Advice Needed - 24v Battery Bank on 48v Turbine

[lowerstoford]

Updated ***

Hi

Hopefully I have put this in the correct section.....

I am new to wind power and need some advice on a few modifications I would like to make to my system.

The story so far.....

About 3 years ago I obtained a 750W 48V 15A ARI (Cheap China Made) Turbine and a combined charge controller and dump load.

After a few 100 hours of research and many hours trying to source all the other parts I needed for the tower and power side of things, I eventually have the system installed and turning at the bottom of my garden.

The location is not idea and I have discovered (like many others) that I do not have enough wind!
What I mean by this is to charge the 48V battery bank I need to produce over 48V , but I have only had around 10 seconds of charge over the last few days of nice stormy weather.
Watching the controller it is producing 22-30v most of the time.

***The wind speed we are talking about are on average 5-12ms with gust of 16m/s. This is being measured via a weather station located at the same hight as the turbine***

I just seem to be generating electricity and wasting it? Where does this voltage go when it not above the battery level?

So after a little more research I have found that if i lower the battery voltage to 24V, which is closer to the voltage levels the turbine is producing. I should be able to get some charge into the batteries.

I understand that i will reduce the output power of the turbine from 750W to 360W (not sure about these figures) but I am more interested in generating SOME electricity.
I also understand that I probably can not use my current controller.

So here are my questions

1. Can I use the dump load that came with the original controller? If I need to get a new one can anyone advise on size, as my turbine is 48v capable of 60V, but I am using 24v battery bank
I may even go down to 12v battery bank.
2. Am i understanding things correctly, with regard to using lower voltage batteries on a 48v system.
3. How can i get more wind? :-)

Thanks in advance for any ideas, suggestions, hints or answers

Kind Regards

Lee

[thirteen]

are there trees in the way can you go higher? Get a ballon and tie some colored tape at certain hights on the string holding the ballon and see if there is wind up higher or maybe from a different direction. Are your blades corrct for the machine?
As for the voltage I know enough to get myself into trouble at times. Could it have been changed internally for a different output? 13

[lowerstoford]

Hi

Thanks for the reply

I should maybe get rid of question 3, there is no way of modifying or moving the tower.

I am going to look inside the charge controller as soon as I can. I was hoping to see a POT that i can move reduce the voltage it is set to run on, but truthfully its so cheap i doubt it.

I am going to get a Tristar TS45 and set it up in diversion mode as described on Hugo's site

With my very limited knowledge, i feel that the dump load will be fine at for the lower voltage battery pack, but I am really not sure and can afford to damage my batteries, turbine or anything else.

[lowerstoford]

The wind speed we are talking about are on average 5-12ms with gust of 16m/s. This is being measured via a weather station located at the same hight as the turbine

I just seem to be generating electricity and wasting it? Where does this voltage go when it not above the battery level?

[Mary B]

You need to change the charge controller to 24 volt. If that is not possible you need a different charge controller as you thought.

[lowerstoford]

MaryAlana - Yes, I have no problem changing the controller

I am going to get a Tristar TS45

I need to know if I need to change the dump load of will the one I have be fine?

[ChrisOlson]

I highly doubt you have an actual charge controller with that turbine.  A charge controller does bulk/absorb/float (and some do equalize) on a battery bank.  I think all you more than likely have is a simple dump/diversion controller.

If the anemometer is showing wind up to 12 m/s and you're not getting proper voltage I suspect either a problem with the turbine itself (shorted wiring or burned out phase), or with the controller (dump load relay stuck on, defective rectifier, etc).

I would start by disconnecting the turbine from the controller and running the three legs thru an external rectifier to the battery bank and see what you get.

It will not work very well to use a turbine wound for 48 volts on a 24 volt battery bank.  The turbine will run too slow and never produce any power.
--
Chris

[lowerstoford]

Thanks Chris

I understand what you mean re the "Controller"

Before I read about lowering the battery voltage I already planned to change the "Controller"

I was thinking of getting this rectifier to start with

http://www.ebay.co.uk/itm/Bridge-Rectifier-3-Three-Phase-Diode-90A-AMP-1000V-SQL90A-High-Quality-/130704677742?_trksid=p2047675.m1982&_trkparms=aid%3D333005%26algo%3DRIC.FIT%26ao%3D1%26asc%3D120%26meid%3D3623407384680969732%26pid%3D100009%26prg%3D1070%26rk%3D5%26sd%3D260841089892%26

do you have any comments?

This will allow me to test the system

[ChrisOlson]

Any three-phase bridge rectifier will work to test it and see if you have a turbine problem or a problem in the "controller".

You won't need any sort of "dump load" to test it and see if it works, because the chances of it driving the battery over-voltage are slim to none with a turbine that small on a battery bank that's not charged up.
--
Chris

[lowerstoford]

OK

Rectifier ordered

I want to order the new controller now...........

but i need to know if I can use the one I have, if i stay at 48v battery bank then there should not be a problem?
it is a copper wire heater type dump?

