Recently, we had a service call to repair a battery charger for a local business which was not operational. The charger has been stored outside for years with little to no protection from the elements. Below we discuss our findings below and the condition of the battery charger circuit boards within.
Initially, the customer had reported that the Powerwise battery charger would not turn on when plugged in. Their EZGO TXT was completely dead due to lack of charge. Since, this cart is used by a business for operations, we decided it was best to bring both the golf cart and the battery charger to our shop for inspection. An issue could be present in either the cart or charger which can produce such an issue.
Inside the Powerwise brand charger, there are several battery charger circuit boards, They are called the power input board, and control board, respectively. In later models, these boards were combined into a single board. In a nutshell, the battery charger circuit boards inside this unit are responsible for the charge process. When plugged into the cart, the battery charger circuit boards are responsible for “sensing” the state of charge within the battery bank. They are also responsible for applying sufficient power to raise that charge level, monitoring during the charge process, and then turning off the charger when the desired charge level is reached.
As you can see from the pictures , the battery charger circuit boards in this example did not stand a fighting chance. Like most electronic circuit boards, it is not water-proof, can be temperature sensitive and achieves its best performance in controlled environments. This charger was left outside for several years with no protection whatsoever from the elements. As you can see, not only were signs of water were present but also the battery charger circuit boards were so covered with debris that it could barely be seen.
There is not a great test for battery charger circuit boards in terms of voltage or resistance readings. Initially, the fuse and diodes tested good, which are common to fail, so we then focused our attention to the board in question. You can either substitute the possible bad board with a known good one and see if it works. If you don’t have another board laying around, you can bypass the relay for test purposes.
Before doing so, be sure the charger is unplugged from both the wall and vehicle. Also, be sure to remove all jewelry, rings, watches, etc. This is a good practice to observe any time you are working with electricity. Remove the two wires leading into the battery charger circuit board relay. The relay is the black cube on the board. The two wires will need to be connected to each other with a jumper wire, paper clip, etc. This effectively bypasses the relay. Plug into the wall first, then the cart. If it turns on and the ammeter moves, it should be fixed.
The battery charger circuit board should be replaced immediately. Do not use it to complete the charge process! By bypassing the board, you have effectively removed the safety cut-off feature it controls to shut the charger down when the proper charge level is achieved. See newly installed board below.