Can I use a 24 volt charge controller with a 48 volt windturbine

[wingnut]

Hi Folks,

I have a question that I am finding very hard to get an answer to and would appreciate your help.

I have a three phase 48 volt 1000 watt wind turbine and would like to know that if I fitted a 24 volt charge controller to it would I be able to get a it to produce twice the power with half the wind speed?

Has anybody every come across this concept?

Thanks

David

[Flux]

Forget the charge controller, that doesn't come into it.

If the turbine is intended for 48v you may possibly get a little more from it in low winds but without more details this is a guess. Even if true when the wind picks up the turbine will stall its prop on a 24v battery and the power produced will almost certainly be less. Even if you get enough wind to get it going at a decent speed the current will be limited by its 48v value so the maximum power from heating point of view will be the same amps into 24v so half power.

The only conceivable way that you can do this is with a mppt controller that actually changes the machines nominal 48v ( probably up to over 100 in this case) to 24v via a converter. This is high tech and no doubt far from anything you had in mind.

Flux

[wingnut]

Thanks Flux for your quick response.

I am trying to learn more about windturbines and I guess I have a long way to go.

The MPPT option is as you said "far from anything" I had in mind.

I was hoping to make use of a redundant 48 volt turbine with a 24 volt system that allready has a 24 volt battery bank and inverter. Without having to purchase more batteries and another inverter.

I should have asked the question a bit sooner as tomorrow was going to be hook up day, having allready installed the wind turbine .

I was hoping that the turbine would stall at at half it´s rated wind speed which is 7/8 m/s and since the average wind speed here is around 4/5 m/s all would be ok.

The worst case scenario is that I get little power from a turbine that was lying in the shed doing nothing, the best case scenario is that I have learned something about wind turbines!

Perhaps I should start saving for a bigger battery bank.

If anyone has any low tech possibilities / soluciones to my problem, I do not mind taking the nothing ventured nothing gained appoach.

[ghurd]

You do not say anything about the 48V machine.

If you can reconnect the phases "Jerry Rigged", it will be better suited to 24V.

G-

[wingnut]

Hi ghurd,

The 48 volt turbine is a Chinese made (shame on me) 48 volt 1000 watt 3 phase turbine, it is mounted on a 20 foot tower and has 9 foot blades.

I have made up a 3 phase bridge rectifier and connected it to a controller with a dump load. The batteries are 900 AH  of 2V x 12 OPZ.

Can I ask what  "jerry rigged" is?  If it is low tec and low cost and how does it work?

Wingnut

[wingnut]

I think that should be 4 and half foot blades!

[ghurd]

It is rectifying the phases individually.

It is probably wired Star (Y) now.  With 3 output wires.

Low tech and low cost.  One snip and 3 solders.

To change to Jerry Rigged, the coil's star point is cut and those 3 wires of the star point are brought out.  6 output wires.

Then each pair is single phase, and goes to a rectifier.

The open voltage at a given RPM will be reduced by a factor of 1.7.  Possibly a factor of 2.

So 48V becomes 28V or 24V.

The effective coil resistance is greatly reduced.

Probably the only practical way to get much power output, without some high tech magic.

Not sure if it is easy, or possible, with your machine.  It can be easy, very difficult, or nearly impossible to do.

It may be taking quite a chance on a factory made machine.

G-

[wingnut]

Thanks for the reply ghurd,

I have no idea if it is star or delta, it could be either as both have 3 wires coming out. It could well be delta as the turbine produces power at very low revs. But this is only guess work.

I can report that the turbine is producing some power, but I will have to wait for more wind to measure just how much. I will be happy with 15 amps, fingers crossed.