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USER'S MANUAL
SECTION 6: BATTERY CARE AND MAINTENANCE (CONT.)
BATTERY RATING
Batteries are rated at the current which will reduce the
voltage per cell to 1.67 volts in 20 hours. The heavyweight
battery has a 12 amp hour rating. However its life at 100
watt continuous discharge would be only 120 minutes.
As the discharge current is increased, the efficiency and
relative capacity decreases (
Fig. 6.1
).
BATTERY LIFE
Each time you cycle a battery it loses some of its ability
to take a charge. Deep cycle batteries are capable of
being charged and discharged from 100 up to 1,000 times,
depending on the depth of the discharge and the type of
charger used. Service life and shelf life are both adversely
affected by extreme temperatures.
BATTERY STORAGE
Batteries stored at room temperature will self- discharge
at 3% to 6% per month. Storage temperature above 20°C
(68°F) should be avoided. Shelf life can be increased by
storing in a climate-controlled environment. Batteries
should be fully charged before storing and should be
recharged every four months.
EFFECTS OF TEMPERATURE
The temperature at which a battery is used also affects
the relative capacity of the battery. In cold weather the
shocking time will be less and the battery will have less
capacity (
Figs. 6.3 & 6.4
).
Life
Load
Capacity
20 hr
0.60A
12.0Ah
10 hr
1.05A
10.5Ah
5 hr
1.95A
9.7Ah
1 hr
7.20A
7.2Ah
30 min
12.00A
6.0Ah
15 min
20.00A
5.0Ah
Fig. 6.1 Relative capacity of 12Ah
deep cycle battery.
Fig. 6.2 Discharge curves for
12Ah and 7Ah batteries.
Fig. 6.3 Effect of temperature
on battery life.
Fig. 6.4 Effect of temperature
on capacity.
SECTION 6