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Bulk

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internal charge capacity. The charger current is flat (constant)
and the battery voltage is rising.  
Maximum allowable charge voltage & current allowed by 
the battery manufacturer should be used to ensure the most
energy is returned within the bulk stage.

 Bulk Charge Stage Time Calculation:
 Max Time (Hr) = (Ahr x 1.2)/Avg. Current (A) 
 Ahr = Amp hours removed during discharge.
 1.2 = Recharge multiplier 
 Avg. Current = Average current available 

to battery from charger.

      Note: Avg. current should be < maximum current limits

for installed battery. Charge current limits available
from your East Penn representative. 

 Max Time (Hr) – Maximum charge time for battery to

reach 80% - 85% state of charge

Absorption

The charger will attempt to hold its output voltage constant
while the battery continues to absorb charge (draw charging
current) from the charger. The rate at which the battery con-
tinues to absorb charge in this mode gradually slows down.
The amplitude of the charger current is gradually decreasing.
The charge current is falling and the battery voltage is flat
(constant).
Some Inverter/Charge Controllers can either use time or 
current to determine the length of the absorption stage.

Time regulated absorption

is based on a predetermined time

after the battery has completed the bulk stage (charge voltage
has reached its maximum set point). A lead-acid battery is said
to be at 80% to 85% SOC (State of Charge) when the voltage
set point is met and the current starts to taper; considered the
start of absorption. The remaining time required to reach
100% SOC is based on ever changing factors: solar isolation
(summer vs. winter), ambient temperature, battery type
(flooded, VRLA), and battery age. 

Absorption stage time should be set to optimize the available
sun hours during the winter and/or cloudy months. If improp-
erly set, there is a risk of undercharging the battery system.

It is recommended to set the absorption time to the maxi-
mum time setting possible to take advantage of all available
charging light regardless of time of year or weather issues.
Using this method, the sun availability will determine the
absorption time. Following this recommendation, there is no
risk of overcharging if the battery charge voltage is set within
the recommended settings.

The amount of available power (current) to the batteries is
important for getting a battery charged. Available power 
(current) to the batteries is the remaining power (current) after
connected loads are satisfied. Maximum charge voltage and
current allowed by the battery manufacturer should be used to
ensure the most energy is returned to the batteries.

The below calculation will assist in identifying the necessary
maximum charge current for the system. If the calculation
shows the absorption time is greater than the minimum
average peak sun hours for the installation location, the
amount of available current to the batteries should be
increased, which could be accomplished by a larger array 
or a secondary power source such as a generator. 

Charge Current Verification:

FLOODED

      C20 x 0.44/charge current available

      Example:

      Maximum Charge Current
      

Battery Rating: 1186Ah (C20)

      

237A – Charge current (maximum)

      

1186Ah x 0.44 / 237 = 2.20 hrs

      Minimum Charge Current
      

Battery Rating: 1186Ah (C20)

      

118A – Charge Current (minimum)

      

1186Ah x 0.44 / 118A = 4.42 hrs

VRLA (AGM & GEL)

      C20 x 0.39/charge current available

      Example:

      Maximum Charge Current
      

Battery Rating: 183Ah (C20)

      

55A – Charge current (maximum)

      

183Ah x 0.39 / 55A = 1.30 hrs

      Minimum Charge Current
      

Battery Rating: 183Ah (C20)

      

18.3A – Charge Current (minimum)

      

183Ah x 0.39 / 18.3A = 3.90 hrs

Current regulated absorption

is using the charge current 

to determine battery state of charge, which eliminates a
majority of the variables previously mentioned with time
based absorption (solar isolation, ambient temperature, 
battery type). Charging in constant voltage, when a
battery/battery system reaches the absorption voltage setting
the current will start to taper. The point at which the current
stops tapering or declining is referred to as the stabilizing 
current. This is an indication that the battery is fully charged
and the current the battery/battery system is drawing is only
needed to keep the battery at the set voltage. This minimum 
or stabilizing current will change based on the charge voltage
setting. Battery manufacturer should be consulted for current
settings. 
An additional option for determining the SOC of a battery is
monitoring the Ah (amp hour) removed from a battery 
during a discharge and the amount of Ah returned during
charge; similar to a gas gauge in a car. The Ah in and out
should be monitored on a continuous basis to keep track of
the overall SOC not just from day to day.

Float

The voltage at which the battery is maintained after being
charged to 100% SOC (State of Charge) to maintain capacity
by compensating for self-discharge of the battery.

Equalize

A charge, at a level higher than the normal float voltage,
applied for a limited period of time, to correct inequalities of
voltage, specific gravity, or state of charge that may have
developed between the cells during service.

Note: Equalize charging not required on VRLA (AGM/Gel)
as part of a daily charge setup. Based on PV applications,
unpredictable recharge availability, periodic equalize may
be required.

Содержание Deka SOLAR

Страница 1: ...Renewable Energy Technical Manual ...

Страница 2: ... 3 Series Parallel Wiring 3 Glossary 5 APPENDIX A Renewable Energy Worksheet 6 APPENDIX B Example of Typical 3 Stage Charger 7 APPENDIX C Example of Depth of Discharge vs Freezing Point 8 TABLE OF CONTENTS PROPOSITION 65 WARNING Battery posts terminals and related accessories contain lead and lead compounds chemicals known to the State of California to cause cancer and reproductive harm Batteries ...

Страница 3: ...sus ceptible to freezing in a particular application If the electrolyte would freeze the internal damage would be irreversible requir ing the battery to be replaced Depth of Discharge DoD Depth of discharge is a function of design The deeper the discharge per cycle the shorter the life of the battery A cycle is a discharge and its subsequent recharge regardless of depth of discharge Systems should...

Страница 4: ...cturer should be used to ensure the most energy is returned to the batteries The below calculation will assist in identifying the necessary maximum charge current for the system If the calculation shows the absorption time is greater than the minimum average peak sun hours for the installation location the amount of available current to the batteries should be increased which could be accomplished...

Страница 5: ...trength and adequately anchored to the floor Battery rack design and anchoring should be reviewed by a structural engineer Ventilation It is the responsibility of the installer to provide detailed methods or engineering design required by Federal State and local regulations to maintain safe levels of hydrogen in battery rooms enclosures The rate of hydrogen evolution is highest when the battery is...

Страница 6: ...gy source Wiring connection assessment difficult to follow with multiple wirings connected to same battery terminal increasing chance of re connection wiring errors Common bus wiring A wiring scheme in which same polarity terminals are con nected to a single termination point All interconnecting wiring should be of same length to minimize voltage drop Advantages Cables can be of same gauge Mainten...

Страница 7: ... conductor If two 12 volt batteries of 50 ampere hour capacity each are connected in parallel the circuit voltage is 12 volts and the ampere hour capacity of the combination is 100 ampere hours Series A circuit that has only one path for the flow of current Batteries arranged in series are connected with negative of the first to positive of the second negative of the second to positive of the thir...

Страница 8: ...6 APPENDIX A Completing all parameters ensures accurate battery sizing Worksheet to be submitted to sales representative for battery recommendation ...

Страница 9: ...7 APPENDIX B Example of typical 3 stage charger ...

Страница 10: ...om the company Domestic Inquiries Call 1 800 372 9253 www mkbattery com e mail sales mkbattery com East Penn Manufacturing Co Lyon Station PA 19536 0147 Domestic International Inquiries Call 610 682 3263 Phone 610 682 6361 Fax 610 682 0891 www dekabatteries com e mail reservepowersales dekabatteries com APPENDIX C Below graph is for general reference only Consult specific battery Installation Oper...

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