User Manual
PCM-924, 9A / 80Voc Input MPPT Controller for Thin-Film PVs
IP67 Weather Resistant
Ver. 1.0
Physical Dimension
Max. input DC. power
250(24V) / 125(12V)
Max. input solar panel DC. voltage*
Max. input solar panel DC. current
Rated battery voltage
12 / 24 (Automatic)
Max. charge/loading current
Degree of protection
*The voltage of solar panel array can not be higher than the max. input
voltage of controller.
*The solar panel components voltage of system could not be lower than
voltage of battery, and not be higher than max. input power.
*The output of Load voltage depends on the output of battery voltage.
-As reference of solar panel components, to calculate open-circuit voltage
(highest values) under the lowest temperature circumstance of
installation. The values could not over the max. input voltage – 80Vdc.
-When sunlight irradiation solar panel components, will be produced
voltage and current in the input line.
-The capacity of the battery pack is unlimited, it will only affect the
charging rate.
-Follow the following guide to use the product, otherwise they may
damage equipment
1. Important Safety Instruction
1.1 common information
2. General Information
2.1 Summary
3. Installation
3.1 Note
3.2 Installation
3.3 Wiring Connection
4. Manual
4.1 Status Indicator (LED)
4.2 Max. Power Point Tracking
4.3 Battery Charging Information
4.4 Loading Control Information
4.5 Protection
4.6 Inspection & Maintenance
5. Trouble Shooting
5.1 Error Instruction
5.2 Q & A
6. Specific Technical Reference
Appendix A – Cable Dimension
1. Important Safety Instruction
Save These Instructions
This manual contains important safety, installation and operating instructions for
the MPPT solar controller.
The following symbols are used throughout this manual to indicate potentially
dangerous conditions or mark important safety instructions.
WARNING: Indicates a potentially dangerous condition. Use extreme
caution when performing this task.
CAUTION: Indicates a critical procedure for safe and proper operation
of the controller.
NOTE: Indicates a procedure or function that is important for the safe
and proper operation of the controller.
General Safety Information
Read all of the instructions and cautions in the manual before beginning
There are no user serviceable parts inside the MPPT. Do not disassemble
or attempt to repair the controller.
Disconnect all sources of power to the controller before installing or adjusting
the MPPT.
There are no fuses or disconnects inside the MPPT.
Prohibition of water into the controller.
Confirm that power connections are tightened to avoid excessive heating from
a loose connection.
2. General Information
Thanks for selecting the MPPT charge controller. This MPPT controller is an
advanced maximum power point tracking solar battery charger and loading
device for stand-alone PV systems. The controller features a smart tracking
algorithm that maximizes the energy from the solar module and also provides
load control to prevent over-discharge of the battery.
The process of MPPT battery charger has been optimized for long battery
life and improved system performance.
Although the MPPT is very simple to operate and use, please take the time to
read this operator’s manual and become familiar with the controller. It will help
you make full use of many advantages which MPPT can provide for your PV
Features of the MPPT controller is shown as below.
1 - Status LED Indicator
Four LED Indicator show charging status and
battery input and low voltage fault condition.
2 - Solar Input Connector
The connecting terminal of systems solar panel
components input.
3 - Battery Input & Loading Output Connector
Systems battery components input and loading out terminals
3. Installation Instructions
Installation Note
Read through the entire installation section first before beginning installation.
Be very careful when working with batteries. Wear eye protection. Have fresh
water available to wash and clean any contact with battery acid.
Use insulated tools and avoid placing metal objects near the batteries.
Explosive battery gasses may be present during charging. Be certain there is
sufficient ventilation to release the gasses.
Do not install in locations where water can enter the controller.
Loose power connections and/or corroded wires may result in resistive
connections that melt wire insulation, burn surrounding materials, or even
cause fire. Ensure tight connections and use cable clamps to secure cables
and prevent them from swaying in mobile applications.
Only charge lead-acid batteries.
The controllers battery connection may be wired to one battery or a bank of
batteries. The following instructions refer to a singular battery, but it is
implied that the battery connection can be made to either one battery or a
group of batteries in a battery bank.
Note: When mounting the MPPT controller, ensure free air flow
through the controller heat sink fins. There should be at
least 150mm of clearance above and below the controller to
allow for cooling. If mounted in an enclosure, ventilation is
highly recommended.
Warning: Risk of explosion! Never install the controller in a
sealed enclosure with vented (flooded) batteries! Do not
install in a confined area where battery gasses can
Step 1: Choose Mounting Location
Locate the controller on a vertical surface protected from direct sun, high
temperatures, and water.
Step 2: Check for Clearance
Place the controller in the location where it will be mounted. Verify that there is
sufficient room to run wires and that there is ample room above and below the
controller for air flow.
