MPPT Controller

[tonys681]

Hi there, I am new to solar so please forgive me if my knowledge is a little lacking. I have purchased a supposed MPPT controller from China but i am not convinced it is a true MPPT unit. I have attached a photo of the inside of the unit and i was hopefull that more learned people than i may possibly be able to tell from the contents whether it is a fake or not. Failing that what would be the process for testing the controller. The reason for my doubt is that i have been told that MPPT controllers must have toroidal coils in the unit. Any assistance would be greatly appreciated.

[Naptown]

The easiest way to test is with an ammeter. Test amps going to controller from panel and controller to battery. If the same it is a pwm.
Depending on panel voltage you will see a slight to dramatic increase in amps to the battery. That would be an mppt

[inetdog]

The easiest way to test is with an ammeter. Test amps going to controller from panel and controller to battery. If the same it is a pwm.
Depending on panel voltage you will see a slight to dramatic increase in amps to the battery. That would be an mppt

Although it is still possible to incorporate a DC to DC convertor to get a current multiplication effect without actually implementing a full MPPT algorithm.
The simplest "pseudo MPPT" algorithm is to measure Voc and then simply set the operating point to a fixed voltage, roughly 80 % of the measured Voc.

[tonys681]

Thank you for the suggestions but i do not have an ammeter. Is it possible to look at the circuit board and identify components that are used only in MPPT controllers and not PWM, is there anyone out there who can assist. If necessary i can re-photo the circuit board from a little closer if you cannot see it properly.

[Mike90250]

without a meter, you cannot test. There may be backside components that dont show in the front view.

it looks like a fancy card, but I don't see an inductor large enough to be a positive indicator of MPPT.

[tonys681]

Thank you for your comment, i have attached a few more photos of the controller hoping that someone can identify components that are solely used by MPPT controllers and not PWM.14-10-1.jpg14-10-2.jpg14-10-3.jpg

[Mike90250]

I see a couple IC's, but you nearly need a special chip for MPPT.

I also see a large heatsink, which indicates either high losses, or it's about a 30amp MPPT unit. I didn't see any thermistors for thermal feedback and current roll back. I still suspect PWM.

[tonys681]

The item is an alleged 40amp MPPT

[Mike90250]

the operative word is alleged . I doubt it. The little inductor mid board, likely can't manage that.

[tonys681]

What would be the reason to have an inductor on the board in the first place.

[tonys681]

I have attached a link which may throw further light in whether the item i bought is a true MPPT controller.

http://rittalups.en.alibaba.com/product/961043241-212463933/12V_24V_40A_with_built_in_copper_coils_MPPT_solar_charge_controller.html

two points i will make

1 Perhaps the inductor is classed as copper coils
2 There was no RJ45 connector on the unit

[Mike90250]

I don't see how it's possible, maybe 20-30 amps. 40, no way. All the 40-80a MPPT controllers I've seen have large heat sinks, and / or forced cooling fans. even with 95% efficiency at 1,000 watts, that's 50 watts of heat that has to go somewhere. the small heatsink and circular holes made to look like there is a fan there, won't do it. When you hook it up, and it'd running , what does the LCD indicate to you? If your PV panel is rated for 3 amps, and the LCD shows it's producing 5 amps, that would indicate some sort of MPPT happening, or just pure fakery. You have to have an ampmeter to be sure. Even cheap $10 multimeter generally will measure up to 10 amps. I can't tell by parts, but the lack of proper heatsink is pretty damming.

[Mike90250]

What would be the reason to have an inductor on the board in the first place.

The inductor, along with a capacitor, are the energy conversion units of a Buck/Boost circuit. That's how the MPPT point is converted from the panel voltage to the battery charge voltage. The theory of how they work is beyond what I can teach here for free. There is an oscillator that chops the incoming DC to 10 - 50 KHz AC, gets stored in transformer/ (copper coil)/ inductor then rectified back to DC. The higher the operating frequency, the smaller the transformer, but the more complex the circuit is.

[tonys681]

If you examine the link that i posted previously you will see from the photos of the controller innards that there is a fan, and the heatsink is a reasonable size within. I am not an expert but can anyone say with certainty that it is not a MPPT controller. The problem i have is that i live in Brisbane Australia and the daily temperature is between 28 and 35 degrees C so i guess this will have an effect. Just to get into the controller i had to drill out the security screws (not easy) to change a jumper to reflect gell cell batteries, not user friendly

[tonys681]

Sorry i forgot to mention the LED. The display shows "Input Solar" amps and vdc and "Output" amps and vdc, they are the only figures shown on the LED the rest are battery idiot lights and power light on the front