Allto Solar 20Amp 12V 24V MPPT Solar Charge Controller User Manual

ALLTO SOLAR

20A MPPT Solar Charge Controller

User Manual

SOLAR CHARGE CONTROLLER

AS-MPPT-20A

Please read all of the installation instructions carefully before installing the product. Improper installation will void manufacturer’s warranty. The installation instructions are written as guidelines to assist in installing the charge controller. Please contact us with the email if you are not comfortable installing the product. Prior to using and installing the MPPT charge controller, please read the safety information provided in this user manual. Be sure to use the product as outlined in this user manual. Altercation or modifications carried out without appropriate authorization may invalidate the user’s right to operate the equipment.

1.0 Safety Precautions

1.1 Installation and wiring compliance

Installation and wiring must comply with the local and National Electrical Codes and must be done by a certified electrician. Please follow these four steps:

1. Disconnect all power sources before carrying out the installation.
2. Make sure the correct polarity is observed when making connections between the solar panel, charge controller, and battery.
3. Make sure all wire connections are secured; loose connections may cause sparks.
4. Wear appropriate clothing and safety gear including protective eyewear when performing any electrical installation.

1.2 Preventing fire and explosion hazards

Working with electronic/electrical equipment may produce arcs or sparks. Thus, such equipment should not be used in areas where there are flammable materials or gases requiring ignition protected equipment. These areas may include spaces containing gasoline-powered machinery, fuel tanks, and battery compartments.

1.3 Precautions when working with batteries

1. Batteries contain very corrosive diluted sulfuric acid as electrolyte. Precautions should be taken to prevent contact with skin, eyes, or clothing.
2. Batteries generate hydrogen and oxygen during charging, resulting in the evolution of an explosive gas mixture.
3. Care should be taken to ventilate the battery area and follow the battery manufacturer’s recommendations. Never smoke or allow a spark or flame near the batteries.
4. Use caution to reduce the risk of dropping a metal tool on the battery. It could spark or short circuit the battery or other electrical parts and could cause an explosion.
5. Remove metal items such as rings, bracelets, and watches when working with batteries. The batteries can produce a short circuit current high enough to weld a ring or similar object to the metal, causing a severe burn.
6. If you need to remove a battery, always remove the ground terminal from the battery first. Make sure that all the accessories are off so that you do not cause a spark.
7. Only use properly insulated tools when making battery connections.
8. Be careful when working with large lead acid batteries. Wear eye protection and have fresh water available in case there is contact with the battery acid.
9. Explosive battery gases may be present while charging. Be certain there is enough ventilation to release the gases. 10. The batteries must be same of type, make and age if you connect several batteries in parallel or series.
11. Do not attempt to recharge non-rechargeable battery, converse with your battery dealer for more info before usage.

1.4 Precautions when working with solar panels

1. Do not make contact with the terminals when the panel is exposed to sunlight or any other light source.
2. A PV array with a higher short circuit voltage above 100V may damage the controller.
3. To avoid a shock hazard, make sure the solar panel is covered with an opaque (dark) material such as paper or cloth during the installation.

1.5 Precautions when working with charge controllers

1.Never choose 24V mode when battery is 12V, otherwise, it will cause over charge and irreparable damage to battery. 2. The solar panel voltage must exceed battery voltage +5V to start charging.

1.6 Routine maintenance

1. Inspect the solar panels and make sure the surfaces are free from dust, dirt, and other debris; clean with a wet cloth or glass cleaner if necessary.
2. Check to make sure all structural components, mechanical fasteners, and electrical connections are secure, clean.
3. Check and maintain the battery electrolyte levels at regular intervals as per the battery manufacturer’s recommendations if flooded wet cell lead acid batteries are used.
4. Check and replace damaged components if necessary.

