Author Topic: EEVblog #1168 - Dumpster Diving UPS  (Read 2947 times)

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Offline EEVblog

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EEVblog #1168 - Dumpster Diving UPS
« on: January 13, 2019, 09:29:03 am »
Dave scores a HP R1500 G3 rack mount Uninterruptible Power Supply (UPS) from the dumpster.
Teardown time!

 
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Online Treehouseman

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #1 on: January 13, 2019, 09:51:35 am »
I don't recall having ever owned a well built UPS that didn't require battery voltage to turn on. It makes sense from a safety aspect. If something happens to make the unit fail or the batteries become useless it takes itself out of service once it no longer has power to hold down the line relay. This is how I've gotten many ups's for free or close to it. 9/10 times they just need a fresh set of batteries, there's nothing actually wrong with the unit, even though they refuse to turn on.
 
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Online edpalmer42

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #2 on: January 13, 2019, 10:01:36 am »
I don't recall having ever owned a well built UPS that didn't require battery voltage to turn on. It makes sense from a safety aspect. If something happens to make the unit fail or the batteries become useless it takes itself out of service once it no longer has power to hold down the line relay. This is how I've gotten many ups's for free or close to it. 9/10 times they just need a fresh set of batteries, there's nothing actually wrong with the unit, even though they refuse to turn on.

+1 for this.  One time I powered up an APC UPS by replacing the 24V batteries with a 24V wall wart that was only rated for a few watts .  The UPS needed the 24V to bias something before it would turn on.  Be careful that your power supply isn't going to smoke when the UPS tries to charge the batteries!

Ed
 
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Offline SeanB

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #3 on: January 13, 2019, 10:20:26 am »
Yes, got 2 that need new 24V battery packs to run, just looking for some used but good lead acid batteries for them, as they are 1kVA units.

You will also notice the heatsinks are just a big thermal mass, no fins to dissipate the heat, just a big enough thermal mass so the power dissipated in them during the 15 minutes or so of backup operation will not get them to the shutdown temperature before the batteries reach low voltage under the massive load imposed on them. Then the unit sits there till power comes back on, waits the on power delay and energises the transformer relay and the output relay and uses the incoming mains to rather brutally charge the batteries till they reach the lower float voltage, then change to trickle charge mode to finish the charge. Periodically it will do a self test on the batteries by powering the DC Dc converter to charge the output capacitors and monitor battery voltage for droop, and sound an alarm ( plus also show on the built in web server if the accessory LAN interface is installed) showing battery health. That 5V regulator really needs a better heatsink, the one it is on is not really going to be good without the fan blowing over it, as it likely has close to the battery voltage on the input, or there is a 12V regulator on the big block of aluminium that feeds it.

More modern ones track battery life as well, so will have reduced predicted runtime as the batteries age, so they can give a predicted shutdown signal when power is lost so the load can initiate a controlled power off and command the UPS off instead of it just dropping the load on low battery without notice. Bet that one was beeping for months before they had a power failure and it simply shut off after 5 seconds, never to turn on again.
 

Offline elliottveares

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #4 on: January 13, 2019, 10:23:26 am »
Would the UPS still attempt to charge fully dead batteries following a power outage where the batteries were fully drained down?
 

Online Treehouseman

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #5 on: January 13, 2019, 10:34:24 am »
Would the UPS still attempt to charge fully dead batteries following a power outage where the batteries were fully drained down?

No, with the UPS off, the relay that connects the line to the output and charge circuit is open, so without battery voltage to close the relay and "boot" the ups it can't turn on.
 

Offline johnlsenchak

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #6 on: January 13, 2019, 11:01:25 am »

Hey Dave,   stop  fingering those ports !   8)

I agree with you those two   XP  computers  are not worth  fixing,  they only have scrape  value  I  would just  grab the CPU and memory  modules


Two  days  ago,  I was dumpster  diving   inspired by Dave   of course, and I found  two  brand new   Epson  Workforce  Pro   WF4720 printers in the boxes
https://epson.com/For-Work/Printers/Inkjet/Epson-WorkForce-Pro-WF-4720-All-in-One-Printer/p/C11CF74201

Most  A.P.C Smart  uninterrupted  power supplies  will continue  to run on the  mains,  if the batteries  dies or  get  disconnected


I  would love to  see  a  repair  video  on that H.P.   uninterrupted  power supplies.
John Senchak "Daytona  Beach  Florida "
 jls (at)  antihotmail.com   http://www.antihotmail.com
https://www.facebook.com/john.senchak.1
 

Offline Zenwizard

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #7 on: January 13, 2019, 11:27:53 am »
Dave

I agree with everyone on the Dell PC's They are a little too old. I work on servers and UPS units for my day job, the batteries in a UPS should not be bulging, any bulging or sometimes rattling rebuild the battery kit. Some of the ups units I have serviced will not start unless it sees battery voltage. They will stay on line once the batteries die or get disconnected. But they wont start up from cold. Also all batteries should be changed at the same time due to age on the cells. Usually what the UPS is protecting is WAY more expensive then a few batteries. Typically the batteries are non-spill able gel lead acid batteries or sealed lead acid batteries. First trouble shooting step I would do is put the needed battery voltage at the connector and see if the UPS starts then go from there.

