Charge controller

[Markcw]

Good day everyone, I am looking at helping my grandson build his first turbine as a little project, a friend of mine has sent me a 28v DC three phase Pmg still scratching my head as there are three wired coming out of it lol I was expecting two. Anyway about a charge controller I was looking at putting it into a 12v battery can you get mppt charge controllers which will sort this out, the Pmg is rated at 11.5 amps at 28 v , hopefully you can get what I am looking at
Many thanks
Mark

[DamonHD]

Firstly, welcome.

Secondly, a grown-up will be along shortly, but I think that you'll need two things:

1) A three-phase bridge rectifier.

2) An (MPPT) wind charge controller.

Rgds

Damon

[Markcw]

Hi and thanks for the kind welcome, I have just ordered a three phase rectifier, I tried testing the voltage on two phases and it was putting out a good voltage at about 80rpm hopefully will be able to do some number crunching so I can get  the open  rpmv after it had been rectified.

[mab]

hello! Don't know about grown up, but:

well you've already sorted out the 2 wire output to battery with the rectifier, so it's just protecting the battery from overcharge.

There are MPPT controllers for wind turbines but I don't know very much about which ones are good unless your happy to buy the very expensive ones like the midnite classic; even the cheap MPPT controllers are quite pricey - beware the very cheap ones from china as they claim MPPT but often are not. You might be better off starting with a cheaper shunt type regulator - may not be quite as efficient at charging the battery but a lot cheaper. If you google wind turbine charge controller there are some cheap ones (from china probably) that will show up.

At the risk of pointing out what you may already know: charge controllers for wind turbines are different from solar controllers in that solar controllers unload the solar panels when the battery is full - running a wind turbine unloaded is generally a bad idea as it overspeeds - hence use a controller that shunts excess power.

[Adriaan Kragten]

On my website: www.kdwindturbines.nl you find a free manual of a 200 W battery charge controller for a 24 V battery. The manual is given at the bottom of the list with KD-reports. You can increase the power which can be dissipated by connecting several dump loads in parallel for one voltage controller. In the manual it is described how the voltage controller and the dump load can be modified for a 12 V battery.

[Markcw]

Thanks for the replies, and the link to the charge controller,  a dump load will be a must, it is very windy at my location I am just under a 1000 above sea level and about 3 miles inland from the coast so loads of wind , I look down on a couple of turbine's Was thinking of dumping it into a water heater, this would be helpful as I heat with fuel oil
It's the wind that will be the problem gusts of 30 MTRS plus are quite
common .

[makenzie71]

Hi Mark!  Two weeks late to the party but hopefully still a bit of help!

I wouldn't worry about trying to find an MPPT controller for that little motor.  A proper MPPT controller is going to be pretty pricy and they generally need a lot more volts than what you're going to be dealing with...and while with a large turbine that 1~5% increase in production might make a difference, on your little 400w (max) motor it's going to be pretty minimal...simply not worth the additional cost.

My suggested shopping list if you're wanting to this to dump into a heating element (I understand you're not in the states so you'll need to find equivalents in your market...this is all generic so that should be easy enough):

Two of these
Two of these
One of these

You will run your three wires to the bridge rectifier.  This will convert your three phase AC current to DC current.

Run the positive terminal from your battery to the positive terminal on your rectifier, and then run another line from the positive terminal of the battery to your heating element.

This is where the relays come into play.  I've tried to write this part out like four times and it comes out wrong...I'll attach a diagram lol

You will then wire in your "brain" controllers with one controlling each relay.  You will set up the controller between the battery and the rectifier to disconnect power at something like 32v and turn back on at something like 26v.  The controller between the rectifier and the heating element you'll program to turn on at something like 30v and off at 28v.

What you're playing with here is a pretty small, low output generator and this arrangement is going to be a really simple and relatively inexpensive way to use the power it's creating...it will also be robust enough to allow you a bit of expansion down the road.

[kitestrings]

Mac, I’m not sure why you need to disconnect the battery at all. Why not just add the load, as needed, with the one control & relay?  ~ks

[makenzie71]

The idea is to disconnect the generator voltage gets too high and disconnect the load voltage gets too low. But I imagine I would wear just the same with such a small system. Who such a little water generator attached to a heating element the boulders republic never get too high anyway.

[kitestrings]

I don't think I'd ever disconnect from the battery, except maybe as a last ditch survival measure I suppose.  If the voltage is too high from the turbine and you remove the battery, it seems like the problem is made worse, especially if the dump load doesn't close in or can't handle the load. 

[makenzie71]

In the arrangement shown by the time the battery disconnects from the turbine the heating element should already be connected.  There is a possibility that the relay or controller will fail but they're both very simple, reliable devices...it's not likely.  If the turbine is always connected to the battery, in a situation where it's pumping out too much voltage the battery will be damaged.

Most of it is a moot point in this context, though...the motor used as a generator here is going to be pretty low wattage, the whole system will be under a fairly small load at all times.  Even if the generator breaks loose and freewheels it probably won't cause much harm.

[Markcw]

Thanks for the replies, that would be quite helpful , if the small one goes ok I might plan on putting up a larger one, I am looking at putting up some solar as well,  it the hot water that would be helpful as it all comes off the boiler I am installing the hot water tank in the next couple of weeks,  I don't use a lot of power so my base load is low , being south facing and on top of a hill with good wind it seems madness not to use it,

[gsw999]

Thanks for the replies, that would be quite helpful , if the small one goes ok I might plan on putting up a larger one, I am looking at putting up some solar as well,  it the hot water that would be helpful as it all comes off the boiler I am installing the hot water tank in the next couple of weeks,  I don't use a lot of power so my base load is low , being south facing and on top of a hill with good wind it seems madness not to use it,

I actually managed to get a solar controller working connected to my wind turbine and it seems to have an automatic dump load , they are only about 10£ , I can post a link to a video me showing it working.

Cheers , I am in the Uk as well , my Youtube is GavinFreedomLover.

[Markcw]

Thanks for the reply Gavin, yes a link would be fantastic, I am just bench testing the Pmg, I wouldn't want to draw more than than 500w out of it in a hurricane, it starts charging a 12v battery at 90 rpm , hopefully I can get our blades to go faster as I was looking at a 24 v bank,  where abouts are you in the UK, I am in West Wales

[gsw999]

https://youtu.be/9sGn1NN4d4o

You may have to cut and paste it .

Cheers


Gavin