I think the HYD3600ES may have the same feature as the ME3000Sp when it comes to setting the CT direction, so this may be a potential gotcha to watch out for. The inverter detects the direction of the CT (import versus export) when first powered up by the DC from the batteries, hence the reason that the PV output needs to be zero when first connected (the line "
Make sure there’s no power generation in HYD-ES inverter’s phase." in the manual). From then on it knows which way around the CT is fitted, so knows export from import. If the DC is ever turned off it will forget this, and go through the direction setting thing again, so unless the PV is also not generating when this happens it can change this setting.
There is an easy fix for this, but it's not very obvious from the manual. The manual refers to the menu option to "freeze" and "unfreeze" the CT direction. This website refers to the ME3000SP, but I'm sure the procedure is applicable to the HYD3600ES as well, as the wording in the manual looks to be much the same:
https://www.setfirelabs.com/building-au ... -inverters
Once the CT direction is "frozen", then it doesn't matter if the PV is generating or not next time the battery is turned off, the inverter will remember the initial setup CT direction and use that. Worth noting that if the menu option "CT Direction" is displaying "freeze" then that means the CT direction is not frozen, and selecting "freeze" will lock it and so it can't automatically change on power up in future. Not that intuitive IMHO, although there is another menu option under system information that does correctly report whether the CT direction is frozen or not.
25 off 250W Perlight solar panels, installed 2014, with a 6kW PowerOne inverter, about 6,000kWh/year generated
6 off Pylontech US3000C batteries, with a Sofar ME3000SP inverter