I just came across this and thought it would be good and save money if it worked. Has anyone trid this? http://www.poormansguides.com/news-June-07.htm
Lots of fun!
.Have Fun! Windstuff Ed
Get a bunch of nuts and big washers to go on it for heat sinking area... Add a fan too to help out.
Would look kind of like a microwave Yagi antenna, sort of.
boB [ Parent ]
might as well heat some water with it?
thanks for the idea,, i have been looking for a large load bank for some testing
pretty cool
bob g
.Have Fun! Windstuff Ed[ Parent ]
You may even end up with a steam explosion: As one end thins, the voltage drop will be concentrated, raising the temperature drastically.[ Parent ]
A related question: we've got a wind mill built for 110 V. We wanted it to charge directly a 12 V battery bank.
Now would be a good way to build a suitable heating resistor element in series of that battery bank to get heat and battery charging at the same time? What would happen with charging when the heating elements' resistance will vary according to the temperature? Would it work well?
- Hannu
In my opinion one problem with this board is nowadays that there are a lot of small questions with little short discussions about each problem. Lots of short threads.
I'm trying to connect somehow similar things together to get a little broader discussion about some ideas.
Cheers,
- Hannu[ Parent ]
Quite frankly, I [we] don't care what justification you cite. Just stop or prepare to enjoy some quiet time from posting.
Thats the bottom line. That clear it up any?
T
The Truth is the Truth, even if no one believes it; and a lie is a lie even if everyone believes it
[ Parent ]
You might be some kind of 'energy tyrant' as you told sometime ago, please enjoy your time.
cheers,
- Hannu [ Parent ]
I for one am not offended by Hannu's comment in this thread. I agree that the forum tends to degenerate to a lot of threads with superficial comments, but that is true of most of the forums (oh, I'm sorry, that's fora) I have been to.[ Parent ]
I must question if HE ever tried it.
Nobody dumps at 12.0V, so change 12V to 14.2V. Now the 3' rod dumps 5,752W (more than enough watts for Dan's 20').
Over 1.9KW per foot.
Over 400A. Meaning 4/0 wire to the rod is undersized. I wonder what relay, mosfet, or IGBT it takes for that, but I know it's not cheap!
Dan's 20'. 5KW, 56.8V, 88A? So about 0.645 ohms. That's 53' 9" of rod.
Something more real. 10' windmill, 12V, 1000W, 70A. That'll take 17'.
Or a more common 400W 12V machine, 28A. That will take 42'! It would be about the same as 20, 10 ohm, 25W resistors. If you bought Ward Leonard / Ohmite 5% low inductance 10 ohm 25W ceramic tube resistors from me, it would be $30 and Easy. No idea what SS all-thread costs, but it certainly can't save much money.
It might work out better with 3/16" or 1/8".
If I was going to make them, it would be Ed's way, or nichrome in a heater like Capt Slog did. G-Ghurd.info
At 14.2V ("12V"), 4000W is 282A and 0.0503 ohms. If the length is cut in half, the resistance is cut in half. With 14.2V and 0.02518 ohms is 564A. Or 8000 watts. So 2000W at 14.2V is 141A, and 0.1 ohms. Meaning the length needs doubled.
Yes. Sort of? Your math is right but your numbers are off. A 4000W heater at 12.0V is 333.3A. But a '12V' battery is 93% 'empty' at 12.0V, depending on who you ask. Nobody wants a '12V' battery below 12.2V. Nobody would want to heat a long bolt with 333.3A at 12.0V for a dump load, because the batteries are nearly dead.
And the "$10" part means $3.33 a foot? That's $140 for a 400W 12V machine, plus SS nuts, connections, etc. And THEN add the controller. A C40 and factory-made resistors could be cheaper than just his way to save money on the resistors.
If you are talking about controlling 3A of HF PVs, and know how to run a soldering iron, then $20 would do it. G-Ghurd.info[ Parent ]
If you use the shunt designer software and put in 20 gauge stainless wire, then 36 inches would work out to about 143 watts at 15 volts. So the example I used is cheap if you have like 3k to 6k to dump. But you would have to use thinner material as your dump power needs decrease. Or use longer, but that can be more expensive.
20 gauge is 0.032 inches in diam. I believe.
But, basically, my point was to improvise and think outside the box.
I didn't use mosfets, I just used a relay that activated two 300 amp selenoids ($19 each) in parallel, to send current to the dump.
Anyway, sorry for the confusion. Hope everyone had a good Christmas.
Richard
Spelljammer
