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Forum Index : Electronics : UPS Fault

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Phil23
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Joined: 27/03/2016
Location: Australia
Posts: 1664
Posted: 03:17am 05 Jul 2018
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Just wondering what people think about a problem with this unit
& what would be considered normal.

SUA300XLI

Unit is 6 years old, batteries 6 months.
4x Panasonic 12V 20Ah, in a 48V bank.

Let it sit on the bench for a few hours & the batteries were floating at 55.8V.

Gave it a 5 minute run on a 1000V load, Battery voltage sitting around 46.7V & drawing 22.5A on a DC clamp meter.

Reconnected the mains & I see 4 amps initial charge for under a minute before it dropped to about 2A.

Got a gut feeling something could be stuffed in the charge circuit, as the specs say typical recharge around 3 hours, which has me thinking it should charge more in the area of 5 to 10 amps.

Either a charging issue, or the batteries are stuffed.

Any general thoughts?


Cheers

Phil.

 
Phil23
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Joined: 27/03/2016
Location: Australia
Posts: 1664
Posted: 08:14am 05 Jul 2018
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Ran a 2000W load test this afternoon.

Pulled around 45A from the batteries before it shutdown after 9:38 minutes.
Specs quote 9 min @ 2000W load.

Back on power it indicated it was fully charged after about 2 1/2 hours, but the numbers don't seem to add up.

Logged the data & might post it later.
Basically V & A at 30 minute intervals.

But checked the sale invoice & it's now 7 1/2 years old.

If the batteries were flat, I'd need 5A for 4 hours as loose numbers;
the figures show I put back in a fraction of that before it indicated it was fully charged again.

Electro's on charge & sensing circuits?
How'd they be expected to hold up after that sort of service?
 
Revlac

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Joined: 31/12/2016
Location: Australia
Posts: 1026
Posted: 10:06am 05 Jul 2018
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Are those Batteries the exact same as the originals that it had in it.?

I had an UPS and replaced the batteries, not long after the batteries were stuffed again, the replacement batteries were identical but made in a different country.

If the battery voltage rises quickly I would suspect the batteries.




Cheers Aaron
Off The Grid
 
Chopperp

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Joined: 03/01/2018
Location: Australia
Posts: 1057
Posted: 02:09pm 05 Jul 2018
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Are you able to measure the individual battery volts while it is charging? One a bit higher than the others will prevent a full charge.
ChopperP
 
Phil23
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Joined: 27/03/2016
Location: Australia
Posts: 1664
Posted: 11:21pm 05 Jul 2018
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Can probably extend the batteries out with a couple of Anderson leads I use for camping, but they are a few metres long.

Still suspect the Charge/monitoring though as I don't see what I could really consider a bulk charge.

Left table relates to discharge, right to recharge.

7 Ah out on discharge seems pretty realistic, considering it's at 40+A, not the rated 1A.

But charge back in only accumulated to about 6Ah, & voltage is more what I'd consider a float than bulk charge level.


 
yahoo2

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Joined: 05/04/2011
Location: Australia
Posts: 1166
Posted: 02:30am 06 Jul 2018
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  Phil23 said  
But charge back in only accumulated to about 6Ah, & voltage is more what I'd consider a float than bulk charge level.


seems like a perfectly normal scenario for a UPS, if you dont have daily power failures it has endless hours to reach full charge, if you wind the voltage up it will cook and corrode the batteries.

car alternators are made to charge the same way.
I'm confused, no wait... maybe I'm not...
 
Phil23
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Joined: 27/03/2016
Location: Australia
Posts: 1664
Posted: 10:31am 06 Jul 2018
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  yahoo2 said  if you dont have daily power failures it has endless hours to reach full charge.


it's not daily outages that create the issue. It's extended overvoltage scenarios that cause issues here.

One site reports it every day when a tranny tap changes at around 4:30am in the morn.
That sends the units into a mode where they draw on the batteries to force the mains back down.

They are all line interactive units I have installed; but am starting to think that Online units might perform better in this situation as they would not be relying on their batteries to stabilise the mains.



 
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