TheBattMan
New Member
This is how I fixed all 3 of my MPPT MAX-8000 inverters. This might be different for other models and hardware reversions. Follow at your own risk.
I bought 3 8kw inverters from Foshan Ouyad Electronic a few months ago and one by one they have all stopped working with various errors and hardware faults. The one fault they all have in common is the Serial number registration failure error - F90
I got impatient waiting for Foshan Ouyad Electronics to respond so I decided to explore other ways to communicate with the main processor without this ridiculously priced board they say we need. I used a 3.3v USB to TTL UART adapter and Axpert Setting Serial Number Tool V1.00. You will be connecting Gnd, TX, RX to the 6 pin plug coming from the inverter. You don't need to do anything else with the other wires.
This is how I connected mine.
Inverter Pin 1 TX to TTL RX
Inverter Pin 2 RX to TTL TX
Inverter Pin 3 GND to TTL GND
Please make sure you only use a 3.3v TTL adapter as the MCU is only 3.3v tolerant. A wrong connection could damage the MCU.
This is the one I used.
Remove AC input power from the inverter, disconnect all 3 connectors from the front panel. Make your TTL connections into the 6 pin plug as above, plug the USB TTL adapter into the computer and load up the software.
Return AC input power to the inverter and wait a moment for it to go red, in the software select RS232 and click Search - it should display a product ID, click apply and you should get settings successful! msg.
That's it, Error F90 fixed. Remove AC, reconnect everything and power back up.
Will report back if it returns again after the 60 day timeout.
Axpert SN Tool - https://www.mediafire.com/file/dc9cq674ult69xj/AxpertSetSN.rar/file
Hope that helps and saves people money.
Enjoy your day and stay safe.
I bought 3 8kw inverters from Foshan Ouyad Electronic a few months ago and one by one they have all stopped working with various errors and hardware faults. The one fault they all have in common is the Serial number registration failure error - F90
I got impatient waiting for Foshan Ouyad Electronics to respond so I decided to explore other ways to communicate with the main processor without this ridiculously priced board they say we need. I used a 3.3v USB to TTL UART adapter and Axpert Setting Serial Number Tool V1.00. You will be connecting Gnd, TX, RX to the 6 pin plug coming from the inverter. You don't need to do anything else with the other wires.
This is how I connected mine.
Inverter Pin 1 TX to TTL RX
Inverter Pin 2 RX to TTL TX
Inverter Pin 3 GND to TTL GND
Please make sure you only use a 3.3v TTL adapter as the MCU is only 3.3v tolerant. A wrong connection could damage the MCU.
This is the one I used.
Remove AC input power from the inverter, disconnect all 3 connectors from the front panel. Make your TTL connections into the 6 pin plug as above, plug the USB TTL adapter into the computer and load up the software.
Return AC input power to the inverter and wait a moment for it to go red, in the software select RS232 and click Search - it should display a product ID, click apply and you should get settings successful! msg.
That's it, Error F90 fixed. Remove AC, reconnect everything and power back up.
Will report back if it returns again after the 60 day timeout.
Axpert SN Tool - https://www.mediafire.com/file/dc9cq674ult69xj/AxpertSetSN.rar/file
Hope that helps and saves people money.
Enjoy your day and stay safe.
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