Short Circuit Protection - Victron energy LFP-Smart 12,8/60 Manual

A residual discharge current is especially dangerous if the system has been
discharged completely and a low cell voltage shutdown has occurred. After
shutdown due to low cell voltage, a capacity reserve of approximately 1Ah per
100Ah battery capacity is left in the battery. The battery will be damaged if the
remaining capacity reserve is drawn from the battery. A residual current of
10mA for example may damage a 200Ah battery if the system is left in
discharged state during more than 8 days.
3 Installation
Note: Batteries must always be installed in upright position.

3.1 Short circuit protection

Single battery installation
The battery must be protected by a fuse.
The battery must be connected to a BMS.
Series connection
Up to four 12,8V batteries or up to two 25,6V batteries can be series
connected.
The batteries must be connected to a BMS.
The string of batteries must be protected by a fuse.
Parallel or series parallel connection
Up to five batteries or strings of batteries can be parallel connected.
The batteries must be connected to a BMS.
Each battery or string of batteries must be protected by a fuse, see
figure 1.
Do not interconnect the intermediate battery to battery connections of
two or more parallel strings of batteries.
3.2 Charging batteries before use
The batteries are aproximately 50% charged when shipped.
When charging series connected batteries, the voltage of the batteries or cells
with the highest initial state of charge will increase when reaching the fully
charged state, while other batteries or cells may lag behind. This may result in
over voltage on the batteries or cells with the highest initial state of charge,
and the charge process will be interrupted by the BMS.
Therefore new batteries must be fully charged before using them in a
series or series-parallel configuration.
This can best be done by individually charging the batteries at a low rate (C/20
or less) with a charger or power supply set at 14,2V resp. 28,4V. An
absorption period of several hours at 14,2V resp. 28,4V is recommended to
fully balance the cells.
If no BMS is used, charge only when a supervisor is present to stop the
charging process in case of malfunction of a battery.
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