Infinisolar E 5.5 KW problems: shuts down at overload without restart and sometimes no recharge after empty battery

Hello,

I am running an Infinisolar E 5.5 KW for about three months.

Setup:

- 8 PV-panels with 2,8KWp total in one string (next year I plan to double the modules)

- grid tied in parallel mode with backup battery

- DIY LiIon battery out of 18650 cells with total of 48V and 7,5KWh

So the mainfunction are working, most of the time.

But I discovered a few misfunctions / bad conditions so far

1. the fans are spinning all the time, even at night when there is no sun-energy to convert and just about 250 watts of IDLE energy for the house. Shouldn't they shut down when there is no power-request? Or can I modify the fanspeed / temperature control somehow?

2. now the bad-weather-days just began and the photovoltaik system can't fully charge the battery over day so it runs out of energy sometime at night. Last week the sun didn't came out for three days and as I looked at the battery the voltage dropped to 29V which is very below the 46V cutoff voltage I set into the inverter settings. So what happened? I am pretty sure that the inverter cuts the battery off at 46V but standby consumption and the permanentely spinning fans are sucking the batteries empty as I can see a steady consumption of 0,2A at my battery monitoring system. Is there a possibility to change this behavior?

3. three or for times since the beginnings I noticed that when there comes a huge power request (for example today I cooked with all of the four electric hotplates and the oven) then sometimes the inverter seems to cut of the battery for some reason and won't use it again unless I restart the inverter. The max discharge current is set to 55A at the inverter and 65A at the BMS of the battery, the fuse between battery and inverter is 63A, the batterie voltage was 52,2V as I discovered the failure (Cut off set to 46V). Can you explain why this happenes?

Oh, and as I mentioned in this thread I would be happy if someone could send me the factory password so I can set the "max feed into grid power" to a lower value so it fits the wire and fuse

Thanks very much for your help