We should all have at least one solar charge controller somewhere in our offgrid system, no matter it’s mount in the wall or in the rvs. but it’s not enough to simply keep one put in there. if you want to keep out of paying electricity bill or live outdoor without Power off anxiety, you have to knowing how to use the solar charge controller correctly.
in case you are a clean energy enthusiast, or obsessed with VanLife, Mastering solar energy acquisition is one of the skills required. here is everything you need to know before take them to your shopping list and use them properly.
Choose the right solar charge controller
the first thing you need to know is the ammpage rate, and the second is the voltage range, you need to understand what types of solar battery you may have to deal with and make sure your solar controller can get the job done. check the 10 tips when choosing the solar controller.
There are two types of solar controllers, mppt and pwm.
MPPT Controller: it’s newly controller with inbuilt Most Power Point Tracking technology, It has a very high solar energy conversion efficiency and many additional features.
PWM Controller: it’s oldly controller type with 3 stage pwm charging technology, It’s economical and able to gets the job done most of the time.
All solar charge controller are labeled to indicate which type of controller they are, amps and voltage they can handle. Most solar controllers are designed for home solar systems, and there are some that can be designed for multiple purposes and can be used for both home and rv. There are some solar controllers that are designed for vehicle solar systems, and there is also a type of solar controller that is a boost type, designed for small solar panels to charge large batteries.
Solar controllers can be classified by purpose into the following categories:
- Type A: Universal Solar Controller for Small and Medium Household system, both mppt and pwm.
- Type B: Universal Solar Controller for Household,RVs and Marines with negative ground design.
- Type C: Dedicate Solar Charge Controller for RVs, Camper Trailer and Trucks,some able to charge dual batteries.
- Type D: Boost Solar Charge Controller for Golf Cart, Charge 36V 48V system with 12V 24V Panels.
- Type E: Hybrid Wind Solar Charge Controller. Get energy both from solar and wind turbines.
- Type F: Dedicate Solar Charge Controller for Street light and monitoring system.
You can choose the right controller according to the purpose of use. we suggest ZHCSolar store, as it has all types of solar charge controller you may need.
Solar charge controller labels also include amps and voltage range to indicate which input amperage and batteries voltages the controller is designed to handle. if there is a battery symbol with battery type shortcuts, that indicates that the charge controller able to use to charge that type of battery.
solar charge controller are mostly rate for the size of amps that they can safely handle. the higher the rating, the larger current the controller can working with.
You can find the controller rate for 10A 20A 30A 40A 50A 60A 80A and 100A on the market.
the battery system voltage rated 12V 24V or 48V 36V is the battery bank voltage you have.
Note that the amps of charge controller you need is based on the system requirement, using this size tool or do the math to get the propel pone before you go purchase.
How to Use a Solar Charge Controller
once you understand the different types of solar charge controllers and their ability, you need to be able to properly operate one.
the best way to be ready for a solar power and use of solar charge controller is to study the steps below and review them regularly so you can get the most out of it.
Condition Check: take the solar charge controller out of box, Check the condition.
Before operating the solar charge controller, make sue you have a intact charge controller with no damage, If there is physical damage to the controller, then it may not be able to charge and there is a risk of fire, it is necessary to check the integrity before installation.
Connect the battery to the charge controller
Select the right size cable and connect the positive and negative terminals of the battery and the controller correctly. the right size wire can ensure transmission efficiency and safety, the following list of wire sizes you can choose.
Solar Charge Controller Charge Voltage Setting
| PV Input current | Max Cable Size at PV | Rated Charge Current | Max Cable Size at Battery |
| 20A | 10AWG | 20A | 10AWG |
| 30A | 8AWG | 30A | 8AWG |
| 40A | 7AWG | 40A | 7AWG |
| 50A | 6AWG | 50A | 6AWG |
in addition we also recommend that the system is connected to a fuse or circuit breaker to prevent the risk of electric shock when wiring or maloperation, and before wiring to ensure that the fuse or circuit breaker before wiring to ensure that the fuse or DC isolator Switch is disconnected.
