Can't for the life of me figure out voltage of batteries in series
The voltage (aka &quot;potential difference&quot;) exists already when the battery is disconnected. Your following assumption is correct: the reason why there is no current is that the resistance of air is too big to allow any electron movement at 1.5V.
&quot;As a conductor is connected the E-field in the conducting material is strong enough to Force the electrons through&quot; -  just to be clear: the E-field does not become stronger, but the resistance of the wire is small enough for current to flow.

The circuit is not closed, so there can't be any current. The voltage adds up to 3V accross both batteries.

&quot;If there are 2 1.5V batteries conected in paralell and connected to a circuit the potential doubles&quot; - I don't know if you are aware of the meaning of the word &quot;potential&quot;. The electrical potential difference (aka voltage) does not double, there will still be 1.5V. But the capability of delivering current doubles (do you mean that with &quot;potential&quot;?). As the E-field is proportional to the voltage, it is the same as for one battery.
&quot;[...] and just connect the cathode of one to the anode of the other?&quot; that descibes a series connection...

No, it's the other way around: no current will flow (it still isn't a closed circuit) and the voltage remains 1.5V