2.0 General Information

2.1 MPPT Technology

The MPPT Charge Controller utilizes Maximum Power Point Tracking technology to extract maximum power from the solar module(s). The tracking algorithm is fully automatic and does not require user adjustment. MPPT technology will track the solar panel’s maximum power point voltage (Vmp) as it varies with weather conditions, ensuring that the maximum power is harvested from the solar panel throughout the course of the day.

2.2 Current Boost

In many cases, the MPPT charge controller will “boost” up the current in the solar system. The current does not come out of thin air. Instead, the power generated in the solar panels is the same power that is transmitted into the battery bank. Power is the product of Voltage (V) x Amperage (A)

Current vs. Voltage (12V System)

Typical Battery Voltage Range
Maximum Power Point

Output Power(12V System)

Traditional Controller Operating Range
Maximum Power Point

Although MPPT controllers are not 100% efficient, they are very close at about 90-95% efficient. Therefore, when the user has a solar system whose Vmp is greater than the battery bank voltage, then that potential difference is proportional to the current boost. The voltage generated at the solar panel needs to be stepped down to a rate that could charge the battery in a stable fashion by which the amperage is boosted accordingly to the drop. This is the essence of the MPPT charge controllers and their advantage over traditional PWM charge controllers. In traditional PWM charge controllers, that stepped down voltage amount is wasted because the controller algorithm can only dissipate it as heat. The above two charts demonstrate a graphical point regarding the output of MPPT technology.

2.3 Limiting Effectiveness

Temperature is a huge enemy of solar modules. As the environmental temperature increases, the operating voltage (Vmp) is reduced and limits the power generation of the solar module. Despite the effectiveness of MPPT technology, the charging algorithm will possibly not have much to work with and therefore there is an inevitable decrease in performance. In this scenario, it would be preferred to have solar panels with higher nominal voltage(refer to Section 4.1.2 for more details about multiple solar panels parallel and series configuration) , so that despite the drop in performance of the panel, the battery is still receiving a current boost because of the proportional drop in module voltage.

2.4 Components

Additional Components-Included.

Remote Temperature Sensor
This sensor measures the temperature at the battery and uses this data for very accurate temperature compensation. The sensor is supplied with 16.5ft cable length that connects to the charge controller.Simply connect the cable and adhere the sensor on top or the side of the battery to record ambient temperature around the battery.

Mounting Screws
Those mounting screws are applied to mount this charge controller.

Optional Components-Not Included

Remote LCD Display
The display tracks several parameters regarding the state of solar panel and battery, and display them on the LCD screen. Several parameters of solar panel and battery were tracked, which can be evaluate the performance of solar panel and battery in past 60 days.

3.0 Overview

1. LCD Screen
2. Mode
3. Type
4. Charging Stage Indicators
5. PV Polarity Reverse Indicator
6. PV Over Voltage Indicator
7. Over Temp Indicator
8. Battery Polarity Reverse Indicator
9. Battery Over Voltage Indicator
10. Temp Sensor Port
11. RS232 Port
12. Solar Panel Ports
13. Battery Ports
14. CAN Port
15. USB Port

4.0 Installation

In this section, we will show the basic 12V connections for off-grid systems that use 20A MPPT charge controller, 100W solar panel and 12V battery and cable adapters. Please follow them thoroughly. Refer to Section 5.0 for multiple PV arrays configuration and Section 6.0 for 24V batteries configuration.

4.1 Configuration Introduce

A solar charge controller is an important component in off-grid solar power systems that are connected to battery systems. It serves as a regulator for the flow of electricity, limiting how fast electric current is added to batteries like the deep-cycle batteries used in many outback power systems. Such batteries are more prone to degradation because of overcharging and over- voltage issues, which can reduce their lifespan and performance.

1. AWG depends on the size of the Inverter (usually ≥4 AWG)
2. 12V Power Inverter

Fuse
Fuse (High Amperage)
   Ring Terminal
  MC4 Connectors

Fusing

Fusing is recommended in PV systems to provide a safety measure for connections going from panel to controller and controller to battery. Remember to always use the recommended wire gauge size based on the PV system and the controller.

