PC not consistently restarting after Back-UPS RS 650MI driven shutdown

[BillP]

Might someone explain the behaviour of the UPS/HP Laptop with power supply as observed below? I want to know how to consistently restore power to a PC when power is restored to a UPC:

A laptop has hibernation disabled (I am conducting tests before connecting a Back-UPS RS 650MI to a server). PowerChute Personal Edition 3.1.0 is used to 'shut down' a laptop connected to the power supply and UPS 'Battery + Surge' outlet. 

After removing the UPS input power, the laptop shuts down as specified in the 'Runtime' settings. BIOS Boot Options on the HP laptop are set to 'Power On When AC Detected'.

Replacing the 240V input plug to the UPS after PC is shutdown does not restart the laptop (more often than not - it has restarted it 2 times - shortly after the shutdown). In instances where the PC doesn't restart automatically after replacing the 240V lead for UPS input power, it has actually restarted after:

1. the 240V UPS input has been removed again

2. The power button on the UPS has been pressed

3. One prong of an voltmeter made contact with a 'battery + surge' outlet pin

4. The 240V end of the power supply lead going into the battery+surge outlet has been removed and replaced

Point 1 above is a concern. Points 2-4 are inconvenient. 

Questions:

a. Is the above usual behaviour? 

b. Is there a way to make the PC restart when power to the UPS is restored (without doing one of the above)?

[BillP]

Hi,

If the UPS restores AC the issue is caused by the BIOS or the power supply. PowerChute cannot restart the system as it is no longer running. 

NOTE: When PowerChute commands the UPS down the UPS waits 2 minutes then kills power to the outlets. It will then wait until AC has been restored and re-energize the outlets. If AC is restored prior to the UPS powering off it will continue the power off cycle, wait a few seconds and then re-energize the outlets. 

[BillP]

Thanks for the response, Bill.

The configured BIOS allows the laptop with AC/DC power supply to restart if the power supply is connected to AC mains power. This confirms that HP BIOS functions correctly by restarting the laptop (PowerChute is not required to restart the laptop).

Some further questions:

1. Does it seem like the UPS is not compatible the laptop power supply? (I'm wondering what the difference is between UPS AC power supply and mains AC power)

2. How likely is it that a HP Desktop with configured BIOS settings will be able to reboot off AC power supplied from the same UPS?

[Brad_C · Accepted solution]

How long is the power remaining off the input power supply before you try and restart?

The background to that question is I've had a power supply on a fully charged laptop sustain its output for an unholy amount of time (> 30 seconds) if the laptop is shut down as it's not drawing any current from the power supply.

On one PDU I've had to set the power cycle time (time the power is switched off) to over 60 seconds on that laptop to get a reliable restart on power.

Not likely, but worth mentioning.