Q&A

Solar panel 10W-80W has one bypass diode; solar panel 100W-320W has two bypass diodes.

Exception: 1100100 (100W) has only one diode and 1160105 (XL 100W) has two diodes.

The bypass diodes’ function is to eliminate the hot-spot phenomena which can damage PV cells and even cause fire if the light hitting the surface of the PV cells in a module is not uniform.

When solar panels are exposed to shady conditions, their efficiency drops, and their performance suffers as a result. Environmental obstructions such as trees or nearby buildings, clouds, self-shading between panels in parallel rows, dirt, dust, and various other trash such as bird droppings, all cause shading. These shading effects may be static as a result of the obstruction’s location, or dynamic in certain situations, such as a shadow cast by moving clouds. Therefore, eliminating solar shading problems is the most effective way to avoid them.

Measure the open circuit voltage and short circuit current of your solar panel with multimeter and compare the result with the technical data of the panel. Please also note that the calculated values from technical data are ideal values and depend on various factors such as temperature, angle, compass direction, irradiance, air mass, humidity, solar radiation (impairment e.g., by high fog), resistances in cables, connectors, and charge controllers, etc.

Solar panels with the same (or slightly deviated value +/- 1V) voltage (V) but different power (W) can be connected in parallel without any problem.

Solar panels of different voltage and power must not be connected in parallel, because the solar panel with the lowest voltage determines the voltage output of the whole array. When connecting solar panels together in parallel it is important that they ALL have the same nominal voltage value, but it is not necessary that they have the same ampere value.

Solar panels with the same (or slightly deviated value +/- 1A) current (A) but different power (W) can be connected in series without any problem.

Solar panels of different current and power should not be connected in series, because the solar panel with the lowest current determines the current output of the whole array.

In fact, we do not recommend a parallel/series connection of the different solar modules, as a loss of power cannot be avoided in any case.

PWM controller: The total open-circuit voltage of solar panels connected in series must not exceed the maximum open-circuit voltage allowed by the controller, and the total short-circuit current in parallel connection must not exceed the rated charging current of the controller.

* The PV modules voltage must match the battery system voltage.(12V/24V/36V48V) , otherwise the utilization of PV modules will be reduced.

MPPT controller: the total power of solar panels must not exceed the maximum power allowed by the controller (1.5 times of the rated power). The total open-circuit voltage in the series connection must not exceed the maximum open-circuit voltage allowed by the controller (the maximum open-circuit voltage at 25 °C).

Bulk charging

In this stage, the battery voltage has not reached constant voltage (Equalize or Boost Voltage) yet. The controller operates in constant current mode, delivering its maximum current to the batteries (MPPT Charging). When the battery voltage reaches a preset value, it will switch to Constant Charging.

Constant charging

When the battery voltage reaches the constant voltage setpoint, the controller will start to operate in constant charging mode, and this process is no longer MPPT charging. In the meantime, the charging current will drop gradually, and the process is not the MPPT charging. The Constant Charging has 2 stages, equalize, and boost. These two stages are not carried out constantly in a full charge process to avoid too much gas precipitation or overheating of the battery. Among them, equalize charging starts only on the 28th of each month.

a) Boost charging
The Boost stage maintains 2 hours in default (user can adjust the constant time and preset value of boost voltage according to demand). When the duration reaches the set value, the system will switch to floating charging.

b) Equalize charging
Some types of batteries benefit from equalizing charges regularly, which can stir electrolytes, balance battery voltage, and accomplish chemical reactions. Equalizing charge increases battery voltage, higher than the standard complement voltage, which gasifies the battery electrolyte.

The equalizing charging time is also 2h by default (settable). Equalize charge and boost charge are not carried out constantly in a full charge process to avoid too much gas precipitation or overheating of the battery.

Floating charging

After the Constant voltage stage, the controller will reduce the charging current to the Float Voltage setpoint. This stage will have no more chemical reactions, and all the charge current transforms into heat and gas at this time. Then the controller reduces the voltage to the floating stage, charging with a smaller voltage and current. It will reduce the temperature of the battery and prevent the gassing and charging the battery slightly at the same time.

The MPPT Tracer AN, Xra N and Triron N solar charge controllers can be configured to charge lithium battery storage devices. but the parameters of lithium battery must be set by app, PC software and MT50 display. It is important that these storage devices have their own battery management system (BMS), which does not require communication with the solar charge controller.

