Samlexpower PST-15S-12A Owner's Manual page 19

Charging Batteries
The batteries can be charged by using good quality AC powered battery charger or from
alternative energy sources like solar panels, wind or hydro systems. Make sure an
appropriate battery charge controller is used. It is recommended that the batteries may be
charged at 10% to 13 % of the Ampere Hour capacity (20 hour discharge rate). Also, for
complete charging (return of 100 % capacity ), it is recommended that a 3 stage charger
may be used (Constant current bulk charging followed by constant voltage boost /
absorption charging followed by constant voltage float charging )
Batteries, alternators and isolators on vehicles / RVs
It is recommended that for powering the inverter, one or more auxiliary deep cycle
batteries should be used that are separate from the SLI batteries. The inverter should be
powered from the deep cycle batteries. For charging the SLI and the auxiliary deep cycle
batteries, the output from the alternator should be fed to these two sets of batteries
through a battery isolator of appropriate capacity. The battery isolator is a device that
will allow the alternator to charge the two sets of batteries when the engine is running.
The isolator will allow the inverter to be operated from the auxiliary batteries and also
prevent the SLI batteries from charging the auxiliary deep cycle batteries when the engine
is not running. Battery isolators are available from auto / RV / marine parts suppliers
A majority of smaller vehicles have 40 to 105 Ampere alternator and RVs have 100 to 130
Ampere alternator. When in use, the alternators heat up and their output current capacity
can drop by up to 25%. When heated up, their charging voltage may also not reach the
desired absorption voltage and will result in return of only about 80% of the battery
capacity. In case the current output of the standard alternator is not adequate to charge
the two sets of batteries rapidly and fully to 100% of their capacity, use heavy duty
alternator that can produce higher current and voltage required to charge multiple battery
systems. These alternators are available with auto / RV parts suppliers
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