UB10.241

U–Series

24V, 10A, DC-UPS

Batteries have a limited life time. They degrade slowly beginning from the production and need to be replaced

periodically. The design life figures can be found in the individual datasheets of the batteries and usually is specified

according to the Eurobat guideline or according to the manufacturer’s specifications.

The design life is the estimated life based on laboratory condition, and is quoted at 20°C using the manufacturer’s

recommended float voltage condition. According to the Eurobat guideline, design lives have been structured into the

following different groups:

3 - 5 years:

This group of batteries is very popular in standby applications and in small emergency equipment.

This represents a 4 years design life with a production tolerance of ±1 year.

6 - 9 years:

This group of batteries is usually used when an improved life is required.

This represents a 7.5 years design life with a production tolerance of ±1.5 years.

10 - 12 years: This group of batteries is used when in applications where longest life and highest safety level are

required. This represents a 11 years design life with a production tolerance of ±1 year.

A battery failure within the specified design life of the battery usually results in a complete loss of the battery

function (broken cell, defect connection, …) and will be detected and reported by the periodical battery tests which

are included in the UB10.241 DC-UPS control unit.

If the operational parameters differ from those which are specified for the design life, an earlier change of the

battery might be necessary. The “real life” is called service life and is defined as the point at which the cell’s actual

capacity has reached 80% of its nominal capacity. At the end of the service life the capacity degrades much faster, so

that a further use of the battery is not recommended.

Temperature effect:

The temperature has the most impact in the service life. The hotter the temperature, the earlier the wear-out phase

of the battery begins. The wear-out results in a degradation of battery capacity. See Fig. 27-1 for details.

Effect of discharging cycles

The number as well as the depth of discharging cycles is limited. A replacement of the battery might be necessary

earlier than the calculated service life if the battery exceeds the numbers and values of Fig. 27-2.

Other effects which shortens the service life

Overcharging and deep discharging shortens the service life and should be avoided. Thanks to the single

battery concept of the UB10.241, the end-of-charge-voltage can be set very precisely to the required value

an thereby avoiding unnecessary aging effects.

Charge retention is important to get the longest battery life. Stored batteries which are not fully charged

age faster then charged batteries. Batteries which are not in use should be recharged at least once a year.

Excessive float charge ripple across the battery has an effect of reducing life and performance. The UB10.241

does not produce such a ripple voltage. This effect can be ignored when the battery is charged with the

UB10.241.

Guidelines for a long battery service life:

Place the battery in a cool location: E.g. near the bottom of the control cabinet.

Do not place the battery near heat generating devices.

Do not store discharged batteries.

Do not discharge the battery more than necessary. Set buffer time limiter to the required buffer time.

When choosing the battery capacity, always try to get the next higher capacity than required. The depth of

discharge reduces the service life of the battery and limits the number of cycles. See Fig. 27-2.

June. 2010 / Rev. 1.3 DS-UB10.241-EN

All parameters are specified at an input voltage of 24V, 10A output load, 25°C ambient and after a 5 minutes run-in time

unless otherwise noted. It is assumed that the input power source can deliver a sufficient output current.

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