03 PDS resurrection

[JohnnieB]

Originally Posted by fingers

1. Pack voltage stays the same, 37.55v pedal up and pedal to the floor after the solenoid clicks.

2. I do plan on staying with stock sized tires, at least for the time being, again on Scotty's advice. And a 2 ga. cable set is going to be in my order. I jumped the motor using the instructions I found here and the motor does turn so I should be in good shape when I get the parts from Scotty and the new batteries. I'll be keeping my fingers crossed.

3. Can you program the controller to limit rpm? That would be another option to prevent over-speeding the motor but keeping the torque gains and some speed of going to 48v would it not?

4. I'm still on the fence regarding 42 vs 48 volts. I "think" I need the extra torque and less weight of 48v since I really don't need the extra range but I don't know if the difference is worth worrying about. The extra range and particularly the extra battery life would be nice as well as being able to test my old controller if the torque of the 42v system is enough for me. I'll be carrying as much as 4 adults and a couple of kids around on mostly flat ground or two adults and maybe one or two kids around the neighborhood which is fairly hilly. All paved but pretty steep in places.

5. kgsc, I do have access to another cart at a friends place, but I'd hate to risk damaging that one just to check my controller. I think I will wait to get the new batteries and cables and try it then. Unless I decide to go 48v of course. In that case, I'll have to come up with plan B to test it.

1. The pack voltage is staying the same, so the voltage drop seen at J4 is occurring in the wiring. The new wiring harness ought to take care of that issue.

Also, 37.5V is 80% SoC, the solenoid is clicking and the throttle input to the controller is in the ballpark, so the cart ought to move when the pedal is pushed, unless there is a problem in the high current circuit, or the controller is bad.

Connect your DVM between the controller's B- and A1 terminals. When pedal is pushed just far enough to make solenoid click, you should read full pack voltage. When pedal is slowly pushed to floor, the voltage ought to smoothly decrease to zero. If you get full pack voltage when solenoid clicks and it does not decrease as pedal is pushed further, the controller is bad. (The other possibility is a bad ITS, but the voltage given for the ITS in an earlier post were close enough to what they should be to get some decrease when pedal is pushed)

2. Cart speed is proportional to tire height while the torque where the rubber meets the road is inversely proportional to it and Stock height tires (18") is the baseline. Install taller tires, you gain speed and lose torque.

3. With stock height tires and a DCX controller, your cart will do about 24 MPH at 36V, about 28 MPH at 42 V and about 32 MPH at 48V. The RPM of a stock PDS motor at those speeds will be about 5600, about 6500 and about 7400 respectively.

You can limit the top speed of a DCX controller, but I've never done it.
The DCX does not use a speed sensor, so it doesn't know how fast the motor is actually spinning and I'm not sure if it whatever it does to limit the top speed affects the low end torque or not. (However, about the only time maximum low end torque is used, is when accelerating from a standstill since once the motor is spinning more than a few hundred RPM, it cannot draw the max amp throughput of the controller.)

Also, turn off the Turbo. That will knock off 3-5 MPH at the top end. (About 1000 RPM on 18" tires)

4. At 36V, a DCX400 will increase low end torque by about 1/3 over the stock 300A PDS controller, but how much a cart slows down going uphill is more a function of high end torque than low end torque.

High end torque, low end torque and max motor RPM are all three increased when the pack voltage is increased. Going from 36V to 42V is about a 1/6 increase and going from 36V to 48V is about a 1/3 increase.

Going to 48V will give you better performance than 42V, but opens the door wider for damaging the motor and when a motor goes during operation, it often takes the controller with it.

I found out the hard way that driving down a long steep hill with the pedal on the floor to find out how fast a cart will go, isn't a good idea and is the reason I'm no longer running a DCX400 and stock PDS motor.

5. If you have a 12V charger, you can charge the existing 6V batteries in pairs (they don't have to be disconnected - see attached) and when the rear wheels off the ground, they ought to have enough oomph to spin the tires a little in the controller is good.