Hi all, hoping someone can share some knowledge on this topic! I've been using Bosch pro 18v power tools now for a number of years and I've built up quite a collection of tools and many batteries at this stage. I've been using the original Bosch charger I got with my first cordless tool, model AL 1820 CV, to charge these batteries to date, without any issue. The batteries are all GBA 18v, various Ah, from 2 up to 6. However when charging a recent 6Ah addition to the collection, I decided to read the instructions that came with the battery and it recommends using the GAL 18 charger. Not a problem, I have a new, unused one in a tool case somewhere, but I am curious, what is the difference? The AL 1820 was good enough up to now and I've not had an issue, is there something I'm missing? Thanks in advance.