Page 510 - Battery Reference Book

Standby power batteries 5013

50.1 Motive power batteries batteries for fork lift truck and electric vehicle opera-
tion. Tubular plate monoblocs (6 and 12V) are avail-
Motive power !ead-acid batteries are the power source able in the 100-256 5-h capacity rate, 6V flat plate
used in every kind of electric vehicle from road trans- monoblocs are available with 5 h capacities of 165 and
port to fork lift trucks in industry. Many manufacturers 192. A range of motive power batteries housed in hard
throughout the world supply these types of batteries rubber containers with tubular positives are also avail-
and it would be impossible to review all their prod- able (Table 50.5 shows some selected examples).
ucts. Instead, the products of one major UK-based Chloride Motive Power also offer two devices for
international producer, Chloride Motive Power, are the automatic topping up of cells. Such devices are
considered in some detail. The applications of these important as accurate topping up will prolong battery
types of batteries are considered in Part 4. life and remove the risk of abuse. Automatic topping
up also assists, of course, in the sense that it is an
Chloride Motive Power important aspect of automation in battery charging and
maintenance operations.
Chloride Motive Power produce five basic ranges The Chloride Motive Power Battopper (Figures 50.1
of motive power batteries, the Classic series (three and 50.2) is fitted with control logic to prevent overfill-
ranges), monobloc batteries and cells in hard rub- ing and is self-powered by a maintenance-free battery.
ber cases. The system is continually monitored for faults. It is
Three ranges of Classic batteries are available, the suitable for use for approximately 5 h between charges.
Classic batteries; the Classic 15 series which have at The Autofil device also automatically tops up the
least 15% more capacity from the same cell dimen- battery to the correct level. The device operates by
sions than the Classic series: and the Classic 25 series controlling the topping up water flow by the formation
which give 27% more capacity from the same cell of an air lock in the cell.
weight and dimensions when compared with the Clas-
sic series. All the Ciassic batteries are housed in heat-
sealed polypropylene containers and nave tubular pos- 50.2 Standby power batteries
itive plate construction. The higher capacities per unit 50.2.1 Chloride industrial batteries
battery volume of the Classic 15 series are due to
increases in the active material available in both nega- Plant6 types YAP, YC? and YHP
tive and positive plates. The higher capacities per unit
weight and volume of the Classic 25 series are due These are designated as high-performance types. The
to a redistribution of the active material of the plates. range available is shown in Table 50.6 (types YAP and
Both the positive and negative have been redesigned YCP) and Table 50.7 (Type YHP). A typical layout of
so that, compared with the plates of a standard cell, a YHP battery is shown in Figure 50.3. Capacities up
there is 20% increase in usable area. The non-active to 2000 Ah per battery are available.
components used in a cell have also been redesigned to The nominal voltage is 2V/cell, i.e. a nominal
optimize performance, with the result that a cell now 1lOV battery will have 55 cells. On discharge, the
has up to 27% more energy density in terms of watt recommended final voltage at which the discharge
hours per kilogram. Table 50.1 shows the relationship should be terminated is shown in the discharge curves
between electrolyte gravity and state of charge for the (Figure 50.4), i.e. the final voltage for the 3 h rate of
three Classic series of batteries. discharge is 1.8V. After the final voltage has been
reached the voltage will fall away at an increasing rate.
The capacity that can be taken from a cell varies
Table 50.1 Electrolyte relative density related to state of charge with the discharge rate as indicated in the capacity
tables. Capacity is also affected by temperature.
State of charge Approximate relative densiry Trickle charging is a method of keeping these cells
(% charged) (corrected to 15°C) in a fully charged condition by passing a small current
Classic Classic Classic through them. The correct trickle charge current does
cells 15 cells 25 cells not allow the cell to gas and does not allow the density
to fall over a period of time. It is normally in the region
~
100 (fully charged) 1280 1 295 1 295 of 1 mA per ampere hour of the 10 h capacity for YAP
75 1240 1250 1 240 cells and 0.3 x capacity at the 10 h rate + 7QmA for
50 1200 1210 1 200 YCP cells. With this small current flowing. the cell
25 I160 1160 1150 voltage will be approximately 2.2.5 V.
Float charging is keeping the voltage applied to
the battery at 2.25V/cell, i.e. constant voltage. This
In addition to the three Classic ranges method is usually used where continuous and variable
(Tables 50.2-50.4 show selected examples), Chloride d.c. loads exist, and has the added advantage that some
Motive Power also suppiy motive power monobloc degree of recharge can be achieved without manual