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User Manual
6 PERFORMANCE OPTIMIZATION
●
Read and understand the information provided here regarding proper installation,
care and maintenance, and storage.
●
US Battery recommends that you limit the depth of discharge to 50% of the 20hr
capacity in order to maximize cycle life.
●
Refrain from discharging more than 80% in order to eliminate the chance of
over-discharging which causes irreversible damage to the battery.
●
If you have any questions or concerns about the proper care and maintenance,
please contact US Battery or your local battery dealer before a problem develops.
6.1 OPPORTUNITY CHARGING
Opportunity charging is a charge given to the battery pack outside of the normal charge
cycle, but in between usages. Examples may include plugging a machine in while on
lunch, charging a golf cart in-between rounds, or simply plugging a machine in when
there is a known break in work. US Battery
recommends
opportunity charging for our
flooded and AGM batteries in all applications. Following this recommendation will as
-
sure that batteries are always at the highest possible State of Charge (SOC) to maxi-
mize performance and range and to minimize the battery’s Depth of Discharge (DOD)
to optimize performance and life.
Opportunity charging can extend the life of the battery by limiting the depth of dis-
charge the battery regularly experiences. Depth of discharge (DOD) is the level at
which a battery is discharged as a percentage of the overall capacity. Batteries that
are limited to shallower depths of discharge exhibit much greater cycle life than batter-
ies that are deeply discharged. By limiting the discharges to shallower levels, you can
increase the energy delivered over the entire life of the battery.
Refer to the expected
cycle life chart in the next section for more info.
Example:
Take the following scenario for example: An operator routinely draws a battery to a
30% DOD, an hour lunch is taken, and then the battery is drawn to a 60% DOD. If
the pack is opportunity charged for the hour while the operator is on lunch, the pack
can regain 10%, and thus be only 50% discharged at the end of the shift. While this
10% may seem insignificant, it can result in longer life of the battery pack and shorter
charge times in between uses.
6
PERFORMANCE
OPTIMIZATION
6.2 CYCLE LIFE
The amount of cycles a
US Battery will deliver
depends highly upon
its depth of discharge
(DOD). In other words,
if you discharge the bat-
tery at a lesser extent,
you will get more cycles
out of the battery. The
relationship isn’t linear
however. As shown in
the following graph, if
you discharge the bat-
tery to 80% of its 20hr
rated capacity, you will
get 675 cycles out of it. If you were to discharge the battery to 40% of its 20hr rated
capacity you can expect to get 1475 cycles out of the battery. That’s more than double
the cycle life.
15000
7000
3300
2050
1475
1150
950
780
675
590
500
3650
1100
700
550
2550
1150
500
250
100
1,000
10,000
100,000
0
10
20
30
40
50
60
70
80
90
100
Expected
Av
erage Cy
cles
Depth of Discharge (% of 20 Hour Capacity)
Flooded Battery Cycle Life (XC & XC2)
AGM Battery Cycle Life (>200 Ah)
AGM Battery Cycle Life (<200 Ah)
Expected Life Cycles vs. DOD (XC, XC2, & AGM)
80% DOD
50% DOD
30% DOD
Average Cycles Expected
20
40
50
60
80
100
120
200
400
600
800
1000
1200 1400 1600 1800 2000 2200
Cycle Line in Relation to Depth of Discharge
DIAGRAM 13
DIAGRAM 14
