Solar Charge Controller How It Works?

A solar charge controller is essential for charging batteries efficiently and safely. A solar panel connected to the battery directly may continue to charge until internal damage occurs. It isn’t too useful to understand the electronics inside a controller, but it is important to understand how and why they are connected electrically, and to have some understanding of the different types.

How does a solar charge controller work?

Figure1: Off-grid Diagram with DC Load – When installing a solar charge controller, it is recommended that you connect and disconnect in the following order:

Battery to the controller first PV array to the controller Electrical load to the controller

When disconnecting, you reverse that order. The battery provides power to the controller so always make sure that solar and loads are disconnected before connecting or disconnecting the battery from the controller. Connections between the battery, load, PV array, and the controller should have disconnect switches to enhance safety and facilitate ease of installation and breakdown.

1. In the wire diagram schematic above with DC load, sunlight contacts the solar modules, which convert solar into DC electrical power that it delivers to a charge controller.
2. The charge controller regulates the amperage and voltage that is delivered to the loads and any excess power is delivered to the battery system so the batteries maintain their state of charge without getting overcharged.

During the evening when there is no sunlight, battery power is used to run the load. You’ll notice that the battery is grounded at the negative battery terminal. This is because all our PWM and MPPT controllers have a common negative ground. Therefore, it is possible to establish a common negative ground for the entire system: the solar array, controller, battery, and load.

1. This meets NEC code requirements for grounding.
2. If you need an equipment ground for any metal parts on a controller enclosure, some of our controllers include an equipment ground terminal lug.
3. Otherwise, for our controllers that don’t have this terminal lug, you can connect an equipment ground directly to the controller enclosure.

The next diagram (Figure 2) depicts the components and connections to power an AC load. This diagram with an AC load looks similar to the previous example with a DC load, except that in this example, we have added an inverter to the system. The purpose of the inverter is to convert the DC power from the battery to AC power that can be used to run an AC load like the TV you see in the schematic.

What does a solar charge controller do when the battery is full?

7.2.2 Solar charge controller – A solar charge controller is used to charge the battery by regulating and controlling the output from the solar PV array; it also protects the battery from being overcharged or overdischarged. Overcharging of the battery creates release of hydrogen and oxygen gases from the electrolyte, which could cause explosion and failure.

If the battery is allowed an excessive discharge of current, the battery charge will be drained. So, the life of the battery will be reduced and cause premature failure of the battery. Solar charge controllers redirect or switch off all or part of the array to reduce the current flow to the battery when it is becoming full.

If the battery is discharged below a specified voltage, which is a low voltage preset point, the disconnection of some or all the loads takes place. To protect the battery from overcharging, the charge controller will have a high voltage disconnect (HVD) point.

So, the controller will have set points such as low voltage disconnect (LVD) and HVD. The controller voltage must be compatible with the nominal system voltage and it must be capable of handling the maximum current produced by the PV array. The solar charge controller protects the batteries from being overcharged by solar PV array/modules during the day.

During night, when solar panels don’t generate and have zero voltage, there will be a current flow from the battery to the solar panels. The charge controller provides controls by incorporating a blocking diode or relay to prevent the reverse flow of the current from the battery to the array to avoid draining the batteries during low solar irradiance or night time.

1. This means that the batteries are not drained during the day and that the electricity does not run overnight back to the solar panels and drain the batteries.
2. Some solar charge controllers, such as the one used for streetlight applications, take care of lighting control as an additional function.
3. Additionally, a load control feature is also available with some solar charge controllers.

Types of charge controllers: There are two basic types of charge controllers used for small PV systems: the series and the shunt type. These are single-stage controllers that disconnect the array when the battery voltage reaches a high voltage level during charging.

Shunt controller—shunts part of the solar array and redirects the charging current away from the battery. During shunting of the solar array, heat dissipation takes place and a large heat sink is required to dissipate the excess current. Series controller—series switch is incorporated between the array and the battery.

The series switch in the controller will be opened based on the state of charge of the battery to interrupt the charging current from the PV array. This series controller has a limitation regarding the capability of the components to handle the current during switching operations.

1. At different stages of battery charging, there is a requirement of different levels of charging current.
2. So, multistage controllers are used to provide a more efficient method of charging the battery.
3. As the battery nears full SOC, its internal resistance increases, and using a lower charging current wastes less energy.

Broadly, there are two different topologies of solar charge controllers available: the maximum power point tracker (MPPT) and pulse width modulation (PWM). The performance of each of these controllers is not the same and MPPT has better performance as compared to the PWM controller.

What voltage should I set my solar charge controller?

