My system has been operating very nicely now for several years but all of a sudden on the weekend it started dropping out of bulk into Absorption briefly then float but staying on the high absorption voltage, it did this at a very early stage long before the battery was charged. We did have a thunder storm on the weekend however i still get a full voltage reading and if i restart the controller i can get maybe half an hour of low current flow. What can cause this problem any guidance greatly appreciated.