size as the controller. The heat sink and controller should be mounted where they get air movement while driving.

Also on the subject of controllers, Not too familiar with the logisystems ones but most controllers have a low voltage cutback function meant to protect themselves and the battery. Basically, they won't allow the battery voltage to go below some threshold. On my non-programmable 144V curtis, I believe it is 72V. Your logisystems is probably programmable, and if the threshold is set too high you won't have any power. Other programmable settings to check is the motor and battery max amps settings. If either of these are set too low you won't have any power.

The motor won't have peak power til the brushes break in which takes a few hundred miles, but you shouldn't be creeping along. If the brushes are badly out of time or the timing is backward you may have loss of power and/or efficiency. If in doubt, set neutral timing.

Are your battery cables and lugs properly sized and properly made? If they are too small or poorly made you will have problems like a loss of power and eventually, melted and burned wires.

Batteries, especially lead acid, don't have a very good shelf life. even if yours are "new" if they are more than a few years old and have been sitting, they may not be much good. A few cycles may or may not revive them in that case. If they are used, like old UPS batteries or something they may very likely not be good for much especially an EV application.

Good luck.
 
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