Charge controls come in 3 general types (with some overlap): – Simple 1 or 2 stage controls which rely on relays or shunt transistors to control the voltage in one or two steps. These essentially just short or disconnect the solar panel when a certain voltage is reached.

For all practical purposes these are dinosaurs, but you still see a few on old systems – and some of the super cheap ones for sale on the internet. Their only real claim to fame is their reliability – they have so few components, there is not much to break.3-stage and/or PWM such Morningstar, Xantrex, Blue Sky, Steca, and many others.

These are pretty much the industry standard now, but you will occasionally still see some of the older shunt/relay types around, such as in the very cheap systems offered by discounters and mass marketers. Maximum power point tracking (MPPT), such as those made by Midnite Solar, Xantrex, Outback Power, Morningstar and others.

These are the ultimate in controllers, with prices to match – but with efficiencies in the 94% to 98% range, they can save considerable money on larger systems since they provide 10 to 30% more power to the battery. For more information, see our article on MPPT. Most controllers come with some kind of indicator, either a simple LED, a series of LED’s, or digital meters.

Many newer ones, such as the Outback Power, Midnite Classic, Morningstar MPPT, and others now have built in computer interfaces for monitoring and control. The simplest usually have only a couple of small LED lamps, which show that you have power and that you are getting some kind of charge.

Most of those with meters will show both voltage and the current coming from the panels and the battery voltage. Some also show how much current is being pulled from the LOAD terminals. All of the charge controllers that we stock are 3 stage PWM types, and the MPPT units. (in reality, “4-stage” is somewhat advertising hype – it used to be called equalize, but someone decided that 4 stage was better than 3).

And now we even see one that is advertised as “5-stage”.

Does a solar charge controller drain the battery?

Reasons and Solutions | Solar Power Princep It’s common to connect a solar battery to your trusty solar panel. But sometimes weird things can occur. For example, your panel deciding to feed on your battery instead of charging it. So why does this happen and what is the fix? A good solar panel won’t drain your battery; even during nighttime,

1. If it happens the main reason is that its blocking or bypass diodes are broken and need replacement.
2. Even then if you have a Solar Charge Controller it’ll prevent battery drainage.
3. Usually, most people’s solar panels drain during the night.
4. Due to this most of the time, people think solar charge controllers or inverters are somehow the culprits too.

The funny thing is Solar Charge controllers actually prevent battery drainage. Therefore it’s actually very improbable that your solar panel or other things are the reason why your battery is getting drained. In the following article, we will take a good look at the reasons why solar panels drain batteries, faulty conditions that cause such distress, how to fix those conditions, how diodes stop battery drainage, how to replace and various trivial solutions you can try.

How do I know when my solar battery is fully charged?

Connect the positive terminal of the meter to the positive terminal of your battery. Check the voltage measurement on the tool of the meter. If the voltage reading is within 2% of your maximum battery voltage, your solar battery is full.

Does a 100W solar panel need a charge controller?

Calculating The Size Of The Charge Controller Needed For A 100-Watt Solar Panel – Since you have worked out all of the above, you can now figure out what size charge controller you will need for your specific 100-watt solar panel array. To do the calculation, we suggest using the formula power = voltage x current.

Can I leave my solar panel connected to my battery?

Step 1: Understand the Wiring Diagram – Here’s the wiring diagram showing how to connect a solar panel to a battery: It’s important to understand the following:

Don’t connect a solar panel directly to a battery. Doing so can damage the battery. Instead, connect both battery and solar panel to a solar charge controller. It’s recommended you fuse your system. Safety best practices, y’all! Place one fuse between the positive battery terminal and the charge controller. Place another between the positive solar panel wire and the charge controller.

How long do solar charge controllers last?

Answers to more detailed questions are available in our Q&A blogs., – MPPT controllers provide more power, especially in colder temperatures. They can also be used with less expensive 60-cell modules which are usually unsuitable for PWM controllers. Weighing these benefits versus The solar electric systems associated with the term “solar” are usually simple grid-tied types, with PV modules and an inverter or inverters for converting DC from the modules to AC A solar charge controller is a solar-powered voltage and current regulator. They are used in off-grid and hybrid off-grid applications to regulate power input from PV arrays to deliver optimal The first solar charge controller schematic below (Figure 1) illustrates how a solar charge controller is connected to power a direct current (DC) load, and the second one (Figure 2) Solar charge controllers put batteries through 4 charging stages: Bulk Absorption Float Equalize What are the 4 Solar Battery Charging Stages? Bulk Charging Voltage For lead-acid batteries, the initial bulk The two major types of solar charge controllers are: Pulse Width Modulation (PWM) controllers Maximum Power Point Tracking (MPPT) controllers As shown in the chart below, PWM controllers tend to Morningstar solar charge controllers are different from other brands, as you can see in this five-minute video. The high-frequency design allows Morningstar solar charge controllers to react more quickly to Morningstar’s MPPT solar charge controllers support oversized photovoltaic (PV) arrays. For example, a 240-watt module won’t damage a SunSaver MPPT solar charge controller and won’t cause it to exceed its In short, the solar charge controller you choose must be able to support the power requirements of your loads, your battery voltage (e.g.,,, or ), and your PV current and voltage inputs. Additionally, you will need to consider whether you need a controller with low voltage disconnect, lighting control, or other features or certifications.

