It will depend where you put the volt meter ?
If you put the meter across the battery cables it could just be a loose connection.
If you put the meter directly onto the batteries posts you have a bad battery.
Always try both points but to test a battery you must measure across the batteries poles.
If the battery starting point is 12.4v and you put a good load on it (lights or stater) it will show a lower voltage _ _. _v
If the battery is good it will recover most of that 12.4v a minute or two after removing the load.
If the battery fails to recover most of the 12.4v starting voltage it is failing and time to think about a replacement.
Most bad batteries will show about 11.2v because of one bad cell.
PS: your battery is like a big sponge and will absorb any power spikes your electrical system may produce.
If you use jumper cables to start the bike from the time you remove the first cable you are putting your bikes electrical system at risk.
Some of the 19 rides in my shed
2014 V2, Snoopy
2009 Wee, Pumbaa the pig
WR450F, The Blue Postie Bike
YZ250N smoker with rego, Stinky.
Yamaha MT09 (FZ09), The Scud missile.
Club Lead not Club Med.
He with the most toys wins.
Out of my depth in a puddle.
Live life on the edge you will see more that way.
Ridding a motorcycle keeps things in balance.
At the end of each trail and at the end of each day history is made.