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mppt solar charge controller

9 Best Solar Charge Controllers: Top Picks, Reviews & Buying Guide

Are you looking for a solar charge controller for your main or backup solar power system? 

You’ve come to the right place.

A solar charge controller is an essential part of a solar charging system. It stands between the solar panels and the battery bank where it regulates the amount of voltage and current reaching the batteries.

A solar charge controller protects your batteries by preventing an electrical overload or excessive discharging. It also optimizes the performance of your solar system.

A solar charge controller also helps you monitor the state of your system. You can check how much power the solar panel is generating or how quickly the batteries are charging or discharging.


What’s in This Buying Guide 

In this in-depth buying guide, we review the best solar charge controllers available in the market, including standard PWM controllers and the more advanced MPPT controllers.

It will help you choose the best one for your needs and budget.

As you compare different solar charge controllers, make sure you know the requirements for your solar panels and battery bank.

Pick a controller that is compatible with your system.

If you have any doubts about what specs to look for (voltage, amps, etc.), contact your solar panel installer or the manufacturer for advice.

If you are also looking for a solar generator backup system, read our guide to the best solar backup generators for the home


Best Solar Charge Controller Reviews (MPPT & PWM Controllers)

EPEVER 40A 100V
  • EPEVER 40A MPPT

  • Best overall
  • PWM/MPPT:
    MPPT

  • Compatible Batteries:
    12V/24V lead acid and lithium batteries

  • Max Current:
    40A

  • Max Voltage:
    100V

EPEVER 100A 200V
  • EPEVER 100A MPPT

  • Best for large solar systems
  • PWM/MPPT:
    MPPT

  • Compatible Batteries:
    12V-48V lead acid and lithium batteries

  • Max Current:
    100A

  • Max Voltage:
    200V

ALLPOWERS 20A
  • ALLPOWERS 20A PWM

  • Best for small solar systems
  • PWM/MPPT:
    PWM

  • Compatible Batteries:
    12V/24V lead acid and lithium batteries

  • Max Current:
    20A

  • Max Voltage:
    50V

EPEVER Dual Battery
  • EPEVER Dual Battery

  • Best for RVs and boats
  • PWM/MPPT:
    PWM

  • Compatible Batteries:
    12V/24V lead acid and lithium batteries

  • Max Current:
    10A

  • Max Voltage:
    55V

solar controller
  • POWOXI

  • Best battery maintainer
  • PWM/MPPT:
    PWM

  • Compatible Batteries:
    12V lead acid

  • Max Current:
    8A

  • Max Voltage:
    22V

solar charge controller
  • PowMr

  • Best 2-in-1 inverter & solar charge controller
  • PWM/MPPT:
    MPPT

  • Compatible Batteries:
    48V lead acid & lithium

  • Max Current:
    80A

  • Max Voltage:
    500V

Outback Flexmax MPPT 80 AMP
  • Outback Flexmax 80

  • Best performance
  • PWM/MPPT:
    MPPT

  • Compatible Batteries:
    12V-60V lead acid and lithium batteries

  • Max Current:
    80A

  • Max Voltage:
    150V

mppt charge controller
  • Renogy Voyager 10A

  • Best for outdoor use
  • PWM/MPPT:
    PWM

  • Compatible Batteries:

  • Max Current:
    10A

  • Max Voltage:
    15V-55V

SmartSolar MPPT 100V 30A
  • SmartSolar 30A MPPT

  • Best Bluetooth-connectivity
  • PWM/MPPT:
    MPPT

  • Compatible Batteries:
    12V/24V lead acid and lithium batteries

  • Max Current:
    30A

  • Max Voltage:
    100V


EPEVER 40A 100V

The EPEVER 40A MPPT solar charger is the best choice for most homes as well as some RVs and boats.

It’s compatible with small and medium-size solar systems and can support four types of batteries, including lithium-ion.

For an MPPT solar charger, the price is not too bad. It’s one of the more affordable medium size MPPT solar chargers you can get.