The controllers of EPEVER are divided into the common positive and common negative. If the common positive BMS and negative ground controller are used together, it would cause damage to the controller or lithium battery. Therefore, when configuring a lithium battery solar off-grid system, please select the corresponding controller according to the BMS specifications (a lithium battery with a common anode selects a controller with a common anode.)

When selecting the “User” type to set the parameters of the lithium battery, the following precautions must be followed:

1) The control voltage parameters must be set by referring to the specifications of the lithium battery protection board, and the accuracy requirement of the lithium battery protection board is not greater than 0.2V. If the deviation is greater than 0.2V, which causes an abnormality in the system, EPEVER shall not directly or indirectly be liable for any loss or danger.

2) The temperature compensation coefficient is changed to 0;

3) The equalized voltage and the boosted voltage are the same, and the time is the same;

4) Each voltage point must follow the following logic.

a. Overvoltage Disconnect Voltage > Over-Charging Protection Voltage(from BMS) +0.2V;

b. Overvoltage Disconnect Voltage > Overvoltage Reconnect Voltage ≥ Charging Limit Voltage ≥ Equalize Charging Voltage = Boost Charging Voltage ≥ Float Charging Voltage ＞ Boost Reconnect Charging Voltage;

c. Low-voltage Reconnect Voltage ＞ Low-voltage Disconnect Voltage ≥ Discharge Limit Voltage;

d. Under-voltage Warning Reconnect Voltage ＞ Under-voltage Warning Voltage ≥ Discharge Limit Voltage;

e. Low-voltage Disconnect Voltage ＞ Over-discharge Protection Voltage(from BMS) +0.2V;

Warning: Please choose a lithium battery controller for lithium battery applications. It is not recommended to use a non-lithium battery controller to charge the lithium battery. If the system fails due to the use of a mismatched controller, EPEVER shall not directly or indirectly be liable for any loss or danger.

Installation location and heat dispatch (can be wall mounted or laydown): The controller shall be installed in a place with sufficient air flow through the radiators of the controller and a minimum clearance of 150 mm from the upper and lower edges of the controller to ensure natural thermal convection. Please see below Figure:

Step 2: Installation Procedure
Connect the system in the order of ❶ battery ❷ load ❸ PV array in accordance with below Connection diagram and disconnect the system in the reverse order❸ ❷ ❶.

* CAUTION1: To avoid load short circuit fire, a fuse current, which is 1.25 to 2 times to the rated current of the controller must be installed on the battery side with a distance from the battery not greater than 150 mm.

* CAUTION2: The output voltage of the Controller load terminals is the same as the battery side. And max output current is the same as the rated discharge current. Make sure surge current of the load doesn’t exceed controller rated discharge current. Or it may cause damage to the controller.

* CAUTION3: If a sensitive or capacitive load (such as the inverter) is connected to the system, and connect the load directly to the battery, not to the load side of the controller. Or it may cause input pulse current protection or damage to the controller.

* WARNING: Risk of electric shock! When wiring the solar modules, the PV array can produce a high open-circuit voltage, so turn off the breaker before wiring and be careful when wiring. Additional fuse and breakers (1.25-1.5 times of total PV Isc current) are suggested to install.

* CAUTION: While wiring, the controller does not close the circuit breaker or fuse and make sure that the leads of “+” and “-” poles are connected correctly.

Step 3: Grounding
Connect grounding according to the electric controller design, or don’t grounding connect. But the grounding terminals must be connected to ground to block EMI and avoid electric shock from the case.

* CAUTION: Choose the correct common positive or common negative controller for your common positive or common negative system. Or it may damage the charge controller.

Step 4：Powered on the controller
Switch on battery fuse. Then check the status of the battery indicator (See detail on User manual). Close the fuse and circuit breaker of the load and PV array. Then the system will be operating in the preprogrammed mode.

Only the MPPT Tracer 50A-100A charge controllers support up to 6 units in prallel by using a parallel adapter (PAL-ADP-50AN). After adding the parallel adapter, the charging current of each controller can be adjusted automatically in real-time. The charging operation status of the controller is automatically adjusted according to the battery charging state to improve the redundancy of the entire photovoltaic system.