Note: The NEC code requires the overcurrent protection shall not exceed 15A for 14AWG, 20A for 12 AWG, and 30A for 10AWG copper wire.

Fuse from Controller to Battery

Controller to Battery Fuse = Current Rating of Charge Controller
Ex. 20A MPPT CC = 20A fuse from Controller to Battery

Fuse from Solar Panel s to Controller

Ex. 200W; 2 X 100 W panels
Utilize 1.56 Sizing Factor (SF)
NOTE** Different safety factors could be used. The purpose is to oversize.

Series:
Total Amperage = lsc1 = lsc2 SF
= 5.75A 1.56 = 8.97
Fuse = 9A fuse  

|

Parallel
Total Amperage = (lsc1 + lsc2) SF
=(5.75A + 5.75A) 1.56 = 17.94
Fuse = 18A fuse

4.1.1 Before starting the connection, keep in mind the following:

• The charge controller should be as close as , possible to the batteries. This helps keep line loss to a minimum level. Remember to always use the recommended gauge size based on the PV system and charge controller.
• The battery supply must be protected by a fuse as per below table. This is also the case even If the solar charger has already been been equipped with an external fuse.

4.1.2 When connecting a solar panel to the charge controller, please ensure that the same type of solar panel or solar panel array is used. Please note the following:

• The nominal PV voltage should be at least 5V higher than the battery voltage.
• The maximum open circuit PV voltage can not exceed 100V. Failure to obey this rule may result in the controller damage or catching fire.
• The boost charge current will be regulated to below 20A if it is over the max capacity of the controller.

The PV array can consist of multiple solar panels. The solar panels are connected in series, in parallel or in series/parallel. See below figure for examples of these configurations| | | |
---|---|---|---|---
12V 100W| 2×100 in Parallel 12V 200W| 3×100 in Parallel 12V 300W| 2×100 in Series 24V 200W| 3×100 in Series 36V 300W

4.2 Charge Controller Installation

STEP 1 – Choose Mounting Location
Place the controller on a vertical surface protected from direct sunlight, high temperatures, and water. Make sure there is good ventilation.

1. warm air
2. cool air

STEP 2 – Mounting
Measure the distance between each mounting hole on the charge controller. Align the Rovers mounting holes with screws

1. warm air
2. cool air

STEP 3 – Battery Configuration
Connect battery terminal wires to the charge controller and tighten the screw terminals.

STEP 4 – Mode Choosing
The LCD screen will illuminate and display battery voltage once battery is recognized. Push mode button to cycle battery types.

STEP 5 – Solar Panel Configuration
Connect solar panel wires to the charge controller. The screen will display PV voltage and current, and charging indicator illuminiates upon charging is activated.

STEP 6 – Optional Components
The controller comes equipped multiple ports for temp sensor, remote LCD monitor, battery shunt and USB device.

4.3 Operation

There are several methods that can be used to change these settings. Some of these allow all settings to be configured.

4.3.1 Mode Setting
The charge controller has 6 modes: 12V, 12V AGM, 12V Lithium;24V, 24V AGM, 24V Lithium, It is important to understand the differences and purpose of each charge mode. Always check with battery manufacturer to confirm the right charge mode for your specific battery. Below is a brief description:

Maintenance-Free and Calcium batteries. When selected, the 12V LED will illuminate
12V AGM| For charging 12-volt AGM batteries. When selected, the 12V AGM LED will illuminate.
12V Lithium| For charging 12-volt lithium-ion batteries, including lithium iron phosphate. When selected, the 12V Lithium LED will illuminate.
24V| For charging 24-volt Wet Cell, Gel Cell, Enhanced Flooded, Maintenance-Free and Calcium batteries. When selected, the 24V LED will illuminate.
24V AGM| For charging 24-volt AGM batteries. When selected, the 24V AGM LED will illuminate.
24V Lithium| For charging 24-volt lithium-ion batteries, including lithium iron phosphate. When selected, the 24V Lithium LED will illuminate.

