Recent Posts

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The Arduino is a very powerful device for control.  If you can load the compiler into your computer and download a BLINK program, you got it made.  I have a real problem with most of the programs found on the internet.  The style of writing is far to complicated for most to understand for almost a one time application a user may have.  I've been writing demonstrator programs for beginners.  The use a boilerplate
setup.  Then the user only has to add or modify applicable code.  I refuse to include do loops, arrays, and other code that doesn't follow intuitive English. each line of code stands on its own.

read voltage
if voltage higher than setpoint turn on
if voltage lower than setpoint turn off
delay  (to prevent rapid cycling)
go back to beginning

There is a lot of power in just those few statements.

Forget displays.  I have a blinking LED for my entire house. From 20 feet away I know the state of battery, hot water and refrigerator. Most of the hard work is done for you with ready made routines.

In my water heater I have to heating elements. One turns on first.  When that gets to a set temp it switches to the other.  If available energy, both turn on till a very high limit is reached.

There really aren't modules that will work with a water heater on ebay, but building one only uses four parts.
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Solar (heating or electric) / Re: Passive solar air heater - for home
« Last post by eidolon on May 23, 2017, 09:24:53 AM »
Heating with PV may not be great area wise, but it is cost wise.  PV also works in the summer which the evacuated tube people never talk about.  If you don't keep the panel voltage at MPPT, you will waste half the power over the day. I do this with elaborate electronics, but if multiple heaters (as few as 4) can be switched in and out throughout the day more than 85% efficiency can be maintained.  See electrodacus.com for an explanation, I don't approve of his product at all.  I have a small efficent system of heating water with waste PV, enough for my limited use.  More interesting is my system works with only one car battery. It is only used for motor surge current and a couple minutes of running the fridge. I store cold with large fluid mass to keep the frequent cycling.  You could easily run the refrigerator all day with PV, switching in and out of grid power during the day.  All this takes intelligent control that isn't practical at this time, maybe in 15 years it will be common.   

Wife wants a dishwasher this year. Saying I thought I married one apparently wasn't a correct answer. So, I will fill and then heat.  When up to temp I'll start the cycles.  A cloud comes over and I will stop for a while then restart.  Might take twice as long, so what.

There is a big difference between possible and probable..
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I think that IF you have the programming skills that the PLC avenue would provide everything either already assembled or available as din modules -simple and reliable but as these are industrial units not necessarily cheap .This however is well beyond me  :'( (still wrestling with arduino  ::) )   
 My hot water unit is a single element with a thermostat
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Solar (heating or electric) / Re: Passive solar air heater - for home
« Last post by rossw on May 23, 2017, 03:01:29 AM »
If you want useless, forget about the Candle in the room, try heating an above ground swimming pool with water running through a bit of 3/4 or 1" copper that's sitting  over an open fire. Now THAT is kidding yourself.

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I also want to incorporate PV for heating.  I just bought another 2.5Kw of used panels for $500. I'll have a large ( and going to be made larger) shed roof that points directly north that I can put a LOT of PV on before I even get to the house which for the most part is east west.

From a purely EFFICIENCY point of view, using all that roof space for PV, at a return of around 15% (by the time you take out inter-cell space, inter-panel space etc), assuming you then use resistive heating to heat water, it's still a low yield.

Evacuated tubes (wet or heat-pipe) can give you around 4 times that, and achieve decent temperatures.

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I'd like to heat water and then back feed the excess through the old analogue meter and run it backwards  so what I make during the day can be used at night.

Of course, it's more difficult to run hot water backwards into the grid :)
Don't count on your old analogue meter staying there for too much longer. As soon as you start using it to YOUR benefit (like, reducing your power bill), they'll be out to change it over. Either because they think it's gone faulty (and reading less power than you're using) or that you're running it backwards (which they don't want!).

