Clarification on Power Supplies

Hello, everyone.

I have two questions.

  1. I bought HRP-300-12 as a 12V power supply, but I couldn’t find out the reference of the 5V power supply.

  2. I can’t figure out how Mother board and AUX board connect to the power supply.

Could anyone help me?


Hi Marty,

Sorry, it looks like this got missed.

  1. You can use something like this for the 5V:

  2. The motherboard and aux board on the gen1 eVOLVERs connect via the molex ultra fit connectors I boxed in red here:

    (figure from the original NBT paper)



Hi Zack,

Thank you for your reply!
I’ll try to connect an eVOLVER to power supply.

I’m sorry but I have one more question.
Could you tell me which cable to connect to which power supply?
Is it indicated in circuit diagrams?
(I’m sorry but I’m not familiar with electrical engineering…)

Best regards,

Hi Marty,

This is the pin out on the schematic for that connector on the motherboard:

Anything not grounded should connect to the 5V output of the power supply. The AUX board is the same except 12 V power should be applied to those pins, and 5V at the same pin specified, and a few pins are not connected as there are only 3 PWM channels to power.

If you apply the incorrect power/grounding at these pins, it could destroy the parts/boards - be extremely careful.

You can refer to this picture from the eVOLVER NBT supplement for how it should look:

In this picture, red is 5V, orange is 12V, and brown is ground. I also just noticed looking at this picture that the top and bottom are flipped - no orange cables should go into the motherboard, and every pin should be connected for the motherboard connector.

I recommend using a multimeter continuity check to make sure you’re applying the right power to the right pins, ie touch one lead at one of the connector pins and the other to the place you want to connect it to, the multimeter should make a beep. Don’t do this while the device is powered on though.

As a precautionary note, please be extremely careful when dealing with AC power. Never handle the connectors/cables while AC power is turned on. If you are unsure about a connection, do not power it on as it could cause damage to the eVOLVER. I usually just have everything unplugged completely from the wall if I need to modify the cables.

1 Like

I just realized that you do need some 12V on the motherboard for the STIR and TEMP PWM boards. Those depend on your motherboard version and setup, so use a multimeter to make sure you connect those properly. Putting 5V on them shouldn’t hurt anything, it just won’t have enough power.

1 Like

Does the power have to be so high for the sources?
The ones linked here use 324W for the 12V source and 25W for the 5V one, that’s a lot of current, is it really necessary?

The power supply will only supply what is needed for the downstream connected components - it isn’t constantly supplying 324W and 25W. You can confirm this by putting a current probe or ammeter at the output of the supplies. There is a safety margin to ensure the supply will be able to meet peak demand, handle any power spikes that might occur for various reasons, and support any additional hardware modifications that users might want to add. You could use smaller supplies, but risk overloading them under full load conditions or if you modify/add components.

For perspective, the standard pumps are 5W. Having two sets of 16 (for influx/efflux) would require 160W if they all ran at the same time. If you wanted an additional pump array (for another input), you would need 240W. And that is just for the pumps, the 12V also might have other loads on it, and we need to have a safety margin.

1 Like