APC Smart-UPS 1500 always overload

[crazy_driver]

Hi,
Can someone help with a suggestion?

This ups was given to me in unkown condition, i put 4 batteries in and it's always on overload.

I found a few videos talking aboud dead capacitors that would cause that on APC ups, so i removed all the caps and tested them with a Mtester.
I only found two 330uF with a value around 300 all the others were close to spec.



I tested the HRF3205 Mosfets all had similar values.



The Mtester can't test the LM317T voltage regulator that i removed last or it's defective.



So any ideas or just buy the new stuff and do the double power conversion while at it?

https://www.eevblog.com/forum/projects/cool-tutorial-converting-an-apc-ups-into-a-powerful-sinewave-inverter/

[LuisHertz]

Can you fix It?

[coromonadalix]

apc in 1kw models had capacitors problems and some noise on op amps in the charging circuit ?? i think tantalum caps where at fault too  ?

[BradC]

That's a late 3G unit. Have you checked the config to ensure it knows what it is? One peculiarity with the 3G units is they keep their config in an external serial eeprom, and it's not unheard of for it to lose its mind and default to believing it is a US 750VA unit. That screws all the configs and calibration constants and causes it to think it's overloaded, boil the batteries and other nasty things.

Read up on how to config those units, put a serial cable on it and check before you go suspecting the hardware. Or of course you could just dive in and start ripping apart, shot gunning parts and making wild guesses

[oldway]

I know nothing about APC ups, I worked with industrial UPS AEG / SVS from 10Kva's to 400Kva's.....
So I don't know if what I'am writing can help.....

I have had the same problem (indication of overload even without any load) and it was a faulty Hall effect  current sensor LEM.

Is there someting like this in APC ups ? I don't know but beter to check.....

[BradC]

Is there someting like this in APC ups ? I don't know but beter to check.....

No, the SmartUPS series use a current transformer which is conditioned and fed into the ADC.