Diversion/Dump Load devices ... anyone used them?

Started by hnash53, April 30, 2008, 05:28:28 PM

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hnash53

I plan to have both solar and wind power at my cabin.  I've read of the need for charge controllers.  I am considering buying an unregulated 12V wind turbine from www.mikeswindmillshop.com .  His, and others, recommend using a diversion/dump load regulator which, when the batteries are fully charged, diverts the incoming energy to another source, such as a 12V water heater, heatsink, heater fan, etc.

Has anyone used these diversion/dump load regulators?  I've read about them online but I'd like to hear directly from someone who has used them.

I plan to have a separate charge controller for my solar panels.

Thanks for any info.

MountainDon

Glenn uses one. He routes the excess power to his well pump that feeds a large (5000 Gal??) water storage tank.

A diverter regulator is not just a recommendation. One of those is an absolute requirement or you will cook the batteries if the power continues to flow to them. A wind generator will self destruct if the power is simply turned off. In short you can't have a wind generator without a diverter regulator. Some use the power to heat water, or for space heating in cold weather.

When Glenn checks in he'll say pretty much the same thing.

Just because something has been done and has not failed, doesn't mean it is good design.


hnash53

Thanks, Don.   I've read about people heating water with them.  But that requires that you have an electric hot water heater, and I wouldn't be doing that since I will be off-grid.  Unless of course I could supply enough heat from my 800 watt wind turbine to heat 10 gal of water...but I doubt it would do that.  I see that some of the places that sell wind turbines sell 12v heating elements that go in electric water heaters.  I just don't see that I could produce enough wind energy to run a 10 gal hot water heater.  Any ideas?

firefox

Just use it as a preheater for what ever you use to heat the water.
You could also use a solar preheater as well. The combination should reduce the amount of fuel
you need to heat the water.

You don't need much to make a simple solar preheater. Just make a simple box, put some copper coils in it
and cover with clear fiberglass. There is some special paint to paint the coils that increases the efficiency
if you can get it. There are also other modifications to help as well, but that is the basic idea and every little bit will help.Obviously you will need the water to flow through the coils and into a tank. There are many ways this can be done, but they don't have to be complicated.

Just my 2 cents. Hope it helps.
Bruce
Bruce & Robbie
MVPA 23824

glenn kangiser

You got it, Don.  2600 gallons is what I have.  If my overflow shows excess we'll use more or figure out something else to do with it.

If a 12 volt system you can use a 12 volt car relay to turn on a 120V relay to power anything you like ( 24 volt - put 2 12 volt relays in series to get the coils to handle the 24 volts then use the extra contacts as yu like. Car relays are cheap)-- I power a 220 relay in combination with a timer -- timer pumps in 15 increments but if power goes over on wind then it bypasses the timer and turns on the pump to pull the excess power off.
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

Please put your area in your sig line so we can assist with location specific answers.


MountainDon

Whatever method you decide on Hal it has to be bulletproof. You need to be quite certain that it will absorb the excess power that would otherwise cook the batteries. To me that means having something that could absorb pretty much the full output of the wind generator, just in case the sun's shining brightly, you're away so there's little power use, and the winds blowing good as well.

I've seen the 12 Volt heater elements advertised. I know they don't burn out often, but if I was going that route I'd want to have at least two, just in case one failed. That's just me maybe, and my penchant for conservative redundant systems.
Just because something has been done and has not failed, doesn't mean it is good design.

hnash53

To Firefox,

Can you give somemore details about the preheater thing you mentioned.  Is it possible to have a propane hot water heater that also has a place to put in a 12v electric heating element connected to the diversion/dump load device?

At my cabin there's no way I can have an electric hot water heater...way too costly in terms of generating power. 

Any elaboration you can provide would be great.  Thanks!

Hal

MountainDon

Quote from: hnash53 on May 01, 2008, 04:31:46 PM
Is it possible to have a propane hot water heater that also has a place to put in a 12v electric heating element connected to the diversion/dump load device?

Allow me to interject on this. Depends. Depends on the type of water heater. Some heaters in RV's, like mine, can use propane or 120 VAC electric elements to heat the water. If the 12 V heaters use the same thread, there you go. RV water heaters come in 6 and 10 gallon sizes as a rule. They are not code approved for houses though, might be a problem in cold weather because of the way they're vented/installed.

You'd have to check around to see if there are any "dual fuel" standard tank type water heaters around.

Pre heater tank: Let's say you have a regular tank type water heater. To use the excess electricity from a wind generator you could install another tank in series, before the main tank. The cold water supply line enters the preheater tank as usual. The "hot" out line from that tank goes into the "cold" inlet on the main tank. That tanks "hot" exit line is connected to the house plumbing system as normal.

Whenever there is electrical excess it heats the water in the preheat tank. As hot water is demanded, the hot water in the main tank flows to the point of use. Warmed or pre heated water then flows into the main tank to replace the hot water drawn off. If it is warm instead of cold the main tank propane burner doesn't have to work so hard to raise the temperature to the set temperature. If the water in the preheat tank is not warmed it is simply acting as a pass through cold water reservoir.
Just because something has been done and has not failed, doesn't mean it is good design.

mvk

And you could also take Don's first tank with the electric heater, paint it black and put it in Firefox's insulated box instead of the copper coils.

Mike


hnash53

Don,
What is the make of your RV hot water heater that can be either propane or electric?

Thanks.

Hal

MountainDon

#10
Hal,

The brand we have is Suburban





Available at pretty well any RV dealer. I got mine HERE when I had to replace the old one a few years back. There are models that use a pilot light and others that use a direct spark ignition to save on propane. There are also some now that have a coil to circulate hot engine coolant to provide heating of the water. I believe Atwood makes some as well.

If you have any RV dealers near you you could MTL see one of the models in many of the new RV's.

ED: fixed 1 link - MD
Just because something has been done and has not failed, doesn't mean it is good design.