Top solar charge controllers compared

If you want to use solar panels to charge a mobile battery bank, you need a charge controllers. Here’s some of the top models on the market now.

If you have a battery bank in your RV, boat, or other off-grid setting that you want to charge with solar panels, you need a charge controller.

In a system where solar panels charge a bank of batteries - whether lead-acid or lithium-ion - a charge controller sits between them and regulates the flow of electricity into the batteries.

While grid-connected solar panel systems also use charge controllers, this article will focus on smaller scale applications, such as 12 volt systems for RVs, boats, and cabins. To learn more about solar batteries for the home, you can read this article.

What is a solar charge controller?

A solar charge controller performs the following functions:

  • It regulates the flow of electricity into a battery bank. When a battery is depleted, you want a high flow of electricity to charge the battery quickly. When the battery is close to full, that flow should be decreased. And when a battery is full, you only want a trickle of electricity to keep the battery topped up.
  • It prevents the backflow of electricity when the sun isn’t shining. Electricity behaves like water: it wants to flow from high to low potential. In a solar panel system with a battery, when the panels aren’t generating power, there will be a tendency for electricity to flow from the battery into the solar panels. While panels should have a blocking diode to prevent this, some cheap panels may not. Your charge controller will only allow electricity to flow from the panels into the batteries, preventing them from being drained when the sun isn’t shining.
  • System monitoring. A good charge controller will tell you the state of the battery (voltage) and the load on the system. Some controllers have a small built-in display, while others have a smartphone app that let you talk to the controller over Bluetooth or WiFi.
  • Load control. Some charge controllers have the ability to automatically turn on a connected load - such as a set of lights - when the solar panels stop supplying power, or according to a schedule.
  • (MPPT controllers) Step-down or step-up panel voltage to match the battery voltage. Normally, if you want to charge a 12v battery, you need a 12v solar panel. While you can use a higher voltage panel, it will be less efficient to do so. On the other hand, if you have a 12v solar panel and want to use that to charge a 24v battery bank, it won’t work. The panel must have a higher voltage than the battery. However, more advanced Maximum Power Point Tracking (MPPT) charge controllers can step-up or step-down the solar panel voltage to match the battery.

As you can see, solar charge controllers provide important functionality and safety features. While it is possible to charge a battery by connecting solar panels to them directly, it is potentially dangerous to do so. A basic charge controller can cost less than $20, so there really isn’t a good reason to try it either.

This guide will introduce you to the basics of charge controllers, and compare some of the most popular models on the market.

What are the different types of solar charge controllers?

There are two basic types:

  • Pulse Width Modulation (PWM) charge controllers. These are less expensive controllers (as low as $11 for a small unit) that nonetheless still provide basic battery charging, monitoring, and safety features. If you have a smaller solar system and don’t care about extracting the maximum electricity out of your panels, a PWM charge controller can be a perfectly good choice.
  • Maximum Power Point Tracking (MPPT) charge controllers. This type of controller adds several features over more basic PWM models: higher efficiency under varying light and temperature conditions, and the ability to step-up or step-down the incoming voltage to better match your battery.

It’s worth taking a minute to fully explain the advantages of MPPT controllers.

What are the advantages of an MPPT charge controller?

The main reason to choose an MPPT charge controller is to maximize the electricity generation from your solar panels. If you have limited space - such as the rooftop of your RV - but have a large battery bank that you want to keep fully charged, going with an MPPT unit will allow you to get the maximum power out of the panels that you have.

On the other hand, if you have light power demands - maybe a few lights, a radio, and a fan - you might not care about maximizing your power generation. If that’s the case, you can save a few bucks and go with a cheaper PWM controller.

MPPT charge controllers deal with shade better

If you’ve taken any time to learn about solar panel specifications, you’ll know that panels become less efficient in high temperatures.

In addition, partial shading can have a big impact on the electricity production of a solar panel, unless you have the electronics to compensate for it. For example, with a home solar system, additional MPPT units inside string inverters, power optimizers, and microinverters are all different technologies designed to improve electricity production under difficult shading conditions.

An MPPT charge controller provides a similar advantage. Many websites claim that an MPPT controller will generate an average of 30% more electricity compared to a more basic PWM controller, but this seems like a dubious claim. The actual improvement will depend on the conditions under which you use your panels. If you use solar panels on a bright, sunny, and cool day, then the benefits of an MPPT controller will be minimized, and you could get by with a cheaper PWM model.

MPPT controllers let you use series wiring to increase the voltage for longer runs

Solar panels output low voltage direct current (DC) power. One characteristic of low voltage DC is that electric current is lost to resistance over long runs of wire. This might not be a problem if you have extra panels to compensate, or its a short distance (say, 10 feet) from your solar panels to your batteries. But if it’s a long run of wire (maybe 25 feet or longer), you could start to see a noticable drop is power output.

To compensate for that, you could use a thicker gauge of wire, such as 10 AWG. But thicker wire is more expensive.

An MPPT charge controller offers you a workaround. If you connect your solar panels in series, you increase the voltage of your system. Let’s say you have two 12v solar panels. If you connect them in parallel, the voltage of the system will be 12v. But if you connect them in series, the voltage of the panel is added together, so will you end up with a 24v system.

The advantage of higher voltage is that you lower your resistive losses in the wire. This means that you can continue to use a skinnier wire or longer runs without having to upgrade to a thicker wire.

What does this have to do with MPPT charge controllers? If your input voltage is much higher than the battery voltage, not all of the electrical current can be used to charge your batteries: some electricity effectively is lost.

