Odd electrics at a mates house (surges)

Discussion in 'Electricians' Talk' started by BikerChris, Sep 10, 2022.

  1. BikerChris

    BikerChris Active Member

    Hey all,

    This is just a curiosity more than anything.

    A mate has a terrace house on a 70's estate. He's got a computer with a UPS.

    Now I know about UPS's and how they have a battery that is switched to when there is a power cut. But when he gets power cuts, sometimes it actually completely switches off? Kills the computer power completely. Now my wife has a UPS and I have had it all running and switched off the power (at the socket). The computer keeps running and the UPS just beeps until power is restored.

    Back at his house, most of the time when there are power cuts, the UPS did kick in as expected (keeping the computer on), but every once in a while, it will just trip.

    He has also had internet routers get fried in some lightning events.

    Does this all point to a severe earthing issue? Obviously this is just guess work without proper testing, just be welcome to hear from anyone. May be he could even do with a lightning rod?


  2. Coloumb

    Coloumb Screwfix Select

    Your mate would really need a spark to check the earth out properly with some test kit if you wanted to be 100% sure. I think it sounds like the UPS is on the way out.
    BikerChris likes this.
  3. BikerChris

    BikerChris Active Member

    Thank you mate, yeah you are right. He's a bit on the old side so lacks money, but I'm going to badger him cos otherwise its just gonna kill a device in his house one day.

    He showed me on the computer that the battery is at 100%, but there is no condition info. I might see if he's ok with me at least unplugging power to see if it can cope when the computer is on. I would plug in a lamp that is 100W so it simulates his computer without mucking it up with a cold shut down.

    cheers again fella.
  4. FlyByNight

    FlyByNight Screwfix Select

    Take teh battery out of te UPS if possible and measure it off load ... and check every 15 miuntes to see if it drops rapidly. Try it with a 50w car/bike head lamp or bulb, see what the voltage does and does it recover. A lot of te basic UPS's use standard sealed lead acid which are cheap/easy to replace.
    BikerChris likes this.
  5. adgjl

    adgjl Screwfix Select

    How old is the battery? They typically only last 4 to 6 years.
    Mosaix and BikerChris like this.
  6. BikerChris

    BikerChris Active Member

    Nice one, thank you. He's really precious about, well everything so I will test with a high watt lamp first, then with his difficult to get permission will pull battery and test drop. yeah it should be easy to replace, i keep thinking he has done that already once.

    He either said it was 2 or 4 years old, I will ask next time I go there, but I remember thinking that its probably shot by now. it's an old ups so i reckon it doesn't do any conditioning cycle.

    ah ha, I just thought I would check my email, he uses it to tell me latest news. he bought a new battery for it in 2016! I will ask if he has bought a new one since then
  7. Bazza-spark

    Bazza-spark Screwfix Select

    You need to check how the UPS works.

    I saw a project engineer fit an 8kW and a 12kW UPS system in a lab with RCD sockets protecting the equipment they were supplying as they werepproducing very expensive medical refinements. Whenever there was a power dip or failure the RCD's all tripped making the whole thing an expensive waste of time as the batteries only kicked in when the power failed.

    The batteries should be "floating" so that they are pemanently on-line, if they aren't this can happen.
    BikerChris likes this.
  8. BikerChris

    BikerChris Active Member

    Yep, I'm gonna do that @Bazza-spark

    What a strange story, how can they do that when they are spending so much? Strange.

    I wonder if his UPS is just a bit on the cheap side, as well as being very old.
    Bazza-spark likes this.
  9. Bazza-spark

    Bazza-spark Screwfix Select

    Not that it is cheap necessarily. Some UPS's the batteries don't kick in until the power fails, there is a changeover relay in them. They will cause the issue you have, others the batteries are floating and on-line all the time. That type also gives some mains conditioning.
    BikerChris likes this.
  10. BikerChris

    BikerChris Active Member

    Ah, all understood. I'm sure we've got the 'on all the time' ones at home
  11. BikerChris

    BikerChris Active Member

    Just some extra info, he said he measured voltage of sockets with plug in tester, lowest he's seen is 190V. I didn't even think that was possible?!
  12. Bazza-spark

    Bazza-spark Screwfix Select

    If he is using a plug in tester it will be manufactured to measure normal mains RMS volage. A UPS isn't normal mains voltage and can vary according to it's waveform.
    BikerChris likes this.
  13. BikerChris

    BikerChris Active Member

    Sorry, I meant he measured voltage directly from a wall socket - not the UPS, sorry about that.
  14. FlyByNight

    FlyByNight Screwfix Select

    If it really is 190v then there is a supply issue that needs resolving. Does either of you have a decent meter with a Max/Min function?

    Leave that runnning and see what comes about.
    BikerChris likes this.
  15. BikerChris

    BikerChris Active Member

    Yes I do have a meter with min/max, I might leave it round there one day. Thanks very much
  16. Denis6482

    Denis6482 Member

    Old UPS units used SLA batteries which have a limited lifetime. I've repaired a lot of them and it's a horrible job involving swollen batteries that are difficult to remove, split battery cases and acid leaks. If it's cheap and/or old it's time for a new one.
    BikerChris likes this.
  17. BikerChris

    BikerChris Active Member

    Cheers for that @Denis6482 , I'm going to see him again soon and check it out.
  18. BikerChris

    BikerChris Active Member

    Just an update to amuse, got this in a text from him, thank god i can copy and paste

    Had a problem with my old APC battery back-up ... it kept tweeting at me all the time and telling me the battery was knackered ... even though it was showing a 100% charge !! Anyway I've bought a new one .. £135.00 ... has slightly bigger battery and six sockets on the back instead of only three on the old one ... so I can protect more accessories plugged in to USB.
  19. Denis6482

    Denis6482 Member

    Good result. Replacing the battery in the existing UPS would have been cheaper however as I mentioned, it's not an enjoyable task. @BikerChris, do you know what battery chemistry his replacement uses?
    BikerChris likes this.
  20. BikerChris

    BikerChris Active Member

    For sure Denis. Yes replacing the battery would have been cheaper, but he doesn't like to fiddle around with stuff any more, though I'd have been happy to help, he's reluctant to ask for it.

    I've asked him what kind of UPS he got in the end, I'm sure he will let me know soon.

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