Technical Issues and Modifications Inquiry for T500 Thruster 50A ESC

Blue Robotics Products Speed Controllers (ESCs)
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We are currently using T500 Thruster 50A ESCs in one of our robotic systems and have encountered some issues that we’d like to report and seek guidance on:

  1. Overheating Issue: The ESCs are getting excessively hot during operation, to the point where the outer shrink tube is melting or tearing. We would like to understand if this is a known issue and if there are any recommendations to address or prevent this.

  2. Power Cable Extension: In some cases, we may need to cut the power cables coming out of the ESC and extend them using another set of wires.

  • Will this affect the performance or safety of the ESC?
  • Are there specific guidelines or precautions we should follow for such modifications?

  1. Soldering Recommendation: We would appreciate your recommendation on the best type of soldering method and materials (e.g., solder alloy, flux type) for joining or extending ESC power wires to ensure high current handling and durability.

  2. Heatsink Replacement: Is it technically safe and permitted to replace the existing aluminum heat sink on the ESC with a larger or custom-designed one to improve thermal performance? If so, are there any mechanical or thermal considerations we should be aware of?

  3. Connector Compatibility: We are considering using a smaller connector (rated for 50–60A) for the T500 ESC’s power connection.

  • Is this advisable?
  • If yes, could you please suggest a suitable connector model or type that would work reliably in this use case?

Below are the specifications of the wire we are currently using to provide power to the thrusters:

  • Wire Gauge: 12 AWG
  • Conductor Material: Tinned copper (stranded for flexibility)
  • Maximum Temperature Rating: 200°C
  • Voltage Rating: Typically up to 600V
  • Insulation Material: High-temp flexible silicone rubber
  • Color Options: Typically available in red, black, blue, etc.

If anyone has faced similar issues or has suggestions, please share your thoughts in the comments – your help would mean a lot.

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Hi @AnkitPandia -
Welcome to the forums!
In answer to your questions -

  1. What sort of cooling are you providing the ESCs? When used in light duty applications, such as inside the BlueBoat, overheating is not an issue. If you’re running the ESCs near their capacity for long periods, adding a path for the heat via heatsinks and air cooling is going to be your best bet.
  2. Extending the red and black power wires is possible, you’ll want to match the gauge of wire or go even bigger to reduce voltage drop. You can use this calculator to see how much power you’ll lose to resistance in your setup. Note that extending the 3 motor wires beyond 1-2 meters is not recommended, as that can make it difficult for the ESC to “hear” the rotation of the motor and properly time the power pulses that create rotation.
  3. When soldering XT90 connectors and heavy gauge wire, lots of heat is required! Avoid a fan, use a powerful soldering iron with a clean tip, at maximum heat, and let things heat up before applying solder. A bit of flux of any kind will help wick solder into your joint.
  4. The aluminum plate inside the heatshrink on the ESC is more of a heat-spreader - coupling this to a larger heatsink, or a metal surface in contact with water is the best way to get more of the heat out!
  5. If you’re running the ESCs hard enough to have heat issues, reducing the connector size doesn’t seem advisable? Typically XT90 connectors or sufficient, but I’ve seen XT60 used as well.
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hi there ,
thanks for your response it will help me a lot . and from my comment below in your respond i have some doubts as i discussed

  1. we are using basic blue robotics ESC 30 A and there is a tiny aluminum heat shrink for heat absorb . so basically we don’t have any cooling system in our ROV .
  2. is there any other alternative to cooling down without aluminum heat shrink ?

thanks for your response
Ankit pandia

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Hi @AnkitPandia
If you’re using the ESCs long enough that heat becomes an issue, improving the cooling is the only option! You could do this with airflow (a small fan) or conduction, using aluminum or copper clamped to the ESC and an endcap flange, to allow the water to cool the ESC albeit indirectly.

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Hi
Thanks for your response, for moreover to getting things know could you please suggest me some pictures about the heat transfer conduction using aluminum or copper clamped to the ESC and an end cap flange.

Thanks