I'd like to start out by thanking this forum for providing the info to be able to repair my 15 year old CP1500AVRLCD UPS. Here is all the info I gathered during my trouble-shooting and re-capping.
Like clockwork, I've had to replace the SLA batteries every 4 years. It was about that time and the UPS was acting like it needed new batteries... randomly shutting off with AC present, not being able to charge fully, and poor runtime when AC was removed. So, I replaced the batteries but noticed that it was not charging properly.
I decided to verify that the batteries were okay. So, I removed them and charged them individually and used a DC electronic load to test their capacity. They were 7.6-7.9Ah and 6.9-7.1Ah across several cycles at a 0.05C discharge rate to an 11V cutoff. They're rated as 9Ah but since they were cheap and I was testing them at about 65 degF it seemed fine. I also tested them at 0.5C discharge and saw 5.4 and 5.9Ah of capacity which was within expectations.
I then stumbled upon this forum and found very helpful threads such as
https://www.badcaps.net/forum/showth...ght=cyberpower
and
https://www.badcaps.net/forum/showth...ght=cyberpower
Upon inspection I did not notice any leaking capacitors or burned ICs. However, since the successful repairs focused on the recharging circuit and my device was not charging properly I though I'd see if I could confirm my device's issue.
I connected a PSU to the battery connection terminals (without a battery present). With the AC cord disconnected I supplied 25V and the UPS was able to turn on. The UPS was drawing 0.71A from the PSU but there must have been a very large variation in the current draw because the PSU was voltage limiting and reporting an average output voltage about 0.5V below the setpoint even though the current limit was set to 5A. An AC voltage reading at the battery terminals reported 0.67Vrms. This confirmed that the current draw was very irregular. I didn't bother checking it out on a scope.
Next, I attached the DC electronic load in parallel with the PSU and set it to draw 0.5A. The PSU happily supplied this extra current. I then plugged in the AC cord of the UPS and was expecting to see the PSU load current decrease as both the UPS would switch to AC and the charging circuit would attempt to charge the "batteries". If the charging circuit supplied more current than my load was set to I would expect the voltage to float up above the PSU's 25V setting. If it could not, I expected by be able to lower the DC load current and at some point the voltage would go above 25V.
Once plugged into AC I did not observe any charging current and the PSU still had to supply 0.2-0.3A or else the unit would turn off. This confirmed to me that the charging circuit was not functioning.
Based on the posts mentioned earlier, the first thing I did was desolder C1 and C3 and measure them with my LCR meter. They pretty obviously needed replacement. I also validated that U2 phototransistor was okay. It had a forward diode voltage of 1.05V on the side away from the board corner and the resistance of the other side was high by itself and about 1K when the other side was forward biased by my other multimeter. I purchased a replacement for U3 (Viper22A) but only planned to replace it if all the other changes failed since it seemed fine (no shorts between terminals with a meter). I desoldered the shunt voltage reference U1 and attempted to measure its expected reverse breakdown of 2.5V with the cathode and reference pins tied together and was unsuccessful so I added it to my list of parts to replace. The exact part was not available so I just chose one of the many other TL431* choices with 0.5% tolerance.
Since the C1 and C3 capacitors were bad I decided to desolder and document the dimensions and type of all of the electrolytic caps as show below.
Capactor Series Observed
-------------------------
Su'scon SK Standard 105C 2000hr (Black)
Su'scon SD Low Impedance 105C 2000hr (Brown)
Su'scon MK One rank smaller than SK 105C 2000hr (Black)
Refs; uF, V, SxDxH(mm), Series, Ripple+ESR Rating
C1,10,12,18,19,22,23; 22u, 50V 2.5x5x10, SK, 83mArms @ 120Hz
C3,6; 33u, 200V 5x10x20, MK, 157mArms @ 120Hz
C2,14; 33u, 100V 5x10x17, SD, 450mArms 0.46Ohm @ 100KHz
C8; 470u, 50V, 5x13x21, SD, 1.45mArms 0.09Ohm @ 100KHz
C9; 47u, 63V 3.5x8x11, SK, 163mArms @ 120Hz
C20; 1.0u, 50V, 2.5x5x10, SK, 15mArms @ 120Hz
C21; 0.22u, 50V, 2.5x5x10, SK, 11mArms @ 120Hz
FYI the dimensions are listed as lead-spacing x diameter x height. Most of these capacitors have no space to support a larger diameter substitution. All of these caps can safely support taller capacitors.