Figure 2: Mounting and cooling.
Step 3: Fasten the Flat
Fasten flats on the three back holes of
Step 4: Drill Holes
Drill dimension 9mm holes (spacing 220mm )in the mounting location.
Step 5: Secure Controller
Then put the the back-end bracket mounting holes of the
controller on the solar panel bracket, aligning the hole drilled in step 4,
using screws and nuts fixed controller, and indeed the case ground
wire connected.
Note: A recommended connection order has been provided for
maximum safety during installation. The controller will not be
damaged regardless of the sequence of connections.
Note: The MPPT controller is a negative grounding controller.
Caution: the total current draw of all system loads connected to the
controller's load terminals cannot exceed the 7A load current rating.
Caution: For mobile applications, be sure to secure all wiring. Use cable
clamps to prevent cables from swaying when the vehicle is in motion.
Unsecured cables create loose and resistive connections which may lead
to excessive heating and/or fire.
Step 1: Load Wiring
The controller's load output connection will provide battery voltage to
system loads such as lights, pumps, motors, and electronic devices. The
voltage of the loads should be depended on the voltage of the battery.
Figure 3 Load wiring
As shown in figure 3, connect load positive (+) and negative (-) load wires to the
system load(s) or load distribution panel.
An in-line fuse holder should be wired in series in the load positive (+) wire as
If wiring the load connection to a load distribution panel, each load circuit should
be fused separately. The total load draw should not exceed the 7A load rating.
Step 2: Battery Wiring
Figure 4. Battery wiring
Before connecting the battery, measure the battery voltage. It must be over 11
volts to switch on the controller. For 24 volt systems, the battery voltage must be
greater than 22 volts. The battery detection is automatic and the check is only
performed at start-up.
Wire an in-line fuse holder no more than 150mm from the battery positive
Step3: Solar Panel Array Connecting
Caution: Danger!! Electrical Shock!! High voltage will occur from the
solar panel, please covering the solar panel before wiring.
This MPPT controller is suitable for 12V and 24V off-grid solar systems, also suitable
for the connecting array which the Voc lower than 80V. The working voltage
should be located between the battery voltage and maximum out-put voltage of
solar systems.
Fig. 5 Solar penal array connecting method.
Step 4: Recheck all connecting points, and confirm all poles at right connecting
positions, check all connecting terminals are fixed.
Fig 6. Reconfirm all connecting points.
Step 5: Fuse inserting
Insert a 15A DC fuse as follow steps:
1. Loads circuit.
2. Battery circuit.
Step 6:Electrify Confirmation
Please confirm the following electrify steps, when the battery electrify the power
to controller, the LED lights on unit will flash in order, and detect the voltage of battery,
automatically. The charge LED light will flash in charging.
Please check chapter 5 Trouble Shooting, if the unit did not work or the LED
lighting shows the wrong identifications.
4. Operation
Status LED Indicator
Status indicator
The status LED indicator charging status and any existing solar input error
conditions. The status LED will off whenever an error conditions exists. The status
LED 12V/24V shows the battery voltage types, the status LED will be flashing in
charging status in the day time and the light will be on solid in the night time. The
“LVD” will be on solid in status “load off”, if the voltage of the battery is too low.
Table 1 gives lists of the status LED indications.
On Solid
On Solid/Flashing
On Solid/Flashing
On solid
Battery Voltage Error
Low Voltage Protection
Voltage Status Error
12V Battery
24V Battery
Charging status only
Table 1 Status LED definition
Maximum Power Point Tracking Technology
This controller utilizes maximum power point tracking technology (MPPT)
to extract maximum power, Vmp, from the solar panel array. The tracking
algorithm is fully automatic and does not require user adjustment. The MPPT
technology will track the solar panel array maximum power point voltage, Vmp,
as it varies with weather conditions, ensuring that maximum power is harvested
from the solar panel array through the course of the day.
In most cases, the MPPT technology will “boost” the solar charge current. For
example, a solar system may have 5A of solar current flowing into the unit and 7A
to charge current flowing out to the battery.
This controller does not create current! Rest assured that the power into the unit
is the same as the power out from the unit. Since power is the product of
voltage and current (Volts x Amps=Power), the following is true.
(1)Power into the unit = Power out of unit
(2)Volts In x Amps In = Volts Out x Amps Out
*Assuming 100% efficiency. Losses in wiring and conversion exist.
If the solar panel array’s Vmp is greater than the battery voltage, it follows that the
battery current must be proportionally great than the solar input current so that
input and output power are balanced. The great the difference between the
maximum power voltage and battery voltage, the greater the current boost.
