Eco-worthy 20a MPPT controller

DSchmidt_2000 wrote:
Did some testing today. (sorry for the data not being aligned- don't know how to post formatted text).

Setup:
45W 12V Solar Blvd panel with these specs
Maximum Power Voltage (Vmp): 18.0V
Maximum Power Current (Imp): 2.5A
Short Circuit Current (Isc): 2.73A

12V 35AH SLA battery which I depleted about 75% yesterday

Watt's-up meter in-line with the battery to measure current INTO the battery, battery voltage, and watts into battery.

DMM to measure the solar panel's voltage at the input of the MPPT controller.

I have Deans Connectors between the watts-up and the MPPT controller and between the solar panel and the MPPT controller so I can easily unplug things and make changes.

Testing: What I did was measure the current going into the battery if the MPPT controller was "in-the-loop", and then connected the solar panel directly to the battery. With the Deans connectors, I could do this switch around in seconds.

Here are the measurements in order they were taken (if no measurement listed - then I forgot to write it down)

With the MPPT "in-the-loop"
Solar V     Batt A     Batt V      Watts
16.76       3.08       12.51
17.00       3.05       12.51

Solar direct to battery
Solar V     Batt A     Batt V      Watts
            2.89       12.50V      35.5

With the MPPT "in-the-loop"
Solar V     Batt A     Batt V      Watts
17.05       3.02       12.51       37.4
16.94       3.07       12.52       37.1

Solar direct to battery
Solar V     Batt A     Batt V      Watts
            2.93       12.51       35.7

The battery voltage and watts were from the Watt's-up meter - it has uncertainty in its measurements hence the watts reported are not exactly that calculated just doing the math.

I'm a bit disappointed to not have a much greater charging amps (only ~ 0.1A greater) given the delta between the battery and the panel is about 4V. Thinking that I may just be so low in power that I'm not in a high efficiency zone for this MPPT controller.

Putting my ear to the MPPT controller, I hear a regular 'ticking' noise. Will at some point drag out my digital scope and take some measurements to see what is going on.