Temu solar street light with generous solar panel & LiFePO4 cell

I have to admit, this exceeded my expectations significantly. The plastic light housing was slightly disappointing, but viable, since the power of the light is only around 5W with a fully charged cell and maximum intensity selected.

The solar panel itself seems fairly robust, and is based on a glass panel with the silicon cells laminated onto the back with a white plastic film.

I'm in the progress of testing the LiFePO4 lithium cell, but it does appear to have the correct dimensions (32700) for a 6Ah cell. The cell test is currently in progress.

First full charge cycle on the 32700 (32mm diameter - 70mm long) lithium cell shows an impressive input of 5.5Ah. And it's notable that the FM2112 protection module (LiFePO4 equivalent to DW01) ended the charge earlier than expected, so it does look like a genuine 6Ah cell.

The circuitry is minimalist with good functionality. I like the fact that it uses coloured battery status LEDs in the main LED window. One quirk is that they are powered from the unregulated positive rail, so if the cell reaches full charge and the protection circuit kicks in, the solar panel voltage could theoretically float high enough to allow current to flow through the battery indicator LEDs and the chip protection diodes on those pins.

With a fully charged (3.65V) cell the eight LED power settings are as follows:-
1.7A = 5.1W (calculated with LED voltage of 3V)
1.5A = 4.5W
1.3A = 3.9W
1.1A = 3.3W
0.9A = 2.7W
0.7A = 2.1W
0.5A = 1.5W
0.3A = 0.9W
0.1A = 0.3W

As the cell discharges the power will fall progressively. Roughly half the power at mid discharge, and progressively lower as the cell drops to its end of discharge voltage of 2.5V. As the cell reaches 2.5V the battery level indicators start flashing and just below that level the unit cuts out.
At that point the LED current has dropped to just 7mA at full intensity setting, so the unit could still be putting out at least a faint glow on dark winter nights with low daytime sun.


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