What is the Maximum Current Limit of the Blue Robotics 5V/6A Power Module (R1)?

Blue Robotics Products
1

Hi everyone,

  • We’re testing a setup using a T200 ESC to drive a T500 thruster.

  • Our input power is supplied at 16.5 VDC 1000W.

  • Based on our calculations, the T500 thruster should draw around 25 A at this voltage.

We’re using the following power module for both the ESC and control electronics:
:link: Blue Robotics 5V/6A BEC Power Module (R1)

**

Connection Diagram**

16.5V DC(1000W)

   │

   ├──> \[Blue Robotics Power Module 5V/6A\] ──> 5V → Arduino Nano

   │

   └──> \[T200 ESC\] ──> \[T500 Thruster\]

Arduino Nano ──> PWM Signal ──> T200 ESC

Problem:

The power module has failed twice after about 30 to 40 minutes of testing.
Once it fails, the full 16.5 V supply passes to the Arduino Nano’s 5 V input, which causes the Arduino to be damaged due to overvoltage.

We suspect this might be related to the over current of the power module when operating at 16.5 V input and 25 A ESC load, but the documentation doesn’t clearly specify the maximum continuous current rating.

Questions

  1. What is the maximum continuous current limit of the Blue Robotics 5V/6A Power Module (R1)?

  2. Is it safe to use a T200 ESC with a T500 thruster at 16.5 V supply through this setup?

  3. What is the recommended method to protect the Arduino Nano from overvoltage in case the power module fails again? We want to ensure this doesn’t happen when using a Raspberry Pi in the ROV, since a previous failure caused 16.5 V to reach the 5 V line and damage the board.

2

Hi @Chandan,

The maximum continuous output it can support is 6A, as mentioned in the product name, and specified in various places on the product page that you linked to.

That said, voltage-based signals like the PWM that is sent to control an ESC should use effectively negligible current. Moreover, an Arduino nano without additional peripherals should have quite low current draw, so unless there are other components you’ve neglected to mention the draw on your 5V regulator is likely below ~50mA (so absolutely no concern).

Purely from the electrical capacities you’ve specified, yes - our Basic ESC can handle up to 30 A of continuous current draw (noting that cooling may be required), and input voltages in the range of 7-26 V, which your specified 16.5 V supply and 25 A load are within.

That being said, you haven’t mentioned what kind of power supply you’re using. If it’s not a battery, there may be voltage spikes on the power supply lines when sudden braking of the thruster causes back-EMF. If those are significant enough they may go beyond the rated voltage of the power module.

You could use a decoupling capacitor, but the power module should not fail, and if it is being operated in a way that causes it to then it’s likely a better idea to fix that source problem than to try to fix/mitigate the symptom.

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