3
1.3. Features & Benefits
• Capacities from 300Ah to 4580Ah at the 120 hour rate
• Products available filled & charged or moist charged
• Up to 5200 cycles to 25% depth of discharge
• Minimal maintenance required (topping-up required only once
a year)
• Excellent operational safety including fully insulated connectors
and terminals, acid-proof flame arrestor plug for each cell and
protection of polarities during transport
1.4. Capacity
Capacity is the number of Ah a battery can supply for a well-defined
current and an end of discharge voltage.
Capacity varies with the discharge time, discharge rate and
temperature.
Example:
Capacities for PowerSafe TYS 5 cell are as follows:
Discharge time
50h
100h
120h
End voltage
1.85Vpc
1.85Vpc
1.85Vpc
Capacity at 25°C
739Ah
790Ah
802Ah
The nominal capacity of PowerSafe
®
TS cells for renewable energy
applications is as follows:
Capacity
Ah
Current
A
Discharge
period h
End voltage
V/cell
C
120
I
120
120
1.85V
Discharge rate:
Is the ratio of discharge current divided by battery capacity.
Depth of discharge (DOD):
Capacity removed from the battery compared to total capacity.
It is expressed as a percentage. The battery will be sized for solar
applications with a DOD <80% for the autonomy required.
Daily cycle:
The battery is normally used with a daily cycle as follows:
Charge during the day hours and discharge during night hours.
Typically daily use is between 2 to 20% DOD.
1.5. Effect of Temperature
On the capacity:
Correction
factors of the capacity according to the temperature are
shown in the following curve. If the temperature is different from
25°C, correction factors must be applied to the installation rating in
order to secure an optimum service life.
On the number of cycles:
A rise in temperature brings about a decrease in the number of
cycles (see below).
1.6. Charge efficiency
The charge efficiency is the ratio between the quantity of Ah
delivered during the discharge and the quantity of Ah necessary to
restore the initial state of charge.
State of charge (SOC)
Ah Efficiency
90
> 85
75
> 90
<50
> 95
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
1.10
1.20
-20
-15
-10
-5
0
5
10
15
20
25
30
35
40
45
C
om
pe
ns
a
ti
on c
oe
ff
ic
ie
nt
f
or
a
120
h
r.
D
isch
ar
g
e
to
1,
85V
p
c
at
25
°C
Temperature in °C
Batteries for renewable energy applications
Effect of temperature on capacity
Batteries for renewable energy applications
Derating factor for number of cycles vs average cell temperature
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
1.10
20
25
30
35
40
45
50
Temperature in °C
D
e
ra
ti
n
g
F
a
c
to
r
Derating Factor for Number of Cycles vs Average Cell Temperature
Effect of Temperature on Capacity
