Best Cheap Wind Dump Load ????

[OperaHouse]

A surprising novel easy way to build a dump load from a 300W inverter board. This uses a
little known method of shutting down a 2153 FET driver.  The 2153 is a half bridge driver
fixed at 50% duty cycle. Two 75N75 75V 75A Fet alternately turn on. While this pair doesn't
reduce the on resistance, it does reduce power dissipated by each FET. This 300W inverter
module can be used as a wham bam regulator by the addition of a TL431 and an opto isolator.
Shorting the oscillator cap (pin6 to common) with the opto isolator transistor shuts down
the oscillator. Board power should not exceed 15V and limited by a resistor and zener.  Load
source voltage of FET should be less than 65V and 20A per module.

To calculate voltage divider visit  ohmslawcalculator.com/voltage-divider-calculator be sure
to subtract half the pot resistance from this value. You should have at least 27K to prevent
damage to TL431.

Modifications include shorting out the relay contacts as the coil draws 140ma which is quite
excessive by removing a diode that powers the coil located between relay and terminal block.
Without this relay, control electronics drops to less than 10ma. Small enough that a 6.2K 1W
resistor and a 15V zener is sufficient to power from a 60V array of grid tie panels. Removing
the resistor to the red LED allows it to becomes the inhibit indicator. Uses world famous inline
opto isolator module, red heat shrink.     

Suitable for a small wind turbine. Multiple inverters can operate together connected at point A.
Part of initial research for a camp 4-6 gallon water heater W/temp control using excess solar.
Check out ECCOTEMP EM-4.0 and WAIWELA WM-6.0 as examples of wall mount units under $200. Having
hot water at the sink is nice and likely enough for a shower.

(1) L1392 board, ebay -- Inverter Driver Board Power Module Drive 300W
(1) TL 431 amplified zener
(1) PC817C opto isolator
(1) 1N4001 generic diode
(1) 20K pot
(1) 470 ohm resistor
(1) 2.2K ohm resistor
(1) 470 to 6.2K ohm 1W resistor, depending on source voltage
(1) 12V to 15V 1W zener
(1) 10K resistor, spare from LED
(1) TBD ohm scaling resistor, >27K

[SparWeb]

I'm looking for something just like this - for kind of different project.  Thanks!

The 1 same item is available from 100 sellers - any to be avoided?
"Cici10086" has the best rating.

[OperaHouse]

That is who I got mine from, didn't seem to take an extraordinary long time to get .  Always buy two of anything.  The board also has positions for TO-247 FET.

[OperaHouse]

PV Hot Water For Your Camp, Simply The Best

Efficient hot water at your camp using existing solar panels and charge controller. Does not
reduce charging capability. It only uses power that would be wasted.  Uses previous, Wind Dump Load, 300W inverter board. Requires existing solar panels to be a 36V or 60V grid tie panel array. Board power should not exceed 15V and limited by a 6.2K resistor and zener.  Source voltage should be less than 65V. See just prior for modifications. Higher voltages, just use TL494 board.

Diode isolates system from charging to prevent damage tp PWM controllers and tracking of MPPT.

Heating water any other way is just wrong! Do not connect heaters to batteries. Inefficient and the batteries will never charge properly. If using less than a 36V array, don't even think about heating water.

A capacitor bank is required to store energy as is done in any MPPT controller. Diode isolation must be included to prevent possible damage to an existing charge controller.  Power consumption is small enough that a 6.2K 1W resistor and a 12-15V zener is sufficient to power board from a 60V array of grid tie panels. A precharge resistor keeps capacitor bank near full voltage while drawing very little current. Capacitor bank prevents arcing when temperature control contacts open. Difference between the switch contacts will always be less than 30V due to capacitor bank
preventing extreme voltage drop.

Suggest using a 4-6 gallon water unit for fastest water heating. Check out ECCOTEMP EM-4.0 and WAIWELA WM-6.0 as examples of wall mount units under $200. Having hot water at the sink is nice and likely enough for a shower. If there is enough power available, use a 9 gallon tank. Add extra insulation to any tank. Try to start off with 85F water in the morning.

(1)  L1392 board, ebay -- Inverter Driver Board Power Module Drive 300W
     See prior post for modification details
(10) 10,000-12,000uF 200V capacitor bank
(1) 12V to 15V 1W zener
(1) 35A diode Additional parallel diodes prefered.
(1) 50K pot
(1) 180K for 50V, 180K for 50V scaling resistor
(1) 1K ohm 3W resistor, precharge
(1) 2.2K ohm resistor
(1) 6.2K ohm 1W resistor

[Bruce S]

I see you're still using the awesome OperHouse CAD BETA version, the ability to zoom into the data is a GOD send !

That FREE ENERGY? looks a bit vague could you elaborate a bit more please?

REAL question,,, what are you're thoughts on using the 12V panels configured as <30V? I have ~ 5 HF units that are now looking for a reason to not be retired (I've replaced them with 12V 30W lexan backed units).

Many Thanks
Bruce S

[OperaHouse]

Any functioning PV system has excess capacity. Otherwise the batteries would never recover. That energy is seldom used so it is free. Whether it is just 5W or 300W any excess is used to heat water. It made a big difference to be able to go to the sink any time and wash with hot water.  I've seen these tanks as cheap as $160 shipped.  Such a small amount of water heats up fast  if the tank starts at 80F. Putting the tank in an insulated box will achieve this.

This same system can be used as a linear current booster for a greenhouse fan or pump.  Why less than 30V.

[Bruce S]

The older HF panels I have replaced with newer 12V 30w panels are beginning to show they're age.
My worry is if I configure them in series they will not behave right for this application. However since they are currently parked inside our shed , this could be a good reuse project.

Seeing the part about the heat pump for my greenhouse has peaked my interest!
I have rescued a smallish 120Vac water heater that may work out perfect for this. Buying 1 - 2 inch foam is cheap and with a heated wire cutter , pretty easy to build a cover too.

I do not have a broken inverter that's above 140W yet but will keep my eye out for one.

Thanks again for a really cool idea!!

Bruce S

[OperaHouse]

NO, it has to use that 300W inverter board to work.  They are only $5 shipped.  For PV heating it requires a capacitor bank.  Wind dump load it does not.

To attract people to this site, you need to use terms like free energy and free hot water.

[Bruce S]

Thanks for the reminder of that board. I'll go digging on free bay.

Capacitor bank I can do, easy enough.

It is a bummer that the words we used to not allow; are now what seems necessary to attract new users

The only types of windmill anything allowed here in town are the lawn art types

Even then I had to explain to the city inspector that came out when our "new neighbors" complained what it was, even put the dog in the house so the guy could come in the yard and see it. He laughed at our "new neighbors" and told them to mind their own biz

[JW]

You guys don't have worry about new users. I was on that kick until got experience being here. Everything will be fine. Post and moderate as you see fit

[SparWeb]

Well, when they say 6-8 weeks for delivery, they aren't kidding!  It arrived in 7 weeks + 1 day. 
It's been so long, I had to check back to this thread to remember what I ordered it for! 

[OperaHouse]

I just implemented this on my pre heater tank and it works like gangbusters. Holds the voltage at precisely the voltage set. As you can see, I breadboarded it. The best breadboards are solid cherry.

[OperaHouse]

Final configuration.