MPPT and PWM charge controllers, What is The Difference?

MPPT And PWM Charge Controllers
PWM and MPPT charge controllers

Both MPPT And PWM Charge Controllers are commonly used to charge batteries using solar energy. In essence, the PWM controller is a switch that connects a solar array to a battery. As a result, the array’s voltage will be brought down to near that of the battery.

What is a solar charge controller?

A solar charge controller is a voltage and current regulator that is powered by the sun. They regulate power input from PV arrays to offer optimal power output to drive electrical loads and charge batteries in off-grid and hybrid off-grid applications. Solar charge regulators are another name for solar charge converters.

Solar charge controllers keep batteries charged to their maximum capacity without overcharging them, preventing gassing and battery damage. Watch our on-demand webinar and read the extra information on this page to learn more.

How does a solar charge controller work?

What are the different types of solar charge controllers?

The two major types of solar charge controllers are:

  1. Pulse Width Modulation (PWM) controllers
  2. Maximum Power Point Tracking (MPPT) controllers

What applications use solar charge controllers

Systems below requiring limited power that have no grid connectivity because they are remote or in developing regions often deploy solar charge controllers with batteries to supply power:

  • Lighting
  • Mobile homes, RV-Caravans, and boats
  • Oil & gas sites
  • Residential
  • Rural electrification
  • Security/surveillance
  • Telecommunications

what is the meaning of mppt and pwm  ?

The solar charge controller sits between the energy source and storage, they prevent overcharging of the bank batteries by limiting the amount and rate of charge to your batteries. They also prevent battery drainage by shutting down the system if stored power falls below 50 percent capacity and charge the batteries at the correct voltage level. This helps preserve the life and health of the batteries.[1]

#1 MMPT solar charge Controllers

A maximum power point tracker, or MPPT, is an electronic DC to DC converter that optimizes the match between the solar array (PV panels) and the battery bank or utility grid. Simply put, they convert the higher voltage DC output from solar panels (as well as a few wind generators) to the lower voltage required to charge batteries.

The main work of the mppt in a solar system 

The MPPT solar charge controller is a charge regulator used to regulate the input voltage from solar cells and has several advantages over the PWM charging system, as it invests the electrical energy out of the solar energy at full capacity in charging the battery bank without the presence of wasted energy.

In the beginning, to understand the topic more, it is necessary to mention the difference between charging using the PWM method and charging using the method of MPPT:

  1. BWM solar charge controllers take only the voltage required to charge the battery from the solar module and leave the excess voltage without investment.
  2. PWM charge controllers are cheap compared to MPPT charge controllers.
  3. PWM are widely used in solar systems of less than 2 kilowatts due to the price difference between them and MPPT charging regulators.
  4. PWM uses Pulse Width Modulation technology, thus helping to increase battery life by breaking down sulfate deposits on lead sheets.

Why MPPT solar charge controllers are best choice ?

To understand why we recommend MPPT charge controllers, it is necessary to give you a practical example:

Example 1️⃣:

If we connect a 30-volt solar panel to a PWM-type charge regulator to a battery of a 12-volt type, in this case the charger takes approximately 15 volts from the module and charges the battery with it, and leaves the remaining 15 volts from the solar panel without investment.

Whereas, MPPT charge controllers take the necessary voltage to charge the battery and convert the excess voltage into current (via a voltage converter) in order to speed up the battery charge process and more efficiently (reduces the panel voltage at the expense of increasing the charging ampere).

Example 2️⃣:

let’s Suppose we have a 30 volt /200-watt solar panel and we want to charge a 12-volt battery with it, since the panel is 30 volts and the power is 200 watts then the output current is 6.6 amps (200/30 = 6.6) because the current equals the power divided by the voltage.
In this case, if we connect the solar panel to the PWM charge controller, it will charge the battery with a voltage of approximately 15 volts and leave the remaining voltage which is also 15 volts.

The charging current in this case will be only 6.6 amps. Thus, the power used to charge the battery is equal to 6.6 * 15 = 99 watts only, while if we connect the same previous solar module to the same previous battery, but this time using an MPPT charger that charges the battery with a voltage of 15 volts and then transforms the remaining voltage of 15 volts into a current, the charging current becomes (200/15) 13.3 Ampere.

Example 3:

If I had a 150-watt solar panel and I have a 100-amp battery, and I used a PWM charge controller (the module is known to be 18 volts) and the voltage needed to charge the battery to the upper limit is 14.6 volts, of course, the PWM charge controller reduces the charging voltage from 18 volts to 14.6 or 14.4 volts and the ampere, of course, is the ampere of the module as it is 8.33 amps, That means I will have 3.4 volts of unused excess voltage.
(18-14.6 = 3.4v)
But if you use MPPT, this excess voltage will appear as amperes in charging the battery.
The charging amp will be in the case of the MPPT regulator:
150W / 14.6V = 10.27A

Compared with the PWM which gives only 8.33 amperes and thus the performance difference between the two types of solar regulators will be:

10.27 / 8.33 = 1.23

This means a 23% performance difference between the regulators
On the one hand, the panels are connected in series (series) in the MPPT regulator thus providing the cable size, unlike the PWM.

Related posts: what are the 3 types of charge controllers?

How to convert V to  I?

There is a general rule in the science of electronics and electricity that says it is impossible to raise the voltage except at the expense of the current and vice versa, so the current cannot be raised except at the expense of the voltage, and this is what MPPT type charging regulators do, as they raise the current at the expense of the voltage, but in both cases, the power ( Capacity) remains the same.
Voltage and current are two parts that do not separate, so by changing one of them, the other changes (considering the power is constant).
It is on this base that the voltage is converted to current in MPPT charging regulators

pwm or mppt charge controllers ?

