Replacing the heat bed connector

- article under development, please add your knowlage and feel free to edit - The corresponding discussion can be found here

A very common issue are scorched heat bed connectors like this:

Root cause

There are several opinions about the root cause of this problem. Which is the main root cause or if it is a combination of them is still to be discussed. Here some collected facts and arguments.

The connector is a VHR-6N from JST rated to 10A. The heat bed draws around 10A at room temperature and less when hotter (click here for details). So theoretically the connector is just enough. But these connectors are not designed to constantly moving aroud so a strain relief(see below) could probaly solve the problem.

Other possible reason for failures could be:

  • poor quaity of the crimps
  • stiff stock wires or wrong size
  • that only 1 of the two + pins and one of the two - pins are used instead of both + pins and - pins reducing the current for each.

There are several options to repair scorched connectors

Option 1 - Replace the connectors with the same type

You will need:

  • 1x VHR-6N from JST
  • 4x SVH with AWG 16 pre crimped pigtails like these or
    • 4x SVH-41T-P1.1 pins
    • crimping tool
    • pliers and side cutters
    • Silicone wires with thins strads AWG 16 to 18.

The heat bed connector has 4 pins for + and -. The + pins can be used in paralell, the - pins also. This reduces the current on the pins and therefore the probability of failure.

It is recomended to add strain relief.

Option 2 - Solder

Soldering cables directly onto the heat bed is a very reliable option if it is well done. But soldering thick wires onto a heatbed with a large thermal capacity is quite dificult and requires some soldering experince to avoid cold joints. As this connection has to withstand a quite high current and a failure may lead to fire, this not recomended for a first time soldering experience.


  • Preheat the heatbed before soldering in a oven or by its own heater.
  • The solder on the heat bed is probably lead free solder. Most peaople use leaded solder at home. As mixing them is not recomended it is better to remove as much old solder as possible before soldering.
  • Foresee an strain relief so that the constant bending of the wire does not stess the solder

video of a heat bed soldering

Option 3 - spade connectors

-feel free to write this chapter -

Option 4 - european style screw connectors

-feel free to write this chapter -

A strain relief reduces the stress on the connector/solder. This is a good idea independently of which option was chosen or as a preventive measure before it fails. Here some options:

  • By replacing the stock wires by thicker ones (AWG 14 or 16) you can increase the heater power (explanation). For the JST crimp connectors AWG 16 is the thickest wire compatible with the SVH-41T-P1-1 pins
  • The connector at the HB is: B6P-VH(LF)(SN)

Also it is prefered to discuss the content in the discussion link (see top) you can add comments here: