Why does my electric golf car jerk, shudder or shake?

Sometimes customers call in to our service department to report that when they press down on the accelerator of their golf cart the vehicle starts to jerk when moving forward. This may happen when only trying to move forward, and going in reverse seems to work fine.

A golf cart may jerk, shudder, or shake when the proper voltage is not reaching the speed controller or electric motor. Generally, this is caused by low battery voltage and/or a corroded battery terminal connection.

Safety Notice

Before attempting any maintenance or repairs on your golf car it is imperative that you consult the owner’s manual and follow all the safety guidelines. The following are a few safety tips, but may not be all inclusive.

  • Turn the golf car ignition key to the OFF position
  • Wear appropriate personal protective equipment
    • Safety glasses
    • Gloves
    • Protective clothing
    • Appropriate footwear (with rubber soles)
  • If your golf car has a (RUN/TOW) switch under the seat, place the switch in the TOW position.
  • Batteries can spark, arc, and ignite. Always use cause when handling them!

Check Battery Terminal connections

The most common reason for your golf cart jerking is often the battery terminal connections are loose and/or corroded. A poor connection prevents the correct amount of current from flowing through the set of batteries to your speed controller (or resistor coil), and ultimately to your electric motor.

If a battery terminal has a lot of corrosion on it, like in the picture, it is not unusual for the battery cable to have completely corroded off. You can check the connection by gently wiggling the battery cable. If it moves freely or breaks off, the eyelet of the cable will need to be replaced, but generally it is recommended to replace the entire cable.

You may also find that with a lot of corrosion on the battery terminal, that the terminal post itself has corroded to the point where a good connection is no longer possible. If this is the case, you will likely have to replace the entire battery.

To clean the battery terminal post, you can spread baking soda (a base) to neutralize any acid on the battery and post and wash it off with water. You may also find it necessary to brush them off with a wire brush.

Having a corroded battery terminal connection can also contribute to your batteries having a low voltage since when the golf car batteries are charged, the circuit is disrupted preventing the charger current from reaching all the batteries at the proper rate.

Note: You should clean batteries outside and away from concrete since the water that runs off the batteries will stain your concrete driveway. It will not kill the grass though.

Check Battery Voltage

Once you’ve cleared all the battery terminals of corrosion, you’ll next need to check that your batteries are providing the correct amount of voltage. This can be accomplished using a simple voltmeter.

I normally check the entire battery pack voltage first because it is a quick check to do and saves time (if all batteries have sufficient voltage and connections are good).

  • Set the voltmeter to Direct Current (DC)
  • Place one of the probes from the voltmeter on the first battery positive (+) terminal
  • Place the other probe from the voltmeter on the last battery negative (-) terminal
    • For a 48V golf car the voltmeter should read anywhere from 48V – 56V
    • For a 36V golf car the voltage should read anywhere from 36V – 42V

If the voltage of your battery pack isn’t within the ranges above, you’ll need to test each battery individually. This is done by placing one of the probes on each of the battery terminals (one on +, and one on -).

The voltage readings should be close to the stated battery voltage on the battery. ~ 6V for a 6V battery, 8V for an 8V battery, 12V for a 12V battery.

If the battery reads substantially lower than it should, you’ll may need to check the water levels in the battery and then plug in your golf car charger.

Check Resistor Coil (For Older 36V Golf Carts)

If you have an older 36V golf car that doesn’t use a speed controller, and you’ve completed all the steps above and your golf car is still jerking in set to forward, but works fine when the direction is changed to reverse you may have a bad resister coil.

This is a very common issue with older 36V Club Cars. This system uses a resistor and all the batteries in the set while going forward, but only 4 batteries when set to reverse.

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