Removing and measuring all of these caps gave the following results. Rather than tan-delta, dissipation factor, or ESR I am reporting the phase angle. A perfect capacitor would be -90 degrees but, depending on the capacitor value, lower readings at 10kHz are normal.
Ref, uF, @10KHz, @1kHz, Condition
C1, 22, bad, 11.1u -21deg, BAD
C3, 33, 19.9u -20deg, 26.9u -66deg, BAD
C6, 33, 13.9u -14deg, 23.1u -50deg, BAD
C2, 33, 29.3u -52deg, 30.9 -83deg, GOOD
C14, 33, 29.8u -55deg, 31.2 -84deg, GOOD
C8, 470, NA, 356u -51deg, BAD
C9, 47, 40.5u -38deg, 43.6u -80deg, GOOD
C10, 22, 12.6u -33deg, 16.6u -73deg, BAD
C12, 22, 12.9u -36deg, 16.8u -74deg, BAD
C18, 22, 0.63u -18deg, 0.50u -24deg, BAD
C19, 22, 10.4u -24deg, 15.8u -65deg, BAD
C20, 1.0, 0.40u -43deg, 0.52u -71deg, BAD
C21, 0.22, 0.18u -83deg, 0.20u -86deg, GOOD
C22, 22, 6.5u -19deg, 13.0 -51deg, BAD
C23, 22, 2.3u -18deg, 6.6u -33deg, BAD
Ultimately, I replaced all of them based on their age. The following parts were purchased and installed. I was able to find cost effective replacements that met the specs of the original parts but had significantly higher lifetime ratings at 105C.
Ref, Qty, $/ea
C3,6, 2, 0.86 https://www.digikey.com/en/products/...E2D330/1245959
Chose long-life, high ripple rating even though original was General Purpose (almost no cost difference)
C2,14
2, 0.64 https://www.digikey.com/en/products/...2A330B/9597100
5x8x13mm rather than 5x10x17 of original (smaller diameter is fine). Even at 160V rating I did not find
an in-stock cap that met the ripple rating and had low enough ESR for 10mm diameter.
490mArms @ 100Khz exceeds original and 0.16ohm ESR is much better
C8, 1, 0.82 https://www.digikey.com/en/products/...2-5X20/3564059
22mm tall, long life high ripple
C9, 1, 0.35 https://www.digikey.com/en/products/...774002/5727468
C1,10,12,19,22,23
7, 0.21@10 https://www.digikey.com/en/products/...15X11/11312828
12.5mm tall rather than 10mm of original, 10000hr@105C
C20, 1, 0.14 https://www.digikey.com/en/products/...672002/5727810
12.5mm tall rather than 10mm of original 4000hr@105C
C21, 1, 0.28 https://www.digikey.com/en/products/...MDD1TD/4342067
Could only find an "obsolete" part
U1, 1, 0.42 https://www.digikey.com/en/products/...AplgMYogC6AvkA
After installing these parts, I performed similar testing to what I described before. With the AC removed, the PSU only had to supply 0.5A at 25V. There was no current limiting or noisyness observed like before and the voltage at the battery terminals had only 0.045Vrms of AC content.
Then, I attached the DC electronic load in parallel and plugged in the AC to determine the battery charging capability. By changing the electronic load current and then adjusting the PSU voltage until it was just low enough that it didn't need to supply any current I captured the IV curve of the charging.
Charging current versus output voltage
A V
0.02 27.25
0.10 27.14
0.20 27.01
0.30 26.77
0.40 26.10
0.42 25.50
0.44 25.00
0.45 24.50
This provides a 0.05C initial charge rate which then tapers off to become a trickle charge at about 13.65V per SLA battery.
