NOTE: Although 200 watts of solar power is relatively benign. Do NOT connect more than ONE panel or combination of panels totaling more than 200 watts of power to a buck converter. If you are uneasy about connecting wires, look at getting a USB Solar Charger instead (see below). Always use common sense when dealing with electricity.

Use this simple emergency solar power system as a backup power source to power devices that use DC current. You can power any USB device, phones, laptops, tablets, radios, 12-volt motors, pumps, fans and appliances for example.

By using a DC-to-DC (buck) converter, we can harvest power directly off the solar panel. Therefore, eliminating the need for an inverter, battery and charge controller, typically found in traditional solar systems. However, this is not a replacement to a traditional solar system and should NOT be extended past its intended use. It would not be cost effective or practical to try and scale this system to power anything other than the devices listed here.

The buck converters, listed below, are unique to this task because of their wide-ranging input voltage of 20 to 90 volts, depending on the converter. Almost all other converters have a fixed input voltage, thereby restricting its use to certain solar panels.

07-31-2023: Some buck converters will serve as an emergency battery charger but should only be used as such. I have been doing more testing with buck converters charging 12-volt batteries and have gotten mixed results. I am not quite sure why, but I think some buck converter expect to see a load in order to output any power. Either that, or it just is plain inefficient. Some will work and some will not. Even the junkiest MPPT is better at charging batteries from solar panels. I have been testing a mini MPPT charger and so far, its going pretty good. I will post an update video about this in the future.

08-29-2023: XWST has produced a custom converter with an input voltage of 18-90V and output of 13.8V @ 20A / 276W. Direct order from China and will cost around $45. See below!

03-01-2024: One of my viewers built this ammo can version.

Schematic

Video

I powered my phone, radios, rechargable AA batteries, air pump, frying pan, rice cooker, coffee maker and charged a battery.
Items marked with * are used in the video.
All items listed below are affiliate links.

Related Video

XWST built me a custom unit that does it all!

Solar Panel Options

> Use NATESDIY at checkout to get a nice discount! (Renogy only)

DC-DC (BUCK) Converter Options

When choosing a buck converter, the solar panel used should match or exceed the rated output power of the buck converter but is not required. For example, if a 16-amp buck puts out 196 watts *, a 200-watt solar panel would be able to fully power the buck converter. If a 600-watt solar panel was used, the buck converter will only use 200 of the 600 watts. Be sure that the Open Circuit Voltage (VOC) found on the back of the solar panel, falls within the input voltage range of the buck converter. Most solar panels under 250 watts will have a VOC lower than 40 volts. Watch this video on reading solar panel specifications. You will be able to power any of the devices mentioned earlier with 200 watts of power.

*** CUSTOM 18V-90V input, 13.8V output (90V VOC PV MAX) ***

ONE CONVERTER TO RULE THEM ALL! After testing many converters from different manufactures. I reached out to XWST to see if they could produce a converter with these exact specifications and they did! XWST's converters have out-performed all other converters I have tested when it comes to versatility. USB/PD devices, all 12V appliances, 12V battery charging. See Video. (I do not get a commission from this item)

DC-DC Step Down 20V-90V input, 12.0V output (90V VOC PV MAX)

Product Catalog by XWST

In my testing, XWST units have proven to work best as an all-around-unit. I have powered appliances as well as charged batteries. Although, the output voltage is only 12-volts, you will get enough charge in the battery to start a car from a dead battery. You do not need a lot of amps to charge a battery, in fact, less than 10 amps is safest and all you need to get enough charge in a couple hours' time from a 50 watt solar panel.

Adjustable DC-DC Converter (not beginner friendly)

USB Panel Options

The 4 in 1 has 16awg wires and will power all the devices in the video without getting too hot. If you are going to be using 12-Volt appliances and do not want to upgrade the wires its better to use this one. The wires are pretty thin on these USB panels. They will get warm at 12A. Some come with a 10A fuse that will smoke using 12V appliances, so it's best replace with a 15A ATC fuse an upgrade the wires to 14AWG.

14AWG Wire Upgrade Parts for USB Panels

USB Anywhere Converter

If you want USB charging ONLY, but with minimal wiring and still be able to use any solar panel, check out this USB buck converter.

If you want USB charging only and do not want to wire up a buck converter, take a look at USB Solar Chargers. They are small and very portable but do not make as much power as larger rigid panels.

Cables and Connectors

NOTE: I did not use BUTT splice connectors in the video but they are good for permanent connections. You will need a pair of wire crimpers as well.

Tools

USB Devices - Video

12 Volt Appliances - Video

NOTE: These items will work with the 16A/192W buck converter, with the exception of the 300W heater. You may not be able to use them at the same time, however. I recommend getting the 20A converter to allow for some headroom and not overload.

More 12 Volt Appliances

High Power Appliances