Hello Jaimie,

This should help. iDRAC user guide: Page 169

https://dell.to/3uuApo0

After Hot Spare is enabled, PSUs can become active or go to sleep based on load. If Hot Spare is enabled, asymmetric electrical current sharing between the two PSUs is enabled. One PSU is awake and provides the majority of the current; the other PSU is in sleep mode and provides a small amount of the current. This is often called 1 + 0 with two PSUs and hot spare enabled.

Charles

I understand the hot spare rule but as you can see most of my servers do not have hot spare enabled and there is still a small mismatch between PS1 and PS2. 0.2A is not a great deal per server but balancing the load between PS1 and PS2 might allow me to fit in another server in the rack without exceeding my power budget

Hello, as far as I know amperage does not need to match however PSUs have to supply enough amperages as required. Unfortunately, I don't have much detailed information to add other than what Charles said. I found a doc for PSU missmatch behavior for 12G. It's useful for generic information. https://dell.to/3yfV28k

The supplied document is about mismatched physical PDUs not current draw. Does anyone have an answer?

Why does the current draw sometimes differ on PS1 and PS2?

When it does differ, why is it almost always PS1 that takes the most current?

Hello Jaimie,

Either PSU1 or PSU2 can be configured as the primary PSU. You may work with trying different ones having different primary PSU selected.

Configuring power supply options using web interface  Page 169 : https://dell.to/3uuApo0

To configure the power supply options:

1. In iDRAC Web interface, go to Configuration > Power Management > Power Configuration.

2. Under Power Redundancy Policy, select the required options. For more information, see iDRAC Online Help.

3. Click Apply. The power supply options are configured.