An MPPT charge controller can help this by stepping down the input voltage to match the battery voltage. Thus, with our panels wired in series that produces 24v electricity, an MPPT controller will step that voltage down to 12v so that it can be efficiently charge a 12v battery.

Keep in mind that series wiring has a disadvantage, which is that it makes the system more suspectible to shading. To learn more, read our article about solar panels for RVs.

Learn more about solar charge controllers

As you can probably tell, you need to know some basics about electricity if you want to make smart equipment choices and wire up your own solar powered battery system. It's not a scary topic at all - you just need to know a little bit about current and voltage.

This article isn't intended to cover all of what you need to know, so I recommend this video from altE. It does a great job of explaining this topic in simple terms in only 13 minutes.

There are a lot of vendors that sell PWM controllers, many of which are very cheap. I’ve narrowed the list down to three popular ones: EPEVER, Renogy, and Morningstar.

Each of these manufacturers offers a range of products to suit different power requirements. These are summarized by model in the tables below.

EPEVER PWM charge controllers

Note: these charge controllers are positive ground. This means that the grounding must be on the positive side, to something such as a grounding rod. If used with a vehicle with the negative battery terminal grounded to the chassis (ie. most vehicles), the controller must not be connected to the chassis.
Nominal voltage12V/24V auto12V/24V auto12V/24V auto
Max input voltage50 VDC50 VDC50 VDC
Battery typessealed, gel, floodedsealed, gel, floodedsealed, gel, flooded
Phone app?NoNoNo
Water resistant?NoNoNo
USB outletsNoneNoneNone
Warranty2 years2 years2 years
(check price on Amazon)
(check price on Amazon)
(check price on Amazon)

Renogy PWM charge controllers

ModelWanderer 10AVoyager 20AWanderer Li 30AAdventurer Li 30A
Nominal voltage12V/24V auto12V12V12V/24V auto
Max input voltage50 VDC26 VDC25 VDC50 VDC
Battery typessealed, gel, flooded, lithiumlithium-ion, LiFePO4, LTO, gel, AGM, flooded, calciumsealed, gel, flooded, LiFePO4sealed, gel, flooded, lithium
Self-consumption< 10mA< 8mA< 10mA≤ 13mA
Phone app?with $30 Bluetooth moduleNowith $30 Bluetooth modulewith $30 Bluetooth module
LCD display?YesYesNoYes
Water resistant?NoYesNoNo
USB outletsNoneNoneNone1
Warranty2 years1 year1 year2 years
(check price on Amazon)
(check price on Amazon)
(check price on Amazon)
(check price on Amazon)

Morningstar PWM charge controllers

Morningstar charge controllers are advanced products with a price to match, but they include features not found on other devices, such as better programability, data logging and transient surge protection.
ModelProstar PS-15Prostar PS-15MProstar PS-30Prostar PS-30M
Nominal voltage12V/24V auto12V/24V auto12V/24V auto12V/24V auto
Max input voltage60 VDC60 VDC60 VDC60 VDC
Battery typessealed, gel, flooded, lithium, NiCd, NiFe, NiZn, Aquion, redox flowsealed, gel, flooded, lithium, NiCd, NiFe, NiZn, Aquion, redox flowsealed, gel, flooded, lithium, NiCd, NiFe, NiZn, Aquion, redox flowsealed, gel, flooded, lithium, NiCd, NiFe, NiZn, Aquion, redox flow
Self-consumption< 20mA< 35-50mA< 20mA< 35-50mA
Phone app?NoNoNoNo
LCD display?NoYesNoYes
Water resistant?NoNoNoNo
USB outletsNoneNoneNoneNone
Warranty5 years5 years5 years5 years
(check price on Amazon)
(check price on Amazon)
(check price on Amazon)
(check price on Amazon)

We list MPPT charge controllers from two manufacturers: Renogy and Victron. EPEVER MPPT controllers aren’t listed because we can’t find warranty information. Morningstar isn’t listed because their MPPT controllers are high end devices and likely beyond what the average consumer needs.

Renogy MPPT charge controllers

ModelRover Elite 20Rover Elite 40Rover 60
Nominal voltage12V/24V auto12V/24V auto12V/24V/36V/48V auto
Max input voltage100 VDC100 VDC150 VDC
Battery typessealed, gel, flooded, lithiumsealed, gel, flooded, lithiumsealed, gel, flooded, lithium
Self-consumption≤ 0.6W @ 12V
≤ 0.8W @ 24V
≤ 0.6W @ 12V
≤ 0.8W @ 24V
0.7W - 1.2W
Phone app?NoNowith $30 Bluetooth module
LCD display?YesYesYes
Water resistant?Yes (IP32)Yes (IP32)Yes (IP32)
USB outletsNoneNoneNone
Warranty1 year1 year2 years
(check price on Amazon)
(check price on Amazon)
(check price on Amazon)

Victron MPPT charge controllers

ModelSmartSolar MPPT 75/15SmartSolar MPPT 100/30SmartSolar MPPT 100/50
Nominal voltage12V/24V auto12V/24V auto12V/24V auto
Max input voltage75 VDC100 VDC100 VDC
Battery typessealed, gel, flooded, lithiumsealed, gel, flooded, lithiumsealed, gel, flooded, lithium
Self-consumption25 mA @ 12V
15 mA @ 24V
30 mA @ 12V
20 mA @ 24V
30 mA @ 12V
20 mA @ 24V
Phone app?YesYesYes
LCD display?NoNoNo
Water resistant?Yes (IP22)Yes (IP22)
USB outletsNoneNoneNone
Warranty5 years5 years5 years
(check price on Amazon)
(check price on Amazon)
(check price on Amazon)

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