No, on the controller you can only choose the battery typ as Gel, Sealed or Flooded and you cannot set the battery parameters. The parameters can be set with controller accessories like eBox-Wifi, eBox-Bluetooth, USB-RS485 Cable through Smartphone, PC-Software or MT50 Display.

Remote Battery Voltage Sensor (RBVS) can eliminate the impact of the voltage drop on the battery connection wire. And it collects more accurate battery voltage to achieve accurate voltage control of the battery.

1). Find a cable (less than 1mm²)

* Attention：There is no current while Remote Battery Voltage Sensor（RBVS）connect to battery，so wire size 1mm² is enough for data collecting.

2). Plug one side of the cable into the RBVS Terminal (shown as Remote Voltage Sensor in the picture)

3). Plug the other side of the cable to the Battery

* IMPORTANT: Please check the print logo carefully, and connect RBVS”+” to the battery terminal ”+” and RVB ”-“ to battery “-“. Don’ t make it reverse, or it will damage the RBVS interface.

1）Always “Read” the parameters before any modification on each page.

2）Check if the parameters are set according to the rules before “Send.”

3）Please “Read” the parameters again after sending successfully and check whether the parameters are as same as the changed values.

4）Restart the device and the App, then check if set the parameters successfully.

1) Please check the input value is in the normal range.

2) Please, check if the input value is under voltage level range and followed the voltage setting rule

3) Please, check if you entered the wrong symbol as period (in US English)

2 years.

1) Please download the software V1.95-Windows.zip. (https://www.epsolarpv.com/downsoft.html)

2) Connect PC software and controller, the controller powers up and runs.

3) Open PC software “Solar Station Monitor” and establish communication.

4) Click “Parameters” → “Control parameter” → “Control parameter (For LiBattery controller product)”.

5) Click “Read”. Receive the prompt of ” Successful operation “. CAUTION: Always click on ‘Read’ first, before setting any parameters.

6) Please modify the parameters according to the lithium battery specification. You have to modify the Libattery type, rated voltage level, and all the voltage from Over volt. Disconnect Volt to Under Volt. War. Reco. Volt.

* CAUTION1: ‘LiBattery Protection’ must be ‘Enable’; otherwise, the lithium battery protection features cannot be activated.

7) After confirming the above parameters, click “Update.”

8) Click ‘Update’ again to double-check if the parameters are successfully updated.

9) Return to the monitoring interface and go to “Parameters” → “Device Parameters” → “Device Parameter Settings.”

10) Click ‘Read’ in the “Li battery parameter.”

11) Please set the “Low-temperature Charging Limit ” and “Low-temperature Discharging Limit ” according to the lithium battery specification.

12) Click “Update” after confirming the above parameters

Only the IP-Plus series and UPower-HI series inverter support lithium battery.

Yes. To avoid danger, the inverter must be grounded due to the high output voltage. If the inverter encounters electric leakage, it is dangerous for people to touch. By grounding, the electric leakage is directed to the earth instead of the human body.

Required information: AC Load Type; Rated Power; Power Factor; Starting Inrush Current Coefficient.

Follow the below formula to calculate the maximum load power.

Maximum load power = (Rated power / Power factor) * Starting inrush current coefficient

Follow the below formula to calculate the continuous load power

Load continuous power = Rated power / Power factor

Follow the rules to select inverter:

a) The continuous inverter power higher or equal to the continuous load power.

b) The inverter allowed overload power is higher and equal to the maximum load power.

Example:

An air conditioner with 735W and power factor of 0.9, which is an inductive load, also it’s starting inrush current coefficient is 5. So the maximum power is (735W/0.9)*5=4105VA, the continuous power is 735W/0.9=817VA. This means the inverter rated power should be higher than 817W and allowed overload power should higher than 4105W to handle this air conditioner.

No, the UPower Hybrid Inverter must not be used with lithium battery, and even though in “USER” modus, the parameter of lithium battery cannot be set. Only the UPower Hi Series Inverter support lithium battery.

2 years.

If the utility is connected to the inverter (as the only input), a ground connection must be made. Nevertheless, we recommend to ground the inverter even if only the solar panels charge the battery. First of all, you must ground your off-grid system, then connect this ground to the ground terminal of the inverter. Details can be found in the manual.