Best Features 

1. Ideal for Small and Medium Size Arrays

With a max input limit of 100V, the EPEVER 40A charge controller is ideal for use with small and medium size arrays.

You can wire up to four 12V solar panels in series (12V solar panels usually exceed that voltage, hence the limit of 4).

If you have eight 100W 12V panels, you can set them up as two parallel sets to avoid going over the voltage limit.

2. MPPT Technology with 99.5% Efficiency

MPPT technology greatly increases the performance of your solar system. With an efficiency of over 99%, the EPEVER charge controller ensures your batteries get the most out of the solar panels.

This charges the batteries faster and maintains good performance on cloudy days.

3. Supports Lithium and Lead Acid Batteries 

The EPEVER solar charge controller is compatible with both lead-acid and lithium-ion batteries.

Compatible lead acid batteries are sealed, gel, and flooded.

These three plus lithium ion cover most of the deep cycle batteries used in homes.

4. Load Output with Multiple Control Modes

The load output allows you to control a load, usually lighting, manually or automatically.

The EPEVER solar charge controller has four control options: a simple light on/off switch, manual control, a timer mode, and a test mode.

5. Temperature Compensation 

High temperatures can reduce the efficiency of a solar system and even cause damage from excess voltage.

The EPEVER is designed to compensate for temperature changes to protect your battery system and maximize charging performance.

But to take advantage of this feature, you’ll need to buy a temperature sensor separately.

Limitations 

The display can be difficult to read in some lighting conditions.

It’s small and doesn’t have backlighting.

Other than that, this charge controller works great.

Technical Specifications 

  • For 12v and 24v battery systems
  • Compatible batteries: lithium-ion, gel, flooded and sealed
  • Current rating: 40A
  • Max PV input voltage: 100V

2. Best for a Large solar system: EPEVER 100A 200V MPPT Solar Charge Controller 

EPEVER 100A 200V MPPT

The EPEVER 100A solar charge controller from the Tracer 10420AN series is perfect for large solar systems at home or an institution.

It can handle plenty of current from the solar panels (up to 100A) and charge high-voltage batteries as well (up to 48V).

Best Features 

1. High Tracking and Conversion Efficiency 

This solar charge controller utilizes the Multiphase Synchronous Rectification Technology (MSRT) algorithm powered by a dual-core processor to improve efficiency, increase response speed, and ensure reliability.

The charge controller can easily keep up with demanding residential and industrial systems.

It quickly responds to changes in temperature and cloud cover, adapting the system load to maximize the amps going into your battery.

Similar to most MPPT charge controllers, the EPEVER controller can achieve a very high conversion efficiency of up to 98.6% whether there is a full sun out or it’s cloudy.

This ensures your system is at peak performance all the time.

2. Ideal for Large Systems 

With a maximum current limit of 100A and input voltage limit of 200V, the EPEVER solar charge controller can handle a large high-output solar system without a problem.

It’s great for completely off-grid homes that need to generate a lot of solar power, especially during winter.

3. Four Battery Options

The solar charge controller is compatible with batteries ranging between 12V and 48V, another reason why it’s the best for large systems with large batteries.

It can charge four types of batteries: Gel, Flooded, Sealed, and User-defined (you can set your battery parameters. Ideal if you have a lithium-ion battery).

4. Easy to Use LCD display

You can track basic information on the small LCD display, including battery level, voltage, and temperature.

Two LED indicators show the system working status and alert you to a fault alarm.

Using two buttons under the display, you can browse and set some parameters, configure load relay, select your type of battery, change temperature unit and clear faults.

5. MT50 Remote Meter and PC Monitoring Cable

The solar charge controller comes with an MT50 remote meter that provides advanced control and monitoring of various parameters.

The meter displays much more data and gives you more control than the basic LCD display on the charge controller.

Another way to monitor your system is to hook up the charge controller to your laptop using the RS485PC Monitoring Cable.