Zen
 

Offline EEVblog

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #8 on: January 13, 2019, 11:47:14 am »
I don't recall having ever owned a well built UPS that didn't require battery voltage to turn on. It makes sense from a safety aspect. If something happens to make the unit fail or the batteries become useless it takes itself out of service once it no longer has power to hold down the line relay. This is how I've gotten many ups's for free or close to it. 9/10 times they just need a fresh set of batteries, there's nothing actually wrong with the unit, even though they refuse to turn on.

This one is a hot swappable battery, so it's designed to be disconnected and still function.
 

Online Treehouseman

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #9 on: January 13, 2019, 12:03:27 pm »
Looking at the manual it doesn't outright state that it can be turned on with or without batteries. It seems to read like it needs battery power to turn on, stating that the ups can only deliver output to the outlets and start charging the batteries if it is already "powered up" or has battery power and no line connected. In the section for troubleshooting if the unit doesn't turn on, it doesn't say that batteries are required but it does say to give them 24 hours to charge, though I'm not sure how that works if it needs to be operational to charge.
 
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Offline KK

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #10 on: January 13, 2019, 12:48:32 pm »
Have seen this behavior in a range of UPS units from small to multi-kw. Hot swappable only means you can swap the batteries while the unit is already on and it won’t interrupt output. This doesn’t apply if the ups is already off and needs to turn on with no batteries or dead ones, because it will not.
« Last Edit: January 13, 2019, 12:50:22 pm by KK »
 

Offline Pentium100

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #11 on: January 13, 2019, 12:49:28 pm »
This one is a hot swappable battery, so it's designed to be disconnected and still function.

Yes, when the power is on, the battery can be disconnected without problem.

But when everything is off, the battery is required to turn the input relay on. After that, the line input can power everything. I have multiple UPSs and they all behave like that.

After all, you cannot trust the input - you first have to measure it to see that it is in spec and only then turn on the relay.

The only exception is my 40kW three phase UPS - that one needs input circuit breaker connected first and battery circuit breaker connected when the LCD indicates so. I presume this is done so that there would be no inrush current as the DC side has something like 16x 470uF capacitors per phase (so 22560uF capacitance total for all phases). Connecting 720V of batteries to those caps would result in some inrush current, so the UPS charges those caps gently from the line input.
« Last Edit: January 13, 2019, 01:03:48 pm by Pentium100 »
 

Offline rs20

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #12 on: January 13, 2019, 01:59:10 pm »
The "BatteryDoctor" australia website sells the individual HRL 634W (or a panasonic substitute) for AU$39. That's $234 to get completely fresh batteries in this thing, which isn't all that bad. For the record, Mouser have them for US$15.20 each, which is even better, but they won't ship them to Australia.
 

Offline Inverted18650

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #13 on: January 13, 2019, 02:03:45 pm »
If you feed the DC side 36V from a power supply with at least 10A capability, do not plug it into mains, and power it up using just the DC side. If you have no use for it, please put it on eBay and let us fight for it.

For a UPS, the battery bank must send a feedback to the CPU saying it is sufficently powerful enough to boot and work, the AC input doent do anything other than charge the battery bank, and in some cases, provide a temporary voltage for "hot swap" capabilities. The unit needs to be already up and running on the DC, it will not boot on just AC. Since the battery bank is more than dead, you can unlpug the AC side and feed it a DC that will "ping back" to the control an 'okay to boot' and get it up and running. Could alos grab three old vehicle batteries and plop then in series to get it going. Or my favorite idea, hence the name, build your own custom 18650 battery bank to drive the inverter. Much love. Ill gladly buy it if you dont find a use for it. :-+
« Last Edit: January 13, 2019, 02:13:03 pm by Inverted18650 »
 

Offline Pentium100

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #14 on: January 13, 2019, 02:28:25 pm »
For a UPS, the battery bank must send a feedback to the CPU saying it is sufficently powerful enough to boot and work, the AC input doent do anything other than charge the battery bank, and in some cases, provide a temporary voltage for "hot swap" capabilities.

This is a line-interactive UPS (when there is power input, a relay connects it straight to the output), because it has only one transformer.

Anyway, initially the MCU is powered only from the battery. When you plug in the line power, the MCU measures it and if it's OK, turns on the input relay. After that, the line input is used to power the MCU and another relay connects line input it to the output. When the power fails, the inverter starts up and provides power to the output.

What you are referring to is an on-line UPS that runs its inverter all the time. Those UPSs either have two big transformers (one for input and one for output) or no transformer at all and enough batteries to be able to run directly on line voltage (I have seen 384V and 720V DC).

