I took mine off charge after 4 hours and it was still pulsing the light indicating the last stage of charging at that point. Will stick it on again at the weekend for longer. Mine is a 70Ah battery, so should take around 11 hours according to their guide
When I checked the voltage with a multimeter, it didn't seem to have made much difference, but it has stopped the instant Yellow battery warning I would get if I put the ignition on without the engine running, so it's clearly done something.
This is exactly what i found too! The stated charge times are utter garbage, it does charge albeit at a much lower rate and im guessing the cars BMS may have something to do with it too limiting it?