Do those cheap charge controlers on Azon work?

[Vortex2]

Azon has a load of Chinese mega cheap PV charge controllers.

Do they actually work?

What is the cheapest tiny/small controller you would trust?

[adam2]

Yes they do work, and are well worth consideration for small or low cost systems.

Avoid for anything critical upon which human life may depend, but fine for a few lights in isolated premises.
Think twice about long term unattended operation, but fine for use in a household or other occupied premises.

Adopt a cautious approach when installing a cheap charge controller.
Limit the charge and discharge currents to 50% of the claimed rating, which is probably in chinese amps.
Fit a fuse close to the battery, do not rely on a fuse built into the controller.
Install in a cool and well ventilated area.
Fit on a fire resistant surface, NEVER ON WOOD.

[adam2]

Features that may be included in the larger and more costly controllers, but that are less common in cheaper units.

1) lights out during daylight, useful for street lighting, or for institutions, seldom needed for a basic domestic installation.
2) Battery temperature compensation. useful for large installations, less important for small and simple jobs with a single cheap battery.
3) Adjustment for different battery types. Flooded lead acid is a a common choice.
4) Lights out at low battery voltage, often after a warning flash.

The above features add to costs and also increase the risks of mistakes in setting up and programming.

[Vortex2]

Thanks Adam!