The controller display will lit up and start to identify the battery types and voltages.
Most solar controllers come with a display. For most batteries, the solar controller system automatically identifies the battery type and battery voltage, some controllers require manual confirmation and setup when charging lithium batteries.
Some controllers without display will use led indicators to tell you the type of battery, sometimes you need to use a dip switch to select it.
Set up the charge parameters according to the battery types and voltages.
After completing the battery identification, you need to follow the system or manually set up the Controllers, include these charging voltage parameters: over voltage disconnect voltage, charge limit voltage, equalization voltage, boost voltage, float voltage and boost recovery voltage.
The following rules must be followed when modifying battery charging and discharging parameters.
- Overvoltage disconnect voltage > charge limit voltage ≥ equalization voltage ≥ boost voltage ≥ float charge voltage > boost recovery voltage.
- Over-voltage disconnect voltage > over-voltage disconnect recovery voltage
The charging voltage and parameters need to be set according to the battery type, which is usually clearly marked on the label of the battery, and the following is a brief overview of the battery type and charging parameter values.
Solar Charge Controller Charge Voltage Setting Table
| Battery Type | Sealed Battery | Gel Battery | Open Lead Acid Battery | Lithium Battery | Custom Battery |
| Over voltage Disconnect Voltage | 16.0V | 16.0V | 16.0V |  —— | 9~17V |
| Equalization Voltage | 14.6V |  —— | 14.8V |  —— | 9~17V |
| Boost Voltage | 14.4V | 14.6V | 14.2V | 14.4V | 9~17V |
| Float Charge Voltage | 13.8V | 13.8V | 13.8V |  —— | 9~17V |
| Boost recovery voltage | 13.2V | 13.2V | 13.2V |  —— | 9~17V |
| Equalization Duration | 120 Min |  —— | 120 Min |  —— | 0~600 Min |
| Equilibrium charging interval | 30 Day | 0 Day | 30 Day |  —— | 0~250 Day |
| Equilibrium charging interval | 120 Min | 120 Min | 120 Min |  —— | 10~600 Min |
Connect the Solar Panel to the Charge Controller
Connecting the solar panel to the controller is the last step, and as when connecting the battery, the positive and negative terminals must correspond correctly. In addition, fuses and DC circuit breakers are necessary to keep them disconnected before connecting.
Common Solar Charge Controller Uses Mistakes
Because we don’t have regular opportunities to practice solar power, it’s easy to make simple mistakes when the time comes. Know where most people go wrong so you can avoid making a mistake while under pressure.
- Don’t ignore the instructions: Thoroughly read the operating instructions that came with your Solar Charge Controller. Make sure all able members of your home read and understand the instructions.
- Danger of electric shock: Be sure that all power supplies to the controller are disconnected when performing the above operations. Do not allow children to touch or operate the controller.
- Don’t ignore the maintenances: In order to maintain the best and long-lasting working performance, it is recommended to check the items twice a year or more.
- Keep the Controller Cool: Make sure that the airflow around the controller is not blocked and remove any dirt or debris from the heatsink.
- Keep the Wire in Good Condition: Check that all exposed wires are not damaged due to sunlight, friction, excessive dryness, insect or rodent damage, etc. If necessary, repair or replace the wires.
- Read Indicators and Error Codes: Ensure that the indicator is consistent with the operation of the device. Take corrective action in the event of any faults or error codes being displayed.
- Terminal Checks: Check all terminals for corrosion, insulation damage, high temperature, or burning/discoloration, and tighten terminal screws if they are loose.
- Clean the Controller: Check whether there is dirt, nesting insects and corrosion, and clean up in time.
- Lightning Protection: If the lightning arrester has failed, replace the failed arrester in time to prevent damage to the controller or other devices.
Next steps
The best way to keep your home power by offgrid solar is to be prepared. Regularly review how to use of solar charge controller and maintenance regularly . A little advanced practice can make all the difference when you’re deal with the solar power system in your home or RVs.
Need a Solar Charge Controller ? Check out our buyer’s guide: Best Solar Charge Controller Guide.