Note: The system is compatible only with Windows OS devices.

Limitations 

The only downside of the 100A EPEVER solar charge controller is the price tag.

But it’s understandable considering its current and voltage limits. At least, it comes with all the accessories you need, including the MT50 remote meter, temperature sensor, and PC cable.

Technical Specifications 

  • For 12V, 24V, 36V and 48V battery systems
  • Compatible batteries: gel, flooded, sealed and user-defined
  • Current rating: 100A
  • Max PV input voltage: 200V

3. Best for a Small Solar System: ALLPOWERS PWM 20A Solar Charge Controller

allpowers 10000mah solar charger review

If you have a small solar system, whether it’s in your home or RV, there is no need to invest in an expensive MPPT solar charge controller.

A PWM controller like this one from ALLPOWERS works just as well. As a bonus, it’s cheap too.

The charge controller protects your battery from over-charging and short-circuiting while keeping it topped off for best performance.

Note that the ALLPOWERS solar charge controller is only compatible with lead-acid batteries, including flooded, AGM, and gel.

Best Features 

1. An Affordable Solar Charge Controller for Small Systems 

If you are looking for a low-cost solar charge controller for your small solar system, we highly recommend the ALLPOWERS PWM controller.

With a max input voltage of just 50V and current input limit of 20A, it’s far from some of the powerful MPPT systems available online.

But it’s perfect for use with small solar panels.

Just make sure the total voltage doesn’t go beyond 50V, and the current at maximum power is less than 20A.

For instance, you can wire two 100W 12V panels in series (max total peak power will be around 36V) or three in parallel (total amps will be around 17A).

2. 4-stage PWM Technology 

PWM (pulse with modulation) technology is less sophisticated than MPPT. But it’s good enough for small to mid-size systems that don’t require very high conversion efficiency.

The ALLPOWERS controller uses a 3-stage process to protect your battery and keep it topped off.

In the bulk stage, the controller delivers maximum voltage and current to the battery for a quick recharge. It kicks in when your batteries are low.

When the battery gets close to full, the controller goes into ABS or absorption stage. It will reduce the current to the battery to top it off slowly without overheating or overcharging it.

In float stage, the controller delivers a trickle current to the battery to keep it charged.

3. Battery Protection 

The ALLPOWERS solar charge controller extends the life of your battery by delivering just the right amount of voltage and current.

There is no risk of overcharging or overheating, which can degrade your battery.

The controller also prevents short-circuiting and provides reverse current protection at night or when the solar panels are shaded.

4. Easy to Use Display 

The display shows essential data and indicates the status of the system. At a glance, you can check your battery voltage, how much power is coming in, and the controller stage.

You can also configure various parameters and switch between modes.

5. USB Ports

The dual 5V/3A USB ports on the controller come in handy if you are using it in your RV or boat. They are also great for campers.

You can directly charge small devices while still charging your battery.

Limitations 

The obvious limitation here is power.

You can only use the ALLPOWERS charge controller with small systems. And even then, it cannot charge a depleted battery (below 8V).

It’s also not compatible with lithium-ion batteries.

Technical Specifications 

  • For 12V and 24V batteries.
  • Compatible batteries: gel, flooded and sealed lead acid batteries
  • Current rating: 20A
  • Max PV input voltage: 50V

4. Best for RVs, Boats, and Vehicles: EPEVER Dual Battery Solar Charge Controller

EPEVER Dual Battery Solar Charge Controller

If you have two batteries in your RV, boat, or truck, it can be difficult to keep both of them fully charged using solar power.

Most people resort to using two separate solar panels wired to each battery.

But that adds more costs to your setup.

The EPEVER dual battery solar charge controller allows you to charge both batteries using the same connection from your solar panel or panels.

The dual solar charge controller comes with a remote meter that lets you monitor the state of each battery and the amount of power they are receiving.

Best Features

1. Dual Battery Solar Charging

The charge controller regulates the voltage and current going to each battery. Instead of setting up a separate solar panel for each battery, you can charge both from a single panel.