**Cautions***

1. Use 12V /24V Lithium mode with extreme care, this mode should only be used with 12v or 24V lithium batteries that have a built-in battery management system(BMS). Lithium-ion batteries are made and constructed in different ways and some may or may not contain a battery management system(BMS). Consult the lithium battery manufacturer before charging. Some lithium-ion battery may be unstable and unsuitable for charging.
2. Never use none of 24V mode to charge 12v battery, otherwise, it will cause irreparable damage to battery.

4.3.2 Three Stages of Charging
The 20A MPPT charge controller has a 3-stage battery charging algorithm for a rapid, efficient, and safe battery charging. They include: Bulk Charge, Absorption, Float Charge These LEDs respectively indicate the charge stages, but are also used to indicate other charge situations. See below charts to help you understand the situations.

LED Indicators

 | Bulk Indicator| Absorption Indicator| Float Indicator| Indications
---|---|---|---|---
LED Status| Blink Green | Off | Off | Indicating charge controller is currently under bulk charging stage.
Off | Blink Green | Off | Indicating charge controller is currently under absorption charging stage.
Off | Off | Blink Green | Indicating charge controller is currently under float charging stage.
Solid Green| Solid Green| Solid Green| Indicating battery is fully charged.

Three Stages Charging

1. Charge Voltage
2. Charge Current
3. Max Current
4. Bulk
5. Absorption
6. Float

Bulk Stage: This algorithm is used for day to day charging. It uses 100% of available solar power to recharge the battery and is equivalent to constant current, the initial bulk charging stage delivers the maximum allowable current into the solar battery to bring it up to a state of charge of approximately 80 to 90%. In this stage the battery voltage has not yet reached constant voltage , the controller operates in constant current mode, delivering its maximum current to the batteries (MPPT Charging) .

Absorption Stage: When Bulk Charging is complete and the battery is about 80% to 90% charged, absorption charging is applied. During Absorption Charging, constant-voltage regulation is applied but the current is reduced as the solar batteries approach a full state of charge. This prevents heating and excessive battery gassing. At the end of Absorption Charging, the battery is typically at a 98% state of charge or greater. When the battery reaches the constant voltage set point, the controller will start to operate in absorption charging mode, where it is no longer MPPT charging. The current will drop gradually.

Float Stage: Float charging, sometimes referred to as “trickle” charging occurs after Absorption Charging when the battery has about 98% state of charge. Then, the charging current is reduced further so the battery voltage drops down to the Float voltage. The Float charge of a battery keeps the battery at maximum capacity throughout the day.. Once the battery is fully charged, there will be no more chemical reactions and all the charge current would turn into heat or gas.

Because of this, the charge controller will reduce the voltage charge to smaller quantity, while lightly charging the battery. The purpose for this is to offset the power consumption while maintaining a full battery storage capacity. In the event that a load drawn from the battery exceeds the charge current, the controller will no longer be able to maintain the battery to a Float set point and the controller will end the float charge stage and refer back to bulk charging.

4.3.3 Temperature sensing
Temperature sensing allows for temperature compensated charging. The absorption and float charge voltages are adjusted based on either the battery temperature (temp sensor is included) or otherwise on the solar charger internal temperature. Temperature compensated battery charging is needed when charging lead-acid batteries in hot or cold environments.

4.4 Main Menu and Error Indicators

This MPPT charge controller comes with user friendly interface, is very simple to operate. Simply connect the batteries, and the controller will automatically determine the battery voltage. The controller comes equipped with an LCD screen and mode button to push cycle battery types. And the visual error indicator helps to quickly identify potential problems quickly.

