Page 604 - Battery Reference Book

Nickel-cadmium secondary batteries 51/41
Table 51.47 Unibloc batteries: dependence of maintenance-free intervals on capacity and charging methods

TYP Capacity at Maintenance interval (years)
10h rate (Ah)
Fully automatic operation Close voltage application with
without boost 6-monthly boost of 1.6511.70 Vlcell
(float voltage 1.47 Vkell) (float voltage 1.42 Vlcell)

5LP7 7.5 8 14
5LP7 12.5 5 9
5LP 12 15.0 4 7.5
5LP27 27.0 2.5 5

Chloride Alkad (UK) lighting and alarm systems. For most applications,
constant-voltage charging is recommended to mini-
Chloride Alkad supply the Unibloc range of alkaline mize electrolyte loss, which is dependent on float
batteries, which are virtually maintenance free but charge voltage, the capacity of the battery and the
unsealed. These range from 7.5 to 27Ah capacity. frequency of boost charge. Table 51.47 shows how
Unlike traditional alkaline batteries, which are built
up from individlual separately packaged cells, Unibloc the maintenance interval across the Unibloc range of
batteries is related to battery capacity and charging
starts off as a five 1.2V cell battery in a lidded method. In many cases it should be possible com-
container. The Unibloc range is available in four
basic capacities, each providing low-rate discharge fortably to exceed these intervals up to a maximum
performance: of around 20 maintenance-free years for the lowest-
capacity batteries on a constant 1.42 V/cell float charge
1. Type SLP7, 7.5 Ah. without any boost charging.
2. Type SLP12, 12.5Ah. The discharge performance of Unibloc batteries is
3. Type SLP15, 15Ah. summarized in Table 5 1.48.
4. Type SLP27, 27 Ah.
The five cells are incorporated in a plastic case 51.1.3 Large vented nickel-cadmium
containing sufficient extra potassium hydroxide elec- batteries
trolyte to enablle periodic topping up of the battery to
extend battery life up to a maximum of 20 years (under Although it is not possible to include all of the many
ideal conditions), although 7- 10 years would prob- suppliers of these batteries, a representative selection
ably be the average. These batteries are recommended is covered below, including the various types of such
for applications such as switch-tripping, emergency batteries that are available for different applications.

Table 51.48 Chloride Alkad Unibloc battery performance to minimum voltage based on current and duration (fully discharged after 3 h
open circuit)
Vlcel! Discharge current (A) at 25°C
1s 10s 30s 1 min 5min 10min 30min lh 1.5h 2h 3h 5h 8h 10h
1.00 5LP7 18 14.0 13.0 12.0 9.2 8.0 6.1 5.1 4.2 3.5 2.6 1.6 1.00 0.83
5LP12 29 23.0 22.0 19.0 14.8 13.0 10.0 8.3 6.8 5.6 4.1 2.6 1.70 1.33
5LP15 33 26.0 25.0 22.0 17.3 15.1 11.5 9.6 7.9 6.5 4.8 3.0 1.90 1.55
5LP27 62 49.0 47.0 42.0 32.4 28.4 22.6 18.1 14.9 12.3 9.1 5.7 3.60 2.92
1.05 5LP7 16 13.0 11.0 10.0 7.6 6.6 5.0 4.3 3.6 3.2 2.4 1.6 1.00 0.83
5LP12 25 20.0 18.0 17.0 12.4 10.7 8.1 6.7 5.8 5.2 3.6 2.6 1.60 1.32
SLP15 29 23.0 21.0 19.0 14.4 12.5 9.5 8.1 6.8 6.0 4.6 3.0 1.90 1.53
5LP27 54 43.0 40.0 36.0 27.2 23.4 17.7 15.1 12.8 11.3 8.6 5.6 3.60 2.90
1.10 5LP7 14 11.0 9.1 8.0 6.2 5.3 4.1 3.7 2.9 2.6 2.2 1.5 1.00 0.81
5LP12 22 17.0 14.7 13.0 10.0 8.6 6.5 6.0 4.7 4.2 3.5 2.5 1.60 1.31
5LPP5 25 20.0 17.2 15.1 11.7 10.0 7.6 7.0 5.4 4.9 4.1 2.9 1.90 1.53
5LP27 47 36.0 32.2 28.4 22.0 18.9 14.3 13.2 10.2 9.2 7.7 5.4 3.50 2.88
1.14 5LP7 12 9.0 7.5 7.1 5.0 4.4 3.3 2.9 2.5 2.1 1.7 1.3 0.95 0.78
5LP12 18 14.3 12.4 11.5 8.1 7.1 5.3 4.7 4.0 3.3 2.8 2.2 1.54 1.27
5LP15 21 16.4 14.1 13.3 9.5 8.3 6.2 5.5 4.7 3.9 3.3 2.5 1.79 1.48
5LP27 41 30.8 26.4 25.1 17.7 15.5 11.7 10.2 8.8 7.3 6.1 4.8 3.37 2.78