Note that the two batteries can be of different capacities but must be the same type and voltage.

For instance, you can connect it to a 20Ah 12V sealed battery and a 200Ah 12V sealed the battery.

But you cannot connect it to a 12V sealed battery and a 24V sealed battery or a 12V flooded battery and a 12V sealed battery.

This is a PWM controller, so it lacks the high efficiency and advanced technology of an MPPT controller. But it still provides the same solid protection to your batteries from overcharging, overheating and short-circuiting.

It also prevents reverse charging, which can drain your batteries.

2. Remote Meter 

The charge controller comes with a remote meter plus a 32ft communication cable.

The meter displays lots of status information about the solar panels and your batteries. You can also configure various parameters.

3. Remote Temperature Sensor

In addition to the meter, you also get a remote temperature sensor designed specifically for the dual controller.

The sensor feeds temperature data to the controller, which then compensates for temperature changes to increase performance and protect the batteries.

4. Compatible with Three Battery Types

You can select from one of three types of batteries: sealed, flooded and gel.

The EPEVER dual solar charge controller is not compatible with lithium-ion batteries.

Limitations 

The EPEVER dual solar charge controller is designed for small solar systems such as those typically used in RVs, boats, and trucks.

If you are looking for a high-capacity PWM solar charge controller, this is not it.

Technical Specifications 

  • For 12V and 24V batteries.
  • Compatible batteries: gel, flooded and sealed lead acid batteries
  • Current rating: 10A
  • Max PV input voltage: 30V for a 12V system and 55V for a 24V system

solar controller

The POWOXI solar charge controller works together with a battery maintainer system to keep a battery charged when it’s not in use. 

Basically, it keeps batteries from going dead. You can use it with a car battery, a lawn mower battery, or any other equipment battery that usually goes for weeks or months without use. 

Best Features

1. Hands-free Trickle Charging 

Batteries require occasional recharging if they’ll not be used for some time. The POWOXI battery maintainer saves you the trouble of charging the battery every few months. 

All you need to do is set up a small 12V solar panel (at least 20W) and connect it to the POWOXI charge controller. Then connect the charge controller to your battery. 

The PWM controller will maintain the battery charge at maximum level, preventing discharging and premature degradation. 

The POWOXI charge controller can accept current of up to 8A, voltage of up to 22V, and power of up to 130W from solar panels.  

2. Auto On/Off

The POWOXI charge controller doesn't consume any power from the batteries. It doesn't discharge the battery at all even when there’s no solar power coming in.

Instead, it relies on incoming solar power to power itself. At night, it’ll automatically turn off and then turn on again in the morning when the sun comes up.

3. Compatible With 12V Lead Acid Batteries 

The POWOXI charge controller works with 12V lead acid batteries. 

It provides protection from overcharging, deep discharge, and short circuiting. It also offers reverse polarity protection. 

If you accidentally connect the plugs the wrong way, you’ll not damage the charge controller, battery, or any connected equipment. 

Limitations

The POWOXI charge controller works only with lead acid batteries. You cannot use it to trickle charge a lithium ion battery. 

Technical Specifications 

  • Type: PWM
  • For 12V systems
  • Compatible batteries: lead acid (gel, flooded, sealed, and others)
  • Current rating: 8A
  • Max PV input voltage: 22V
  • Max PV input power: 130W

6. Best 2-in-1 Inverter and Charge Controller: PowMr 5KW Inverter and 80A Charge Controller

mppt charge controller

The PowMr 2-in-1 inverter and charge controller is perfect for limited spaces such as boats, off grid cabins and RVs.   

Instead of installing separate components, the inverter and charge controller are integrated into a single compact unit. 

Best Features 

1. 2-in-1 Unit 

A typical off-grid solar setup involves mounting the charge controller and the inverter and wiring them to the battery. 

If you don't have space for both components or just want to avoid the hassle of connecting lots of cables, the PowMr 2-in-1 unit is a great alternative. 

