This is my guess as to what you are trying to do. (If I guess right, do I get a prize?)
You are trying to create a solar tracking device and check the charging results.
As mentioned earlier, I believe you only need a single ACS712 in series with the battery. The output is Vcc/2 if no current is flowing. It is above Vcc/2 if the current is flowing one way and below if flowing the other. If you power the Arduino and the ACS712 then you should read 511 or 512 about half scale of 1023 values. Therefore, you do not need your voltage divider to find the midpoint.
I assume that your tracking algorithm is independent of the solar cell output. Therefore, unless that information is important to you, you can simply monitor the net results. "Solar Cell Output" - "Load Consupution" = "Current Into or Out of the Battery"