2002.5 Club Car DS 48V controller upgrade questons

[hrk]

Been reading some of the threads to get general information on upgrading the cart in regard to power delivery. Right now it has 2 year old set of batteries, 48V, new cables and runs well flat or downhill however it does slow down uphill, even though in FL we have few hills.

The wife wants me to remove the golf club parts on the back and put in a second folding seat, raise the cart 4-6 inches with bigger tire/wheels. My concerns are that the stock controller and motor are going to be overworked, or underperform.

Can I simply upgrade the controller and solenoid to gain power for uphill and not the motor to obtain more TQ for starts and uphill. Not looking to go drifting or racing, but more speed and power is good. One of the roads we use has heavier traffic and a 30 mph limit that of course no car exceeds.

Like to pick up some MPH top end, and also have more pull speed uphill since that's when we need it most, I was looking at the Alltrax controllers on carts unlimited, lots of choices, I'd also like to get a controller that would allow me to move to Lithium once these LA are retired.

I was looking at the 48400 but it's out of stock, would the 48500 be a good choice for future upgrades including motor...

[Wakko47]

You're on the right track. Where in Florida are you? Is your cart an IQ cart?

[hrk]

Central FL, it's not IQ, its a series cart, 2000.5 model DS.

[CP241]

48500 would be a great choice. I’d also recommend a HD FNR switch.

Keep in mind, the design of a series cart/motor will always slow up hills. The sepex ones do a lot better stock. But even with upgrades you will notice a loss of speed up hills. My last series DS would do nearly 30 on flat ground, but lose speed up hills Still. Big hills it would drop to around 17-18mph. It has an admiral motor, 48400, FNR, solenoid, big cables, 6” lift and 25” tires. It had the torque to spin the 25” tires in dirt or asphalt. It might have done better with a 48500 but I’m not sure.

I did use light weight tires so I did not notice any torque loss going from stock 18” tires to the big ones. It did the same thing with the stock tires on big hills. But depending on what tires you pick, you will lose a bit of torque with bigger heavier tires.

[CP241]

It would also be beneficial if you knew voltage readings both on flat ground and up a hill. Big voltage drop going up hills can indicate a connection problem, and really make an impact on hill performance.

[DaveMJ]

Here are my thoughts. Unless the current set up is limiting the voltage to the motor you will not gain anything by changing to a higher capacity controller, etc.. Your limiting factor may well be the motor or batteries.

As the name implies in a Series Motor the Field Coils and the Armature Coils are in series. If your current system provides full pack voltage to the motor under hard acceleration and at max speed - there is nothing to gain by upgrading the controller.

What I did do evaluate this on a cart I'm rehabbing now was to monitor voltage between pack positive and controller M- while driving. This gives you a reading of the difference between available pack voltage and voltage applied to the motor. In my case I got a reading of just over 0.5v under hard acceleration and at max speed. This basically meant that motor is seeing full pack voltage less a small (expected) loss through the controller.

If you see a significant difference, check throttle input to controller and all your heavy gage wiring before rushing out to buy a replacement controller.

If anyone thinks there's any fault in my logic - let me know.

I bought a 98 DS 48v Series cart that was totally stock, it maxed out at about 13 MPH. I installed an EMP motor, with no other changes to the cart it achieved 24 mph on the flat. Three years later it's still running strong.

[CP241]

Originally Posted by djohns18

Here are my thoughts. Unless the current set up is limiting the voltage to the motor you will not gain anything by changing to a higher capacity controller, etc.. Your limiting factor may well be the motor or batteries.

As the name implies in a Series Motor the Field Coils and the Armature Coils are in series. If your current system provides full pack voltage to the motor under hard acceleration and at max speed - there is nothing to gain by upgrading the controller.

What I did do evaluate this on a cart I'm rehabbing now was to monitor voltage between pack positive and controller M- while driving. This gives you a reading of the difference between available pack voltage and voltage applied to the motor. In my case I got a reading of just over 0.5v under hard acceleration and at max speed. This basically meant that motor is seeing full pack voltage less a small (expected) loss through the controller.

If you see a significant difference, check throttle input to controller and all your heavy gage wiring before rushing out to buy a replacement controller.

If anyone thinks there's any fault in my logic - let me know.

I bought a 98 DS 48v Series cart that was totally stock, it maxed out at about 13 MPH. I installed an EMP motor, with no other changes to the cart it achieved 24 mph on the flat. Three years later it's still running strong.

Here’s where I will disagree.

Voltage is speed. More voltage = More speed. Top speed, not acceleration.

Amperage (current) is what creates torque. This is the ability to GET that voltage to the motor quick and in a hurry.

Think of it like this. You have a gallon jug of water, with a small fixed opening, say a straw sealed on the end. You turn it upside down and you’ve still got a gallon of water, but it’s going to take an hour to drain it into a bucket.

Same gallon, wide open top. Turn it over and it’s going to empty that same gallon in a couple seconds.

Voltage is the gallon of water. (And the subsequent gallons behind it waiting to get through). Current is the ability to move that water. In a golf cart, the controller is the biggest limiting factor (the straw). When demand increases (hill) the available voltage is the same. But it chokes the current back to limit the amperage the motor sees. So you slow down considerably as it creates a balancing act between voltage and amperage. Most stock controllers are around 250amps or so. Upgrading to a 400 or 500 amp controller allows the motor to see the current demand it requires to keep chugging up those hills.

There are other factors involved, but that’s the general gist of it.

The only down side to upgrading controller and motor is range. Because the controller is allowing a lot more current to pass through, it bears a heavier load on the battery pack so it won’t last as long. Just something to keep in mind.


And with the 500 amp controller, you should be able to use the toolkit to program it to limit the current at 400 amps, effectively turning it into a SR48400 but with a LOT more headroom. On a stock motor this would probably be advisable. But once you upgrade the motor (let’s be honest, it’s gonna happen ) you’ll be able to turn up the controller and really wake her up.

[DaveMJ]

A controller cannot push current into a motor. It makes voltage available, the impedance of the motor determines how much current it will draw. Current=Voltage/Impedance.

If the current drawn by the motor reaches the maximum capability of the controller the voltage available to the motor will be decreased. Under these circumstances a controller with a higher current rating could improve performance.

But in my example (probably a similar situation to the OP) with a stock 225 Amp controller, the full pack voltage was available to the motor under hard acceleration and at max speed. So the cart did not get to the point where the controller was a limitation. Therefore I believe upgrading the controller would not improve acceleration or top speed, the motor was the limiting factor.

[CP241]

No the controller does not “push” current into the motor. It restricts what the motor is allowed to pull. Actually... This is the reason voltage does not drop.

I’m not going to argue about it. But your thought process is not accurate. Measuring voltage alone does not give all the information when you do not take into account all of the other variables.

[DaveMJ]

Originally Posted by CP241

It restricts what the motor is allowed to pull. Actually... This is the reason voltage does not drop.

Not trying to argue either, just having a discussion - if the motor is seeing full pack voltage the controller is not restricting current. If the controller were to restrict current, the motor would not be seeing full pack voltage.