It’s also a good bargain when you compare it to the cost of buying an inverter and charge controller separately. 

2. Suitable for Large Solar Systems

The PowMr inverter and solar charge controller is designed for use with medium to large off-grid solar systems. 

Let’s start with the MPPT charge controller. 

It has a max current rating of 80A, making it compatible with a large solar panel array. It can accept up to 5000W and 500V from solar panels. 

As for the inverter, it’s a pure sine wave inverter with a max output of 5000W at 110V. It can support multiple high-wattage loads such as appliances. 

The 2-in-1 kit should be more than enough for most off-grid applications such as cabins, boats, and RVs. You can also use it for a home solar backup system. 

3. Compatible With 48V Lead Acid & Lithium Batteries

The PowMr solar charge controller and inverter only works with 48V systems. 

It’s compatible with both lead acid and lithium battery banks. 

Limitations

The PowMr 2-in-1 kit is designed for use only with larger 48V solar systems. If you have a 12V or 24V system, don't get this one. 

Technical Specifications 

  • Type: MPPT
  • For 48V systems
  • Compatible batteries: lead acid & lithium
  • Current rating: 80A
  • Max PV input voltage: 500V
  • Max PV input power: 5000W
  • Inverter output: 110V AC, 5000W

Outback Flexmax MPPT 80 AMP

The Outback Flexmax is not quite as powerful as the EPEVER 100A controller we recommended for large systems, but it’s one of the highest performance solar charger controllers.

It has a maximum current rating of 80 amps, a maximum voltage of 150V and can charge batteries between 12V and 60V (the EPEVER controller goes up to 48V).

So if you have a high-voltage battery bank, this is the best solar charge controller.

Best Features 

1. Ideal for Large Systems

The Outback Flexmax is a great choice for homes using a large solar array to charge a large battery bank.

The controller can handle an input power of up to 5,000 watts (for 60V batteries) and current up to 80 amps.

2. MPPT Technology 

The Flexmax automatically tracks how much power the solar panel is generating and adjusts the voltage to deliver maximum power to the batteries.

This increases the efficiency of your array in all weather conditions.

The controller also monitors the status of the batteries to keep them from overcharging or short-circuiting.

It’s compatible with the most common types of lead-acid batteries and can also be hooked to lithium-ion batteries.

However, if you are charging a lithium-ion battery bank, you have to adjust various voltage parameters to maximize charging performance.

3. Intelligent Thermal Management

The Flexmax solar charge controller can operate in temperatures as high as 104F thanks to an intelligent thermal management system that keeps it cool.

For the best cooling performance, the manufacturer recommends buying an external temperature sensor.

4. Backlit Display

The display is quite small. So it displays only basic data.

It only displays current flow in and out of the batteries. You can also see performance data from the last 128 days and configure various settings.

If you want to monitor your battery voltage and other parameters, you’ll need a separate meter.

Limitations

Flexmax 80 is one of the most expensive solar charge controllers you can buy.

If you are looking for a budget MPPT solar charge controller, this is not it.

Technical Specifications 

  • For 12V, 24V, 36V, 48V and 60V batteries.
  • Compatible batteries: gel, flooded, sealed and lithium-ion batteries
  • Current rating: 80A
  • Max PV input voltage: 150V

solar charge controller

If you have to install the solar charge controller outdoors, we recommend the Renogy Voyager 10A solar charge controller because it is waterproof. 

Best Features

1. IP67 Waterproof Rating

The Renogy Voyager solar charge controller has the third highest level of water protection and the highest dust protection. 

It is completely impervious to dust and debris, and can withstand heavy rain. So it is safe to install outdoors. 

It is a good choice for RVs, cabins, sheds, gazebos, and boats where it makes most sense to install the solar charge controller on an outside facing wall or surface. 

2. 10A Charge Controller

The Renogy Voyager can handle up to 10A of solar input, making it suitable for smaller solar setups such as those used in RVs, boats, and cabins. 

