BATTERY REPLACEMENT : ABOUT
All modern UPS have a low-battery alarm and run a periodic self-test; they will alert you when battery replacement is needed. Usually they both flash an indicator and make an alarm sound. If you have a monitoring daemon set up, they will alert it and you will probably get warning mail. If you ignore the alarm it will time out, but be repeated at intervals.
You will occasionally get a false alarm. It’s a good idea, if you get an alarm, to explicitly trigger a UPS self-test the next day and see if the alarm goes away (the procedure for doing this varies depending on your UPS software). If the alarm is persistent, you need to replace the batteries.
It has been reported that bad batteries can also produce symptoms that mimic inverter failures or wonky control electronics. Even if your UPS is displaying epileptic symptoms like repeating alarms and flashing panel lights, a bad battery is the first thing to suspect.
It’s best to wait until the low battery alarm before ordering a replacement; keeping batteries on the shelf reduces their life unless you keep them fully charged.
Do not throw old batteries in your regular trash! They contain toxic metals and acids. Be kind to your environment and hand them to a qualified party for recycling. Most battery dealers will cheerfully do this for you. If not, your local garbage company or waste-disposal authority can explain to you how and where to turn them in safely.
Many UPS models use gel-cel batteries in standard formats like 12.0 V, 7.2Ah (151x64x94 mm). Warning: Many manufactures sell two or three different types: standard use, cyclic use and high-current use. UPS require high-current and some UPS don’t work well with batteries for standard use, because the voltage goes low too early under high load (the UPS turns off too fast or the output voltage drops so that the computer turns off). Standard batteries are for alarm devices, emergency lights or things like that. For instance Panasonic sells the “LCR127R2PG1” (standard), and “UPRW1245P1” (high current), Fiamm the “FG20271” (standard) and “FGH20902” (high current), CSB the “GP1272” (standard) and “HR 1234W” (high current).
Below, you will find some suggestions for buying replacement batteries. One important note of caution: at least one user purchased one of the aftermarket batteries noted below and found out that they would not fit into his unit. This required cutting and soldering and other very undesirable things, so be extremely careful in measuring your batteries — including every millimeter of the terminal connections, which can cause problems.
Although you can do a hot swap of your batteries while the computer is running, it may not be very satisfactory, because the unit will not know that the batteries have been swapped and your monitor daemon will continue to show a low-battery indication. To correct this situation, you must do a discharge and recharge of the battery. At that point the battery should be calibrated better.
It may take several discharges and recharges of new batteries before they reach full capacity and the dwell-time calibration is accurate. If your UPS contains two or more battery units and your monitoring software reports separate voltage levels for them, one way to tell is to watch the divergence in voltage levels. As the cells reach nominal full capacity, their voltages should converge.