MPPT trucks are often used when:
1) There is a large voltage difference between the solar panel voltage and the battery voltage, thus there is large energy waste.
2) The system size is large (greater than 2000 or 3000 watts), so raising the current a little help dispense with purchasing additional solar panels.
3) MPPT is preferred in cold regions because in cold climates the voltage of the panels is increased, and this increase is exploited by the MPPT and turns it into an ampere that charges the batteries.

2 PWM solar charge controllers

PWM charge controllers are often used in the following situations:

  1. The voltage of the solar panel is close to the battery voltage, so there is no big waste of energy.
  2. The system size is small (less than 2000 watts).

PWM ControllersMPPT Controllers
Array voltage is “pulled down” to battery voltageConvert excess input voltage into amperage
Generally operate below VmpOperate at Vmp
Suitable for small module configurationsSuitable for large module configurations that have a lower cost per watt
Often chosen for very hot climates which will not yield as much MPPT boostProvide more boost than PWM especially during cold days and/or when the battery voltage is low
difference between Mppt and PWM charge controllers

MPPT And PWM Charge Controllers FAQs

What is the efficiency of a solar charge controller?

The efficiency of a controller is defined as the ratio of controller output power to PV array input power. Lower efficiency means the controller loses more power in the form of heat.

How do I choose a solar controller?

In brief, the solar charge controller you select must be able to accommodate your loads’ power demands, battery voltage, and PV current and voltage inputs. You should also examine whether a controller with low voltage disconnect, lighting control, or other features or certifications is required. Your environment, module selection, and budget will all influence whether you go with a PWM or MPPT controller. A good solar distributor can assist you in sizing and configuring your modules, batteries, and controllers for the best system possible.

Can solar charge controllers monitor data?

Yes, some controllers can track battery voltages, system current, absorption, and float charge measures, as well as errors and alarms.

What temperature ranges do solar charge controllers support?

Many solar charge controllers can operate in temperatures ranging from -40 to +60 degrees Celsius.

Are MPPT controllers worth it?

MPPT controllers supply more power, particularly in cooler temperatures. They can also be utilized with lower-cost 60-cell modules that aren’t typically suited for PWM controllers. If you compare these advantages against the cheaper cost of a PWM controller, you’ll know if an MPPT controller is ideal for your system.

Can two solar charge controllers charge the same battery?

Yes. Parallel Charging Using Multiple Controllers With Separate PV Arrays has further information 

on this.

What solar charge controller accessories should I consider?

Meters, adapters, remote temperature sensors, relay drivers, and other balance-of-system components are all things to think about.

How can I purchase a solar charge controller?

On our Daily store, which includes links to a product catalog, you can define what type of charge controller and system you’re interested in adopting.

How long do solar charge controllers last?

The brand of charge controller and the system environment has an impact on its longevity. Some Professional Series controllers come with a 5-year warranty, and several have been in use for more than ten years.

What is lighting control?

The ability to create controller settings to turn lights on and off during the day and nighttime. Simple controls on certain controllers allow you to switch lights on at dusk and off at dawn. Other controllers feature more advanced programming capabilities, allowing for multi-event on/off light switching over the course of a 24-hour period.

What is diversion control?

A controller will divert excess current from the battery to a specialized loan that is large enough to absorb the excess energy but not large enough to produce a controller overload condition as the batteries get completely charged.

What is a charge controller’s rating?

The current it can accept from a PV array to charge batteries, as well as the battery voltages it can sustain, are used to rate charge controllers (e.g. 60 amps for 12, 24, and 48-volt batteries).

What is the load current rating?

The controller’s rated current that it will supply to loads.

Are all charge controllers suitable for marine use?

Some, but not all, controllers are designed to survive the extreme conditions found aboard boats and at marinas.

What are the finest controls for RVs, caravans, mobile homes, campers, and boats?

See the Solar for RVs, Caravans, and Boating page for further information.

What battery system voltages do solar charge controllers support 12V, 24V, and 48V systems

It is important to check the operation manual or datasheet to see what battery voltages your controller supports. Some controllers support voltages from 12, 24, 48 volts, and higher, while others might only support 12 volts. 

What is the definition of self-consumption?

The charge controller consumes a tiny quantity of electricity for its own operations rather than distributing to loads and batteries.

What is the purpose of a solar charge controller?

To prevent the battery from being overcharged or undercharged, and to prevent the battery from reverse-discharging to the array at night or when there is no power from the sun, electricity from the PV array is regulated.

What other names have you heard for a solar charge controller?

Solar charge controllers are also known as solar panel controllers, solar panel charge controllers, solar power charge controllers, solar charge controllers, solar controllers, solar charge regulators, solar regulators, and charge regulators.

What is a shunt charge controller, and how does it work?

A charge controller that short circuits the array in order to minimize the amount of current transmitted to the battery. Shunt technology is older and less common than PWM and MPPT controller technology.

What is the maximum PV Open Circuit Voltage (Voc) limit of a controller?

The maximum voltage that a controller can support, as mentioned in the user manual. To see if your system will work under this Voc restriction, figure out the lowest temperature your system will be exposed to and the voltage your array will produce at that temperature. Your controller will be damaged if you exceed the VOC restrictions.

[1] : Reongy

Scroll to Top
%d bloggers like this: