Parallel lead-acid battery strings initially seem like the ideal solution, you can start with 1 inexpensive string, e.g. 4 batteries for a 48V system, and add more strings, maybe another 4, 8 or 12 batteries, at a later stage. Some people start off with 2 or more strings, but while it seems fine, it is not at all the best way to go.
This is a topic which surfaces regularly and I decided to put together this guideline to assist fellow forum members and to hopefully reduce the number of times this topic will be discussed in future.
It explains the caveats and hazards of incorrectly connected parallel battery strings and the complexity of battery balancer and battery monitor connections on parallel battery strings.
Hopefully PV solar newbies will find this document valuable and hopefully it will save them from ending up with multiple parallel battery strings and endless frustration.