Golf Cart Charger Diodes: How to Check

We often receive questions about checking golf cart charger diodes.  We have prepared a Checking Golf Cart Charger Diodesgreat tutorial to explain what a diode is, what it does, how to test it, and replacement procedures.  These procedures are relatively simple, but a multi-meter with the capability of testing continuity will be need for testing.


In the most general terms, a diode, whether in a golf cart charger or any other application, is a one way gate for electricity.  It is direction sensitive and only allows power to flow one way through it.  They are generally installed as protection against polarity reversal.  Golf cart charger diodes do just that, protect against polarity reversal. Golf cart charger diodes are generally connected directly to the transformer which converts AC power to DC and are used to protect it from damage.

How will I know there is a potential problem with my golf cart charger diodes?  Most people won’t be checking their diodes for fun, but rather tracking down an existing issue.  If you are having issues with your batteries run out of power prematurely, chances are good that you either have battery issues or the charger is not charging them fully.  Most chargers have two diodes inside.  If both go bad, the charger will not come on when plugged in an

4 thoughts on “Golf Cart Charger Diodes: How to Check

  1. This sounds like my problem. Charging is not good with my charger but good with my neighbors.

    • If the problem does not exist when using your neighbors charger, the issue is either in your charger itself or within contacts of the plug where it plugs into the cart. Be sure that DC plug, cord and contacts are in good shape as well. Issue may be inside as suggested in my diode test for the previous post.

  2. I did the test and looks like diodes are OK. Is there any other thing that will keep the charger from fully charging the battery set?

    • If your diodes test good (see procedure below), and the relay is clicking & working, then only one other thing could cause the charger to shut down prematurely. There is a circuit board inside which controls the power accordingly. It could be going bad. Originally, these chargers had two boards inside. The input board which sits horizontal inside and has the relay and the control board which mounts vertically between the heat sink and charger face. However, they have since discontinued both boards and combined into one board. It requires a bit of simple retrofit wiring, but we have instructions for that. The new combo board is about $93 and is available here :

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