Specifications

6
The Three Stage Charging processes in detail:
The main advantage to solid-state controllers is that they offer more advanced charging modes than single stage
controllers. We will briefly discuss the three stage-charging modes used by the Coleman Air C60-PWM
• Bulk Charge
• Absorption Charge
• Float Charge
The 1
st
stage in a 3 stage-charging mode is the bulk charge: In this mode, most if not all of the available charge
current is sent to the batteries until they reach the bulk charge voltage set point, which will generally equate to
about 80% of the capacity of the battery. The bulk charge rate should be set to between 13.5 and 14.5 volts for a
normal flooded lead acid battery. There is really is no perfect voltage setting here as there are many factors
involved. The ambient temperature, the size of the energy sources verses battery size, the desired length of time
in this mode, the cost of the energy etc. The factory setting for the Bulk Charge set point is 14 volts.
The 2
nd
stage of the 3 stage-charging mode is the Absorption Charge: As the batteries gets full; due to internal
resistance, they accept less charge current. During the Absorption charge, the charger will hold voltage at the
bulk charge for specific amount of time. During this stage, the current flowing into the batteries will begin to
decline, but the voltage will be higher. Via this stage, the battery will be brought up to its maximum capacity
(fully charged). During this stage, battery gassing is normal and required in order to complete the chemical
reactions to obtain a fully charged battery. On the Coleman Air solid-state controllers, the Absorption Charge is
held for one hour once the batteries reach the bulk voltage setting.
The 3
rd
and final stage is the Float Charge: This mode is the charge mode that the battery is under most of the
time for a properly designed system. Once the batteries are brought to a full state of charge, the float charge
mode maintains the batteries at a voltage level of about 13 to 13.5 volts (for a flooded, 12 volt lead acid
battery), by applying pulses of current as required. These pulses may last less than a second or be several
seconds long. By applying the required amount of charge current to offset any load the battery might be
powering, as well as overcoming the batteries natural self-discharge, the batteries longevity is greatly increased.
Allowing a battery to sit in a depleted state of charge for long periods of time significantly reduces battery life.
A good quality battery, kept at its proper float setting, will last many years. The factory setting for the float
charge of the Coleman Air solid-state controllers is 13.5 volts. When the battery drops down below the float
charge for an extended period of time, a new bulk charge cycle will automatically be started.
The Equalize Charge: This mode is not a part of the normal charge cycle, but is instead initiated to help mix the
electrolytes of the battery. During normal use a battery’ s chemical mix becomes stratified. (Separated from top
to bottom). An equalize charge uses an approximately seven percent higher voltage to help mix these elements
in your battery. Equalize charging also helps bring all of the batteries in a multi-battery bank to an equal state.
Most people agree that an equalize charge should be run once every 10 to 40 days, for 2 to 16 hours. During this
charge cycle quite a lot of gassing will occur, which causes the fluids to be mixed and the plates to be
"Cleaned".
To start the equalize mode, press and hold the equalize button at any time. The equalize function will run for
two hours once the voltage of the battery rises to the equalize trip point.
Hold down the Equalize button during power up (trip and reset the battery breaker), to enable the automatic
thirty-day equalize function. Note, the 30 day function may not be exact and is likely to wander somewhat as it
will not begin unless the charge source is capable of bringing the battery to the equalize voltage. A cloudy day
may not allow enough solar energy to bring the batteries to the equalize voltage; therefore, the equalize charge
will be delayed.