My battery is dropping still 48/47.6V at the moment

Forecast winds of 13 to 29 tonight so I am really hoping to see some charge went in over night.

I have one question that is puzzling me....

Is there anyway i can use/store the voltage that is being produced if it is below the battery voltage. i.e. when the turbine is running, it is producing 20-30v on average. There must be someway of using this voltage, there must be???

[lowerstoford]

Thought I better add this bit of info

Im not sure if it is making any difference

I am running this turbine on my test battery bank

This consists of 8 12v 7ah (Yes, you read this right!)

I have used this battery with my 7W solar cell and a number of 2A led strips for a few months

at 12v it is 56ah but at 48 it is only 14ah

could this cause a problem?

This is only while i make sure everything is working, before I invest in 125ah batteries

[ChrisOlson]

If the turbine is working properly on the 48 volt battery, I'm afraid there is no real practical way to use the lower voltage power when it is "idling" on the tower below battery bank voltage.  The amount of watts the turbine develops at those low wind speeds is barely enough to charge a cell phone battery.
--
Chris

[lowerstoford]

i am really not understanding the principles of a turbine

If I look at the power curve of the turbine and take the figures from that and the wind speed data I have, if i can collect the power at lower voltages I should have useable amounts

if 750w at 48v =15a

The at 8 m/s the turbine produces 240w the voltage reads 28v which I work out as 8.5a

What am i not understanding?

Thanks for your help so far.

I

[ChrisOlson]

if 750w at 48v =15a

The at 8 m/s the turbine produces 240w the voltage reads 28v which I work out as 8.5a

What am i not understanding?

The voltage of the battery should not drop too much below the nominal of 48 volts.  So assuming the battery is at 48, and the 750 watts does equal about 15 amps.  However, as the wind dies down and the output drops to 240 watts, the voltage of the battery will still be at 48 so the amps is now about 5 amps.

With a wind turbine the voltage is always "clamped" by whatever voltage the battery bank is at and the only thing that varies is the amps it outputs to the bank.  If the turbine is running too slow to provide battery voltage for charging then it is "idling" on the tower and needs stronger wind to get the voltage up enough to start charging again.

It is possible that the turbine you have is a high wind turbine and is designed for very poor performance in low winds.  This is pretty typical of most of the Chinese built turbines.  However again, testing it without the "controller" that comes with it will tell you if it is operating correctly, or if there's a problem in the controller or with the turbine itself.  Even most of the Chinese models produce some power at their nominal voltage rating down to about 3 m/s wind speed.
--
Chris

[lowerstoford]

Chris, Thank You

This is just how I thought turbines worked

I knew that I would not get 750W out of it as the wind is not great here, but I thought i Would get something out of it

I think there is some problem with the "Controller" The charge light starts flashing at 10V (Shown on the LCD screen) which happens at 3.2m/s
But its not charging?

If I am understanding it, it should be producing and charging the battery at most speeds above 3m/s, just not as much as at its rated speed 12m/s

Lee

[lowerstoford]

Here is a update on the situation and what I have learnt from this forum
Also some more question.

Thank you all for your help so far

1. New Rectifier Purchased - SQL100A/1000V
2. New Controller Purchased - Tristar TS45
3. Parts ordered to make new brake switch - anyone know of any good plans?

I believe the controller is faulty or just plain rubbish.
I believe the turbine is OK, but further tests are needed when i get the new rectifier.

I should get a nominal voltage of 48+ from the turbine at its incision speed of 3m/s but lower current.

Current should increase as speed increases

As long as my turbine is running at over 3m/s the batteries should get some charge

I had a 48v to 12v step down connected direct to the battery, is this OK or do i need a diode or something else between this dc-dc convertor and the battery?

[tanner0441]

Hi

I have a Chinese turbine and controller and it is as Chris says. Just a diode block in a box with a couple of meters and a diversion dump load with a fan behind it using a big relay, my dump load is a NiChrome, element inside a steel sheath.

What height is your turbine because ground turbulence could also be affecting the performance.

Brian.

[lowerstoford]

Im almost convinced the controller is at fault, because the turbine spins and spins fast.

We have 9.2m/s at the moment with 12m/s gusts so using the power curve it should be producing around 360W min, but its not charging at all
Voltage meter shows 24.9V current 00.0

Just need the wind to go away for a few days so i can test the 3 phases and then get the new parts setup and installed.

I don't understand why there is a voltage meter for the turbine? if what Chris says about the voltage should stay around 48V but the current should increase with wind speed.

The current meter only shows a reading when the voltage meter goes over battery voltage?

The tower is 6.5m on the edge of open farmland. I was limited to where I could put it, but it looks fine apart from when we get strong S winds, it gets blown around a bit, this is caused by the barns on the south side of it. SW and SE its fine. Nothing can be done about location.

I just want it to create something

[ChrisOlson]

I really think you have a mechanical problem with something there - either the "controller" or the turbine.  You can check voltage from the three legs coming from the turbine if you can gain access to them inside that "controller" box.  You'll see at least about 35 volts AC checking phase to phase if the turbine is running fast enough to make 48 volts DC.  If you get normal phase voltage, but no DC voltage, then the controller is junk.