Because the Renogy Voyager 10A solar charge controller works with both 12V and 24V systems, it can accept a wide range of voltage from 15V to 55V. 

As for power, the max for a 12V system is 130W and 260W for a 24V system. 

3. Compatible With 12V and 24V Systems

You can hook up the Renogy Voyager to a 12V or 24V solar system. You don't have to select a particular voltage; it will automatically detect battery voltage once you hook it up. 

The Renogy Voyager is compatible with both lithium and lead acid batteries. It provides the usual protections including overcharging, over discharge, and reverse polarity.  

Note that the Renogy Voyager is a PWM charge controller, so it will not charge batteries as efficiently as an MPPT type controller. 

However, for the small systems the charge controller is designed for use with, PWM works well enough and it’s affordable. 

4. Temperature Monitoring & Compensation

In addition to the usual battery protections, the Renogy Voyager also protects against high temperatures. It’ll detect high temperatures and adjust voltage input to the battery to prevent overheating. 

You’ll need to buy the Renogy battery temperature sensor and plug it into the temperature sensor port. 

Limitations 

The product description says that the Renogy Voyager has a backlit LCD display. But, as many customers have pointed out, that’s not actually the case. 

The display is not backlit, making it hard to read in low lighting. 

Technical Specifications 

  • Type: PWM
  • For 12V/24V systems
  • Compatible batteries: lead acid & lithium
  • Current rating: 10A
  • Max PV input voltage: 15-55V
  • Max PV input power: 130W(12V), 260W(24V)

9. Best Bluetooth-Connected Solar Charge Controller: SmartSolar MPPT 100V 30A Charge Controller

SmartSolar MPPT 100V 30A

If you’d like to check your battery or power flow status without having to look at the display on the charge controller or a connected meter, we recommend the SmartSolar Bluetooth-connected MPPT charge controller.

As long as you are within range, you can easily check important metrics on your smartphone.

The solar charger controller itself is rated at 30amps and 100V, making it ideal or small and medium-size systems.

Best Features 

1. Remote Smartphone Monitoring

Instead of trying to squint at a tiny display with small numbers, you can use your smartphone to monitor your battery and check the power flow.

You’ll need to connect to the charge controller via Bluetooth and then download the free VictronConnect app that is available for both iOS and Android devices.

The app displays the battery voltage, current, and state (bulk, absorption, or float).

You can also check how much charge your battery contains, how much charge you have consumed, and how much time is remaining before it is fully charged.

It’s much more information than you get on a standard charge controller display.

It’s also easier and more convenient than a meter (you can still connect a meter if you want).

The app stores information for the last 30 days in case you want to check past performance data.

2. MPPT Technology 

This is an MPPT solar charge controller.

It greatly increases the efficiency and performance of your solar system, allowing your batteries to charge faster and more efficiently in all weather conditions.

It also ensures your batteries do not overcharge or overheat.

3. Temperature Compensation

An internal temperature sensor measures ambient temperature. The controller then compensates for temperature changes throughout the day to maintain charging efficiency.

Limitations 

The controller has no display of any kind; just three indicators to show the current state.

The only way to check the status of the system is by using your smartphone. This is probably not an issue for many people but can be a limitation for those who’d love a backup option.

Another issue is that the charge controller does not come with an external battery temperature sensor, and there doesn’t seem to be one available separately on Amazon or the manufacturer website.

I’m not sure whether it is compatible with other temperature sensors.

Technical Specifications 

  • For 12V and 24V batteries
  • Compatible batteries: gel, flooded, AGM, lithium-ion and LiFePO4 batteries
  • Current rating: 30A
  • Max PV input voltage: 100V

What is a Solar Charge Controller and How Does it Work?

mppt solar charge controller

A charge controller is an electronic device that monitors and controls the amount of power – current and voltage –going to the battery from a solar panel.

It’s an essential part of most solar systems.