Your climate, choice of modules, and price will also determine whether you choose a or an, A good solar distributor will be able to help you size and configure your modules, batteries, and controllers for an optimum system. Yes, some controllers are equipped to monitor data including battery voltages, system current, absorption and float charging metrics, and faults and alerts.

Many Morningstar solar charge controllers support operating temperature ranges between -40C and +60C. to consider are meters, adapters, remote temperature sensors, relay drivers, and other balance of system components. You can describe what type of charge controller and system you are interested in deploying on our page which includes links to a product catalog.

• The longevity of a charge controller depends on the brand and the system environment.
• The Morningstar Professional Series controllers have a 5-year warranty and many have been in operation for 10 years or more.
• A feature that protects batteries from over-discharging by disconnecting electrical loads when a battery’s voltage drops below a certain setpoint.

Load control and low voltage disconnect are two terms that mean the same thing. The ability to program settings on controllers to power on and off lights during the day and evening. Some controllers have simple controls to turn lights on as dusk and off at dawn.

1. Other controllers have more sophisticated programability to allow for multi-event on/off light switching during a 24-hour period.
2. As batteries become fully charged a controller will direct excess current from the battery to a dedicated load that is large enough to absorb the excess energy, but not too large to cause a controller overload condition.

A charge controller is rated by the current it can accept from a PV array to charge batteries and the battery voltages it will support (e.g. for 12, 24, and 48-volt batteries). The rated current that the controller will deliver to loads. Some controllers, but not all, are built to withstand the harsh environments associated with boats and marinas.

• It is important to check the operation manual or datasheet to see what battery voltages your controller supports.
• Some controllers support voltages from,,, and higher, while others might only support 12 volts.
• The small amount of power that the charge controller uses up for its own operational purposes rather than delivering to loads and batteries.

To regulate power from the PV array to prevent batteries 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. Other names for a solar charge controller include: solar panel controller, solar panel charge controller, solar power charge controller, solar controller, solar charge regulator, solar regulator, and charge regulator.

• A type of charge controller that short circuits the array to reduce current sent to a battery.
• PWM and MPPT controller technology is newer and more prevalent than shunt technology.
• The maximum voltage, listed in the operator manual, that a controller can support.
• To determine whether your system will operate under this Voc limit you must know the lowest temperature your system will be exposed to, and calculate the voltage produced by your array at that temperature.

Exceeding Voc limits will damage your controller. : Solar Charge Controllers FAQ l Morningstar Corp

How Far Can solar panels be from charge controller?

If you don’t have enough space on your roof to install solar panels, ground mounts are the best option. But the question is, how far can the solar panels be from your house? That’s a question you need to answer before any setup. If you’re too far away and you’re not getting the results you want, what’s the acceptable limit? In this article, we will tell you How far the solar panels can be from the house. You can install solar panels up to 500 feet from your home, but that will require long and expensive wires to prevent energy loss. A distance of 50 feet or less will keep the voltage drop at 2%, which is the acceptable limit for current.

Should I unplug my solar panel at night?

Summary – Do solar panels drain batteries at night? Solar panels should not drain your batteries at night. They should only draw power from them and leave them running smoothly. Draining them can be harmful to your solar PV system’s battery. You should always properly prepare in case of a malfunction.

• Be sure to read the whole article in case you need more information.
• Solar charge controllers are a way that manufacturers stop your battery from overcharging and over draining for them to live a longer life and function longer and better.
• They also limit the speed of power being added or taken away from the batteries which also elongates their life.

Solar panel reverses current is another thing the solar charge controller can prevent. This means that the current flows in the opposite direction of where it needs to go and it can have serious consequences. This should be covered by chargebacks and warranty by the manufacturer but be warned because it also may not be.

Can I use my solar battery at night?

Solar Battery Storage Offers Energy Freedom – It’s your home, your energy. Use it when you want. A second way solar panels can indirectly power your home at night is battery storage. Solar batteries work the night shift to make the most of your panels’ daytime production.

Solar panels fill your battery with energy from the sun. So, you have electricity stored for future use. With this stored solar energy, your battery provides power throughout the night. Instead of sending excess electricity to the grid, store it for yourself. You’ll consume electricity first from the solar battery storage before drawing from the grid.

