First, There must be constant current in the discharge process of the mobile power supply. And the current can't be too big or too small. General Digital current between 600 Ma to 1000 ma. Tablets require about 2000 MA. This data is also the standard parameter of most mobile power supply in the market.
Second, The mobile power supply must conform to the electronic product three C standard
Third, The output voltage of the mobile power supply must be stable. The output voltage is guaranteed to be in the stable region between 4 and 2v~5v. Because most of the digital products in the market charge voltage is 4.2V, too high is likely to damage the electrical appliances.
$ord, The protection circuit of the mobile power supply must pass through. A lot of junk product protection circuits in the market are completely off. Over-release, over-current and short-circuit must be done triple protection.
In general, the mobile power output voltage and current stability, protection system in place, will not be the digital products and battery damage.