We have two SmartSolar MPPT 150/70 solar chargers in our off grid power system. Each is powered by eight 300 watt panels in a 4s2p configuration (two parallel strings of 4 panels in series). They are charging a 48v battery bank. Every morning when the sun first hits the panels, they produce around 155v while the dew is burning off. This lasts for 30-60 minutes each day. Once the dew burns off the voltage drops to around 120-140v and stays there as long as there is sunlight.
While the dew is on the panels and they are producing over 150v, the solar chargers throw error 33 (panels over 150v) and will not charge. Once the voltage drops below 150, the chargers clear the error and start happily charging.
Two questions:
- Will the overvoltage cause damage to the solar chargers, or do they handle it gracefully? They appear to handle it gracefully, but our dealer is worried it will cause damage long-term.
- Would we be better off reconfiguring the strings to keep the panel voltage always below 150 (perhaps add a panel to each and run 3s3p)?
