Hi all new here so sorry if I put this in the wrong forum.

I have recently brought a 2016 for transit custom, its a high roof and has a spinny fan thing on the roof, It doesn't use power to run it it just runs off the fan thing on top

This is probably as stupid question.

Is there anything that I can do to get it or buy something that will make it generate power.

I Run all battery equipment in my gardening business and have a leisure battery, connected to an inverter and is all wired in so it charges while the van runs this is how we charge the batteries on our travels, but I would love a way to have it trickle charged while the van is off and the batteries are still charging

I am pretty sure someone will have a sarky comment like Ive had on other forums think its just a thing in forums

But I keep looking at this spinny vent thing a keep thinking what if.

Whilst I don't know of any device that you could replace the ventilator with, other than this (which I think is a bit rubbish):
https://www.ebay.co.uk/itm/197918758861
No link to device above?
It may be useful to charge whilst stationary and windy f you can find something more like your vent.
Another idea (from the caravan world) if you want to charge would be to fit a solar panel to the roof but don't expect much in winter and ensure you use the correct seal device for the hole in the roof!

I have a small solar panel on the dash, done that this weekend so gotta see how that goes but that fan could work if it could be converted , Thank you

Wind powered roof fans (roof turbines) on vans are intended to ventilate the cargo space while driving. As a bonus it also ventilates the cargo space on windy days when the vehicle is stationary.

In most countries these roof turbines are mandatory on vans that carry or transport flammable gases.


These roof turbines are way too small to generate any significant power. In theory the turbine shaft can be extended, and a permanent magnet rotor can be put onto the extended shaft. Add a wire wound stator and the spinning turbine will generate AC power.

The main problem however is that the permanent magnet generator generates load and mechanical losses. The load + mechanical losses must always be less than the wind power otherwise the turbine will not run at all. In practice this means that these type of roof turbines are only capable to drive a very small permanent magnet generator.

Another problem is that the generated AC power needs to be converted to a suitable DC power to charge the battery. This requires a rectifier/regulator system that is also capable to measure/calculate the state of charge of the battery.

The power output will be extremely limited and the wind speed will almost certainly be only sufficient while the vehicle is driving.

Yer I knew about what the fan/spinny thing was there for , just wanted to try and use it another way but from what ya saying it aint gonna work, Thank you