Eco-worthy 20a MPPT controller

JiminDenver wrote:
A second member just received one so we should be getting another review here soon.

I'm the other guy that bought one of these from the Eco-Worthy website. $102.50/shipped, and it was shipped from a US address (I think it came from So. Cal). Bought it May 10th, I think it was in my hands on May 15th.

Opened it up and saw the large toroid in there for the buck topology. Power transistors and flyback Schottky are TO-220 cased and clamped to the sides of the case. The thermister is also clamped to the case to the upper right side.

Not 100% sure as I haven't poked too much at it, but I think the buck controller IS the microcontroller - a PIC 18F series chip. There are a pair of 25-turn trimmers on the board - not sure what they're used for but maybe to calibrate the current and voltage measurements. Not much else on the board semi-conductor wise.

There is a 5 pin header (or was it 6?) at the top of the PCB which looks like the same in-circuit serial programming header used for PIC controllers. I haven't tried to read out the contents of the chip to see if it is read protected.

As far as operation goes, my test setup right now is just a pair of 8AH 12V SLA batteries and a single 45W 12V panel. Again, this is just for playing - it's what I do.

I have a Watts-up meter right now in series with the battery to measure current INTO the battery. I have a second Watts-up that I need to repair and once I do will go in-line with the solar panel. For now I am measuring solar panel current with a DC clamp meter and measuring the voltage with a standalone DMM.

Around 9AM with the panel tilted to the sun, I was measuring ~ 2.5A into the battery and 2.05A from the solar panel. Measuring the voltage from the solar panel the controller was finding Vmp at ~ 17.4V (solar panel is marked Vmp at 18V).

Every 2 mins the controllers re-seeks MPPT as evidenced by the solar panel voltage shooting up to 21V, then dropping down to under 15V and quickly creeping back up.

As I do more testing I'll post more but likely not before I get my 2nd Watts-up meter repaired. Also will hookup a larger SLA battery (35AH) later but need to drain it a bit.

Lastly I do have a USB data logger (MCCDAQ 1208LS) that someday I'll get wired up to automatically track solar/battery voltage/current over time but I need to get some current measurement IC's on order first.

Happy with the 'performance' right now. As mentioned elsewhere, this will allow me to buy and play with those cheap 24V panels from Solarblvd.