I am quite ignorant in electronics, but I am now building a small off-the-grid installation to be freely cloned (CC-BY) in rural areas of Eastern Poland (and perhaps Ukraine). The vital part of it is the battery bank, which will be built from recycled car batteries etc. So we need some intelligent charger/regenerator/desulphator/monitor/controller to take care of them.
What I am looking is pointing to some low-cost DIY solutions and perhaps some support in prototyping.
The concept is to set up a matrix of batteries (mostly recycled, in various levels of wear) and provide them highly controlled environment - separate chargers, monitoring, on-the-fly desulphation, separate discharge controllers etc. etc. People who will use this design cannot afford buying new batteries, lest replacing whole parallel banks once one unit breaks down. So we shall be dealing with a variety of batteries and the challenge is to make them work efficiently, long term and happily. :-)