I love the Linux documentation project. Just about every aspect of Linux is documented there some how. This is the first place to look for any Linux related information.
Unfortunately, the UPS Howto is quite dated. It hasn't been updated since November 1997.
There is a diagram of the pinouts for TrippLite BC750LAN (Standby UPS) by Tom Webster <webster@kaiwan.com>, the author of the genpower package.
Interestingly enough, TrippLite no longer carries BC 750 LAN on their catalog, so I couldn't compare it with the BC Pro (600, 850, 1050, 1400). This does point me to genpower as a package to try.
I tried genpower with the TrippLite OmniStart 675 PnP that I got from Price Club. It didn't work correctly for me. But I did notice the package is fairly well set up.
In the last couple years, Google has quickly risen to become the number one search engine. In fact there is even a very helpful directory for using UPS with Linux.
This is one of my favorite places to start looking. People may ask questions and "talk", before taking the time to put the same info on the web. This also tends to have the most "current" information.
This used to be one of the most popular search engines until it was surpassed by Google. It may still be one of the most comprehensive in terms of the raw amount of documents indexed (anybody has the stats?). It's also blazing fast. The hardware behind it is a marvel of Digital (now Compaq) technology, multiprocessor Alpha's, giga bytes of solid state disks.
When I first searched (back in 1999), out of the 110 links I browse through, the following 3 additional pages seem useful.
This has a good coverage of general informations on UPS.
This document became part of Linux Howto in 2001. This is very useful specifically for unix users on PC's. He is very enthusiastic about TrippLite's. He used to like APC, but not any more because of their not releasing specs (see more about this later).
I personally am not very thrilled with TrippLite. I emailed their tech support because their Power Alert package for Linux doesn't extract correctly. The installation script does a "cpio", and the command line options were incorrect. It took over a week before I got a response. If a vendor can't respond to email request in a reasonable fashion, IMHO, one shouldn't bother with them. Eventually I did get the Power Alert package to work--no thanks to TrippLite's tech support.
This used to be called SmartUPSTools. It is being actively maintained by Russel Kroll for the last few years. It supports several different brands of UPS, including APC, Best Power, etc. It is very well done, and has a web interface (CGI) that supports monitoring multiple UPS' simultaneously with various master-slave configurations. I highly recommend this. This is probably the best Linux UPS tools out there. I have used this with APC SmartUPS 1000VA, 2200VA, and 3000VA since 1999.
It may be of interest that APC also released its PowerChute software for Linux. Personally, I am not very thrilled about it. It's still not open source. But it's a step.
In 1999, this was relatively new. In the last few years, APC seems to have extended their official support to Linux. One may find many such references in their faq.Over all, I find scant information on TrippLite. I looked through about 10 different packages listed on the UPS-HOWTO. Many of the support APC SmartUPS, and Best UPS.
Most of these packages available are user contributed. As I previously pointed out, there are many for APC and Best UPS.
Vendor support is mainly referring to how much spec they release. Out of the top 3, APC, Best, and TrippLite. Best is the "best" of them all. The driver is open source. APC has been criticized much for their unwillingness to release specs. Thankfully, the specs were reverse engineered, since apparently APC UPS's are fairly popular. As as of the end of 1999, APC's PowerChute software was released for Linux.
Incidentally, PC magazines in general rate APC's very well. In the future, I would seriously consider Best as well.
Historically, Best Power
Pay special attention to the warranty period. Both APC and Best offer 2-year warranty. This seems to be the norm. Most of the problems I have encountered occur within the first few months. It should raise some red flags if the warranty period is less than 2 years.
First, you need to know how much load you are going to put on this UPS. A typical PC comes with a 225-300W power supply. For example, a midtower may have a 250W power supply. It doesn't mean that it has that much load. It depends on how many harddrives, and other devices on the machine. It simply means that the power supply can support a maximum of 250W. There is also a matter of whether you want to put the monitor on the UPS as well. Monitors tend to be heavy loads. Then again, one does need the monitor on in order to do a shutdown.
As a rule of thumb, I estimate 100VA (65W) per workstation, excluding the monitor. Keep in mind that over time, people tend to add more load to the UPS. If you intend to keep the unit for years, you may want to at least double the load requirement.
Once you know how much load the UPS needs to support, you can decide the length of run time on battery. IMHO, 10 minutes is the minimum for an orderly shutdown, 30 minutes is preferable. APC has a runtime chart for the Smart UPS'. For example, if I want to put 4 PC's on a UPS, and I would like the battery to run for an hour. I would estimate a 400VA load, with a run time of 1 hour, and the table shows that a SU1400 can sustain that.
This tells you how long does it take for the UPS to kick in, after a power outage. "2ms" is typical for a higher end model. If it's longer than 10ms, devices such as modem may experience problems.
A "pure" sine wave is the best. The cheaper models frequently features "stepped approximation to a sine wave", e.g., Back-UPS.
A UPS tends to be heavy mostly because of the battery. For example, SU1000net weighs 42 lbs. I have had users declining to have a higher capacity UPS because it's simply too heavy. For example, a SU2200net weights 112 lbs. Dimension wise, SU1000net and SU1400net are both only 8.5" tall, and take up relatively little space. SU2200net and SU3000net on the other hand are twice as tall, and deeper. Keep this in mind if you are planning to send some of these equipments to your users' homes.
This is where you figure out how to get the bang for the buck.
If you are planning for the long term and there are some flexibility in terms of budgeting, it's worth while to do an incremental cost benefit analysis. As an example, we will use the APC SmartUPS models, and some theoretical prices.
| model# | Price | $/VA | Inc.$/Inc.VA |
|---|---|---|---|
| 700net | $329 | $0.47 | |
| 1000net | $500 | $0.50 | $0.57 |
| 1500 | $610 | $0.41 | $0.22 |
| 2200net | $878 | $0.40 | $0.38 |
| 3000net | $1449 | $0.48 | $0.71 |
First, you want to look at how much you are paying per VA, or bang for the buck. As one can see 2200net presents the lowest $/VA at $0.40/VA. This means you are paying $0.40 for every VA that it delivers. The 1500 model is very close at $0.41/VA. You can immediately tell that for one reason or another the vendor has set this up to be the price sweet spot. It's likely that these two models are the most popular in its product line.
Secondly, you may check the incremental cost over incremental capacity. This is how you figure out how much more it will cost you to get more capacity. A low incremental dollar per incremental VA ratio means that it's relatively cheap to upgrade.
For example, to upgrade from 1000net to 1500, the incremental cost/incremental VA ratio is the lowest at $0.22/VA. If you look at the prices, comparing $500 to $610, by paying $110 or roughly 20% more, you are getting 50% more capacity. This is quite attractive.
On the flip side, there is a huge incremental cost upgrading from 2200net to 3000net. Based on this, unless you absolutely need the extra capacity, 2200net is a better buy.
One interesting fact about UPS prices is that they seem to be in steady state. In the last 3-4 years, the prices for the same models are exactly the same, while the prices for practically all other computer related hardware are plummeting. One would hope that this means the vendors are constantly improving their products. :-)
Here is an interesting note I found from Fenton (another UPS
vendor) web site
<http://www.fentonups.com/ppal.htm>
Every PowerPal model has built-in voltage correction for brownout protection - "boosts" low voltages and "bucks" high voltages, extends battery life, and reduces stress on your electronic equipment. Don't be fooled by other UPS companies' confusing product lines: APC's Back-UPS models and TrippLite's various BC models do NOT provide voltage correction. For APC and TrippLite, you have to at least buy the Back-UPS Pro or the OmniSmart in order to get this valuable feature.