They all can but rarely freeze solid but cold temp does reduce power
As long as you keep them charged you do not have to remove them. A fully charged battery will not freeze, but a dead battery will.
Yes, the battery is fully charged.
A fully charged 12 volt automotive battery should have 12.68 volts.
Normally, no it should be fully charged if it is a fresh battery.
You can tell your car battery is fully charged by checking the voltage with a multimeter; a fully charged battery should read around 12.6 volts or higher. If your car has a built-in battery management system, it may provide indicators or alerts when the battery is fully charged. Additionally, if the battery has a built-in hydrometer, a green indicator often signifies a full charge. Lastly, after charging, the battery should start the engine without any issues.
A fully charged 12 volt battery will read about 12.6 volts, or 2.1 volts per cell.
Depends how flat it is and the capacity of the charger and also capacity of the battery. A 6 volt battery fully charged should read about 6.5 to 7 volts when fully charged.
6.4
Usually from being discharged in below freezing weather. The water will freeze in a dead battery, expand, & swell the battery. This won't occur with a fully charged battery.
If the charger has a ammeter on it then it should show close to zero which means the battery is no longer pulling any current from the charger which would mean the battery is fully charged. If it has only a voltmeter then it should show 12.5-13.5 vdc
When it is charging the screen reads: Battery Charging. When it is fully charged it reads: Battery Charged.
With a fully charged battery (12.68 volts) and engine running at idle with no accessories on, 14.5 volts. You will not get a accurate reading if the battery is not fully charged.