blocking diode

[billi]

Thanks Fred

very much appreciated   and strengthen   my believe in Mankind   


Billi

[billi]

thanks a lot  Fred  arrived today   and they look sechsy   

[Outtasight]

Hi Billi,

Couple of things from your plans...

You need to bolt the diodes to a bus bar heat sink so that when running at high current they can get rid of the heat they generate.  20 Amps flowing through a diode drops 0.7 to 1.0V and would generate up to 20W of heat.  This needs to escape from the diode to whatever it is bolted to.

Next is the use of Grid Tied Inverters (GTIs) in your plan.  Doesn`t seem like it would work.  Where are you getting the 120V AC to power them from (they won`t start up on DC alone as they`ll have anti-islanding protection - even the cheap 600W Chinese one someone gave me does).

Then, even if you have a 120V AC supply to start them up, that AC supply will try to run the 500W dump load when there isn`t enough wind power to do it.  So you`d be heating your dump load from the "grid" source!

Next are the solar panels.  You show 20Voc panels connected in parallel.  This is too low to charge a 24V battery (fine for a 12V one).  You need pairs of 20Voc panels in series to make at least 30V at maximum power point of the panels - Vmpp (at Voc they make NO power - it`s the open circuit voltage with no load).

Finally, you`ve got a diagram that suggests connecting two 120VAC GTIs to two spurs on your consumer unit and implying that you`d get 240V AC from them.  This won`t work either.  They are designed to run in parallel but syncronously, so they`d pump 120VAC into your house via the two spurs.  But only if your house was running on 120VAC.  If you feed them 240VAC they`ll probably blow up.

[billi]

Thanks outa  

Actually  the drawings are from a guy in the USA   and not showing my system .... so  what i got now is a 300 watt 230 AC GTI

And  i have now connected it up   in parallel to my charge controller   and the blocking diode  as well  fixed to a  copper heatsink (actually just a pipe   )

The GTI  works and  feeds the house , as well if turbines output exceeds my actually consumer needs in the house , the internal charger of my inverter starts charging the battery.....

But  there are a few things i did not know up front  ,  
- The GTI  holds down my 24 Volt  Turbine to the GTI s Voltage range (11-30 V )   so the turbine is producing  ,power that i have never been able before in low wind (cause turbine was not generating enough volt to reach battery voltage) , but it does not speed up anymore  cause the GTI  holds down the Volt somehow  

- I have a 1000 watt turbine and i thought the charge controller , cause wired in parallel , will take care of the watts exceeding the GTI  nominal watts , but that is not the case , or i have not seen this happening  yet


So actually i think now , i should have got the bigger China  GTI  say 1000 watt and with a  voltage range 22-50 Volt

And  have the two in parallel , but to optimize this idea , i would need a voltage sensing relay , that switches from the low voltage GTI  to the 22-50 Volt 1000 Watt GTI  ,when wind catches up and exceeds 22 Volt at the generator  


So a lot learnt from this 100 Euro project  so far

Hope that makes sense

[billi]

- I have a 1000 watt turbine and i thought the charge controller , cause wired in parallel , will take care of the watts exceeding the GTI  nominal watts , but that is not the case , or i have not seen this happening  yet


So actually i think now , i should have got the bigger China  GTI  say 1000 watt and with a  voltage range 22-50 Volt

And  have the two in parallel , but to optimize this idea , i would need a voltage sensing relay , that switches from the low voltage GTI  to the 22-50 Volt 1000 Watt GTI  ,when wind catches up and exceeds 22 Volt at the generator  Tongue


So a lot learnt from this 100 Euro project  so far

O dear    i must be lonely....   (start quoting my self) .....

I  was ignoring the GTI setup for a while and just disconnected the GTI  cause it is breaking  the windturbine too much ( trying to hold her to lower Volts) , and let it run on direct charging the batteries  for months now  ,  but due to the sunny weather in April   Battery was full  early , or in other words , windturbine chargecontroller started to dump into   its air heater in the shed

I found a bad connection to the air heater , a typical Chinese problem   called corrosion of material in harsh climate of Ireland 

So the say 10mm2  DC cable to the Dump heater  was melting

So  i switched the GTI back on to direct feed  my Island System   to use windpower direct in the house   and  Dump on the AC side in the house instead

We had some windy days recently  and the 300 Watt GTI  was running flat out at 300 Watt  and 29 Volt ( 30 Volt is its limit)

The nice  thing i found out  , when there is more than 300 watts , that the GTI can feed into the house , the parallel installed charge controller kicks in and takes care about the exceeding watts ...

So   as a resume  for now of this experiment, 

I gained  some watts in low wind , cause the 24 volt windturbine   starts feeding my off grid house at 10 volt (generator output) , but breaks down the turbine too much  to get  up for the "right" speed   , so loose in midrange windspeed conditions , in high winds all is fine again

But overall  my impression is , that it supplements our PV much better with the GTI  than  as direct battery charging , cause for the reason  that  the battery Voltage is high  during the day (cause PV is charging)  and the turbine hardly gets over that voltage point to feed the battery 

So for us  it seems  to be the better idea   cause we gain  on days  now  some power , that would be lost  with direct charging ......
 Even  its only 30-60 Watt   per hour steadily over the day /night in low wind  , but its a  difference in the morning  , when i look at our battery monitor  and see  that PV has lesser work to do during the day

I  would really like to find/built a turbine  for low windspeed   ..................... but safe in high winds



Billi

[biff]

Hi Billi,
   "  I would really like to find/build a wind turbine for  low wind speed but is safe in high wind."
     Thats is truly a tricky one billi.That is exactly what all my experimenting with the different blades and hubs was about.The origional 2kw had very big low wind speed blades and performed even in a light thermal breeze.This was brilliant in nice weather but a nightmare in a force 8,It could not be left to its own devices and needed constant attention to draw off the power in ac lecky fires.
 So eventually after much faffing about i finally fitted 3 smaller 1kw blades on the origional hub and lo and behold it worked.Not only that..It works beautifully.I also added an extra controller because we now had a 120vdc x 650watt array.So one controller directing the solar and the other looking after the turbine both these controllers carry 2kw of resistors so there is an exellent safety margin.
   Its early days yet and we still need a good blow to test it properly but the signs are exellent.We are still waiting for on water heaters (2kw x 120voltdc immersions) and when i get it set up i will post some pics.
                                        Biff

[billi]

  

Hey Biff , for my situation   i think a wind driven Waterpump   would be ideal ,  cause i have a ca 100 kwh  storage lake 

they seem to work in low wind and my neighbour has one ...........  and still alive since i know this part of the world ( ca 30 years)

When i started  off grid , i figured out , wind energy needs  a lot of battery , or a big turbine  to supply  a daily need to the house .......



Hybrid  is the key 

Billi