F02 UPS failure with specific PSU

L

Lava Lamp Freak

Limp Gawd
Joined
Jun 20, 2004
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421
I purchased an NZXT C1200 for my new build, and it immediately tripped my UPS with F02 failure on first boot. The alarm went off with F02 on the UPS screen, and it required turning power off and back on to reset. That seems to indicate a short in the battery, but this is a new battery (just replaced about a month ago), and it happens with only this specific PSU. I swapped out the new PSU with the PSU from my old build, and it boots up without an issue.

I decided to try the new PSU again, after finding everything good with the old PSU, and again it had the same F02 failure. Strangely, after trying several times, it finally booted with the new PSU without error, and I was able to shut down and reboot with an issue. As a test, I disconnected power from the PSU and plugged it back in, and it started up again with the F02 failure.

When connected directly to the wall the new PSU works fine. So at this point I have no idea if there is something wrong with the PSU or UPS.

For now I've switched back to the old PSU, which 100% works with the UPS without any errors. Has anyone had this happen before with a UPS issue with only a specific PSU?
 
MANY devices draw a lot, max, or sometimes even over their rated limits when they first boot up or are connected. I have a 60W USB-C PD 12v power charger that works fine in my car but in my battery power station dealio it spikes 100w for a second and trips a safety. Even though my rig usually doesn't draw over 400w even when gaming the lights in my office always dim for a second after hitting the power button.

It sounds like your UPS is sensitive to the initial draw from your power supply. You need to take a look at the rating on your power supply. I almost universally use 1500va APCs for gaming rigs for this reason. If you have a 600va UPS and your PS Is 600w or higher, I can say this is likely the case.

I don't know how invested you are in your current UPS, but it's not a big deal getting used 1500va APCs on ebay. Then just install new batteries.
 
That's an interesting thought. I hadn't considered that, so thank you for sharing.

The new PSU is 1200W, but the UPS is 1000VA. The old PSU is 750W. So maybe that's why it works with the old but not with the new. I bought more PSU than I need so that it will remain in the passive fan mode most of the time.
 
Yea, it sounds like to much inrush current when charging the capacitors for the UPS to handle.
 
I have a dumb idea that might just work. Get a longer PSU <-> UPS cable. And try coiling it quite tight. The idea is to get the current slightly out of phase with the voltage.
Otherwise NattyKathy's explanation is I believe spot on.
 
michalrz said:
I have a dumb idea that might just work. Get a longer PSU <-> UPS cable. And try coiling it quite tight. The idea is to get the current slightly out of phase with the voltage.
Otherwise NattyKathy's explanation is I believe spot on.
Click to expand...
No. You would need a few thousand feet to actually start to make that happen and the resistance it would add would create a voltage drop too high for the psu to function off that.
 
Darunion said:
No. You would need a few thousand feet to actually start to make that happen and the resistance it would add would create a voltage drop too high for the psu to function off that.
Click to expand...
^ yeah, an air-cored coil of heavily-insulated wire isn't going to do much to add inductance to the circuit. You'd need at the minimum an actual ferrite-cored common mode choke and some Class X or Y caps to have any hope of suppressing inrush and other spikes.

Awhile ago I built this in an attempt to get some old Mac Pros (1050W Delta PSUs with lots of caps and giant relays, yikes) to stop pissing off my UPS and tripping the AFCI
SpikeSuppression.jpg

It did absolutely nothing!
If the inrush current from a switchmode PSU is enough to cause trouble with UPS and/or breakers, it's gonna take a LOT to suppress that.

Sounds like OP needs at least a 1500vA UPS.
 
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Darunion said:
No. You would need a few thousand feet to actually start to make that happen and the resistance it would add would create a voltage drop too high for the psu to function off that.
Click to expand...

NattyKathy said:
^ yeah, an air-cored coil of heavily-insulated wire isn't going to do much to add inductance to the circuit. You'd need at the minimum an actual ferrite-cored common mode choke and some Class X or Y caps to have any hope of suppressing inrush and other spikes.

Awhile ago I built this in an attempt to get some old Mac Pros (1050W Delta PSUs with lots of caps and giant relays, yikes) to stop pissing off my UPS and tripping the AFCI
View attachment 565919

It did absolutely nothing!
If the inrush current from a switchmode PSU is enough to cause trouble with UPS and/or breakers, it's gonna take a LOT to suppress that.

Sounds like OP needs at least a 1500vA UPS.
Click to expand...
Thanks for the correction, guys.

That device looks awesome NattyKathy, and I guess you just saved me some time somewhere down the line :D
 
Okay, outside of getting a bigger VA unit (which BTW would work and it's what I'd do if I had a "production" computer to power), would a soft-starter device help the OP as a band-aid? Anyone tried?
Even something primitive like a SCR waiting for zero-crossing and engage?

(Between UPS and PC)
 
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michalrz said:
Okay, outside of getting a bigger VA unit (which BTW would work and it's what I'd do if I had a "production" computer to power), would a soft-starter device help the OP as a band-aid? Anyone tried?
Even something primitive like a SCR waiting for zero-crossing and engage?

(Between UPS and PC)
Click to expand...
I'm also curious about the soft-starter thing, it's something I've considered due to the horrible early-gen AFCI breakers in my apartment being real finicky about inrush.

I feel like an external Soft Starter might not work well tho since the ideal ramp time for a high-power motor is a lot longer than the charge time for some caps, but idk. There's the regulation and PFC circuitry in a switchmode PSU to contend with, dunno how that would deal with a slow ramp. Internal soft-starter that trickle charges the bulk filtering caps could do it, modding PSUs is scary tho.

I think you are onto something there with the zero-crossing-triggered SCR- I wonder if that combined with a choke and some low-esr caps would do the trick.
 
Any kind of soft start circuit is going to put a draw on the ups its not designed to handle and present power to the power supply it is not designed to handle.
Double boom eventually if the protection circuits don't just shut them down.
 
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