If your car battery charger has stopped and is not charging your dead car battery or has became faulty, try the solutions given below to help towards fixing your broken car battery charger:
1)Check the fuse, the fuse that's inside the car battery charger, is it blown? To find out if the fuse is blown, look in the middle of the fuse, there will be a wire, using the image below to identify if the fuse is blown.
1)If the fuse is blown, then replace it with the exact same amps fuse. Make sure you don't use a fuse that is rated at a higher rating then the recommend fuse for your car battery charger. See your use manual for a better guidance on which amp fuse is required, in order for a proper operation.
2)Check the fuse in the plug, the plug that you connect to your electrical outlet. If its blown, again replace it.
3)If you have checked both fuses and still you car battery charger does not work, then i suggest you test the voltage the car battery charger produces. Using a multimeter, set it to read volts and using it, read the car battery charger's voltage. It should be around 12 volts, if not then i am sorry to say, you are forced to buy a brand new car battery charger because it knackered!