Another benefit to the MPPT technology is the ability to charge lower volt battery
with solar panel array of higher normal voltages. For example, a 12V battery bank
can be charged with 15-18-Vdc normal solar penal array. Certain grid-tie solar
penal array may also be used as long as the solar penal array open circuit voltage,
Voc, rating will not exceed the controller's 80Vdc maximum input rating at coldest
panel temperature. The solar panel documentation should provide Voc vs.
temperature data to users.
Higher solar input voltage results in lower solar input current for a given input
power. High voltage solar input strings allow fro smaller gauge solar wiring. This is
especially helpful for systems with long wiring runs between the solar panel array
and the controller.
Traditional controllers connect the solar panel directly to the battery when
recharging. This requires that the solar panel operate in a voltage range that is
below the panel’s Vmp. For example, in a 12V system, the battery voltage may
range from 11-15Vdc but the panel’s Vmp is around 17Vdc. Fig 7 shows a typical
current vs. voltage output curve for a normal solar panel.
Fig. 7 Normal solar panel I-V curve
The panel Vmp is the max. power point, and before and after this point, the output
power is reduced. (shown in Fig 7.)
Because traditional controllers do not operate at the Vmp of the solar panel, energy is
wasted that could otherwise be used to charge the battery voltage and the Vmp of the
panel, the more energy is wasted. The MPPT technology will always operate at the Vmp
resulting in less wasted energy compared to traditional controllers, and transfer all the
power from solar penal to loads or battery.
Information of Battery Charging
The MPPT unit has a 3 stages battery charging algorithm for rapid, efficient, and
safe battery charging.
In this stage, the battery voltage has not yet reached absorption
voltage and 100% of available solar power is used to recharge the
When the battery has recharged to the absorption voltage set point,
constant-voltage regulation is used to prevent heating and excessive battery
After the battery is fully charged the unit reduces the battery voltage to
a float charge which is sometimes call trickle charge.
Information of Load Control
The primary purpose of the load control function is to disconnect system
loads when the battery has discharged to a low state of charge and reconnect
system loads when the battery is sufficiently recharged.
CAUTION: Do not wire a AC inverter of any size to the load terminals
of the controller. Wire inverters directly to the battery or battery
Solar Overload
The unit will limit battery current to the 7A and 80Vdc maximum ratings. A
over-sized solar panel array will not operate at peak power. The solar panel array
(Volts x Amps) should be less than the unit's normal maximum input power
rating for the optimal performance.
Load Overload(Status LED light ”LVD” On Solid)
If the load current accessed the maximum load current rating, the unit will
disconnect the load. The unit will attempt to reconnect the disconnect load
Night Time Solar Short Circuit
Solar input power wires of the controller has short-circuited to prevent the battery
voltage re-flow back to the solar panel due to the solar panel voltage lower than
battery voltage in the night time.
High Voltage Transients
In lightning prone areas, additional external suppression is recommended.
Inspection and Maintenance
Recommend at least two times per year for best controller performance.
Tight all connectors. Inspect for loose, broken, or corroded connotations.
Verify that all wire clamps and tie-downs are secure.
Check and ensure the controller is mounted in a clean, ventilated environment,
and no covering of the solar panel array.
Verify LED indication is consistent with the present system conditions.
5. Troubleshooting
Error Indications
Status LED Error Indications
Battery Empty or System damage
Battery un-recognize, not 12V or 24V
ERR On Solid
Battery voltage error
ERR On Solid
Over power input
12V/24V On Solid
Load over current
LVD On Solid
Battery low voltage (no error occur)
LVD On Solid
Common Problems
Problems: No LED indications
Solutions: With a multi-meter, check the voltage at the battery
terminals, the battery voltage must be at least
11V/22V to power the unit.
Problems: The unit is not charging the battery.
Solutions: If the status LED “ERR” is solid, see section 5.1 Error Indication. If the
status LED is off measure the voltage across the solar input terminals of
the controller. Input voltage must be greater than battery voltage.
Check the fuses and solar wiring connections. Check the solar panel
array for shading.
6. Detail Specifications
General Parameter
Rated Input DC Power
250(24V) / 125(12V)
Input Voltage Range
Maximum Input Current
Maximum PV Voc
Maximum PV Isc
Battery (DC) voltage
12 / 24 (Automatic)
Max Charge/Load Current
No.of Charge stage
Self-consumption (in active status)
Weight [kg]
Dimensions [mm]
L (with connectors)
Protection class
Operating temperature
IP67 Outdoor Use
Humidity (non-condensing)
Natural Convection
MPPT Tracking
Maximum Efficiency
Automatic load disconnect
V (maximum load 7A)
Over load current protection
Over charge protection
Default settings
Absorption charge
14.4/28.8 V
Float charge
13.65/27.3 V
Low voltage load disconnect
11/22 V
Low voltage load reconnect
12.3/24.6 V
Appendix A – Wire Charts