ALM
®
12V7 s-Series User’s Guide
Chapter 3: Handling, Storage and Installation
406014-02EN, Rev. 05
© 2016 NEC Energy Solutions, Inc. All rights reserved.
Page 19 of 49
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Configuring Batteries in a Parallel Group (1S2P up to 4S10P)
To achieve higher capacity, arrange the batteries in a single series (1S) parallel group by
connecting all like‐polarity wires on adjacent batteries to an appropriately sized terminal
block for your application. To ensure even loading, make two star connections; one for the
positive battery terminals and one for the negative battery terminals. The cable lengths in
each star group should be of approximately equal measure as permitted by the physical
layout. From each star connection, use a twisted pair of cables to the load.
Reference local electrical codes and/or relevant standards for terminal block specifications.
Bus bar connections are recommended for current exceeding 400 amps.
The nominal capacity for the parallel group can be calculated by multiplying the number of
batteries in the group by 5 Ah. For example, three batteries in parallel provides:
3 x 5 Ah = 15 Ah.
The maximum number of ALM 12V7 s-Series batteries that may be connected in parallel is
ten.
Series and Parallel Battery Configuration Warnings and Notices
WARNING
When configuring the ALM 12V7 s-Series batteries in series or in parallel, adhere to
the following Warning notices:
•
Do not connect more than four batteries in series. Connecting more than four
batteries in series may damage the battery’s circuitry, leaving the battery without
critical safety features such as over‐voltage and over‐temperature protection.
•
Do not connect more than ten batteries in parallel.
•
Configuring more than one series string of batteries in parallel is allowed under
certain circumstances. The maximum supported array is 4S10P. When designing
and constructing any series-parallel battery combinations, contact NEC Energy
Solutions Technical Support for assistance in determining appropriate wiring and
bus bar configurations to address current sharing and stray inductance
requirements.
•
Consider inductance during system design. An ALM 12V7 s-Series battery can
accommodate a maximum inductance of 5 μH. Exceeding this limit during
operation will cause voltage or current spikes, resulting in possible damage to the
battery’s circuitry.
•
Consider capacitance during system design. When a battery or battery group is
connected to a heavy duty charger, external capacitance may need to be added to
the circuity to address the output inductance of the charger. The CV
2
of the
attached capacitor should be larger than the LI
2
of the charger. The charger
inductance is the sum of the internal and external inductances.
