Originally Posted by bhumik147
you think the battery will blast, because its 12% now and the voltages are 4200mV , i never reached to that limit
Cellphones these days use a type of battery called a lithium polymer battery, often abbreviated LiPo. These batteries have a "nominal cell voltage" of 3.7 V, or 3,700 mV (though some newer phones have batteries with higher nominal cell voltages, like 3.85 V). This voltage, from what I understand, is the average voltage which the chemicals in the battery would produce. However, when fully charged a LiPo cell will briefly hit anywhere from 4.15 V (4,150 mV) to 4.30 V (4,300 mV), depending on the battery and the charging circuit which charges the battery. This is perfectly normal for LiPo batteries.
In other words (and to repeat what pico hackr said above), just charge your phone. The built-in charging circuits and safety cutoffs will charge your battery properly and yet shut off if something goes wrong. If you really want to make sure it doesn't blow up, take off the back cover of your Moto G and watch the battery for any signs of swelling. LiPo batteries will swell up (just like a balloon about to pop) before actually exploding. If it does begin to swell, unplug it immediately, don't put the back cover on it, and put it somewhere safe where it could blow up and catch fire without harming anything. Though extremely rare, cellphone batteries do occasionally explode and if yours does, such an event would definitely be covered by Motorola's warranty.