APC brand UPS (BK500) Kit Teardown! - Page 1
Forum section: electronics / general

author: CodyShaw
author_rank: Contributor
timestamp: September 27, 2012, 11:48:56 pm
content: Heya EEVBlog!This is my first post here, and I decided to have it on a piece of kit I acquired today. It's a nice APC brand UPS with a shot battery, with a ton of goodies inside!Take a look!Pretty case, quite functional, especially if you have a data connection to it.Input distribution in the back, what a cool concept! I'm pretty sure this is standard for power bars though, I've just never torn one apartAlso note the ethernet and phone line protection off to the right.High voltage, watch out! *drool*Note the lack of gunk to keep the tall components from shaking loose... the big filter cap had nearly fallen off (off to the top right of the image)!Oh sweet Tesla that's a massive inductor. That will be put to good use if I can't find a batterySpeaking of batteries,What a piece of shiet! 12V, 7.2 Ah (ok, maybe not a piece of shiet... just broken!) bu CSB Battery.Quite a pretty wiring job with the spade connectors. Also, loving that high current transistor heat sinkage beside the battery relay!Front end with some mystery chips! Lets take a look!Unfortunately, I couldn't read the ST Micro package (gunk and such), but it was obviously some sort of main microcontroller processor for the data I/O in the back, because the other chip isA Cypress Semi USB controller! Coolio! Loving the front end layout of the board, with the on board replaceable fuses scattered about and such.Everything else was a little bland, mostly passives and some voltage control circuitry, what one would expect from the power supply with a digital front end.I learned quite a bit from this in terms of layout and design, as I am an Electrical Engineering student (aspiring in Analog Hardware/Silicon Chip design!), and university is (almost too much) theoretical (which is nice, but being able to play with the real deal is even better!)I'm hoping you guys enjoyed the very brief look at this piece of office gear, I'm hoping to get into the swing of things again since I just got out of exams and am now on a Co-op term (Woohoo free research time)! If you want to check out more of my stuff, with this teardown in particular, check outwww.codyshaw.ca.Comments? Questions? Would you like to see more of the UPS? I am willing to take more detailed pictures if anyone wants to see something closer. Have any of you designed something like this before? Is this a nice design, and is there anything that could be improved?Best,Cody

author: FenderBender
author_rank: Super Contributor
timestamp: September 28, 2012, 02:57:55 am
content: Looks like a good quality unit. APC is generally a good brand.

author: gxti
author_rank: Frequent Contributor
timestamp: September 28, 2012, 03:36:05 am
content: I just took mine apart, that I had just retired last week as the battery was dead and the old "square wave" style didn't get along with my electronics anyway. It's a XS model which is pretty much the same deal.I don't buy APC anymore, at least not the Back-UPS models, because of the square wave output and the inane modular connector they make you use for USB or serial connection to a PC. They also have a habit of changing the pinout of that connector every few years for what I can only assume is a malicious hatred of the customer. The PC it was connected to did not get along with the USB connection and would regularly lockup any process trying to talk to it until rebooted.Now I have 3 CyberPower PFC (sine-wave output) units. Real USB and serial connectors, amazing! And it doesn't reset my DSL modem every time the power blips, but I blame Belkin for that one because the power supply is a friggin' 12VDC battery pack, but tickle the input right and it resets anyway. How do you cock up a DC battery backup?

author: SeanB
author_rank: Super Contributor
timestamp: September 28, 2012, 07:14:52 pm
content: Easy, switching transients.......... Add a LC filter on the input to the UPS, and hang a big capacitor across the battery terminals. The killer of the batteries in these is heat from the hot electronics above it, they run much cooler and last longer if you extend the wiring to them with some 4mm cable and lead it to an external battery box, preferably with a much bigger capacity battery inside as well.Mine sits with 2 17AH batteries in parallel sitting next to it, and a capacitor bank of 74800uF made from 11 6800uF 35V caps ( removed from a big power supply board in a dead tag reader) to provide decoupling for the batteries.

author: Amarbir[Lynx-India]
author_rank: Frequent Contributor
timestamp: September 30, 2012, 02:18:45 pm
content: Quote from: SeanB on September 28, 2012, 07:14:52 pmSean Sir ,Can You Show Some PICS and post some hand schematics of the same and explain what the capacitors do there ? .Sounds interesting

author: SeanB
author_rank: Super Contributor
timestamp: September 30, 2012, 02:39:06 pm
content: Capacitors are there to do decoupling of transients, and reduce the voltage drop across the battery internal resistance during the switching transients. No diagram needed, just wired the 11 capacitors in parallel after mounting them on a piece of veroboard, and wired them to a pair of lugs that are connected to the battery terminals. I stripped the wire end at the capacitor end so that it was long enough to reach all the terminals in a line, and soldered it along the row. 3 rows of capacitors, 4 in 2 and 3 in the last ( no more capacitors left to salvage from the PSU board) and then the 3 rows commoned at the terminal and soldered and crimped in. Added a foam plastic bottom ( sheet of adhesive backed foam rubber used to make furniture protectors) and a cable tie to hold the cable and that was all it needed, sits now loose on top of the one battery.

author: Amarbir[Lynx-India]
author_rank: Frequent Contributor
timestamp: September 30, 2012, 02:43:17 pm
content: Quote from: SeanB on September 30, 2012, 02:39:06 pmOne Photo Please

author: SeanB
author_rank: Super Contributor
timestamp: September 30, 2012, 02:53:14 pm
content: One persistent guy you are..........

author: Amarbir[Lynx-India]
author_rank: Frequent Contributor
timestamp: September 30, 2012, 03:03:16 pm
content: Quote from: SeanB on September 30, 2012, 02:53:14 pmAwesome ,Thanks You Sean Sir .

author: madires
author_rank: Super Contributor
timestamp: September 30, 2012, 03:09:16 pm
content: Quote from: gxti on September 28, 2012, 03:36:05 amThe Back-UPS series are very basic UPSs (simply switching between line and inverter, therefore slow response time) and the 9pin D-Sub port is actually no serial port. The Smart-UPS series are line-interactive types (faster response time, buck/boost feature) with real serial/USB ports. But check the new low-end Smart-UPS models carefully, they seem to be feature stripped-down.QuoteI bet those are line-interactive types, and that's the UPS type we should use for PCs.

author: gxti
author_rank: Frequent Contributor
timestamp: September 30, 2012, 04:31:51 pm
content: Both the APC and the CyberPower are line-interactive. I don't think I've ever seen a UPS that was less than line-interactive, except maybe the "brick" ones that look like bloated power strips (plugboards for you Aussies) which are total rubbish. I don't much care for the buck/boost feature because PC power supplies are very flexible with respect to input voltage, it's just added weight to me. The problem with the APC resetting my modem actually came when it switched back to mains power, something about jumping from square wave to sine and the gap in between reliably reset the modem.

author: Monkeh
author_rank: Super Contributor
timestamp: September 30, 2012, 04:42:59 pm
content: Quote from: gxti on September 30, 2012, 04:31:51 pmYour modem needs a better power supply.

author: Amarbir[Lynx-India]
author_rank: Frequent Contributor
timestamp: September 30, 2012, 05:42:10 pm
content: Quote from: Monkeh on September 30, 2012, 04:42:59 pmSir ,Its Always Not The UPS ,I have noticed that sometimes linear power adapters are prone to this ,Changing it to a SMPS based Adapter solved the issue