Dump Load

[leesafur]

In my quest to eliminate running my generator for 5 hours a weekend in my fish house this year I would like to put up a windmill.

My system consist of 8 220 AH 6 volt batteries and a Pro Sine 2.0 inverter, the system is wired 12 volts.

I would love to build my own wind turbine but as I'm Writing this, ice-fishing season is nearing. I am thinking about buying the 10-foot axial flux wind turbine kit offered on otherpower.com.  The problem is it puts out more power than a C-60 can handle.

Which brings me to my question. I am thinking of running a 1000W 120 Volt heater as a dump load as I do not have running water in the fish house but could use the heat. Is there a way to sense the batteries voltage?  Once the batteries are fully charged is there a timed relay that can turn the heater or inverter on to drain the batteries for five to ten minutes and cycle again once the batteries are fully charged. So I am hoping someone on here can tell me where to get a timed relay and something to tell the relay when it is time to turn on.

Thanks for your time

Lee

[wpowokal]

you could try this.

http://ghurd.info/

and he is a member of this board.

I put dump load controller into Google and what do you know it answered your question for me.

allan

[ghurd]

I will stay on record as being against 120VAC inverter powered dump loads.

That said, my circuit could be wired to a small time delay relay (Grainger), that relay controling a larger relay, which would switch the heater on and off.

Why 2 relays?  Because large time delay relays are not cheap.

Even the small time delay relays are not cheap.

Some use (used?) a diaphram, and I don't know how good that would be in a humid area in winter.

Or could add a 555 based timer to control a relay, thus avoiding a time delay relay all together.

I would be inclined to say 5 or 10 minutes is too much.

Maybe closer to 30 or 60 seconds.

G-

[wpowokal]

I suspect that in reality Lee is overestimating what the wind turbine will actually produce as oposed to rating.

A dump load on the DC side would most probally serve just as well in this situation, as it does for most other people.

allan

[leesafur]

Thanks for the quick replies!

Thanks Ghurd, I seen you controller on the net but wasn't sure it could be used to turn on a relay. I'm electrically challenged but learning. As far as dumping the load on the DC side, I know of no controller that can handle 900+Watts at 12 volts. I've read somewhere you can use 2 C-60 and 2 HEL-100 to hand the 60+amps the turbine can put out but that setup is close to nine hundred dollars... not going to happen. I do plan on a lot of power from the turbine. The average wind speed where my fish house is 17MPH. Last year I was stranded 10 miles from shore because the win was 30 to 40 MPH for four days, got a little worried when we got low on beer! Anyway, I think I'm going to use Ghurd controller to trigger a timed relay that will tie in to the remote switch for the inverter. Ghurd why are you against shedding a load this way? I Google 555 based timer and came up with this, do you think it is up to the task?  http://www.apogeekits.com/555_timer_module.htm

Thanks again I wouldn't be thinking about this stuff if wasn't for this board!

Lee

[wpowokal]

Automotive starter selonid springs to mind.

[alibro]

You could also try cutting up a room heater and using it as dump loads. Take a look at my diary for some ideas. I am using two of Ghurds controllers to split the power over two dump loads. When the batteries are charged there is quite a bit of heat from them. For some of the guys on this site, doing this is very basic stuff. For the rest of us it is a big challenge but with a lot of reading and a little help not impossible.

Good luck

Alibro

[JSNH]

I can think of a great reason to not use a Prosine 2.0 as a dump. we have 9 Prosine 1.8 12 volt inverters at work. They are in our work vans conected to 2 6 volt golf cart batts. and charged thru a battery isolator from the alt. They work great but you need a reliable way to protect you batts from over charging we do not. The prosine has features to protect itself but not the batteries. We have had the ground fault outlet in one unit fail. For us it was no problem and easily replaced but for you in that situation you could loose your batteries.

JSNH

[ghurd]

"why are you against shedding a load this way?"

OK, 30~40MPH wind for 4 days.  The inverter is running the 1000W AC heater.

Maybe... The inverter's $3 fan has its 10 cent bearing stick. The fan stops.

The inverter overheats and shuts down.  Or dies.

Or maybe... Someone does something stupid like try a 1750W hair dryer while the 1000W heater is running, blows a fuse that needs mail ordered from 8 states away, from a company that ships UPS, and the tracking says you will get it in 10 days.

Or maybe... The 1000W heater's nichrome snaps.

Then the batteries are getting 1000W more than they should.

Simple oversized DC stuff is more reliable IMHO, or at least easy to fix!

G-