Charging 4 batteries

I know this thread is almost a year old, however I have an answer to solve this problem. In our Solar setup I had 16 lead acid batteries connected in parallel on two shelves. The problem you described was a constant headache. A professional installer explain to me that the only way you can charge all of the batteries equally is to connect the positive lead from your charging circuit on one end of your bank of, and your negative lead on the opposite end of the bank of batteries. In this way all plates in all batteries, regardless of the amount, see the same charge amperage. If you install four new batteries and use all new cabling, using Dielectric grease, and attach the batteries this way, not only will they all see the same charge current, but they will last three or four times longer. Since I started wiring batteries this way I haven't needed a jump start or to replace a single battery. On a side note, I recommend connecting any load wiring on the same lugs as your charge wiring. What I mean is don't attach wires going to any loads in the middle of your string of batteries. Connect your positive load wires to the same lug as the positive charge wire and your negative load wires to the same lug as your negative charge. I hope this helps someone.