I have a 24/3000/70 Inverter/Charger that is connected to 3 strings of 24-Volt battery bank consisting of 9 SPRE 12 225 Trojan batteries. It charges the batteries with city power and goes into inverting mode when there is a city power outage. When the city power is on, it supplies power to the loads from city power only, and only when the city power is out, it goes into inverting mode. Where I am located, the city power does go out at least once every 24-hours for a few hours. The device works fine most of the times, but every now and then, it acts strangely. Lets say that the city power has been on all night long and the batteries have been fully charged with almost zero load on them. In the morning, the inverter lights indicate that it is float charging. However, when the city power goes out, the low battery indicator comes on and the inverter doesn't output any power from the batteries as it should. It stays like that for a while (minutes and sometimes a few hours), and then suddenly, while the city power is still out, goes into inverting mode and starts outputting power. Like I said, it doesn't happen consistently, only sometimes. My batteries are fairly new. They were installed about two months ago.
Thanks for your feedback in advance.