Hi, I have recently installed 2 Pylontech batteries. They work fine except that 2 green lights remain on, on each battery all the time. Yesterday was very cloudy so the batteries hardly charged. The 2 lights were on last thing last night and first thing this morning. During the night I seem to be drawing all my power from the National Grid. My question is that the 4 lights equate to about 33% of the total capacity which is not used. Is this a fault or do the batteries retain a third of their capacity as a buffer ? Thanks for any tips.