Caring, Feeding and Enhancing UPS Battery Systems? 50
"Now - the SBS people have been very professional and have provided good technical engineering data. I haven't been able to find much data on the MGE EL4 and I wonder if this cheap little UPS has the proper smarts to take good care of my new battery? If it does not - then why not and what models/manufacturers should we be considering?
For instance, what is the ripple characteristics of the EL4 and how can I measure it? Since the SBS60 is HUGE in comparison to the original batteries (Panasonics - 7.2Ah - 2x6V) is ripple even something to worry about?
Does the EL4 charging system 'cycle' in a harmful way? I tested the float voltage levels and found that they varied from 13.89 to 13.42 over the course of a day. But this battery has only been hooked up for a day so maybe its stabilizing. The nominal float should be 2.27 per cell according to SBS so that works out to 13.62 for the battery.
Does the EL4 have a temperature sensor? This is something else that the charging system should do according to the SBS people because optimal float voltage varies with temperature.
Finally, I'm interested in doing a load test to determine how healthy by batteries are. I'm thinking that a very simple test can be a couple lamps - say 100 watt - that can be plugged into the UPS. Since I've never done anything like this before the thoughts in my mind are that all I would need to do is take a voltage reading say every 5 minutes over the next few hours and if I can find the proper curves this should yield enough data to determine the life expectancy of my battery.
If anyone has actually done tests like this it would be wonderful if they could tell us how to do this."
A Short Battery HOWTO (Score:2, Informative)
After you've read that, you'll need to get additional information on rechargeable batteries [sciencenet.org.uk]. Note that that page talks about nickel oxide batteries but the information applies to lead acid batteries such as you find in a typical UPS (and cars, for that matter).
It is also crucial to understand that the battery is an el
Re:A Short Battery HOWTO (Score:1)
Re:A Short Battery HOWTO (Score:3, Informative)
Rechargable batteries of different types have different characteristics. Beyond the most general platitudes, Nicad-type batteries are very different than led acid. and even the two families can variy between themselves. I managed to find a number of good books in the library about rechargable batteries that described the differences well
Re:A Short Battery HOWTO (Score:2)
Car batteries are designed to source a kilowatt or more for the starter motor (moving all that metal takes a fair bit of energy), so this shouldn't be too suprising.
Re:A Short Battery HOWTO (Score:2)
Larger batteries = more charging current/voltage (Score:4, Informative)
I've seen car batteries work connected to small UPSes for years until the power went out for an extended time, the battery was significantly drained, and the charger failed when the power came back on. Just something to be aware of.
Re:Larger batteries = more charging current/voltag (Score:3, Interesting)
A proper "universal" charger design (which I wouldn't expect to see in a UPS that doesn't accept add-on batteries) would charge properly, but more slowly.
Re:Larger batteries = more charging current/voltag (Score:2)
Car batteries, on the other hand are probably getting into a completely different scale of size. I'm not terribly surprised that the charger would fail going to that capacity size. It's It's like the difference between putting a small U-Hall trailer on yo
A couple of problems... (Score:5, Informative)
Smaller chargers are not meant to charge larger batteries - you may well be overstressing your UPS charger by expecting it to charge your new, larger battery for so long.
Lead Acid batteries and their variants (gell-cell, deep cycle, etc) do NOT like to be discharged more than 50%, yes, that includes so-called deep cycle batteries. Deep cycle means that deep discharges won't hurt the battery as much as it would hurt a regular gell cell, but it'll still be damaged.
Most consumer and low end UPS systems do NOT monitor battery temperature. They simply charge the battery so slowly that there is little risk of overheating, boiling, or overcharging.
Cycling the battery with light bulbs may not be a good idea, because many UPS systems allow more than 50% battery discharge. You'd have to monitor the voltage, then shut it off when it drops below 11 or 12v.
Light bulbs will not pull power the same way your computer will, so the best load test is the real load you intend to use. a 400W powersupply doesn't draw 400W. Depending on how you measure it, it may pull more or less from the AC line (read about Power Factor and power factor correction). This is one of the reasons these supplies are rated in VA and not Watts. Of course, the real question is, Why? When you have few power outages, what is the reason to use such a large capacity battery, but more important, why do you even need to characterize it?
Lastly, make certian you aren't pulling more current than the supply is regulated for. As you suggest a larger battery does not make it more able to handle larger loads. You'll be tempted in the future to add more stuff because 'it should handle it', but it'll only make it fail faster.
