Anyone familiar with LED strings?

DIY
1

I have the following setup for my veranda: a 12-volt battery, a SmartSolar MPPT, and several LED strings.

The LED strings consist of two copper wires with small glass droplets, each containing a tiny LED. The LEDs are mounted alternately (positive, negative, positive, etc.). When I connect them to DC power, they light up alternately. If I reverse the polarity, the other half lights up.

To make the LED strings usable, I route the output through a cheap inverter from AliExpress that converts DC to AC.

Now here’s the strange part: when I connect two strings in series, my SmartSolar reports a power draw of 7 watts. When I connect three strings in series, the controller reports a power draw of only 1 watt.

Can anyone explain this behavior?

2

do you have this “cheap” inverter connected to the battery or the load terminals of the MPPT?

3

the inverter is between te MPPT and the led-strings, so on the output side

4

so on the load terminals of the MPPT.

The change in load measured may be due to a change in the inverter’s efficiency, or the power factor of the load.

5

Leds are non linear components. They do not behave like a resistor. Instead they behave like a Zener diode with strong temperature dependance. Therefore you need a constant current source to operate them properly. I am using the Meanwell current sources for my direct DC light installation. Some know how description is here.