If the phase voltage is low but the same on all three legs (checking leg to leg), then verify that you actually have a 48 volt turbine.  Could it be a 24 volt model instead?
--
Chris

[tanner0441]

Hi Chris,

If it is the same as mine it is three bridges on a sheet of ally, my volt meter is 30V FSD with a red line at 12 and 24 the ammeter is 48 FSD.  There is a bit of mixed discreet and IC electronics and a big enclosed relay with a TIP something or other to switch it.

Could he short the three legs and see if it brakes the turbine smoothly or it turns lumpy.

My turbine came with a book with the model number and specs for all the turbines in the range with a hand written tick in the margin.

Brian.

[ChrisOlson]

Yes, shorting the legs will tell if all three phases are functional.  That's assuming you can see and hear the turbine when you short them all together.  If it vibrates when you short them then you have an open wire or dead phase.  It stops smoothly then they're all working fine.  If it don't stop at all then you have two open wires or dead phases.
--
Chris

[lowerstoford]

Hi Guys

I have had to turn the turbine off

I have flicked the brake switch, which does indeed short the three phases

The wind speed here is 11.2 with gusts of 18 at the moment.

The turbine is stopped, not lumpy. When a big gust comes it turns a little, but that is normal, i have read.

I had to turn it off due to the batteries being flat!! i mean completely flat!

I removed them all and tested each one I have 2 at 10.03 and the others at 11.30

I am trying to charge 4 of the 11.30 on a 12v charger in the house to see if I can get something into them, but i fear they are gone (Being SLA for test purposes, they cant go this low)

I will test the 3 phases from the controller, when I have some type of battery to put back on the system and the wind is less............................................

[tanner0441]

Hi

I see your in the UK, I wonder where? I am in North Wales and we are having very high winds and flooding round here at the moment.  I have everything shut down, and a tree down at the bottom of my garden.

Brian

[lowerstoford]

Hi Brian

I am in Somerset, we had major flooding yesterday.

Out house gets cut off in heavy rain so yesterday we lived on own own little island for most of the day.

Its looking like that will happen again tonight.

The current Wind Speed here is 15.4 m/s with gusts of 19.4m/s

Its coming your way, watch out!

It will die down here at around midnight

[Mary B]

Surprised nobody mentioned going MPPT with the controller. Morningstar MPPT45 could handle it.

[lowerstoford]

Out of my budget at the moment

I need to prove I can create energy first then I will tweak the system to get every little bit out

At the moment I can only USE energy

[tanner0441]

Hi

Have you looked at getting one of Ghurd's controllers, they come in bits you solder together yourself. You could most likely use your existing case and dump load.

Brian

[tanner0441]

Hi

Have you had problems with the weather? According to Sky News you have had it really rough down there.

Brian

[lowerstoford]

Hi Guys

I now have all my new parts, but before I go ahead and install, I would like to check a few things

Yesterday I tested the turbine in a 5m/s wind, without battery or load.

The 3 Phases are equal output, very hard to read on a digital MM
DC output voltage was low for a 48V, it was pushing out 30v.

I am temped to think it is a 24v turbine??? Comments?
With the old controller it only got up to 51.2v at 16-20 m/s wind!!!??

What is the max voltage a 24v turbine will produce?

If I try it at 24v, i understand it may stall, etc, but it would show me if it 24 or 48.
Could this do any damage to the turbine? the new controller can run at 12,24,48 mode.

May I thank everyone for their help so far and hopefully, together we can soon start producing some energy!

Lee

[equiluxe]

I don't know about other makes of machine as I have no experiance of them but the Bergey unit that I installed for my father has a buck boost converter in the control box so that at less than optimal wind speed the unit will still charge the batteries. I would have thought that all small wind turbines would have something along these lines in the control circuitry.

[lowerstoford]

OK

I wired the system as per instructions at 48V for now

and I have a problem!!!!!!!!

I have started a new post to try and answer that problem directly

http://www.fieldlines.com/index.php/topic,147299.0.html

 

[lowerstoford]

I think the LED's are telling me battery voltage is low

All the FAULT code are sequencing LED's, not solid

6 m/s wind and turbine is spinning very fast?

20v per AC phase

49.6v on DC, which is the same as the battery voltage if measured direct

i am worried about over speeding, I am worried I will brake something

Any suggestions will be gratefully appreciated

[lowerstoford]

Yet another update!
Hope I get to the bottom of this soon.

I have been watching the wind speed and the MM

When the wind hit 8m/s the voltage went from 49.5 to 50.0 for about 5 seconds

The wind speed here tonight is 5ms with 9ms gusts

All I keep thinking is its 24v not 48v (Note - It has a tag on the back stating 48v, the company list a 24v version as well)

Can anyone tell me the voltage they get out of a 750W 48v turbine at 5m/s? and 750W 24V?

I have left it running and will see if the battery voltage rises, there is no load on the battery at the moment.
As far as I can tell from looking at similar turbine, it should charge the batteries at these speeds.


And it continues.......................