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Using the grid for a power bank and getting a 1:1 feed / return ration although a little " grey" market is very efficient

There seem to be different interpretations of "net metering". A number of authorities add up the "numbers" and then charge you at their sell rate, or pay you at THEIR buy rate, on the net. That's not "net" in my view. Still, it's better than the alternative of selling ALL your power to them at their buy rate, and buying ALL your power from them at their sell rate!

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Solar (heating or electric) / Re: Passive solar air heater - for home
« Last post by DJ on May 22, 2017, 09:52:55 PM »

I have just bought a new home with a metal roof.  A roof is a huge area for solar heat gathering and I plan to use it.
The place has ducted air but I have spoken to a fridgy and he says it's no problem to set up an extra inlet that will draw this warm ceiling air  and pump it into the house in the fan mode of the AC. I'll stick a filter on the end of the pickup to eliminate any dust being blown into the home. I already have some thermostats like linked in the previous post so I can compare the home temp and the roof air temp.  My thought is that I probably won't be able to run the thing constantly but have to wait for the air to heat up and then run that into the house. Then again, probably depends on the day and if only a small rise is required, may be ok. Otherwise, anything is a bonus and cheaper than running the compressor on the AC unit.

I'm not sure if there is insulation under the tin itself, there probably will be a form of it in a waterproof/ insulation membrane but given the area of the roof and the amount of sun falling on it, I believe worthwhile amounts of heat can still be harvested. There is insulation on the ceiling and the good part about this system is any escaped heat will be re used as it were.

I'm also looking at adding another similar pickup on the AC and putting a radiator in front of it so it can draw through and heat air from an oil fired water heater and disperse that into the house. Main thing is to work out a practical and aesthetic place to put the burner/ boiler.

Looking on the net at DIY heating ideas always does my head in.  I literally want to pound my skull against a brick wall at so many of the idiotic concepts and moronic rubbish people go on with.
Are these people mentally impaired to think that a few tea light candles are really heating a room? Are they too stupid or just so wanting to believe it works to do some simple research as to how much heat a candle generates and not see that their plasma TV generates a load more heat and does it at a fraction of the cost of buying tea candles?  Amazes me when you see these people are talking about heating a dorm at a university! So much for higher education and learning.
It beggars my belief that they just can't look at the thing and know it's going to put out no worthwhile heat at all.

But then there is the be all and universal method of DIY heating.... a bit of copper pipe coiled  and sat over a typically open fire.
Yep, if you wanted to go low efficiency, Couldn't think of anything much worse... or better if low efficiency is what you are after. Just let 99% of the heat from that fire blow away doing nothing at all but kid yourself you are putting 100Kw worth of heat into that pool and it will be warm as toast come summer.
 If you want useless, forget about the Candle in the room, try heating an above ground swimming pool with water running through a bit of 3/4 or 1" copper that's sitting  over an open fire. Now THAT is kidding yourself.

The internet is for more than watching porn and recordings of video games. There is an incredible amount of information and calculators that would let you see how useless this is through all sorts of heat rise tables and calculators, thermal capacity charts and many other related information.  Once you look a couple of these things up and even get a slight feel for it, you can then look at something and straight away have a fair idea how poor it's going to be.... unless you are one of these people that likes to kid themselves badly and cheat themselves.
   You don't need to be smart to look this up, I'm dumb as dirt but fortunately, smarter, educated people made it easy for pelicans like me to look up what is going on so we can see if something it worth while or a complete waste of time.

As I like results and loathe Kidding myself, I like to make things that WORK. Like really work.... using all that stuff most of these DIY heating clowns hate... like fact... and physics and scientific principals.... and lord forbid..... Measurements and reality.  Yes, I know, using all that stuff limits your thinking and it's much easier to make something that keeps you warm if you don't actually measure the results using something as sophisticated as a thermometer
to verify your delusio... work but it unfortunately, paying attention to fact and scientific principals and laws at the end of the day will keep you warmer.
Like as in really warmer, not just mentally warmer.

