Most of the UPS keep the CPU in low power mode but they still draw some current (though very small). But keeping it off grid for more than half a year is just too long. Either recharge it every couple months, or remove the battery and recharge it once or twice a year.
Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts
From your experience of APC UPS units, after how many years of light use of a SMT1000I would you consider replacing the 22uF caps?
I have a 2010 (week 44) SMT1000I that I have owned since new. I think it is just coming to the end of its second set of APC batteries as the runtime is not what I was used to. There is no sign of bulging on the batteries and PowerChute reports 27.5V on the batteries when the unit is on mains under light (15%) load.
Nine years, I'd do it this time replacing the accumulators.
Voltage won't tell you anything when it's running, even if acting only as capacitors, they'd read correct voltage as the charger constantly feeds them. If the unit detects high ESR or way too short runtime under periodic runtime test (unless you turned that off), than it reports them bad, but that does not always has to occur and yet they could be pretty much dead.
You can try hooking something with high power draw on it, like some incandescent lamps or a hair dryer and than checking runtime. If it dies in a minute or so, time to replace soon, if within seconds, time to replace right away
Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts
Thank you - I will take the opportunity to replace the small caps at this time then.
Assuming I don't spot any discoloured resistors or any visible signs of heat, is there any other preventative maintenance I could do at the same time? For example I have read on the forum that on some models there are a couple of resistors that are a little underrated for their workload and need replacing with a higher wattage standing off from the board?
Since this is an SMT1000I without a fan, is it possible to easily add in a fan? The case has pre-drilled holes on both sides and the SMT1500I that I also use has the fan fitted. I don't know if the SMT1000I has a fan header or not.
Those were likely the close to 2 decades old platforms, SU1000I.
The boards are pretty much the same for 1000- and 1500VA units, but the fan circuitry incl. the connector are missing for 1000VA units, you'd have to fit everything in. They have smaller capacity accumulators though so they won't pass such an energy (incl. losses) as the 1500VA version.
Mods I do on old units are improving better heat transfer from the board and transformer, but it's not necessary if you stick with 12/15Ah accumulators (otherwise with some small changes it does fit 17/20Ah ones, where the cooling improvements are needed for safe operation for longer runtime on battery).
Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts
Thank you - I will stick with the original sized battery pack on the SMT1000I.
If I may ask a different question about some odd behaviour that my in-warranty 2017 (week 28) SMT1500I is showing as APC are closed for the holidays at the moment...
The SMT1500I batteries are the original ones inside the UPS which was bought in September 2017. The whole UPS was supplied by APC themselves direct to me. While I believe the UPS itself is under warranty still, I am not sure about the original batteries.
When running on mains, the unit appears to function and self test correctly. When switching to battery in a power outage the unit does something unexpected. The % charge indicator drops rapidly within 60 seconds from 100% down to 76% then slowly recovers to about 83% by 90 seconds. This is with a 200W load. Afterwards the charge indicator slowly decreases correctly in line with the load and time.
Would I be correct in thinking there might be either an issue with a bad cell in one of the batteries or might the unit need recalibrating? The battery pack does not show any swelling or leakage.
Good point. It has never been run down except once when new.
The catch is that I don't have a suitable load that I can put on it for a long period of time that will be constant as we have gone all-LED on our lighting here. I will have a rummage and see what I can find that will be around 500W and see how it responds to a Calibration before going further with warranty calls.
There we go - first half of the Calibration done on the SMT1500I. A constant 400W load measured on a Watt Meter lasted exactly 40 minutes till shutdown which indicates that the battery was healthy after all.
It did droop quickly down to around 85% in under a minute then climbed up a little to 93%. After that it was a steady run down to 10% then it fell off more quickly, lingered at 0% a short while and stopped.
The Watt Meter on the load showed a clean 400W draw all the way down to the last percent or two when it showed about 392W. The UPS shut off cleanly once it was exhausted. I let it cool a short while (not that the air flow from the fan was more than warm), disconnected the load and plugged it back in to recharge.
We'll see whether the droop on battery is still present in a day or so once we are fully charged again.
Guess it was just initial drop due to high initial current draw. Plus, pretty much no accumulator has flat didscharge curve - it usually drops quickly from full charge to about 11.5 volts, than discharges slowly to 11 volts and than again drops rather fast to 10.5 when the UPS usually cuts it off.
Now the programming should consider this, but you never know. Besides, it indeed is good to discharge it once in a while so it has accurate battery constant values (otherwise it shows crap and could turn off the connected device prematurely, with still plenty energy in the pack).
Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts
Hi
Got a SUA1500I bought oct.2009 and its still chugging along on its third battery pack, mostly in cold environment except for like 3 months in a year. But I see these mentions everywhere about the 5 22uF caps and im kinda worried.
Or are these ones ok for this unit? Lead spacing, 35v? Found that originals are likely 16v, cant open the unit yet. 5eu postage and caps 0.2eu it seems.
You would be better off with this series because I prefer using 50 volt ones instead of 25 volt or 35 volt for capacitors with low UF values under a 100 volts
Thanks. Luckily they were on this conrad shop and ordered a bunch just now. Hopefully can coerce a friend with proper soldering equipment to help me so that I dont cook everything with my noname 8eu iron
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