For the bulk of the time I can remember we have always fitted and maintained lead acid batteries for off grid installations. This has always been difficult as you can imagine as wet cell lead acid batteries like to be transported level and not every off grid installation is a perfect flat level block. This has made for both an WHS issue but also is just flat out inconvenient, not to mention their weight, size…..
Finally now there is a real supported solution. We have been using LiPoFE4 lithium batteries by BYD. Their 48v, light, mount in a 19″ rack, they have an amazing D.O.D and battery life, aswell as a full BMS to supported inverters so you can see exactly what’s going on. You can also add to your array later unlike lead acid batteries that cannot do this quite so well.
Below is a link to their information documents.
http://www.byd.com/energy/download/low-voltage/B-Box%20Low%20Voltage%20Specification.pdf