It amazes me the way people will spend so much more on their hair brained schemes to save money that what they would spend on conventional practices like electricity or gas.  Look up the actual heat energy in that packet of $4.99 tea candles and work out the cost per BTU or KW. Then compare that to what you pay for a KW of electricity.  Yes, you just spent 20x more on the candles didn't you? Amazing! Who could have ever worked that out.... except anyone with access to the net and a desire to separate fact from stupidity.

I also want to incorporate PV for heating.  I just bought another 2.5Kw of used panels for $500. I'll have a large ( and going to be made larger) shed roof that points directly north that I can put a LOT of PV on before I even get to the house which for the most part is east west. The way the property is means there is nothing to stop me just putting up a ground mounted system which I will use the panels as a roof for a shed or pergola anyway and seal them together with silicone when I mount them.
I'd like to heat water and then back feed the excess through the old analogue meter and run it backwards  so what I make during the day can be used at night.

As mentioned, PV, particularly used is so cheap now if one has the situation for it, it's a very viable and practical thing. You hang your panels and don't have to change anything else in your home or the way you live. Using the grid for a power bank and getting a 1:1 feed / return ration although a little " grey" market is very efficient and serves the green principals and objectives that we are constantly having shoved down our throats so is something able to make use of that crock as well.
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Steve / Re: My Scratch Pad
« Last post by MadScientist267 on May 22, 2017, 09:22:43 PM »
"Toys for Turk"... For once, an animal that keeps playing along, even knowing it's just me messing with him... (in fact goes into "dude what did you do with it" mode when you stop haha)

ila_rendered

ila_rendered

It still needs his approval... We shall see ;D

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Very interested to do the same sort of thing only with a prebuilt unit. For what they are these things seem very expensive. 

I'm wondering if something could not be tied together with prebuilt Chinese boards or something SIMPLE with an arduino that didn't require a circuit board of it's own to be constructed but rather relied on pre built boards wired together or the built in features of the arduino itself.

While everyone says it's inefficient, I'm also thinking about actually trying to direct wire a couple of arrays to a HWS going a little over voltage on the array and using 2 in parallel to keep the amps up without over shooting the voltage too much on the bright sunny days. I believe for something like an element, thee is a fair bit of tolerance for over driving anyway so if one did set it up to be somewhat over voltage on the brightest days it should still fall back to producing good output on the not so bright days.

Once the heater was up to temp, I believe the local units here have a thermostat available for twin element heaters that first run the top then the bottom element. Using one of these on a single element setup would give an automatic " Changeover"  to divert the current elsewhere when the heater was up to temp.
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Yeah I probably wouldn't do it with descrete singles as a general rule either... With KAK pack it's not much of an issue because they're on the same substrate and then sunk on the same slab of aluminum. I have seen them go off under those circumstances, but usually it's traceable back to thermal contact with the sink or shoddy balancing in the board.
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Steve / Re: My Scratch Pad
« Last post by lighthunter on May 21, 2017, 10:11:49 PM »
Very good explanation, quite a few things i had not thought about. The Scientist part of your handle is accurate i'd say  :).   So is this why the newest miller welder line, (continuum) is using over 1000v in the power supply? This fact has puzzled me for a year or so now because the previous models were rectifying 3phase 480 to something like 640DC and then using igbt's at high freq to cntrol power. The newest line steps 480 3phase up well above 1000v before they use a very late technology igbt i cant remember who makes it but i know its 1400-1600v rated. I long for the days when you could flip the switch on and start welding. You can go get coffee before these are ready to go.

Anyways, i thought the reason for the high v was for efficiency improvements and "because they can" After reading your explanation i'm betting its all about pfc and the utility and of course more money from the customer.    These things really blow up hard when they crossfire. Though weve had some hardware failures its not miller's weak point, the power units are fairly solid for as much as is happening in them. Software is another matter, always updating...related to microsoft i guess :)   

Thanks again for explanation, good stuff!
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Users Projects / Re: basicly what i been up to last few years
« Last post by bj on May 21, 2017, 07:57:09 AM »
Looking good Kurt
We are still too wet to do anything.  Hoping to be able to plant in a few days.
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