But if Dave wants to start up this UPS without buying new batteries, he should connect a 36V (a few amps) power supply trough a diode to the battery input, connect the line input and push the button.
« Last Edit: January 13, 2019, 02:30:06 pm by Pentium100 »
 

Offline Inverted18650

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #15 on: January 13, 2019, 02:39:20 pm »
Thanks for clarifing. I have several models of UPS that I run random tests on. Many are mil grade and have been tossed into the dumpster because due to batteries going 'way under voltage' and their subsequent refusal to take a charge ever again. I did not check the datasheet for this unit and jumped to conclusions, but I am really interested to see his followup videos.

Offline Zenwizard

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #16 on: January 13, 2019, 03:54:04 pm »
I know from personal troubleshooting, That Leibert and APC 900VA to 3000VA ups will not start without modest battery voltage on the input. Batteries can be drained but not flat At .6V those batteries arnt just dead I would be willing to bet one is shorted and nuked the rest of the pack. The bulging mentioned in the video defiantly needs a battery replacement. I have not worked with larger then 3000VA single phase.

APC units will trickle charge the batteries even when the UPS is off so If you have one that is flat you can wait about 10 minutes and it will kick on when you hit the button. That is assuming the batteries are taking a charge.
 

Offline Brumby

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #17 on: January 13, 2019, 04:21:58 pm »
But when everything is off, the battery is required to turn the input relay on. After that, the line input can power everything. I have multiple UPSs and they all behave like that.

I only have one UPS - and it needed a voltage on the battery connection to start up as well.

Hot swappable doesn't mean cold startable.
 
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Offline Pentium100

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #18 on: January 13, 2019, 04:31:38 pm »
If the batteries are discharged, but not dead, then the voltage of a 12V nominal battery would still be >10V. 0.6V for the entire pack means that the batteries are dead completely and you need to replace all of them (one new battery in series with 5 old ones means that the new battery will be undercharged and fail rather fast, better to get all new ones, preferably from the same batch).

I did not check the datasheet of Dave's UPS either, but I had multiple UPSs that work exactly like that - battery power up the MCU, the MCU then switches on the input.  The only exception I know of is the 40kVA three phase UPS that has a startup procedure (4 circuit breakers need to be turned on in specific order at specific times).

Hot swappable doesn't mean cold startable.
For a UPS cold-start usually means initially starting the UPS without line power (the cheapest models and the 40kVA cannot do that). Normally you don't run a UPS without batteries and this actually seems like a good thing - if the batteries are completely dead or disconnected, the UPS does not  turn on and you notice that there is a problem.
 

Offline TruslowPJ

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #19 on: January 13, 2019, 05:12:38 pm »
Those units are manufactured by Eaton for HP. I have a slightly older model, in the tower config and it won't turn on without batteries present. they can be completely garbage batteries but as long as they present some sensible open circuit voltage, the UPS will turn on and attempt to charge them. 9Ah 6V SLA are hard to come by, but 7Ah would run it and should fit. alternatively you could have external batteries, use 3 12V (edit: or 6 6V) 9Ah SLA AGM batteries (with F2 Terminals) and you will have an incredibly high quality UPS. these things ran like $500+ new. I was lucky to get one free with also dead batteries and I love mine. I did have to swap the fan for a quieter noctua fan though.
Mine is a T1500 G2. It was a royal PITA to find any information on these models though. HP didn't put out a whole lot of documentation but here is the overview page from HPE if anyone is interested: https://support.hpe.com/hpsc/doc/public/display?docId=emr_na-c02851095#N101D9
Edit: also found the user guide: https://support.hpe.com/hpsc/doc/public/display?sp4ts.oid=5106177&docLocale=en_US&docId=emr_na-c02867104&withFrame
« Last Edit: January 13, 2019, 05:23:25 pm by TruslowPJ »
 

Offline Pentium100

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #20 on: January 13, 2019, 05:18:59 pm »
The 9Ah battery is a high discharge rate version of a 7Ah battery, it's the same size.
 

Offline TruslowPJ

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #21 on: January 13, 2019, 05:26:18 pm »
The 9Ah battery is a high discharge rate version of a 7Ah battery, it's the same size.
I figured as much. I tried to match the specs in my case as well as I could, but you have to take what you can get.
 

Offline Orips

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #22 on: January 13, 2019, 07:39:22 pm »
Hey Dave,

You normally need to HOLD DOWN the power button until the unit turns on. Same to shut it down  :)
 

Online NANDBlog

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #23 on: January 13, 2019, 07:49:20 pm »
Those heatsinks.
"Should we place an extruded aluminium HS?"
"Nah. Lets just place there a chunk of metal cut to size by a saw."

I'm not sure if this is over or under engineering.
 

Offline tigrou

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Re: EEVblog #1168 - Dumpster Diving UPS
« Reply #24 on: January 14, 2019, 12:45:16 am »
I was expecting to see huge capacitors in that UPS to maintain output when the mains goes down and relays are switching (which take some time). How does it work then ?
« Last Edit: January 14, 2019, 08:16:22 am by tigrou »
 


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