Another Remote Power Off/ON Question

Anonymous user · ‎2021-06-29

After reading through many posts, I'm not 100% confident I've found a valid answer. I have (2) SPC SMART UPS 3000 units. I would like to be able to remotely poweroff and poweron the UPS themselves. My intent is to save the batteries. The equipment is used maybe 2-3 days per week and when it's not being used, people forget to go to the UPS and power it off. The batteries wind up dying in no time and then need replacement. I want to put physical switches in a location that people can see and is easy to get to so they remember to power off the UPS. It looks like the DB9 connector with shorts of 7-9 for ON and 7-8 for OFF would work, but then I read about the "vampire" situation. It also sounds like after 10 minutes of being powered off, the unit becomes braindead and can't be remotely powered on. Any way around any of this confusion?

BillP · ‎2021-06-29

Here is what I have:

Remote On/Off Control

DB9 – Turn On/Off

Remote On

Application of a short (or a momentary button) connected between pins 7 and 8 of the DB9 for 200 ms (60Hz) 240ms (50Hz) will result in the UPS detecting an ON command. The UPS will then process its on sequence.

Remote Off

Application of a short (or a momentary button) connected between pins 7 and 9 of the DB9 for 200 ms (60Hz) 240ms (50Hz) will result in the UPS detecting an OFF command. The UPS will then turn off immediately.

See Answer In Context

BillP · ‎2021-06-29

Here are my personal comments.

1.) If the UPS is off with the batteries still connected internally, they'd still be susceptible to discharging in the UPS since when the UPS is powered off, the charger is inactive and not maintaining a float charge on the batteries. That is why we always recommend you disconnect the batteries when storing your UPS for any amount of time to be safe. Your comment regarding how the batteries die in no time made me want to understand why and ask more questions because with little to no use (no deep discharges and just light use for a couple of transfers to batteries) in a situation like this, I would think you are definitely getting 3-5 years battery life. What are you actually seeing for a lifespan? When the UPS is powered up the 2-3 days a week, what kind of use are the UPSs seeing? Just powering the equipment and no transfers to battery?

2.) You're right - without AC power, the UPS will go "braindead" in 8-10 minutes. This means no power to the serial port. Before you'd be able to do anything with it, you need to restore AC power to it and then it would come back alive (the electronics become energized) and you could command the output back on or just push the power button. (A Network Management Card is also an option to remotely log in and command the output on).

My thought also is a UPS is designed to remain on most of the time and the vampire current will power the internal UPS electronics and help keep the batteries at float charge which should be minimal if they are not discharged often.

Also, for any further response or comments, could you provide the exact model of the UPS from the back of the UPS so we can ensure the comments made above are 100% accurate? Sounds like you have something like SUA3000RM2U or similar.

Anonymous user · ‎2021-06-29

Very good and valid comments/questions Angela.

1. I think there are small units that are connected to the UPS system that most people aren't paying attention to that continue to drain the batteries (almost hidden within the racks). There are generally no transfers to battery only situations, but when people are done using the racked equipment, sometimes the AC is disconnected from the area. Although the majority of the equipment is off, there is still those few pieces here and there that aren't paid attention to.

2. If I can ensure the AC power remains constant, I shouldn't have to worry about the "braindead" state right? So I should still be able to use the DB9 based switching system for powerup?

It's going to take a few minutes for me to get to the back of the UPS and see exact model, but I think your correct with SUA3000RM2U. I'll verify and reply again with exact info.
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BillP · ‎2021-06-29

Ok, I'll wait for the model number.

Regarding # 1 - do you mean while the UPS is on battery, they drain the battery power? If the UPS is running online yet the hidden equipment is not being watched, it should not be draining the batteries unless the UPS is operating on battery power. (So I am still a little confused here).

Regarding # 2 - yes, you are correct. You can just keep the power output off on the UPS if you'd like and it'd keep charging the battery as needed and remain alive. And yes, you can use the DB-9 port since the UPS will be alive.

Anonymous user · ‎2021-06-29

I can only see half the model number, but I do see SUA3000.

Yes, when the AC has been removed, people leave things plugged in drawing current and don't shutdown the UPS. I'll work to ensure that AC is kept constant. Can you just verify for me that my 7-8 is OFF and 7-9 is ON for the DB9?

BillP · ‎2021-06-29

BillP · ‎2021-06-29