-Adam
Re:A couple of problems... (Score:1)
Re:A couple of problems... (Score:3, Informative)
If devices like this [realgoods.com] are being marketed to (albeit a niche of) homeowners, I wouldn't think it'd be too difficult to find something similar that has a more informative readout.
Re:A couple of problems... (Score:3, Interesting)
Re:A couple of problems... (Score:1)
Re:A couple of problems... (Score:2)
Re:A couple of problems... (Score:2)
Re:A couple of problems... (Score:2)
Also, having few power outages has nothing to do with having a large battery. With a large battery, your com
Stay close to the same battery (Score:3, Informative)
I would stick with batteries that have similar specs.The charging and inverter circuitry on the UPS expects something in that neighborhood. Those are probably gel-cells which are very common for UPS and other applications like alarm systems. Sounds like the two 6V batteries are connected in series, you could go with a 12V battery which may be easier to find. It depends on the physical dimensions.
I changed the batteries in my APC UPS for $50 using two batteries from batteries.com; APC wouldn't even sell me replacement batteries. They wanted to offer a small tradein allowance on a new unit that would have cost me $400.
Re:Stay close to the same battery (Score:5, Informative)
Overheating on long use is the issue. (Score:4, Informative)
Earlier posters mentioned that a bigger battery would draw more current at a particular charging voltage. This is true, but irrelevant. The chargers are designed to be constant-current, or close to it. The current drain does not depend on voltage.
I've powered a telephone answering computer from an 18 volt UPS using a 6 volt and 12 volt car battery in series, with no problems. However, the unit was arranged that there would be much more air flow for cooling than it would normally get.
Re:Overheating on long use is the issue. (Score:3, Informative)
I agree, the main thing is that the designers of the UPS were expecting a certain length of operation, given the normal battery of the unit, and therefore lie about specs.
An example:
A 500VA UPS is rarely able to handle 500VA continuous and sustained for long periods of time. The battery it comes with might give only 5 minutes of usage at full load, so the designers usually cut corners and just made sure it wouldn't overheat in 5-10 minutes at 500VA, but that's about it. Run the unit
Re:Overheating on long use is the issue. (Score:2)
It depends on the charger. constant-voltage is generally considered to be better for the battery (good chargers will provide different voltages at different stages of the charge cycle). Constant-current chargers can be easy to build and won't burn out with lar
My two cents (Score:4, Informative)
My translation of your question (Score:2)
Answering that question is difficult. I realize that you probably got a good deal on your new battery, but you could've gotten a good deal on a correctly-sized replacement battery too and avoided the problem.
You also write:
The big battery *will* help with longer outages, as
Re:My translation of your question (Score:1)
Move the printer. Do not test with lightbulbs.
If your server gets fried --
What exactly is the question ? (Score:2, Funny)
You should test it a bit with computer, not just a lamp. I plug in a "test" system and my biggest monitor, check to see that the system hasn't rebooted a couple of days later, yank the plug and see that it stays up long enough for me, and maybe repeat the process once. I sniff for burning wire insulation as I do it.
I get small UPS's for $5 at the Goodwill Computer Works in Austin, and they usually
Re:What exactly is the question ? (Score:1, Informative)
Take heart, you're on the right track. (Score:2)
FuturePower (above) was right, every UPS I've seen has current limited charge circuitry. Not because they are anticipating larger battery packs, but because that is the easiest way to do it.
The cheap systems just had a current limiter on the float charger. They tried to bring the battery to some float voltage (let's assume a 12V system) like 13.6 and li
Re:Take heart, you're on the right track. (Score:2)
If he's like me and leaves the computer on while away (and doesn't connect the serial cable from the UPS to the computer), doesn't really matter
This brings me to a question... and I'll admit I haven't researched it much... what UPS-monitoring software have people been successful in using under Linux, and which UPS's did it work with?
Re:Take heart, you're on the right track. (Score:2)
--Belkin UPS that I bought from Circuit City comes with Linux software but I'm not sure if recommending it is a good idea... Their Xwin monitor comes with a memory leak.
Re:Take heart, you're on the right track. (Score:1)
Network UPS Tools.
I use it with my APC SU1400RM, and couldn't love it more. client / server design, nice looking CGI front end, easily extensible. Its great.
--
lds
Re:Take heart, you're on the right track. (Score:1)
I have a similar set-up (SmartUPS 1400 Rackmount) but I'm having trouble getting more than 5 minutes of run time at 50% load. Front-panel calibration doesn't fix this. Was there any undocumented calibrating you had to do?
Re:Take heart, you're on the right track. (Score:1)
APC claimed it was because of the APC power bars plugged into the unit.
