Hello all. I'm new to this forum and fairly new to the AE world.

I have 4 Evergreen 102watt panels connected to a ST1500. On gloomy days the DC voltage will climb to the high 70's but when the inverter tries to make power the voltage dives and the inverter stops. I assume this is because there is not enough DC amperage.
So, question is, if I were to add a fifth panel and boost the open voltage to 100 would I make more power on not so sunny days and would I be asking for trouble on full sun days? The inverter says it can take an ablolute max open DC voltage of 125V and a MPP tracking range of 42-85V so it looks like it could handle the additional voltage but perhaps the MPP tracking would not function.
Thanks in advance.