Hello,
i am using a polyntech battery stack build from one US3000C (master) and four US2000C (clients). They are connected to a Solar ME3000SP. Stack worked over summer without any Problem. Now in wintertimes one us2000c which is connected as first after the master goes very often in red alarm "under protection". Battery load on all others looks nearly same on the others that time with glowing around 2 or three green LEDs. Anybody has a idea what's wrong here?