When I ordered this the idea was brilliant, 4 batteries, 2 docks for spares, and 2 docks for remotes fitted with the batteries. Ideal, no play breaks waiting for a charge. There were no set up instructions, and so I was caught out with the slightly unusual wiring arrangement and had to contact the company to work it out, but hey,an illustrated though terse response soon sorted that out. So lets set it up, but only one of the batteries worked on one of our two remotes. The knee shaped terminal means that it contacts the remote terminal at a single point, and when locking the battery into place, it can miss its target. Solution, the terminals on the batteries will require adjustment to make a connection, just bend it gently to flatten it out a little. Both simple problems to solve once you know how, a real pain when you're trying to work out what's going wrong.