So, everything seemed to be working perfectly and there was no need to replace U3 in my instance.
Like clockwork, I've had to replace the SLA batteries every 4 years. It was about that time and the UPS was acting like it needed new batteries... randomly shutting off with AC present, not being able to charge fully, and poor runtime when AC was removed. So, I replaced the batteries but noticed that it was not charging properly.
I decided to verify that the batteries were okay. So, I removed them and charged them individually and used a DC electronic load to test their capacity. They were 7.6-7.9Ah and 6.9-7.1Ah across several cycles at a 0.05C discharge rate to an 11V cutoff. They're rated as 9Ah but since they were cheap and I was testing them at about 65 degF it seemed fine. I also tested them at 0.5C discharge and saw 5.4 and 5.9Ah of capacity which was within expectations.
I then stumbled upon this forum and found very helpful threads such as
https://www.badcaps.net/forum/showth...ght=cyberpower
and
https://www.badcaps.net/forum/showth...ght=cyberpower
Upon inspection I did not notice any leaking capacitors or burned ICs. However, since the successful repairs focused on the recharging circuit and my device was not charging properly I though I'd see if I could confirm my device's issue.
I connected a PSU to the battery connection terminals (without a battery present). With the AC cord disconnected I supplied 25V and the UPS was able to turn on. The UPS was drawing 0.71A from the PSU but there must have been a very large variation in the current draw because the PSU was voltage limiting and reporting an average output voltage about 0.5V below the setpoint even though the current limit was set to 5A. An AC voltage reading at the battery terminals reported 0.67Vrms. This confirmed that the current draw was very irregular. I didn't bother checking it out on a scope.
Next, I attached the DC electronic load in parallel with the PSU and set it to draw 0.5A. The PSU happily supplied this extra current. I then plugged in the AC cord of the UPS and was expecting to see the PSU load current decrease as both the UPS would switch to AC and the charging circuit would attempt to charge the "batteries". If the charging circuit supplied more current than my load was set to I would expect the voltage to float up above the PSU's 25V setting. If it could not, I expected by be able to lower the DC load current and at some point the voltage would go above 25V.
Once plugged into AC I did not observe any charging current and the PSU still had to supply 0.2-0.3A or else the unit would turn off. This confirmed to me that the charging circuit was not functioning.
Based on the posts mentioned earlier, the first thing I did was desolder C1 and C3 and measure them with my LCR meter. They pretty obviously needed replacement. I also validated that U2 phototransistor was okay. It had a forward diode voltage of 1.05V on the side away from the board corner and the resistance of the other side was high by itself and about 1K when the other side was forward biased by my other multimeter. I purchased a replacement for U3 (Viper22A) but only planned to replace it if all the other changes failed since it seemed fine (no shorts between terminals with a meter). I desoldered the shunt voltage reference U1 and attempted to measure its expected reverse breakdown of 2.5V with the cathode and reference pins tied together and was unsuccessful so I added it to my list of parts to replace. The exact part was not available so I just chose one of the many other TL431* choices with 0.5% tolerance.
Since the C1 and C3 capacitors were bad I decided to desolder and document the dimensions and type of all of the electrolytic caps as show below.
Capactor Series Observed
-------------------------
Su'scon SK Standard 105C 2000hr (Black)
Su'scon SD Low Impedance 105C 2000hr (Brown)
Su'scon MK One rank smaller than SK 105C 2000hr (Black)
Refs; uF, V, SxDxH(mm), Series, Ripple+ESR Rating
C1,10,12,18,19,22,23; 22u, 50V 2.5x5x10, SK, 83mArms @ 120Hz
C3,6; 33u, 200V 5x10x20, MK, 157mArms @ 120Hz
C2,14; 33u, 100V 5x10x17, SD, 450mArms 0.46Ohm @ 100KHz
C8; 470u, 50V, 5x13x21, SD, 1.45mArms 0.09Ohm @ 100KHz
C9; 47u, 63V 3.5x8x11, SK, 163mArms @ 120Hz
C20; 1.0u, 50V, 2.5x5x10, SK, 15mArms @ 120Hz
C21; 0.22u, 50V, 2.5x5x10, SK, 11mArms @ 120Hz
FYI the dimensions are listed as lead-spacing x diameter x height. Most of these capacitors have no space to support a larger diameter substitution. All of these caps can safely support taller capacitors.
