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Running a DC 12V trolling motor with a 4.20. Hidden current limit?.

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Joined: 2018-06-11 23:21
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Running a DC 12V trolling motor with a 4.20. Hidden current limit?.

Hi! I'm running a 4.20 on a DC 12V 400w trolling motor in DC mode. I'm running the latest Vesc tool (pc version )from this site and it seems there's a current limit I cant get past in the setup. The motor is spec'd to 400w at 12V but seems it tops out at about 250w for some reason. The battery current draw seems to top out on about 22A even with battery draw limit is set to 34A and motor amp is set to 100A. I also tried running 24V on the motor and it still didn't develop more power. On 24V it didn't have enough torque to spin up the propeller and weeds could stall it out. I figured it was caused by low duty cycle since 50% duty would give me 12V and 400w, but overheating in the vesc I assume would back off the throttle. I also assume that switching losses and the fact that transistors were off half of the time on 24V the vesc couldnt handle the current in DC mode.  

I rebuilt the batteries to 12V and on full throttle power increased greatly but still not as much as motor directly connected to 12V in stock form. I have a battery bank of 6 105Ah batteries so the power supply shouldnt be an issue. I'm using two trolling motors with its own 4.20 to push a 22ft sailboat hull and I get 4knt at 460w, but I'd like to get the 800w combined rated power. This is the first time I use DC mode and I'd tried changing the usual current limits without getting rated power from the motors.. I assume the motor test tab is not relevant in DC mode. I haven't touched the TRV current limit(16A stock) either since I'm not sure what this does. Any help to what could be cause of this would greatly appreciated!