How to check a golf cart battery charger with a multimeter

How to check a golf cart battery charger with a multimeter

Owning a golf cart often requires you to upgrade and maintain your cart in a variety of ways.

For example, you should make sure your golf cart's battery is fully charged before you ride it.

However, this unit may experience problems that decrease its effectiveness over time.

Therefore, you need to understand how to test a battery charger to ensure that it works as efficiently as possible.

Fortunately, this process is relatively simple and shouldn't take long.

We'll cover the testing process here, as well as why testing is smart and what problems it can uncover.

How to Test a Golf Cart Battery Charger

The most common problem with an electric golf cart is starting it up. The battery powers the car's engine.

If you continue to recharge the battery without routine maintenance, it will eventually no longer hold a charge.

There are cables that need to be cleaned and checked for fraying if the golf cart battery is to be fully charged and received.

The battery charger cannot charge a battery that is low in acid or has a leak.

How to test golf cart battery charger ? Make sure the golf cart battery charger is working and you have voltage at the battery charger plug with a multimeter or voltage tester.

Let's go over some of the simple basics and get your battery charger working like it should.

Determine if the battery charger is faulty

Did you know that most modern battery chargers will not even start charging the batteries if the batteries original charge is not high enough?

The automatic battery charger needs a minimum amount of voltage across the batteries to start working, say around 20 to 35 volts total.

test the batteries

Take your golf cart battery voltage measurement and test the output voltage of all batteries together. See if they measure the voltage required to activate your charger.

If the batteries do not match the minimum voltage or higher, then you have found the problem. What are you doing right now?

Check the synchronization mechanism

Your golf cart battery charger will either have a manual mechanical timer or an automatic electrical timer. If it's a manual timer, it's pretty easy to test.

Turn on the timer and check if there is power coming from the timer. With an electric timer, you just have to trick it into turning it on.

The other possible problem is that your timer has failed and you leave your charger always on. To verify this, turn off the timer and check the power. If you still get power, replace your timer.

Check the charging cable

You can check this by testing for power at the end of the cable, and if there is no power, check for power where it connects to the golf cart battery charger.

If there is power to the charger but not to the end of the cable, then it's as simple as replacing the cable.

Another easy way to test a cable, if you have an ohmmeter, is to check the cable for continuity. This is done by measuring the resistance in the wire, which should be slightly above zero.

If your ohmmeter reads zero or infinity then the wire is broken and needs to be replaced.

Check fuses and diodes

If you don't have power on the cable connection, don't worry too much just yet. Hopefully, it's just a fuse.

These are pretty easy to find, and once you locate them, just remove them and look for wear. If you can't see the wear, recheck your ohmmeter for continuity.

If the fuse is broken you need to check a couple of things before replacing it, if not reinstall it. Sometimes this will fix the problem by draining the capacitors and restarting the machine.

If your fuse is blown, it is very possible that one or both of the diodes have blown. Check that both have continuity in both directions. A diode is like a gate, so it must have continuity in one direction, but not the other.

To check for continuity, remove the diode completely from the machine and use your ohmmeter to check resistance the same way you checked the wire, then change the direction you're testing.

If both are continuous or neither is continuous, then you have a bad diode. You may need to replace both if one fails.

Once you've checked and possibly replaced your diode, replace your fuse and check to see if your golf cart battery charger is now working. If not, start the isolation process again, it is possible that there was more than one failure.

Charge batteries individually

If the batteries are too low, charge them individually with a regular old car battery charger, usually the 12-volt type.

You can charge them to full capacity or just high enough to meet the minimum required voltage. If your cart has 12-volt batteries, this will be a simple procedure, but if you have 8-volt batteries, you have two options.

You can use the 12 volt configuration, but connect a 4.5 ohm, 10 watt resistor in series with the charger. This will limit the current when fully charged to about one amp.

The other method would be to set the car battery charger to a 6 volt setting and charge the individual battery for an hour and see if it reaches 7.8 to 7.9 volts. This will be enough voltage for each battery to collectively power the golf cart battery charger.

Check the output voltage

How do you test a golf cart battery charger with a multimeter?

No clicking noise from the relay followed by a buzz or slight vibration in the case is a good indication that the battery charger is not receiving power, so before opening the case, let's test the voltage at the charger plug.

With the battery charger off, set the multimeter to measure voltage and connect it to the output contacts on the plug, then turn the timer knob to "on." If there is no voltage, it's time to try one more thing.

Unplug the charger and connect the leads from the continuity tester to both blades of the power cable (8 and 9) then turn on the timer to "continue". There should be continuity at this point.

open the case

Once you have access to all the internal components, first use the continuity setting on your multimeter and check the timer switch.

Other than the fuse, this is the most common point of failure on a charger. If your charger has an automatic timer then there won't be a rotary knob on the front.

Connect the wires to both contacts (6 and 7) and turn the dial. there should be continuity at this point. If the meter indicates no continuity, then you have a faulty timer switch.

The next step is to measure continuity between the charger contact end (10 or 11) and the Termination Point inside the case (12 or 14).

Check both the positive and negative as well as the ground and if they do, start testing the connections between the components on the front of the battery charger.

Check for continuity across the meter and the connections leading to the fuse.

capacitor test

good condenser

The ohmmeter is first set to read resistance and the capacitor leads are disconnected from the transformer.

On a good capacitor, when the ohmmeter leads are connected to the capacitor terminals (4 and 5), the meter needle jumps to the center of the scale and moves rapidly to a higher resistance.

open condenser

When the ohmmeter leads are connected to the terminals, the meter needle remains with high resistance. If the condenser has not "opened", there may be a visible bulge at the top.

shorted capacitor

When the leads are connected to the capacitor terminals, the meter needle immediately jumps to zero ohms and stays there.

Test all transformer windings

In the illustration above, the primary winding is the two white/brown wires, while the secondary windings are the light brown wires.

If you've checked everything and everything seems fine, but your golf cart battery charger still won't charge the batteries, then the last thing to check is the transformer.

The transformer should be buzzing if it's working, so if it's not buzzing, it's either not getting power or it's broken.

Check your connections to the circuit board, and if everything seems fine, then the only real way to test it is to replace it with a good transformer.

Unfortunately, this is very expensive and requires very special soldering or replacement of an entire circuit board.

You may need to take your golf cart battery charger to a store if you suspect the transformer is the problem.

Also, this repair can be very expensive and you may want to consider a new golf cart battery charger.

final word

With an automatic battery charger, the batteries must be connected before the charger is turned on.

Wait 3-4 seconds for the delay time to elapse. And if there is no click and hum from the transformer, we need to make sure there is a proper connection between the battery charger and the batteries.

Check the plug-in receptacle public art on the cart for corrosion or dirt, and if in doubt, clean it and try again.