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Forum Index : Windmills : Dump Load Revisited
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| jagged Newbie  Joined: 30/10/2011 Location: CanadaPosts: 5 |
I just finished wiring up my dump load made of 12 60W high beam quartz headlight bulbs. The final resistance of the assembled unit is .3 ohms, so at 13.8 volts cut-in it should draw 46 amps. I'm just waiting for the cooling fans to come before I finish the assembly. Everything will be mounted in a dustproof enclosure to keep contaminants from getting on the bulbs. So far I've got 4 bucks invested. 
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MacGyver Guru  Joined: 12/05/2009 Location: United StatesPosts: 1329 |
jagged Welcome to the 4m. 4 bucks? Does that include the cooling fans? Where do you shop? From now on, that's where I want to get my stuff from too! Anyway, I'm a bit confused here. Are you using the dump load as heat or as light or as anything? Nice, clean work by the way. . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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| jagged Newbie Joined: 30/10/2011 Location: CanadaPosts: 5 |
Add another 10 bucks for the fans and dust screens for the fans from e-bay. The lights, sockets and wiring comes from my local wreckers, if it is mostly glass and plastic he doesn't want it, so basically help yourself. I've built the box everything goes in from an old aluminum running board extrusion that I straightened out to get the width I needed, he charged me 5 bucks for that. Heat and light will be the result whether I need it or not *S*. I'm just putting it back into the grid, along with the 6KW of solar I have. |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Ligh bulb resistance changes as the filliment grows, so the best way to work out amps is using watts and volts. You have 12 60w bulbs. The 60 watts is their rated power at operating voltage. All up thats 720watts. Amps = Watts / Volts, so 720 watts at 13.8 volts is about 52 amps. Its going to get hot, and hard to look at without going blind, so a ventilated cover it a must. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| jagged Newbie Joined: 30/10/2011 Location: CanadaPosts: 5 |
I figured the resistance will change from cold to hot, so it will even handle more amps is great. I already hooked it up to a fully charged 12V battery and it is very bright and gets hot quite quickly. My fans haven't arrived yet. I will be mounting them on each end of my box, one sucking and one blowing. Hopefully they will draw enough air over the bulbs to keep them from getting too hot and the heat will be an added bonus in my workshop because it's already getting cold here. |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Jagged The radiant energy may be enough to set the wood base on fire, may be a good idea to mount the globes the other way around to give more clearance and make a metal shield on the wood. All the best Bob Foolin Around |
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| jagged Newbie Joined: 30/10/2011 Location: CanadaPosts: 5 |
We will have to wait and see. The top of the box is glass so most of the radiant energy will be directed away from the wood. I will monitor the temperatures after the fans are mounted. I could always use foil over the wood to direct it away more. Wood has to reach around 414 deg F to burn...........that's hot! |
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Fernbrae Newbie Joined: 06/10/2007 Location: AustraliaPosts: 7 |
Be careful ,a 50 watt Halogen bulb operates at 360 degrees celcius . that is approx 680 degrees farenheight. Living loving life always |
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MrDelanco Senior Member  Joined: 12/11/2011 Location: United StatesPosts: 101 |
How much do you intend to dump ? Why waste the extra just use a electric stove with a kettle of water and have tea. Cheers  MrDelanco:Project Videos It is not only too know what it does but to understand how it does what it does. |
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kensue49 Newbie Joined: 05/12/2010 Location: United StatesPosts: 1 |
Low temperature heating of wood can cause the ignition point of wood to change to a much lower level than normal. The fix would be cheap insurance, use metal. see- www.doctorfire.com/low_temp_wood1.pdf Just an old firefighters thoughts. Kenneth Say it aint so |
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| flc1 Senior Member Joined: 20/11/2011 Location: New ZealandPosts: 242 |
gday Jagged,not a good idea to use bulbs for dump load,they do eventually burn out,then maybe you cook your batterys. and wood burns aswell |
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