APC Smart-UPS float voltage experiment

[marvin-miller]

Re: APC Smart-UPS float voltage experiment

That link was interesting. I could certainly believe that I've gone a little far with this. The thing about sulfation on the negative plate was interesting. Maybe a better float voltage would be that 26.5 or 27 if you wanted to tweak with a couple of resistors. Maybe I'll put the 1.5 megaohm back in. But my current 25.6 volts is higher than the 2.10 volts per cell they mentioned for sulfation. For me, this isn't an especially expensive experiment. The batteries were $66 and I have about ten UPSes. I haven't bothered to count them and I only use two at a time. They were throwing them out after all.

Personally, I think the perfect float voltage is 27.27 volts. It should be high enough to stay out of the sulphation issue and gentle enough to make the batteries last a long time.

I have a SU300NET and added a potentiometer as a replacement to the R118 resistor so that I could adjust the voltage with a screwdriver. The original batteries were more then 2 litres low on electrolyte due to an improperly high float voltage (just short of 28 volts).

While you're in there be sure to check out R38 & R43 - it's really common for those resistors to fry, fry and fry. The OEM spec for them is 1/4 watt 470 ohm but most folks replace them with 1/2 watt units as a means of future-proofing

Much thanks for posting up your piece here - it got me started on this quest as I have a mint SU3000 and I just bought new batteries and want to see them last many years

[alphaa10]

Re: APC Smart-UPS float voltage experiment

I've been testing this further and have more data. This is with a different UPS and rather weak batteries. These are the batteries that I replaced because the server UPS was running with its fan on all the time... But my goal is to find a configuration that can gracefully use these cheap batteries, so that makes sense... After all this and from the discussion in this thread, I've settled on using the 2.2 megaohm resistor. [for a 26.8V charging current] That seems to be a good compromise between overcharging the batteries and sulfating the negative plates. I hope someone finds this interesting. I'll have to remember to report back when I have to replace the batteries.

----------------------------

So.... some years later, what do you have to report about the 26.8V "centrist" value? I found your analysis fascinating, especially since I am in exactly the same dilemma as you were back in 2009. I have an APC SU1400NET, (1) I chose the cheaper Rhino batteries, rather than APC (2) have had fairly good life and performance (two years+) during modest UPS activity and (3) now the fan is running all the time.

Time to replace the batteries, of course, but since another poster considered two years "just about right" for the cheaper sealed lead-acid cells, is there anything I should do differently next time?

I cannot depend on an automatic float charge any longer, because I trustingly took an APC tech's advice to run the dreaded Calibration Key. Now, my only option is manually to set the charging voltage at an optimal level for my Rhinos. In view of your experience, what do you now consider that optimal charging voltage for my Rhinos to be?

[BlueSkyy]

Re: APC Smart-UPS float voltage experiment

Hello to all from a new user. I have a 1999 vintage SU2200 that I'd like some help with. The battery charger never seems to make it to 100% and hovers around 94% - 96%. I, therefore, cannot run a runtime calibration test which I'd like to be able to do. I've tried different sets of batteries, old and new, with the same effect. Other than that the unit appears to function normally. I also have a NMC card installed so that I can look at the UPS via the web interface. Any help or guidance would be greatly appreciated! Thanks and advance!

[Behemot]

Re: APC Smart-UPS float voltage experiment

You can do proper calibration only with the right HW and SW, this like „calibration“ which the UPS itself provides is more like a joke. I suggest, if it works and give some usable runtime, let it be…

Yeah, if it would charge really low (like, say, 80 % or even 10 %), than you would have to reset some constants and do really low-level calbiration. If you got over 90 %, than theres nothing you should worry about I think.

[Kiriakos GR]

Re: APC Smart-UPS float voltage experiment

this like „calibration“ which the UPS itself provides is more like a joke.

I think that you have never touch APC before.

[Kiriakos GR]

Re: APC Smart-UPS float voltage experiment

Hello to all from a new user. I have a 1999 vintage SU2200 that I'd like some help with. The battery charger never seems to make it to 100% and hovers around 94% - 96%. I, therefore, cannot run a runtime calibration test which I'd like to be able to do. I've tried different sets of batteries, old and new, with the same effect. Other than that the unit appears to function normally. I also have a NMC card installed so that I can look at the UPS via the web interface. Any help or guidance would be greatly appreciated! Thanks and advance!

What is your run time? (by using a simple clock)
How many minutes it holds a single desktop before it close down.

[Behemot]

Re: APC Smart-UPS float voltage experiment

I think that you have never touch APC before.

OK, that's your opinion, but it's wrong.

Btw, have you ever put your hands on some enterprise APC stuff? No? I administer one.

[Kiriakos GR]

Re: APC Smart-UPS float voltage experiment

1) You are trying to show off in a topic about a specific product range.

2) If you have complains against the APC PowerChute Business,
notify APC to make one software that will be just under your likes.

3) Show a pictures of your self next to your enterprise APC stuff

[Behemot]

Re: APC Smart-UPS float voltage experiment

I have experience of my own with APC, thank you very much. For example their KVM stuff is crap. If I won't find solution for it, we will have to change it, preferably for HP or some other "brand".

Consumer-grade UPS, from my experience, are much more "dumb" than people think. Not that it is wrong, more like on the contrary. For example, no matter what battery capacity you use, you usually just plug it in, charge and discharge and thats it. It works. If not, than you need to calibrate, but calibration is something else than pressing some funny button.

