Old cables vs New cables.

[JohnnieB]

My 2008 TXT PDS had 4ga cables on it when I bought it and they looked to be in fairly good condition, but they weren't. Closer inspection revealed the cable strands were corroded within the crimped on connectors, so I ordered a complete set of 2Ga cables with solder on connectors.

As I posted in a previous thread, all the new cables had less than 0.001 ohms of resistance and when I put them on I got a noticeable increase in torque.
My top speed is now 18.2 MPH, but I didn't measure top speed with old cables. (I doubt if it changed since the PDS controller limits motor RPM.)

I finally got around to measuring the old cables today and here's what I found.
All cable ends under the controller cover were in excellent condition.
Cable ends at motor were dirty, but not corroded. (<1 milli-ohm)
Both ends of Short cable from solenoid to controller was like new. (<1 milli-ohm)
One end of B+ and B- cables had corrosion in the cable end, the other end like new. (about 2 milli-ohm each)
Both ends of all five cables connecting batteries together had corrosion in the cable end. (about 5 milli-ohm each)

That gave me a total of about 30 milli-ohms (0.030 Ohms) in series with the battery pack, so when my battery was fully charged (38.2v) and the motor was drawing 100Amps, the controller was only having 35.2v applied to it. (The missing 3.0v was being dropped across the resistance in the cables.)

In essence my cart thought the batteries only had a 25% charge when my size 16 foot was pressing down hard. No wonder my torque increased.

Needless to say, I'm amazed such a small amount of resistance can cause so much trouble, but I'm still learning about the ins and outs of carts.

[LostHusker]

Originally Posted by JohnnieB

My 2008 TXT PDS had 4ga cables on it when I bought it and they looked to be in fairly good condition, but they weren't. Closer inspection revealed the cable strands were corroded within the crimped on connectors, so I ordered a complete set of 2Ga cables with solder on connectors.

As I posted in a previous thread, all the new cables had less than 0.001 ohms of resistance and when I put them on I got a noticeable increase in torque.
My top speed is now 18.2 MPH, but I didn't measure top speed with old cables. (I doubt if it changed since the PDS controller limits motor RPM.)

I finally got around to measuring the old cables today and here's what I found.
All cable ends under the controller cover were in excellent condition.
Cable ends at motor were dirty, but not corroded. (<1 milli-ohm)
Both ends of Short cable from solenoid to controller was like new. (<1 milli-ohm)
One end of B+ and B- cables had corrosion in the cable end, the other end like new. (about 2 milli-ohm each)
Both ends of all five cables connecting batteries together had corrosion in the cable end. (about 5 milli-ohm each)

That gave me a total of about 30 milli-ohms (0.030 Ohms) in series with the battery pack, so when my battery was fully charged (38.2v) and the motor was drawing 100Amps, the controller was only having 35.2v applied to it. (The missing 3.0v was being dropped across the resistance in the cables.)

In essence my cart thought the batteries only had a 25% charge when my size 16 foot was pressing down hard. No wonder my torque increased.

Needless to say, I'm amazed such a small amount of resistance can cause so much trouble, but I'm still learning about the ins and outs of carts.

New cables along with proper maintenance will help the life of your cart and batteries.

[jwdixon]

Originally Posted by JohnnieB

when my size 16 foot was pressing down hard.

Holy crap!

Seriously that was some good info and an eye opener on the importance of cables.

[JohnnieB]

Originally Posted by jwdixon

Holy crap!

Seriously that was some good info and an eye opener on the importance of cables.

Yes, I do have a "good understanding".

Like I said, I was amazed and I've been repairing electronics and electrical devices for more than half a century.
But it is simply Ohm's law. (V = I * R). For every Milli-Ohm of resistance, you drop 0.001v for every amp that passes through it and in high current applications such as carts, it adds up fast.

The nutty thing is that my cables didn't look all that bad, even to my discerning eyes.
I suspect some of the cables seen in many of the posts I've seen here, have more resistance than my old ones.

One thing for sure, keeping your battery terminals and cables clean is a must.

[rxp-rider]

Nice break down.......