In may cases they are
Batteries in parallel maintain constant voltage across the load rather in a series, so it is better to arrange the batteries in parallel Batteries in series deliver a higher voltage, batteries in parallel have longer life use.
Yes, series and parallel connection of batteries is possible. When connected in series Voltage increases. In parallel, Current increases but voltage is constant.
When batteries are connected in parallel, the total voltage remains the same as the voltage of a single battery.
Parallel or Series Connections for BatteriesTo increase current [measured in Amperes], you connect batteries in parallel. To increase voltage, you connect batteries in series.
Curve line?
When connecting batteries in parallel, the total voltage output remains the same as the voltage of a single battery.
No it will impose the voltage of the three series batteries across the terminals of the paralleled battery. Batteries can only be parallel when all of the voltage potentials are near equal.
Parallel
I would opt for the two twelve volt batteries in parallel. This configuration will give you the voltage that you need for the system to properly operate plus the endurance time that you can draw from the batteries will be doubled. The amp/hours capacity of batteries when in parallel are additive.
to boost current, you parallel in additional sources. Such as adding batteries in parallel.
When you connect batteries in parallel, the positive terminals are connected together and the negative terminals are connected together. This increases the total capacity of the batteries, allowing them to provide more power for a longer period of time.
Batteries in parallel is not recommended. Not unless they are equalized. the appliances can be one guess since the battery only see a load