The answer is 12 volts, unless the ohms meter says different,check first before you assume.
It uses a 12 volt lawn mower engine battery.
Usually 12 volt negative ground.
Battery is 12 volt, U1 group
It should be 12 volt.
My lawn tractor is 12V, but I bet there are 6V ones also.
The majority are all 12 volt.
Positive 12 volt
Most typically lawn mower batteries are 12 volt but there are the occasional 6v versions out there. you canLook at the battery - somewhere on it, it should reference the voltageRefer to your manual to identify the type of battery if you don't have the battery in your possessionUse a look up such as this - www.batterystuff.com to find the correct battery for your mower.You can usually find a suitable replacement at your local Home Depot or Lowes hardware store.
12Volts
The best way is by the number of lids or cells in the battery. Each cell is approx. 2 volts. 6 volt has 3 lids 12 volt has 6 lids.
12 volt
6volts 2amps for 6 volt battery, and 12 volts 6amps for a 12 volt battery. Don't charge a 6 volt battery on the 12 volt setting or it will explode!!!!!!!!! you're ok going the other way though.