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MPPT regulator is genuine MPPT

May 22, 2019 — BarryK

I posted about a couple of very cheap Chinese MPPT regulators that I purchased, for use with my 12V battery and photovoltaic solar panel:

As I mentioned in that post, there are many cheap regulators labelled as "MPPT" but are actually only PWM type. There is one particular model, that is very cheap yet does seem to be genuine MPPT, but there is some conflicting information in YouTube videos. So, I wanted to find out for myself.

As reported in that post, I ordered two, that seemed to be the same, and upon arrival I opened them up and they are identical inside. I paid AU$46.71 and AU$48.44, and just now looking at the eBay links, I see that the prices have gone up, now AU$64.99 and AU$49.46 (latter with discount code). Vendors are "intl-trading" and "sunyee-au", respectively, Aussie businesses, with AU stock.

As they looked identical internally, I only tested the one from intl-trading, and I am pleased to report that it is a genuine MPPT regulator. Photo of test setup:


I have not tested conversion efficiency, nor idle current, just wanted to confirm that it is genuine MPPT.

Passing puffy clouds in the sky, which was a very good opportunity to observe peak-power point tracking of the regulator. The digital power-meter on the input side, displays voltage, amperes, and power, and I was very pleased to observe the regulator accurately tracking the peak-power point as the sun faded and came back.

The three state-of-charge LEDs also did their job. I started off with the battery slightly discharged, which I achieved by running a desk lamp via a small 12-240 volt inverter. After plugging the regulator to the battery, solar panel not yet connected, two LEDs lit up. Yes, I also tested before having discharged the battery, and got three LEDs lit up. Very good.

After connecting the solar panel, all three LEDs lit up, which is to be expected. The LEDs would only be expected to give an accurate indication of charge without charging, and the battery voltage stabilized. Note, a stabilized battery voltage is quickly achieved by connecting a load to the battery (without charging connected), then remove the load, and the voltage will rise up, within 3 minutes and stabilize -- that voltage is what you read to determine state-of-charge. There is a bit of variation depending on what type of lead-acid battery, but for most deep-cycle batteries, from memory, it is 11.7V 0% up to 12.7V 100% -- I will check this with my battery, need to recharge it fully first.

EDIT 2019-05-25:
Open circuit stabilized voltage of the Waeco "CoolPower 44" at 100% charge is 12.85V. So, 0% will be about 1V below that.

Probably when I get setup for a camping trip, will configure the two sides of the folding solar panel in series, giving "24V", as this will result in lower current along the cable and into the regulator, which may be "better" for the regulator. 

Tags: nomad