# What happens if we connect an AC to a battery to charge?

The battery will not charge. AC is a pulsating signal with half of its amplitude in the positive half and the other half in the negative half. For suppose a 220V Ac, the maximum amplitude is 311V, once on the positive and once on the negative side. So its resulting voltage is 0V. You can test your line voltage using multimeter by keeping the multimeter in Dc voltage. You will get 0V. So for the battery it won't charge. And if you don't know how 220V arrives, it is derived by Root mean Squre (RMS). And the line frequency 50Hz means your line will have 50 positive and 50 negative sides in a second. Also battery don't receive such a high voltage. It usually takes 3.7V to 12V depending on the battery. I did not tried to put a battery in direct 220V AC. So I don't know what will happen for that. Also remember, every battery charger has a AC component (but only in the positive half), which is known as ripple. The less ripple it has, the better ch