The results of a voltmeter vary depending on the type of voltmeter used. For a more accurate result, be sure to use a voltmeter with more than 1 megaohm input resistance for alkaline buttons batteries or a 10+ megaohm for lithium batteries.
No. All Panasonic rechargeable batteries come pre-charged. However, due to changes in conditions and temperature during transportation, some discharge may have occurred - meaning the battery may not be at full capacity when you take them out of the package.
In appliances without a charging function, yes. In appliances that do have a charging function, be sure to check whether the function was specifically designed for Ni-MH. If not, it’s best not to use Ni-MH batteries.