Main Menu

(1) 0A      (3) 0V
(2) 0V      (4) 0A

(1) Solar Panel Current
(2) Solar Panel Voltage
(3) Battery Current Voltage
(4) Boost Charge Current

Error Indicator

Icon

| State|

Description

---|---|---
| Solid Red, Buzzing | Polarity of solar panel is reversed.
| Solid Red, Buzzing | Solar panel voltage is too high.
| Solid Red. Buzzing | Battery temp is too high
| Blink Red, Buzzing | Charge controller temp is too high
| Solid Red, Buzzing | Polarity of battery is reversed.
| Solid Red. Buzzing | Battery voltage is too high

Note: there is no way to cycle battery type once charging is activated

5.0 Solar Panel Installation

5.1 Solar Panel Installation

Once the battery is connected to the charge controller and the panel(s) are positioned and mounted in the desired location, we are ready to connect the panel to the charge controller. Panel should be mounted in a place that is free from shading by neighboring obstacles such as vents, air-conditioners, TV antennas, etc.

5.2 Steps to install solar panel

Fig 5.2 1

Step-1: Mate the “Male” MC4 Connector from the solar panel with the “Female” MC4 Connector of your adapter kit as shown in Fig 5.2.1. Then connect the bare stranded portion of the cable to the positive (+) solar input terminal on the charge controller.
Step-2: Mate the “Female” MC4 connector from the panel with the “Male” MC4 connector of your adapter kit as show in Fig 5.2 1
Step-3: The positive (+) solar cable can be fused for protection; an in- line fuse can be added to this cable in the same way as described in the instructions for battery to controller connection.
Step-4: Once the fuse holder is in place, don’t attach a fuse just yet. Connect the bare stranded portion of the cable to the positive (+) solar terminal on the charge controller. Ensure that all connections are made properly, and that there are not any loose connections present. Finally, insert the fuse into the fuse holder and remove the protective cloth. If there is enough sunlight present, the controller will start charging the battery.
Step-5: If opting for no in+-line fuse, connect the bare stranded portion of the adapter cable to the positive (+) and negative(-) solar input terminals on the charge controller, red is positive and black is negative. If there is enough sunlight present, the controller’s solar LED indicator/icon on the LCD display should show that it is now charging your battery(s).

6.0 Battery Configurations

The battery system voltage is automatically detected at the very first power- up of the solar charger and the battery voltage is set accordingly. Further automatic detection is disabled. In case the solar charger does not measure a battery system voltage, it will default to 12V and store that. This will happen if the solar charger is powered via its PV terminals, while not connected to a battery. Note that the charge controller will not automatically detect battery type, this will need to be set manually. After automatic detection has taken place, the battery voltage can be changed and set to 12V, 24V.

The battery system can also be configured to create a “bank” of batteries. In this section, we cover the most basic configurations. When wiring batteries, extreme attention should be given. Never short a battery, as high currents can cause severe burns or even death. It is recommended that insulated/non- conducting tools be used when working with batteries. Never leave tools on top of the battery. Always wear eye protection. Never touch both of the battery terminals at the same time with your bare hands.| | | |
---|---|---|---|---
2x6V in Series 12V System| 2x12V in Parallel 12V System| 4x6V in Series 12V System| 2x12V or 4X6V in Series 24V system|

2X12V in Series, 2X12V in Parallel 24V System

7.0 Technical Specifications

 |

AS-MPPT-20A

|

AS-MPPT-30A

---|---|---

Rated Battery Current

| 20A| 30A
Battery system Voltage|

12V/24V

Max PV Open Short Circuit Voltage

| 100V
Starting Min PV Open Short Circuit Voltage|

15V

Max PV Input Power

| 12V@260w
24V@520W| 12V@400w
24V@800W
Electronics Protections|

Reversed battery polarity, Reverse PV polarity, PV over voltage, battery over- voltage, PV over-current, Battery over-current, Over temp

