What do the error codes on Delta Pro mean?

301: Cell Under Voltage - Need timely recharge
302: BMS Lost Connection - Reboot
303: INV Lost Connection - Reboot
102: Cell Under Voltage Alert - Do not discharge, timely recharge
077: Cell Voltage Differences are too great - Long press the power button for 10 seconds and wait for half an hour.

Can I use the Delta Max Extra Battery with both Delta Max 1600 and Delta Max 2000?

Yes, Delta Max Extra Battery is compatible with both Delta Max models, 1600 and 2000. Each supports up to two Extra Batteries.

When does the fan work and when does it stop? (at what temperature)

Different Ecoflow power stations have different internal logics that prompt the fan to start functioning. For RIVER series, you can set that manually in the app, or set it to always be on. For Delta (1300), the fan will turn on when the internal temperature is greater than 45°C

https://ecoflowtechhelp.zendesk.com/