APC UPS units - troubleshooting

[paulzak]

Re: APC UPS units - troubleshooting

After recapping I started wondering if I wasn't getting charging because of a flakey 7815 as the old one looked as though it had gotten hot. I replaced it and it's charging now! It gets pretty hot when it starts charging so I added a heat sink. As battery voltage comes up, it gets less hot. Still not clear if there is something defective upstream causing the heat other than the inherent inefficiently of these linear supplies, but I buttoned it back up and we'll see. You may be able to see the heatsink in the attached photo. Paul

[paulzak]

Re: APC UPS units - troubleshooting

Definitely no inline diode from the transformer. I'm certainly learning as I go.

[paulzak]

Re: APC UPS units - troubleshooting

I think I can answer my own question. It looks like it could be a center tap but I'm not clear why it would be on the positive lead.

[Behemot]

Re: APC UPS units - troubleshooting

Isn't there some diode? BTW often there is separate winding just for some low voltage…you don't need much power from that, just like an amp or so.

[paulzak]

Re: APC UPS units - troubleshooting

I'm still waiting to receive the filter cap for the 15v linear supply but I have a question related to UPS design theory. I have 15.1v at the output of the 15v voltage regulator which is all good.

The positive battery lead comes from the transformer. As far as I knew, you can't use a transformer for DC. How is this part of the charging circuit working? I understand the basic linear supply with bridge rectifier/voltage regulator chip/blocking diode, but the transformer has me stumped.

The negative lead comes from the PC board.

Are they using a winding as a choke?

Thanks, in advance!

Paul

[Behemot]

Re: APC UPS units - troubleshooting

Sorry, I meant from the transformer, to feed the battery. Indeed, this linear regulator design is very ineffective (but easy and cheap). APC abandonded that very long time ago. Yet all the cheap plastic units of (most likely) Must Power origin use this in 2016. Sometimes the regulators overheat so badly they bake the board around them with all the caps. I think this is connected to particular revision/version of the board. They also use aluminium wires for the main transformer.

It was very pitiful display at CeBIT - there was like 6 to 8, companies, including Delta Electronics, some others calling themselves OEM supplier, and EVERY SINGLE ONE OF THEM had that thing in their portfolio. They are all the same (besides the configuration of sockets and the front panel - OFC every one has to look slightly "different", but you can recognize that on first look). So bad units and they even argue with you that they definitelly "design and manufacturer" that by themselves.

But somehow could not explain why 5 more companies around them have the same units and they don't make it for them And why all the other units in their portfolio - why I am positive actually aretheir own designs and made in their fabs - look completelly different I mean even low-end and high-end units from Eaton or APC share similarities among them. These chinese rebrands are completelly different than everything else they got. But they definitelly make that on their own

Well, I guess they can have it licensed…but than, another thing I noticed: all of them regardless the brand also have the same label sticker on the top-back part, which is the same style (color, font, layout, everything) for all, only the brand name is different. Yeah, they make it my ass As even Delta is just sourcing it from other fab as it makes more sense to buy this cheap crap and make high-quality units in their own tier 1 lines, those ppl either did not *really* know or they new but could not tell. But even arguing with me telling me those lies to my own face after SO MANY of them I have seen with my own eyes, man…

For example, check the Sweex http://www.sweex.com/nl/notebook-pc-...res/ups/PP200/

They are made both as off-line and line-interactive, this single-battery and also two-battery versions. 1500-2000VA models use small fan in the backside.

[paulzak]

Re: APC UPS units - troubleshooting

Thank you! Bhemot, I've replaced 8 of 10 electrolyics so far. I'll replace the last two in the next couple of days. It's good to know that some designs do charge from the SMPS. This unit was, in hind sight, probably a good starting point. At least I recognize the components in a full wave rectifier PS. SMT would seem to make repair considerably more challenging. I'm vaguely following so far. As long as I don't need to do anything with an SMT device, I'm happy.

[Behemot]

Re: APC UPS units - troubleshooting

This is some older design, the later CyberFort II units (Back-UPS something) used SMPS for charging. It has to take the voltage from the battery.

In those newer designs the small caps almost always go bad. Check them too, there will definitelly be some feedback for the microprocessor.

[paulzak]

Re: APC UPS units - troubleshooting

I found pcb schematic, the battery is charged by LM78M15, 0.5A max.
The schematic shows 2 diodes (D18 and D2) that are connected to OUT pin one after another. This lowers voltage as diodes have voltage drop.