Charge Circuit voltage drop

| ≤0.26V
Discharge Circuit voltage drop|

≤0.15V

Self-consumption

| <40-60mA
USB Port|

5V/2.4A

Operation Temperature

| -40 °C-80°C
Max terminal size|

10mm2, 8AWG

Humidity Range

| ≤95% (NC)
Temp Compensation|

-3mV/°C/2V

Communication

| RS232, RS485
Dimension|

17213646.7*mm

Protection Level

| IP54
Weight|

0.58kg

Electrical Parameters

|

Battery Parameters

---|---

Battery types

| Wet,Gel Cell/Flooded/ Maintenance-free| AGM|

Lithium

Boost Charge Voltage

| 14.4V/28.8V| 14.6V/29.2V| 14.6V/29.2V
Float Charge Voltage| 13.8V/27.6V| 13.8V/27.6V|

/

Boost Charge Recovery

| 12.8V/25.6V| 12.8V/25.6V| 12.8V/25.6v
Float Duration| 2 Hours| 2 Hours|

2 Hours

7.1 Dimension

8.0 Package List

1 x 20A MPPT charge controller
1 x5m temperature sensor cable
4 x Mounting screws
1 x User Manual

9.0 FQA

1.What is the minimum voltage to light up the controller alone?

The minimum open short circuit of solar panel is 15V, or the minimum battery voltage is 3V to light up the controller.

2.What is temperature compensation?

The ability of the battery to store and accept charge varies with temperature. For optimum battery performance the charge controller needs to adjust its output voltage control to correspond to the needs of the battery as the temperature changes.

3.What is the remote control?

The remote control is a dedicated to read out the live and historic solar panel and battery data and it can be used to configure solar panel and battery settings. Also, it tracks and stores the data of solar panel and battery in past 60days.

4.Why My Solar Panel is Under-producing?

As you may know, the solar panel is affected by lots of factors. Such as the intensity of the sun and the angle of the solar panel on the ground, cloudy sky, temperature rise, and the dirt and stain built up on the surface of solar panels.

5.What is the effect of solar panel’s temperature?

Heat is the nemesis of a MPPT controller. As the solar panels get hot, the MPPT voltage droops, and you no longer get great gains in charge current – indeed on some panels and very hot temperature. However, even in these situations, great gains are made in off-hours where the temperature is reduced and the sun is not directly on the panels.

6.How long can my wires be?

Keep in mind that long wires loose power especially at higher currents. Use at least #12 for BOTH input and output. Solid THHN wire is easier to work with. Panel wires can be longer than 50 feet just keep in mind the power loss in the wire when sizing a system. #10 AWG wire can be used to reduce this loss on longer runs.

7.Battery voltage difference between MPPT charge controller display and multimeter?

According to the Ohm’s law V=IR, the voltage difference depends on 1=charge current and cable R=resistance between battery and charge controller. For Best Performance keep the battery and connection cable as short as possible – less than 5 Feet on the battery side, or consider to use #10 or #8 cable.

8.Can two charge controllers charge the same battery?

Yes, you can use multiple charge controller and solar panels to charge the same battery.

8.Will a solar panel supply electricity 24 hours a day?

No, solar panels convert light into electricity. So as the light reduces in the day so does the output of the solar panel.

9.What is the best orientation of a solar panel?

The sun rises in the East and sets in the West, but never goes North. Therefore if the Solar PV is facing South the more direct sunlight it will receive, which will produce more energy. To get the maximum benefit from the Solar Panel it needs to face between the South East and the South West otherwise its energy generation will be reduced.

10.Is maintenance required on solar panels?

Clean using a non-abrasive cleaner. In the long term check the sealing especially in marine use and reseal with a silicon sealant if damage is suspected. Check battery connections periodically when you check battery levels. Fuse holders and connections should be kept dry and clean.

10.0 Warranty

Thank you for purchasing the mppt charge controller, should you experience any defect due to the manufacturer of this product, you are entitled to get a replacement or refund. If you have any questions, feel free to sent us email support-us@alltosolar.com, we will get back to you within 24h.

ALLTO SOLAR
Customer Support Team

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