Hi,
I recently bought 2 each 10 amp controllers from
AliExpress.com I did a search for PWM 10 amp controller, and then sorted by cost. I bought them for $13 each.
Did I get my money's worth? I don't know for a couple of years, but it is controlling properly a pair of 45 watt panels I removed from my RV and installed on a friends house. He is running some 24 LED panels to light up the front of his house at night, so the controller also runs the lights dusk to dawn with it's built in output control.
I checked the voltage a few days ago, during the daytime, it was charging at 13.4 volts, and worked great. The lights work great as well, lighting up the front of the house pretty well.
By the way, I used #18 gauge wire from the solar panel to the controller - about 4' and 2' from the controller to the battery (26 AH 12 volt sealed battery) and about 30' more #18 wire to the light panels, a total load of around 1 amp for up to 12 hours per day, though now the sun sets at 9:30 and lights are going off before 5:30 am now.
This is a no frills controller, so I have no idea how many amps the 20 year old solar panels are putting out. Probably less than 6 amps per hour around noon.
I don't really think that a MPPT controller will put out that many more amps than a PWM controller like I have.
You can use a much less expensive PWM controller, and install another 120 watt solar panel if you need to add more amperage. The $100 spent on the panel will make a lot more power than spending a additional $100 on a higher quality MPPT controller.
This place will sell a 12 volt nominal solar panel for about $1.50 per rated watt. My suggestion is to not install a solar panel larger than about 150 watts, though if you get a good deal on a 180 watt, it might work if you have enough space on the roof. Even my 120 watt panels where difficult to locate a place to install them. 12 volt nominal is a 19 - 22 volt open circuit output voltage (without wires connected to a load or battery, in full sun.).
SunElec.comThe PWM controller will turn on and off the full output from the panel like a light switch, and only use about 0.050 volts drop across it. I have seen higher output amperage from my solar panels when camping in cold weather at 4,500 feet of elevation, in November. This was with a Mark 15 amp controller, back in 1994.
MPPT controllers can use more power than a PWM controller, though they do "Try" to increase the amperage by transforming the 19 volts to 13 volts, and increase the amperage that way. However nothing is 100% energy efficient.
Though I have a 1999 model year Solar Boost 50 amp MPPT controller on my motorhome, I am no longer sold on their advantages of increasing the amperage. I have not tried to bypass my controller, and measure the amperage going into my battery bank, to compare the output with my 50 amp controller.
And with the lower priced solar panels today, the advantage of a small boost using a very expensive controller, the extra cost is no longer justified. I think my controller was around $400 back in 1999.
Fred.
