With multiple batteries run in parallel, the draw is not always equal on all batteries in the circuit. Its funny
you mention plumbing
, as it's very similar in many respects.
In a plumbing
situation, say, you have two equal tanks
sitting on a level plane. you plumb a 1/2 drain pipe from both tanks
to a 1 inch pipe at the same point, one foot below the level of the tanks. one tank is two feet away and the other tank os 100 feet away. Due to the friction/resistance in the pipes the nearer tank will empty first.
in a battery
bank run in parallel whilst a draw is present the last battery
will contribute the least and like wise receive charge last. electricity flows the path of lest resistance or the shortest path. in essence, the successive batteries from the back foreword would drain into the previous battery. If all the batteries in a parallel circuit were wired to a single
point respective of + and- with all cables
the same length and size and the load taken from that point, then you would have an equal draw and recharge of the batteries in that bank
unlike plumbing, if you increased the wire size of the jumper from the back battery the resistance in the wire would increase too. A physicist might be able to figure a balance, but electrolysis
in the wire would change the balance in time. Its easier and longer lasting to wire it to a central point. Say #4 jumpers coming into a #2 wire or #2 jumper wires into a 00 wire and so forth.