-Hello, welcome to my garage I recently upgraded my portable off-grid system. The core system you may know is this MPPT solar charge controller from Victron Energy So far, it's functioning normally It also has additional functions. You can connect to it using a mobile app through its Bluetooth module. And look at the power it currently produces, how much electricity it has produced in the past. All in all, this controller is great… …But there is only one problem: price. The controller itself is about 90 Euros; the overpriced Bluetooth module costs about 50 Euros. So to save a little money, you might say "Well, why not use those cheap Chinese-made PWM solar charge controllers, you can find them on eBay." I would say "Okay. Let's try it." So, here we have two charge controllers; One is 25 Euros and the other is around 30 Euros. Now let’s go back to where I tested those controllers yesterday And see how they perform.
(Opening music) -First, I use the controller app to read the solar panel power output about 53 watts. This value will be used as a reference value because solar radiation is almost unchanged during the test. So I removed the load wire and solar panel wire from the expensive controller, Pull the load wire out of the DC junction box, And connect them with the solar panel wires to the screw terminal block of the 30 Euro PWM controller Before I remove the battery cable, I removed the positive lead from the battery terminal to prevent a short circuit. After that, I connected the two batteries to the new controller And reconnect the positive battery cable to successfully start the controller. The first thing I noticed is that the LED lights on the output of the load can still operate normally As you can see, the charging current of the battery is 3.2 amps. The only problem is that the input voltage of the solar panel is obviously not right. So I measured the input voltage with a three-way meter to be about 13.5 volts This means that the controller gets about 43.2 watts from the solar panel The power is about 18.5% less than the MPPT controller.
So, let’s switch to the last contestant and take down all the wires again, And connect them to the 25 Euro PWM charge controller… …Its screw terminal block is definitely not as reliable as the other two controllers. However, despite this, the system successfully started… …And after starting its load output, the LED light still works normally. This time, the controller shows that my charging current is 3.8 amps The input voltage of the solar panel is about 13 volts… This is equivalent to 49.4 watts of power This is only 6.7% lower than the MPPT controller. Seems a bit too ideal? So I measured the correct charging current output should be 3.3 amps instead of 3.7 amps or 3.8 amps This corresponds to a 19% loss of 42.9 watts of power. This means that if we assume that when using my system, the average power difference between the MPPT and the PWM controller is 10 watts.
The average charging time is 6 hours a day, and we can get 60 watt-hours of electricity every day. Since 1 kWh sells for 0.29 Euro in Germany, We can save 0.0174 euros per day. This means it takes 3448 days, or about 10 years, To make up for the purchase price difference of expensive controllers Of course, unless the PWM controller goes on strike a few years later, this is quite possible. So, all in all, the performance of these two charge controllers surprised me a bit. If we only look at their power output, they will definitely be suitable for small portable systems Because the power output difference is not worth spending more money to buy a better controller. Of course, if you use the controller with a larger system, Then the output difference will be more significant. Therefore, in the long run, the expensive controller is worth it. But it's not just about power output, it's also about trust.
Would you believe a cheap, unbranded, PWM solar charge controller from China? And may it operate in an unsupervised environment for up to one to two weeks? Buy a controller made by a big company It will definitely give me more confidence, so it won't burn my garage or something. Of course, there are other differences, such as overall assembly quality, reliability, and user friendliness.
I will not discuss it in detail now. Nevertheless, I think the more expensive controller may win all these categories. But for now, you should be very clear when to use a cheap PWM solar charge controller When should you use expensive MPPT solar charge controllers. I hope you like this video. If so, please don't forget to like, share and subscribe. Stay creative, see you next time!.