Cheapest DIY non PWM wind charge controller


Well-known member
Mar 7, 2018
I have a 700W wind turbine that I use in a remote location and have learnt quite a bit about how they can steal any any hope of a decent nights sleep in a storm (especially with the wrong blades on). The turbine eventually took ultimate revenge on me when I broke a rib taking it down one day.

What I did learn though is that the vast majority of cheap wind turbines sold on various sites always seem to bundle in a PWM charge unit, which effectively destroys any hope of getting the most (or anything) out of the turbine. Turbines work with a power profile the opposite to solar. The more wind, the higher the rpm, the more volts BUT the current does not necessarily increase. This is why PWM will tend to burnout and overload turbines in high winds, they just try and keep pulling more and more amps at the same volts, overheating the generator.

Therea are also some smaller turbines, which are sold as 12V (with a cheap PWM controller) when the generators are wired for a much higher voltage and then there is no wonder as to why there are so many complaints the turbine "does not work". 0.5A at 12V is not a lot, but at 200V it's a little different.

My turbine is "rated" for 20A but I have already managed to melt one winding to the outer casing (think this was when I had a slight different incident in a storm very early on, which is where I thought the turbine was going to fall on me in a gale)

Scanning for parts I noticed this boost controller and had a thought.....
1614037649741.png (check for other sellers and pricing)

I currently use a combination of a 1kW grid tie inverter (GTIL) and an 1800W boost controller. The reason is the wind turbine is "rated" at 24V and the 1kW unit only starts to pickup around 18-20V. So, when the wind is calm I disconnect (NO relay connected to the supply feeding the grid tie unit) the 1kW unit and attach the boost controller (switch the breaker on) with the input voltage set and held at 12-18V depending on the wind. This allows a few extra Wh to be captured and also allows me to switch off the main inverter (I run the grid tie connected to my inverter ouput - don't try this without reading up more) saving an additional 23W. Not ideal as it requires a bit of manual intervention, which is not good at 3am when an unexpected squall starts pushing out 400W and overloading at 18V, needing me to switch the inverter on.

The boost unit has a wide input range (upto 60V) and the wind turbine can get over 60V if it goes open circuit, but I have a bridge rectifier hard wired and connected to the battery as an effective safeguard and this then caps the voltage and always provides a fail safe load. The boost controller output is upto 120V so more than ok for a 48V pack. Input current is limited to 15A though and trying to work out if these would work in parallel because the shunt line appears to be at the +ve side of the output (can't see an image of the reverse of the PCB to check).

The controller is programmable via the serial port, which is on the left of the LCD panel with the tx and rx marked.

So this got me thinking, why not track the input voltage and adjust the output current to allow the input to rise and decrease with the wind. Effectively tracking the volts to rpm to get the maximum output from the turbine. With 9600bps serial line an update rate of at least 4Hz should be possible.

This may be a complete fail if the firmware for the unit does not like to work with a varying input voltage and may yet fail if the output is not updated fast enough and the input voltage collapses.

This should in theory allow for around 700W between 12V and 48V (battery voltage) output from the turbine to be optimised at a fraction of the cost of any comparable tracking charge controller. If they can work in parallel, then this get's really interesting as it could then scale to work with 2kW turbines.

For the 700W unit I have the output starts effectively around 12V and the current output capability rises with voltage upto about 23V when about 15A is possible, from there the voltage rises and the current rises upto about 18A at over 50V, giving peaks of over 1.2kW in stormy weather.

So, question is, has anyone played around with these particular boost units or have seen any others (cheap) that could work ?