UPS Batteries - Your best defence against downtime
A UPS battery will not last forever.
UPS Solutions offer proactive battery replacement programs to minimise the risk of downtime, lost revenue and reduce the risk of damage to valuable electronic equipment. We can rejuvenate your UPS systems with new batteries and warranty for a single UPS or multiple UPS systems to prolong the life of your existing UPS equipment.
The size of a battery connected to a UPS is what governs its overall backup time. Most manufacturers will provide run times in minutes usually printed on the packaging. Large systems like ones used to power data centers require more detailed calculations of inverter efficiency, load, and the characteristic of the battery for max endurance.
Because of this interface charge short UPS self test functions that last a couple of seconds is not able to accurately reflect the runtime capacity of a UPS, but rather a recalibration or a rundown test may be required.
It is important to note that deep discharging to test the battery can be damaging to it because the chemicals in a discharged battery can start to crystallize into more stable shapes which means that they will not dissolve when the battery needs to recharge this reduces the capacity permanently. Often referred to as sulfation in lead acid batteries it also affects nickel cadmium and lithium batteries. This is why the rundown test should only be performed every six months or every year.
Testing strings of batteries
Larger uninterruptible power supply systems that have easily accessible but large battery banks are able to isolate and test individual cells within every battery string. This string can consist of either combined batteries (like 12V lead acid cells) or chemical cells which have been wired in series. A single battery can be discharge tested by isolating and then installing a jumper in place, while the other batteries are charged and still able to provide backup.
You can also measure the chemical and electrical characteristics of each cell in a string, using an intermediate sensor which is installed on each cell to cell junction and are monitored both collectively and individually. Battery strings can also be wired in parallel and series for instance you have two sets each with 10 cells. However, when wired in such a manner it is important to monitor the flow of current between the parallel strings, as the current may circulate between strings in order to balance the effects of a week cell or a dead cell having high resistance. For instance, a stronger string can easily be discharged through weaker strings until the voltage imbalance is equalized.