I am in the process of adding a 50 Watt solar panel; I already have a 75 watt installed. My questions are as follows:1. How do I (or should I) tie my two batteries to the new system. At this point only one is directly charged by the existing solar panel.2. Do I need something after(or before) the blocking diodes to charge the batteries in 3 phases as the current dogma recommends?