I would like to start this topic to get some efficiency information. So if you have efficiency information on MPPT chargers I would like to encourage you to post it here. Also the measurement methods are of interest.
What I did was the following:
- I use a lab power supply and set the current limit such that the output of the charger is the current at which you want to determine the efficiency.
- I set the voltage to 17V because that resembles the MP for a 12V panel
- I assure that the battery is sufficiently empty to assure charging is in CC mode.
- I have two power meters that I calibrated by measuring the energy for a certain time for a load at the current at which I want to determine the efficiency. One in front of the DUT and one behind the DUT.
- I measure the energy for a time that gives sufficient accuracy and divide the outgoing energy (Wh) by the incoming energy. This number is the end-to-end conversion efficiency.
Today I tried a setup to measure efficiency. The DUT was the Genasun GV-10. The result at an output current of 5A was 0.948. So 94.8% Not really the 96-98% they claim.