Hey everyone,
I have been testing 4 R4850G2s in parallel to charge a 16s LiFePO4 pack with some great results in terms of amperage and voltage control. After receiving the units I used a USB-CAN analyzer to change the Off-line default voltage to 50V and the Off-line default current to 30A. During a charge cycle I set the On-line voltage to 55V and On-line current to 30A - Repeat packets every 45 seconds until the charge is complete.
The problem is the fans on the R4850G2s don't change speed and the units are generating a huge amount of heat during charging. They hit between 60-73c after only 20mins.
I noticed a few people have had problems with fans running full speed with no load, the only condition I could find this happened in one unit dated 2015 spins up full when no CAN communication is detected, as soon as you connect it to the CAN bus it drops back down. Also noticed fans ramp up slightly when the battery is disconnected from the DC output. Once you reconnect the battery it ramps back down.
Clearly the fans do work to some degree but oddly not during extreme heat conditions when you need them to be 100%. Also would have expected the one R4850G2 that reached over 70c to shutdown or throttle but it continues to run regardless.
Could be some flag that needs setting to automatically control the fans, perhaps they are set in manual mode and are expecting a SMU02 module to change the speed depending on temp. Observing Unknown frame 83 during a charge cycle shows 01 83 00 00
10 00 00 00 for a few minutes before returning back to 01 83 00 00 00 00 00 00. I believe this could be a flag to indicate a fan error.
Does anyone have any idea why they refuse to ramp up? anymore have experience with a SMU02 controller, does it have any settings for fan control?
Any help would be much appreciated.
Thanks for looking and stay safe.