Installing a solar battery with your solar panels lessens your reliance on the antiquated grid and enables you to lock in dependably lower electric bills. Solar battery storage gives you control of your energy finances and peace of mind. Homeowners also value battery backup power during outages.

1. Utility grids go down due to either technical malfunctions or natural disasters such as wildfires.
2. Protect yourself day and night with a home battery.
3. Battery storage gives you to access your own electricity when solar panels are dormant.
4. Solar battery storage is the best energy solution for backup energy at nighttime.

Now is the time to make your own energy. With a battery, your solar installation becomes a sustainable 24/7 energy storage solution. Sunrun’s Brightbox battery has got you covered.

Can you just unplug solar panels?

How should I disconnect my solar panels? We often get asked the question how should I disconnect my solar panels. I would say for the majority of installs once the panels are up and installed they will very rarely, if ever, be disconnected. Your panels are doing their job and you just sit back and enjoy the clean & quiet power.

• However it might be the case that you want to disconnect you panels safely, here’s a few scenarios:
• – You’re a weekend sailor and you are only putting the panels out for the weekend and then disconnecting them to stow under a bunk during the week.
• – You have a camper and have run out some extra panels into the sun on a 50ft cable and now need to disconnect them, stow them away and move on to the next campground.
• – Maybe there is a hurricane forecast and you want to remove the panels from your bimini and stow them away.

1. The orange MC4 disconnect tools (sold as a pair in our )
2. It’s worth noting that you can never really “turn off” a solar panel and so it’s very important to be aware that your panel is always generating DC voltages (potentially very high if they are connected in series) so there are steps you can take to safely disconnect your panels:
3. Step 1 – Turn off the circuit breaker between the MPPT charge controller and battery bank
4. Step 2 – Turn off the MPPT controller in the VictronConnect app
5. Step 3 – Turn off the circuit breaker between the solar panels and the MPPT charge controller (if installed)
6. Step 4 – Cover the solar panel with a dark material OR flip over the solar panel so the logo side faces the ground
7. Step 5- Use the MC4 disconnect tool to separate the negative MC4 connectors between the solar panel and the PV extension wire then use the MC4 disconnect tool to separate the positive Mc4 connectors second.
8. The MC4 connectors actually have very small – and + symbols printed onto them and the positive and negative connectors from the SunPower E-flex solar panels look like the image below:

The below warnings are copied from the SunPower “safety and installation guide” “Do not connect or disconnect modules when they are energized by exposure to light or external power sources such as a battery. Disconnection under load will result in arcing and damage to the connector.” “Direct current will arc across a gap and may cause injury when improper connection or disconnection is made” There are many videos you can find on YouTube about DC arcing, bear in mind these are at higher voltages than you will typically have on your smaller sized system.

How can I check that my solar controller is working?

How can I check that my solar controller is working? – One of the easiest ways to check that a solar controller is working is to read the controller’s LED display and use a multimeter to read the power output. If there is no voltage output or if it is very low, there is probably a problem with the controller.

How long does it take for a 100W solar panel to charge a battery?

How long will it take to charge a 100Ah battery with a 100W solar panel? Here is a list of things you need to know before answering the question:

how much power can a 100Ah solar panel produce?what is the irradiance (sun’s energy) level in your location?what type of solar charge controller will you use?which type of battery will you use, lithium based or lead-acid? what is the usual Depth of Discharge for your 100Ah battery?

The biggest factor is to determine how much energy needs to put back into the battery. Everything else flows from this. A 100W rated solar panel using an MPPT solar charge controller will take approximately 12.5 hours to fully recharge a 50% discharged 100Ah lead-acid deep-cycle battery.200 watts of solar panels is recommended to recharge the same 100Ah battery in one day, if the battery is used for home energy storage.

What are the two types of solar charge controllers?

What are the Different Types of Solar Charge Controllers? l Morningstar Corporation The two major types of solar charge controllers are: As shown in the chart below, PWM controllers tend to be smaller and they operate at battery voltage, whereas MPPT controllers use newer technology to operate at the maximum power voltage.

This maximizes the amount of power being produced which becomes more significant in colder conditions when the array voltage gets increasingly higher than the battery voltage. MPPT controllers can also operate with much higher voltages and lower array currents which can mean fewer strings in parallel and smaller wire sizes since there is less voltage drop.

PWM controllers need to be used with arrays that are matched with the battery voltage which limits what modules can be used. There are many 60 cell modules with maximum power voltage (Vmp) equal to about 30V, which can be used with MPPT controllers but are simply not suitable with PWM controllers.