Samlex Solar SCC-30AB Owner's Manual page 16

3
GENERAL INFORMATION: BATTERIEs
Loss of Battery Capacity at Low Temperatures
Batteries lose capacity in low temperatures. At 32ºF (0ºC), a battery will deliver about
70 to 80% of its rated capacity at 80ºF (26.7ºC). If the electrolyte temperature of
the battery bank is lower than 80ºF (26.7ºC), additional batteries will be needed to
provide the same usable capacity. For very cold climates, an insulated / heated battery
compartment is recommended.
Freezing of Electrolyte
For applications with low ambient temperature, the lead-acid battery must also be
protected against freezing of the electrolyte. The risk of freezing depends on the state
of charge. The chart given below illustrates the freezing limit as a function of the state
of charge.
Series and Parallel Connection of Batteries
Series Connection
Solar Charge Controller
SCC30-AB (rear view)
When two or more batteries are connected in series, their voltages add up, but their
Ah capacity remains the same. Fig. 3.2 above shows 4 pieces of 6V, 200 Ah batteries
connected in series to form a battery bank of 24V with a capacity of 200 Ah. The
Positive terminal of Battery 4 becomes the Positive terminal of the 24V bank. The
Negative terminal of Battery 4 is connected to the Positive terminal of Battery 3. The
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0° 0°
- 20° - 20°
- 40° - 40°
slushy until hard slushy until hard
- 60° - 60°
- 80° - 80°
0 0 20 20
State of Charge (%)
Cable "A"
Battery 4
PV +
PV -
BAT +
6V Battery
BAT -
Cable "B"
Fig. 3.2. Series Connection
40 40 60 60 80 80 100 100
State of charge [%] State of charge [%]
Battery 3 Battery 2
6V Battery 6V Battery 6V Battery
Battery 1
6V Battery