Battery configuration, simultaneously in parallel and series

Question

Can someone please explain to me what would happen here?

If you take two 12 V 1 Ah batteries and simultaneously connect them in series and parallel with diodes to prevent the shorts. At the ends you'd have both the equivalent of 12 V 2 Ah and 24 V 1 Ah from the same sources? There have to be notable issues with this, please help me understand what's going on.

(sorry for the terrible phone drawing)

Edit: assuming you were going to use the top left red as the positive and top right black as the negative for your power source. Yes, the red aren't actually touching in the picture, pretend that they are touching, please ignore my poor touch screen drawing abilities

Answer 1

Another way to draw this same connection scheme is:

^{simulate this circuit – Schematic created using CircuitLab}

The batteries are effectively connected in series, which creates a 24 V battery bank. The diodes are each then reverse-biased across each battery, which means they don't conduct.* Ultimately, you have a 24 V battery with the current capacity of one, or 24 V 1 Ah.

You should be able to easily see that they are not also in parallel. Another way to examine this is to see that the voltage at the node between the diodes is 12 V, but because the D1 cathode has a higher voltage than its anode, it isn't doing anything.

If you break the connection from BAT1 positive to D1, then you would get ~11.3 volts at R1. This is because the voltage at the anode is now greater than the voltage at the cathode, and the diode itself has a voltage drop of 600-700 mV. However that puts D1 in series with the load, which means the voltage is dropped by the diode and the diode has to be able to handle the load current.

^{simulate this circuit}

^{* Ignoring leakage current.}