Removing and measuring all of these caps gave the following results. Rather than tan-delta, dissipation factor, or ESR I am reporting the phase angle. A perfect capacitor would be -90 degrees but, depending on the capacitor value, lower readings at 10kHz are normal.
Ref, uF, @10KHz, @1kHz, Condition
C1, 22, bad, 11.1u -21deg, BAD
C3, 33, 19.9u -20deg, 26.9u -66deg, BAD
C6, 33, 13.9u -14deg, 23.1u -50deg, BAD
C2, 33, 29.3u -52deg, 30.9 -83deg, GOOD
C14, 33, 29.8u -55deg, 31.2 -84deg, GOOD
C8, 470, NA, 356u -51deg, BAD
C9, 47, 40.5u -38deg, 43.6u -80deg, GOOD
C10, 22, 12.6u -33deg, 16.6u -73deg, BAD
C12, 22, 12.9u -36deg, 16.8u -74deg, BAD
C18, 22, 0.63u -18deg, 0.50u -24deg, BAD
C19, 22, 10.4u -24deg, 15.8u -65deg, BAD
C20, 1.0, 0.40u -43deg, 0.52u -71deg, BAD
C21, 0.22, 0.18u -83deg, 0.20u -86deg, GOOD
C22, 22, 6.5u -19deg, 13.0 -51deg, BAD
C23, 22, 2.3u -18deg, 6.6u -33deg, BAD
Ultimately, I replaced all of them based on their age. The following parts were purchased and installed. I was able to find cost effective replacements that met the specs of the original parts but had significantly higher lifetime ratings at 105C.
Ref, Qty, $/ea
C3,6, 2, 0.86 https://www.digikey.com/en/products/...E2D330/1245959
Chose long-life, high ripple rating even though original was General Purpose (almost no cost difference)
C2,14
2, 0.64 https://www.digikey.com/en/products/...2A330B/9597100
5x8x13mm rather than 5x10x17 of original (smaller diameter is fine). Even at 160V rating I did not find
an in-stock cap that met the ripple rating and had low enough ESR for 10mm diameter.
490mArms @ 100Khz exceeds original and 0.16ohm ESR is much better
C8, 1, 0.82 https://www.digikey.com/en/products/...2-5X20/3564059
22mm tall, long life high ripple
C9, 1, 0.35 https://www.digikey.com/en/products/...774002/5727468
C1,10,12,19,22,23
7, 0.21@10 https://www.digikey.com/en/products/...15X11/11312828
12.5mm tall rather than 10mm of original, 10000hr@105C
C20, 1, 0.14 https://www.digikey.com/en/products/...672002/5727810
12.5mm tall rather than 10mm of original 4000hr@105C
C21, 1, 0.28 https://www.digikey.com/en/products/...MDD1TD/4342067
Could only find an "obsolete" part
U1, 1, 0.42 https://www.digikey.com/en/products/...AplgMYogC6AvkA
After installing these parts, I performed similar testing to what I described before. With the AC removed, the PSU only had to supply 0.5A at 25V. There was no current limiting or noisyness observed like before and the voltage at the battery terminals had only 0.045Vrms of AC content.
Then, I attached the DC electronic load in parallel and plugged in the AC to determine the battery charging capability. By changing the electronic load current and then adjusting the PSU voltage until it was just low enough that it didn't need to supply any current I captured the IV curve of the charging.
Charging current versus output voltage
A V
0.02 27.25
0.10 27.14
0.20 27.01
0.30 26.77
0.40 26.10
0.42 25.50
0.44 25.00
0.45 24.50
This provides a 0.05C initial charge rate which then tapers off to become a trickle charge at about 13.65V per SLA battery.
So, everything seemed to be working perfectly and there was no need to replace U3 in my instance.
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