Installation and Operation Manual
6
Float Charge
Once the battery is fully charged the charge control system switches to the float charge stage. During float charge,
a constant float voltage of 26.6/53.2 volts is applied to the battery to maintain it in a fully charged state without
excessive water loss. The purpose of float charge is to provide a very small charging current to offset self discharge of
the battery. During float charge a healthy lead-acid battery that is fully charged and stabilized will draw approximately
0.1 - 0.2 amps per 100 amp-hours of battery capacity. For example, a typical 330 amp-hour battery will draw
approximately 0.4 - 0.7 amps. If the battery attempts to draw more current than the Float Transition Current, the system
will switch back to acceptance or bulk. Continuous application of a proper float voltage to a fully charged battery will not
harm the battery or lead to excessive water loss.
TWO STAGE CHARGE CONTROL
Certain battery types or system configurations may require two stage charge control. Solar Boost 3048 can be
configured for a two stage bulk-acceptance or bulk-float charging process to accommodate these batteries or systems.
Refer to the Solar Boost 3048 Setup section to configure two stage charge.
EQUALIZATION
WARNING:
Not all batteries can be safely equalized.
Equalization should only be performed on vented liquid
electrolyte lead-acid batteries. Follow battery manufacturers
recommendations pertaining to equalization.
Equalization is essentially a controlled over charge and should only be performed on vented liquid electrolyte lead-
acid batteries. Since each cell of a battery is not identical, repeated charge/discharge cycles can lead to an imbalance
in the specific gravity of individual battery cells. Stratification of the electrolyte can also occur. Equalization brings all
battery cells up to the same specific gravity, and eliminates stratification by heavily gassing the battery. Note that the
three stage charge technique matched to battery size, type and temperature provided by Solar Boost 3048 minimizes
the need for equalization, as the battery is properly and fully charged on each cycle.
A proper equalization cycle is a substantial over charging of the battery at relatively high voltages with significant
battery gassing. Solar Boost 3048 features a manually operated equalization function since an operator should always
plan and monitor the process. The operator should ensure that equipment connected to the battery can tolerate the
high equalization voltage which will be applied to the battery, and that the battery attains the proper voltage for the
desired time period. Battery voltage setpoint during equalization will be the bulk voltage plus 2.0 or 4.0 volts for 24 or 48
volt systems respectively. Note that with temperature compensation, the equalization voltage can be quite high at cool
temperatures.
As shown in Figure 1, the equalization push-button is located on top of the enclosure. Equalization is enabled
when the push-button is out, and the Charge Status LED blinks rapidly. Equalization is normally conducted
approximately once per month, with the battery held at the equalization voltage for a period of approximately two hours.
It is best to equalize a battery that is already fully charged so that the desired equalization voltage is reached quickly.
Following the desired equalization period, the equalization cycle is terminated and normal charge operation is resumed
by again pressing the equalization push-button. The battery should then be topped off with distilled water per the battery
manufacturers recommendations.
Disabling Equalization
For certain battery types or electrical systems, it may be desirable to eliminate the possibility of initiating the
equalization cycle. This can be accomplished by gently pulling the red equalization push-button cap off of the equalize
switch and ensuring that the remaining switch plunger is in the normal position. Use needle nose pliers and gently rock
the cap side to side while pulling to avoid damaging the switch mechanism.
