How can you tell if the battery charger for vehicle battery is actually working?

Answer 1

If you are talking about battery chargers you buy to charge your vehicle's battery, you will hear a slight hum or a feel a slight vibration as it is charging. Some chargers have a meter which will show the current (Amps) being put into the battery. If you mean the vehicle's own battery charging system, if that system is not working it is likely that a red warning light on your dashboard will not go out after you have started the engine. Vintage cars or special-build vehicles often have an Ammeter to show the current (Amps) being put into the battery. If the vehicle's own charging system is not working you can still drive the vehicle for some distance but don't rely on the battery's charge lasting for long: if the battery is not being re-charged it will go flat because of the current drain taken by the vehicle's electrics. (Ignition, fuel pump, lights, etc..) If you can't get the vehicle's own battery charging system fixed but still want to use the vehicle for short distances you will have to re-charge its battery regularly using a mains-powered battery charger. When you eventually get the vehicle's charging system fixed it would be a good idea to have the battery tested too, to be sure it is ok. If your battery is too flat to start the engine then there may be 2 different reasons why it went flat: 1) because the battery is old or has a fault so that it cannot hold a charge any more - the battery needs to be replaced. 2) because the vehicle's battery charging system has a fault so that it has stopped charging the battery. In that case it is the charging system which must be replaced. This assumes of course that the battery itself is ok.