Without a solar charge controller, your batteries would get damaged and wouldn’t last long because of too much or too little power.

A charge controller does several important things to protect your batteries and improve performance:

Prevents overcharging: The charge controller monitors the voltage of the battery and reduces current or stops it completely when it gets to a certain point.

Prevents extremely low voltage: If your battery’s voltage gets too low, it will struggle to recharge again and can deteriorate if such voltage drops happen frequently. A charge controller can prevent this by automatically turning off the load when the battery drops to a certain voltage.

Prevents overheating: Some charge controllers come with a temperature sensor that you install near the battery. If the battery temperature rises, the controller lowers the voltage input to prevent overheating.

Prevents reverse charging: At night, your battery can discharge because of the voltage difference between the solar panel and the battery. A charge controller prevents this.

Increases performance: An MPPT solar charge controller allows your battery bank to charge faster and more efficiently, even in cloudy weather.

A solar charge controller works by detecting the voltage of the battery and then adjusting how much current it delivers and how. 

For instance, if it detects battery voltage is low (meaning a low charge), it delivers the maximum current possible. As battery voltage increases, it delivers less current and in shorter pulses. 

Different types of solar charge controllers work a bit differently. Check the next section below to learn about the different types of solar charge controllers and how they work. 


Types of Solar Charge Controllers 

OOYCYOO 60A 100V MPPT
EPEVER 40A 100V

There are three types of solar charge controllers: simple shunt controllers, PWM controllers, and MPPT controllers.

The first type, shunt controllers, are outdated and are not used anymore. They work by simply switching a shunt on or off to allow or block current to the battery.

They are ideal if you don’t want any electromagnetic interference.

Since you are unlikely to find a shunt solar charge controller, we’ll focus on the other two.

PWM Solar Charge Controllers 

allpowers 10000mah solar charger review

PWM stands for Pulse Width Modulation.

It works by sending a series of pulses to the battery rather than a single continuous output.

When the battery level is low, the pulses will be long and far between; an almost continuous flow.

As the battery fills up, the pulses become shorter and quicker until they become just a trickle to maintain the full battery.

This keeps the batteries from overcharging.

PWM solar charge controllers are great for small systems where efficiency is not essential. They are common in RV, boat, and camping solar systems.

They do a great job protecting the battery but they ‘waste’ some power.

A 12V solar panel will typically output 16V-18V of power depending on the weather. But to charge a 12V battery, the charge controller has to step down that voltage to match that of the battery.

If you want to capture this lost power, get an MPPT controller.

MPPT Charge Controllers 

SmartSolar MPPT 100V 30A

MPPT stands for Maximum Power Point Tracking.

An algorithm in the controller constantly checks the maximum amount of power the solar array is delivering.

The controller then adjusts the voltage to maximize the amount of power going into the batteries.

An MPPT controller will still step down the 16-18 volts to a safe 12V for the battery. But it doesn’t let the remaining voltage go to waste. It converts it into amps.

Your battery bank receives more current and charges faster.

A good MPPT solar charge controller can increase your system efficiency by 30% or more.


What to Consider When Buying a Solar Charge Controller 

best solar charge controller review

1. Type 

PWM vs. MPPT: which one should you go for?

The answer depends on your needs.

If you have a small or medium size solar system for your RV, boat, or small home, a PWM controller will do.

But for most residential solar systems, an MPPT solar controller is far more efficient.

2. Max Voltage and Current 

The next thing to check is the controller’s capacity – how much voltage and current can it handle.

Max voltage ranges from as little as 12V for the smallest controllers to as high as 150V for powerful MPPT charge controllers.

Make sure the open circuit voltage of your solar array does not go beyond the set limit. 

When calculating the total voltage from your solar panels, don’t forget to add a 25% margin. Most solar panels often produce a higher voltage than the one specified.

Do the same when calculating the total current.

Maximum input current ranges from as little as 8A for RV and truck charge controllers to 80A for high capacity charge controllers.

