This Solar Charge Controller 12V can connect up to 4 panels (25×4=100 w). At first, I had to figure out how to connect the panels to the controller and the battery. I just got a camper and this tool is great for connecting the devices. 

This is is a nice, solid-state PWM charge controller to more carefully charge batteries using a solar panel. While not as good as an MPPT charge controllers, at these level of power it's more than good enough. It can handle the electrical flow from a 100W, 12VDC solar panel which makes it very useful for car-camping, keeping vehicle batteries charged up while in storage, or to help power things in a grid-down situation. However, since it's limited to 10A and 12V, it's not the best choice for larger van-life or homepower solar panel systems.Input from the solar panel is through standard MC4 electrical connectors and the output uses a common SAE plug. Note, because SAE plugs are polarity-specific, you'll need an SAE crossover connector to plug it into an SAE plug attached to the battery. This is what I'm talking about --> https://www.amazon.com/Sunway-Solar-Connectors-Disconnect-Maintainer-3Pack/dp/B07GPGPTFVIn addition to the SAE cable, the unit also has a USB and USB-C port to directly charge electronic devices, even while charging larger batteries. I really like that feature.The overall quality of this charge controller feels nice and well-made. I'm very pleased with it's construction and performance.

The Sunapex PWM charger will maintain or even recharge an RV or other small battery bank. You should expect 80-120 AH from 200W of solar panels with good sun exposure. I like the USB output for directly charging cell phones or USB power banks. The connectors plugged right in to my Renogy panel and the SAE connector is common for 20A connections. This is keeping my boat batteries topped off and would be fine to give you enough power to run a few electronics without draining your batteries. While it's not as efficient as MPPT chargers, it's sufficient for maintenance duties.

This is not the best charge controller, but it does get the job done for my small solar panel and boat battery. I was having issues with my boat battery going dead if it sat for so long. My solar panel was putting out a higher voltage than what is needed to keep the battery from overcharging. Using this small controller kept the voltage at the correct level. I like that this controller can be used with different battery types. If I upgrade to a different chemistry battery I will still be able to use this controller to keep it topped up. I found the controller to be easy to use and setup. I feel most people will have no trouble doing the same. I also feel this charge controller is a good buy for those not needing the top of the line efficiency of a maximum PowerPoint controller.

For a simple pulse width modulation (PWM) charge controller, this is on the more expensive side. At this price point you are close to low end maximum power point tracking (MPPT) charge controllers. MPPT controllers are generally considered more versatile and are likely to extract the maximum power output from a solar panel under various shading conditions.This PWM charge controller can also only charge 12 volt (12V) batteries.Being PWM limited to 12 volt systems means it is really designed for “in a pinch” solar charging of small electronic devices and not really meant to be part of a larger solar installation.With that in mind, this is one of the nicer looking charger controllers on the market. It has a sleek low profile and easy-to-read LED light indicators to show approximate state of charge (in 20% increments) of the attached battery as well as the type of battery. Selecting the battery is easy and intuitive with a long-press of the type button then a short press to cycle between various lead-based or lithium ion battery types.True to the “in a pinch charging of small devices” mission, this smart controller comes with a built-in USB and USB-C output behind the rubber panel that helps keep out moisture when not in use. Most lower cost charge controllers have one or two old-style USB ports if any at all and nothing for modern USB C devices.Another nice feature of this charge controller is the fact that it comes with industry standard connectors hard-wired into the unit. Nearly every other charge controller, including many high end models only come with bare wire connections.This unit comes with an MC4 connector pair for the PV input side; Smart as nearly all solar panels these days ship with MC4 connectors. For most other controllers you either need to make a custom MC4 to bare wire cable or strip off the MC4 connector (in reality creating a long MC4 to bare wire cable is typical as the panel is nowhere near the controller). Again, for a design that appears to be intended for things like “charge your phone with a solar panel while in the woods” this is a good design as you can easily attach this charge controller directly to the back of the solar panel as in our photos attached to this review.On the output side of the charge controller, the “to the battery” side, is another standard connector - an SAE connector that is often found in hobby electronics like drone power or automotive devices such as RVs or some older car wiring harnesses. We paired this to another product that was readily available - and SAE to alligator clip cable with an on / off switch (Amazon ASIN B0DKP7HP46) which is perfect for being able to charge up our small 12 volt LiFePO4 battery.So I am torn as to how I feel about this product. For the price an MPPT controller is in play, however this is the first charge controller I’ve seen made specifically for quick in-the-field connections for charging small devices and nearly everything about it is designed well for that purpose. Not as versatile as some others, but for a plug-and-play solution it works well.If they made this 12/24 volt compatible it could charge far more devices. Make it an MPPT controller and this would be a home run.

It works, simple to install and will keep batteries charged, I wish it had BT or other wireless options, but simple and effective it is.

Doesn't come with the battery terminals.Honestly, I was super excited for a small, compact controller. Figured I could use it while traveling.But alas, doesn't come with the shown battery terminals.Steer clear.