I'm trying to help some friends who live in a remote village in Africa to get the best out of their solar installation, and I'm trying to understand whether there's an optimal way of hooking up the batteries and if there are any pitfalls.
This installation has 20 batteries, each 12V 120Ah and should be combined to give 48V 600Ah and a peak load/charge of ~50A/48V. They have three groups of solar panels each having their own charge controller.
Initially I was thinking that the arrangement was of lesser importance. But then I found this article [http://www.smartgauge.co.uk/batt_con.html] explaining the importance of the details in parallel connections. This made me wonder if there is some pitfalls when you combine parallel and serial connection of batteries
In the original installation the batteries was first linked in series of 4 which then was connected in parallel. Rather than following the guidelines from the article linked above, we actually had the load and charge on opposite sides of the bank. Charge at A/B and load at C/D in this illustration, and I think this made the batteries to not charge optimally and discharge unevenly.
So, to my question. Is there any preferable way of connecting these batteries? Or is for instance the lengths and maybe that these should be as equal as possible?
My intuition now is to rather do it like this: parallel groups and then in series. In this setup I would try to:
- Make all wires the same length
- Pay attention to keeping each parallel group connected diagonally in each step
Side question; is there a optimal place of connecting the wires from the charger, load and batteries? Hook both load and charge directly to the terminals?