3. Battery Compatibility 

Check what battery voltage the charge controller is compatible with.

Most can be connected to 12V or 24V batteries. Some are 12V only while others can charge any battery up to 60V.

In addition to the voltage, check the battery type requirement.

Most PWM charge controllers are only compatible with lead-acid batteries (gel, sealed and flooded) while MPPT controllers can also support lithium batteries.

But you can still find PWM controllers that are compatible with lithium batteries and MPPT controllers that are ideal for lead-acid batteries only.

4. Load Control 

Charge controllers turn off the output load automatically if the battery gets too low. This prevents extreme discharging, which can reduce the lifespan of your battery.

If you’d like to be able to turn off the load at any time, look for a charge controller with manual load control. This will usually be a switch you can press or toggle.

Some controllers also have a timed on/off feature. You can set the load to go on or off at a specific time.

This is handy for applications such as outdoor lights.

5. Temperature Compensation 

Check whether your solar charge controller has a temperature compensation feature. It’s especially useful if you live in a hot area.

The controller will reduce the voltage if it detects the battery temperature is rising.

Overheating can damage your battery and reduce its lifespan.

If the charge controller has that feature, it will likely come with an external temperature sensor, or you’ll need to buy one separately.

6. System Monitoring and Control 

One of the biggest advantages of a charge controller that I haven’t mentioned yet is that it allows you to monitor and control your solar system.

You can easily check the status of your battery, how much power the solar panel is producing, and other performance data.

Most solar charge controllers come with a simple integrated display where you can see basic details and configure various parameters.

For easier monitoring and more advanced control, look for a charge controller that comes with a remote meter or is compatible with one.

Alternatively, get a Bluetooth-connected charge controller that you can monitor from your smartphone.


How To Connect A Solar Charge Controller?

A solar charge controller goes between your solar panels and the battery. That way, it can control power coming from the solar array before it gets to the battery.  

Check the type and gauge of cables recommended in the user manual. 

Note that the solar panels, the charge controller, and the battery all have negative and positive terminals and they all need to match up. 

You normally don't need to worry about messing up the polarity because most solar charge controllers have reverse polarity protection. But it’s safe that you get it right the first time. 

Run the cables from the solar panel to the solar charge controller, making sure to match the + and - terminals. Then run cables from the solar charge controller to the battery, again being careful to match terminals. 

The solar charge controller should have clear labeling showing which cables to connect to each port. 

Next, select your battery type on the solar charge controller and, if necessary, the voltage (most charge controllers can automatically detect voltage).


Frequently Asked Questions

solar charge controller

Can a solar charge controller work with a wind turbine?

No. Solar charge controllers are designed specifically for use with solar panels. If you have a wind turbine, look for a charge controller specifically for wind power.

How do solar charge controllers work?

PWM solar charge controllers detect the voltage of the battery and then decide how much power to send.

MPPT solar charge controllers detect the maximum power generated by the solar panels and turn the excess voltage into amps to charge the batteries faster and more efficiently.

How do I choose a solar charge controller?

Check the voltage and current produced by your solar panels and add 25% to both. Then look for a solar charge controller with maximum current and voltage above the figures you get.

What size solar panel do I need to charge a 12v battery?

Look for a solar panel that produces at least 13.6V in the worst-case scenario. Most solar panels can do this.

When do I need a solar charge controller?

Not everyone using solar panels needs a charge controller. Generally, a charge controller is essential in situations involving a significant amount of current, which could overcharge or damage the battery.

But if you are using small solar panels that output a limited amount of current and voltage, you likely don’t need a solar charge controller.

To check whether you need a charge controller, compare your battery amp hours with your solar panel max power. You generally don’t need a charge controller if the solar array puts out less than five watts of powerfor every 100 amp hours of battery capacity

For example, you can safely charge a 40,000 mAh (40 Ah) power bank with a mini 2W solar panel.


About the Author David Roberts

I'm a Mechanical Engineer who's obsessed with solar energy and sustainable living.

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