I added third diode (in a row to them) and now I have steady 13.00 - 13.09 Volts varies with AC voltage.
So now my batteries will no longer dry out !

I think this may be the key to a problem I'm having with the charging circuit on an APC BE500R. I've taken this device on as a science experiment rather than to save it; it's a mostly worthless device but what better to learn on? I'm $25 into this.

I'd surmised that charging wasn't derived from the switching supply; the inverter is working fine with an externally charged battery. I'm very excited to learn that this positive regulator is likely a place to begin looking! Nothing on the board looks blown, but the LM78M15 looks like it has been hot at some point!

Do you guys generally make extensions to the connectors to work these devices live? Given the short leads, this may be my only option.

I will next probe the VR and I'm still waiting for a 220uF 50v cap which lives nearby and looks to be relevant.

Any help full thoughts other than don't electrocute myself?

Thanks, Paul

[sadeoo7]

Re: APC UPS units - troubleshooting

i said that they where optimized for a higher depth of discharge but the NPX series are in fact high rate. sorry for my mistake.
here is the datasheet if you want to check them out
https://cdn.badcaps-static.com/pdfs/...f090d72a8a.pdf

[Behemot]

Re: APC UPS units - troubleshooting

Deep cycle, or cycle-use batteries are better for different kind of use, especially for different kinds of go-carts (like golf carts, baby cars etc. etc.) where you regularly do full discharge and full charge cycle.

For UPS I'd take if any, than high-rate. Those are usually of higher quality and should provide higher currents - neccessary for high-loads of the UPS when there is often as much as 40 A draw.

[sadeoo7]

Re: APC UPS units - troubleshooting

i find that Yuasa Batteries specially the NPX series are higher quality than the batteries offered by CSB.
the NPX series from Yuasa are made for higher depth of dicharge and oftimized for standby use.
the equivalent to a NP9-12 (12v9ah) is a NPX35

[smile]

Re: APC UPS units - troubleshooting

Also what can you guys say about

CSB-HR1251WF2 - 12V 12.75Ah 51W Pb CSB - 37.36 €
CSB-GPL12120 - 12V 12Ah F2 Pb CSB - 40.84 €
CSB-EVH12150 (blue one) - 48.66 €

I always thought that deep cycle is better hence the higher price for EVH version. Then how come they rate the HR 8 years (plain marketing nonsense ?), the

The usual CSB-GP12120 is 37.50 € same as YUASA NP1212, but YUASA has additional membrane that prevents evaporation, CSB does not. Hmm....

Is there some site where I could see dissembled new batteries from CSB, YUASA etc. and to see that it's really different products, not just marketing nonsense.....

[smile]

Re: APC UPS units - troubleshooting

Just use Panasonic batteries and you won't need any crazy adjustments. I suggest LC-RA1215P1.

I had better luck with YUASA NP1212 and the price is right. The Panasonic is not available locally in my country !

What I wonder is why England has CSB EVH12150 red, made in VIETNAM.


While the rest of the Europe has EVH12150 BLUE made in CHINA.

[smile]

Re: APC UPS units - troubleshooting

I found pcb schematic, the battery is charged by LM78M15, 0.5A max.
The schematic shows 2 diodes (D18 and D2) that are connected to OUT pin one after another. This lowers voltage as diodes have voltage drop.

I added third diode (in a row to them) and now I have steady 13.00 - 13.09 Volts varies with AC voltage.
So now my batteries will no longer dry out !

[Behemot]

Re: APC UPS units - troubleshooting

Just use Panasonic batteries and you won't need any crazy adjustments. I suggest LC-RA1215P1.

[smile]

Re: APC UPS units - troubleshooting

I have ACP BACKUPS 650MI , how do I change charge voltage to lower value?
The VR1 does not adjust it, I set it back to where it was default.

Any ideas?

[Behemot]

Re: APC UPS units - troubleshooting

Seems like the batteries are bad, you have a multimeter?

[dark84]

Re: APC UPS units - troubleshooting

Hi!
Sorry for my bad english!
My UPS do same thing that on the video:

http://www.youtube.com/watch?v=htykTLWTsH4

Anyone has an idea what is the problem?

Thanks!

[Toasty]

Re: APC UPS units - troubleshooting

Found some of them:

http://www.jjoseph.org/notes/apc_sma..._float_voltage

http://osdir.com/ml/monitoring.nut.u.../msg00120.html

Not responding: http://www.networkupstools.org/protocols/apcsmart.html