Can show you pictures of component I have been repairing in our UPS (I am in process of writing an article about it because doing something like APC did is just disgusting). Believe or not, I don't care. Won't be doing idiot in our server room with freshly configured camera just because of some random guy…

[Kiriakos GR]

Re: APC Smart-UPS float voltage experiment

Back to the topic, I have see some one to mention battery life.

Well, Panasonic haves an specific battery series which it has a stand-by life of 10 years.

Naturally it is much better than then cheap made in India, which the most APC units comes from the factory.

My SUA1000XL now haves those LC-XD1217P.
Naturally are costly, but they become less costly if you pay shipping three times in 10 years about getting cheap ones.

[Behemot]

Re: APC Smart-UPS float voltage experiment

It depends on physical dimension/capacity. See, the bigger it is, the lower usually the ratio of drained current vs. rated current. I mean like if you take 40 A from 17Ah battery or 40 A of 9Ah battery sure has impact on its life. It's also about lower wasted power (less heat) and so.

IIRC 7,2/9Ah have 5-8 years, 12Ah have 6-9 years and these big have 9-10 years. Of course the value is much greater, you pay like 30-50 % extra on price but have twice the life. People just have to think and use math

[BlueSkyy]

Re: APC Smart-UPS float voltage experiment

What is your run time? (by using a simple clock)
How many minutes it holds a single desktop before it close down.

It will go 30 - 35 minutes without much of a problem. I guess, as was suggested, that I will leave it alone for now. Thanks for the response.

[BlueSkyy]

Re: APC Smart-UPS float voltage experiment

You can do proper calibration only with the right HW and SW, this like „calibration“ which the UPS itself provides is more like a joke. I suggest, if it works and give some usable runtime, let it be…

Yeah, if it would charge really low (like, say, 80 % or even 10 %), than you would have to reset some constants and do really low-level calbiration. If you got over 90 %, than theres nothing you should worry about I think.

Yes, I can agree that "if it ain't broke, don't fix it". Probably some of the components on the board have drifted over the past 13 years and that's why it's "off". Thank you for the info!

[Rocketman59]

Re: APC Smart-UPS float voltage experiment

Anyone still have a Schematic for the APC(Schneider Electric) 1400 Smart UPS. The Russian site listed above no longer has any APC Schematics available.

If you have them could u send them to: KQ6EF@att.net

Tnx Rich

[Behemot]

Re: APC Smart-UPS float voltage experiment

It also depends on which version it is. Even rackmount, they hadloads of versions over time. Like 4U, 3U, 2U, 1U and many designs in every size… Not that I have schematic of any of them though.

[goontron]

Re: APC Smart-UPS float voltage experiment

wholly thread revival batman

[smason]

Re: APC Smart-UPS float voltage experiment

Speaking of APC UPS battery life, keeping the unit cold really helps.

I have an RM3000somethingerother in one of my server racks. It sits at the bottom in a constant 18degree C air stream. Finally had to replace the batteries after 7 years.
An external one that sits beside the rack at room temperatures only gets about 4 years.
Another in the switch room at 28 degrees gets 2-3 years tops.

[StephenR0]

Re: APC Smart-UPS float voltage experiment

It's been five years since I replaced the batteries and they finally failed their periodic test. So, I'm calling the experiment a success. I replaced them again with some cheap batteries from ebay. However, I've become persuaded that a 3.3 megaohm resistor might be better than the 2.2 megaohm resistor that I used the last time. I've modified another ups with that resistor and I get a float voltage of about 27.2. We'll see how that goes. In addition, I used apcfix to restore the battery constant. I did try to adjust the float voltage with the serial port using the procedure that's described earlier in this thread, but mine won't actually change the float voltage when I do that. Again, I'll have to remember to update this when these batteries fail.

[DZelmer]

Re: APC Smart-UPS float voltage experiment

Further Experiments:
can anybody tell me, which parts to change to modify the "Low Battery" level?

I run a Smart-UPS 1400 with large external batteries in a photovoltaic application.
Output of the solar regulator feeds the ups, loosing a few 100 mVolts on the powerMos Fet of the regulator, and therefore my ups "believes" that batteries always are low.
thanks to the experts.

The serial battery voltage adjustment seems to be a offset or correction for the software and cpu at least on my smart ups 1000 built in 99 or so i can change it but the only thing it seems to change is what it displays in the software and the ups thinks the battery is low. I would adjust it up if you can that's what im going to do when i get done changing the resistors i have 4 of the smart ups 1000 and 1 smart ups 1400. that i,m going to do this to. The one ups is charging to 27.9 at the batteries and reads 28.1 in the software. I adjusted the offset using the serial cable and it didn't change any thing at the batteries. only made the ups thing the battery wasn't at 100% and the software displayed the voltage i changed it to with the batteries hooked up and unhooked at the same 27.9 volts i moved the offset all the way down to 25.5 and it only made the battery % go down. no change in voltage at the batteries At least on two of the smart ups 1000. If any one has any updates or still has some of this stuff still working i would love to see and hear about it.

[smile]

Re: APC Smart-UPS float voltage experiment

My SmartUPS 1000, made in year 1999, now is charging 2 year old YUASA NP-1212 batteries at 27.602volts, battery at the negative is 13.60v at positive 13.70v

So far batteries in this UPS live 3 years max. I would really love to improve that.
I have made holes in the front cover at the bottom so you cant see them. This made big difference in battery life added 1 year. And I can see way more dust inside UPS, that means ventilation holes are working !

I did not want to add a fan because of the noise and huge dust buildup it would cause.

Now this Russian guy here, recommends to add a little of standard electrolyte 1.27 gravity to new batteries. He says it improves their life cycle to like 5 years as they do not dry up that fast !
http://nepropadu.ru/blog/guestroom/10408.html