I suspect the AH capacity of the 2nd battery is limiting the duration of a heavy pull and extending the time needed to recover because it can only charge at 5A.
The charging capacity of the stator is unlikely to be the bottleneck because the battery is unable to absorb more than 5A. The output of the stator can only help feed the winch until the isolator opens.
The True website indicates there is a 10 second delay when connecting or disconnecting. When you winch you may draw from both batteries for 10 secs before the isolator opens. This could draw down the primay system voltage for 10 secs and impact the power steering. The isolator will not close back in until the primary system voltage reaches 13.4volts for 10secs. The primary system voltage should reach 13.4volts for 10secs with the engine running and close back in for 10secs. The winch might be able to overload the isolator during the 10secs if it pulls too many amps from the primary battery through the isolator. I am not sure if the isolator works as expected with the engine running and a heavy load on the 2nd battery. Did the winch change speed every 10secs when the engine was running?
If you want to pull multiple buddies out of deep mud I think you will need a larger 2nd battery and you will still need to watch overheating the winch motor. I suspect winches are like welders where you have to pay more to get a higher duty cycle.
The charging capacity of the stator is unlikely to be the bottleneck because the battery is unable to absorb more than 5A. The output of the stator can only help feed the winch until the isolator opens.
The True website indicates there is a 10 second delay when connecting or disconnecting. When you winch you may draw from both batteries for 10 secs before the isolator opens. This could draw down the primay system voltage for 10 secs and impact the power steering. The isolator will not close back in until the primary system voltage reaches 13.4volts for 10secs. The primary system voltage should reach 13.4volts for 10secs with the engine running and close back in for 10secs. The winch might be able to overload the isolator during the 10secs if it pulls too many amps from the primary battery through the isolator. I am not sure if the isolator works as expected with the engine running and a heavy load on the 2nd battery. Did the winch change speed every 10secs when the engine was running?
If you want to pull multiple buddies out of deep mud I think you will need a larger 2nd battery and you will still need to watch overheating the winch motor. I suspect winches are like welders where you have to pay more to get a higher duty cycle.