Re:Take heart, you're on the right track. (Score:2)
It think part of it is the fact that the batteries are rated to a much lower drain than the UPS can use them (like rated for a drain down to 9 volts when the UPS kicks off at 11) and that the UPS step-up powersupply has significant inefficiencies.
When I first got it. With that weaselly little battery that comes in side it, I got ~35% load (which is only 350w) for about 9 minutes. So, you're not far off the mark here.
Re:Take heart, you're on the right track. (Score:1)
Regarding the why: My ISP's POP for the local phone exchange is located in my basement. In return for providing power and rack space, I get T1 access. <Really Big Grin> (Their equipment on my UPS is a "temporary" situation, but I'm not complaining.)
The extended run time is necessary because there are usually customers who aren't affected and want to be on-line. (Even in the middle of a lightning storm.)
The UPS is repor
Re:Take heart, you're on the right track. (Score:2)
On a typical 12V battery under medium load (say one that would take an hour to drain it of it's rated amp hours), 10.8 volts
7AH vs 50AH battery (Score:2)
I can see two problems with this setup. One is the oft-mentioned capacity of the unit to handle a long-term outage and/or the resulting charge cycle (possibly fixable with bigger heatsinks).
The other is that you're talking about a 7-1 capacity ratio for the replacement battery. I'm guessing that the UPS may not recogniz
what I did (Score:2)
Or so he thought. I opened it up and discovered that the SLA batteries were swollen and some had split open.
I watched ebay carefully and found direct replacements for about $7 each plus shipping. So, for under $30 I got a killer UPS. just get the model numbers from the internal batteries and find them on ebay..
mailto:spammesilly@gt.rr.com [mailto]
Surprised you got any info at all. (Score:1)
Had an older unit that used something like 15 AH battery, and asked them about using the panasonic replacement which was something like 17ah. they wouldn't talk to me at all beyond saying no it can't be done.
But then again, considering they don't care about the security holes in their powerchute plus 5.02 software either, I'm not all that surprised
oh yeah (Score:3, Interesting)
Take an OLD PC case and fill it with whatever size batteries you want, wire them in parallel and run the cables into your UPS. Wire the external battery pack into the UPS in parallel.
The voltage must remain the same but you get more amp hours this way. You can also use batteries that are physically larger that normally won't fit inside the UPS.
You can get LOTS of run time this way, hours and hours of run time..
mailto:spammesilly@gt.rr.com [mailto]
Life of Breadbox UPS systems (Score:2)
One thing people fail to mention, though, is the expected life of the batteries. Usually, you will only see these batteries last 5 years if you never use them. If you deep-cycle them, don't expect more than 10-20 uses! Short (...unless it catches fire.
Depends on the UPS (Score:3, Informative)
If anything, with almost any battery chemistry, charging a battery with a charger designed for a lower-capacity version of the battery at the same voltage will rarely be a problem. It will, of course, take MUCH longer to charge.
Typical lead-acid charging schema: Constant current with a max of 14.5 volts or so. The charger will somehow detect end-of-charge and switch to "float" mode, which is typically 13.8 volts constant voltage for a 12V battery. Constant voltage at 13.8 with a current limit is perfectly safe. Note that if the charger is REALLY dumb and doesn't have a current limiting circuit (almost all do, even if it's as simple as a resistor), a 50AH battery could overload it.
NiCd and NiMH batteries require the most sophisticated end-of-charge detection. This entails reading the battery voltage during brief pauses in charging - NiCds and NiMHs will actually start DROPPING in voltage if charged past their max capacity. No end-of-charge detection is needed if you charge them slowly though. (C/16 or slower. i.e. if it's a 1600 mAh battery, if you charge it at 100 mA, you can leave it on for hours past full charge, but you want to take it off eventually.)
Li-Ion: These aren't really that hard to charge. Constant-voltage at 4.1 or 4.2V/cell with a current limit is all you need. I know people who charge Li-Ions with benchtop lab power supplies (current/voltage limits adjustable). The real trick with Li-Ion is that pack protection circuitry is an absolute must. Short-circuit = BOOM. Overdischarge = Dead and useless pack. Charging beyond 4.1 or 4.2v/cell = Dead and useless pack.
You're worrying too much... (Score:1)
I get at least a good 4 hours battery life out of it, and I think more if I left the monitors off of it.
The charger seems to cope ok, although it does take a long time to fill these batteries.
BTW, the original batteries were something like 20ah and I replaced them with 85ah batteries. They also have a nice design where any gas is e