Author Topic: New system voltage options and total costs involved  (Read 457 times)

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Gary D

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New system voltage options and total costs involved
« on: March 10, 2006, 05:40:35 PM »
 In selecting a system voltage, there are multiple things to price in.

 The cabling down the tower, to the battery bank, and the heavy supply to the inverter for starters. If a comparison were done sizing the various wire needs for a potential or existing  system for what has become a modest turbine, 8 - 10 footer, and now Hugh's 12 footer... It could give a newby and even some of us on the board an eye opener I think! A dump load diverson at 12 volts needs to handle 4 times the amps (added hidden cost?)of a 48 volt equivilant etc.

 With the same wattage inverters, would this be a worthwhile addition to the fax section? I realise it would take time in making the comparisons but might give some extra insite? I've just gotten around to some of this myself and it is astounding!

 Dumb of me for listening to the boss(ie. the wife I love) going 12 volts. Just a thought that deserves in rants or deleted. I'll leave it up to the moderators to decide...  Gary D.
« Last Edit: March 10, 2006, 05:40:35 PM by (unknown) »

Gary D

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New system voltage options and total costs
« Reply #1 on: March 10, 2006, 10:56:04 AM »
There are many other costs directly relating to system voltages. The rectifiers on a lower voltage system need to be bigger, or ganged with heftier heat sinks. If each battery set would be fused, more cost, as with the heavier main fuse/ breaker to the inverter. Bet I've missed a bunch of others as well... Sorry the max line default kicks in, made subject too long....
« Last Edit: March 10, 2006, 10:56:04 AM by Gary D »

windstuffnow

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systems are ever expanding...
« Reply #2 on: March 10, 2006, 11:56:49 AM »
  There has been a lot of chatter about voltages... The voltage you choose should be based on what your expecting from your system.  If your set up to run 100 amps you'll get 1200 watts from a 12 volt system 2400 watts from a 24 and 4800 from a 48 over the same line.  


  For the most part, I can only do so much with the money I have so when I started the cheapest things on the market (still are) were the 12volt systems.  I figured my system would be continuously expanding as I could afford them and adding circuits to power more things later.  As it stands my 12volt system works very well but I'm limited ( by the cables ) as to how much power I can run down them.  Sometime down the road I may change the 12 to 48 on the old system.   I've also considered putting up a 3-4kw machine that would be about 250ft from the house.  In this case I might simply put a battery bank and inverter at the base of the unit and run AC lines to the house at 120 volts.  This would eleviate the problem of costly transmission lines and expensive components.   On a short run it's not a problem pushing 300-400 amps into an inverter or the batteries but the cables I would need to run that power 250 ft would be very costly.  There are many ways to cure the problem reguardless of the system you put in originally...  when sometime in the future there are cheap higher voltage inverters and/or the 12v unit fails then the option is there to convert it.  Everything I've done will work and the change will simply be wiring the battery bank, the solar panels and making a new stator for the turbine.


  Work with what you have keeping in mind it will be an ever changing system.  I don't have deep pockets so my system needs to "evolve" as I can afford it... I'm having a heck of a good time doing it as well!  Also, I've taken my electric bill down from 140 month to 40 a month.  It's like a hobby that pays for itself...I have more fun tinkering and tweaking my system than I do reaping the benifits from it but the money I save goes toward the tinkering and tweaking.  


  Do what you can today and you'll be able to do more tomorrow...


.


 

« Last Edit: March 10, 2006, 11:56:49 AM by windstuffnow »
Windstuff Ed

Gary D

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Re: systems are ever expanding...
« Reply #3 on: March 10, 2006, 12:36:28 PM »
Thanks for the insite Ed. I just thought John's poll was meant for polling. I thought it was a fairly straight forward poll. Thought this should be put in rants. Yes, if someone "has" a system, it gives quite a different spin to things. You work with what you have. My thoughts were meant to people thinking on starting from "scratch". The pro's and con's of various voltages, depending on if one expected to go for more power down the road, and such. A comparison type of thing. I can see now, in just a few hours that this could be a powderkeg/ flame/ contentious issue. I definatelly didn't mean for it to be. Nor did I want it to compete with John's poll. My apologies to anyone that may have been offended by my thoughts.  Gary D.  
« Last Edit: March 10, 2006, 12:36:28 PM by Gary D »

Chiron

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Re: New system voltage options and total costs inv
« Reply #4 on: March 10, 2006, 11:04:15 PM »
Note of caution.


I've been an Electronics Tech. for 25 years and have experience with utility scale wind turbines and the power conversion technologies they use. 200VDC could cause severe death or injury. The only thing I know of less forgiving is a wife who has proof that you've told something and been wrong.....


For safety reasons I'd say stay at 48V or less unless you know what your doing or have someone handy who does and never work on anything over 50V without someone nearby in case you do screw up.


Another thing to consider, currently I'm a Tech. at an electronics design/manufacturing company and have access to the prototyping lab. This isn't something that can be done with a screwdriver and a cheap multimeter. I'm putting up with the low pay, nightshift and general BS of the place because from 2:30 to 6AM 4 nights a week I get to "play with the toys". Have to hide everything from nosey Engineers when I leave in the morning..... Being able to play with a 4 channel scope with all the goodies, priceless.


I've been experimenting with an idea for a system that would use a battery bank of about 200V. To simulate this I'm using caps charged with household AC through a rectifier/thermistor combination. Most electronics use switched mode power supplies (SMPS) that run off rectified AC to provide the low DC voltages they use and I've taken that concept and applied it to RE. If you have a desktop/tower PC it probably uses something like I'm working on but instead of 6 or 7 different voltages I'm only using one at a time.


The concept for the system is that the turbine, battery bank and main wiring would be at the high DC voltage and use an SMPS for each DC voltage required or one to supply each device. An inverter for "standard" 110 or 220VAC for larger appliances is down the road a bit as is a driver for CFLs.


The big advantages of working with such a high voltage to start with is the current required per Watt is smaller saving on wire size/loss and the rectification losses become negligable. Cheap and plentiful transistors exist that work well in that voltage/current range (horizontal output drivers for TVs/monitors for example) and integrated circuits designed for just such uses. Everything I've done so far is "off the shelf" for any TV repair shop that has a well stocked parts inventory with the exception of the tranformers and cores.


Being able to maintian the system/s with common parts is one of the design considerations.


The eventual plan is to have 3 smaller turbines (redundancy) and a standby gas/diesel/whatever gennie and tell the power company to get thier poles off the property. Oh, BTW, this project is aimed at my Fiance's property. That she has a home on a class 4 ridge had nothing to do with the proposal. If she lived at the bottom of the Grand Canyon I'd have asked her anyway. (Hydro?)


Anyone know a Minister that would administer wedding vows on a platform 60' up a tower? ;) Have to beef it up for us, 2 witnesses and the clergy.....


I already have a down and dirty 200VDC/12VDC (192V average input) converter that can put out 50A at 12V (600W) using a pair of transistors and a hand wound transformer with a ferrite core, plus other ancillary pieces, that at the upper end of the output is over 90% efficient and has an "idle" draw of 5mA (1W). Switching frequency is about 30 kHz and uses a torroidial transformer for those interested.


I've been watching this board for over a year and am impressed with the ideas that come up here. Small windpower is my main interest/focus right now. I've experimented with a couple of small generators of different design from any here and if I can work out a couple of problems I'll post details of a design for a genny that will work efficiently at lower RPM than the dual rotor type. More difficult to build and more "touchy" than the dual rotors, I'm considering bailing the concept and just building a high voltage dual rotor.

« Last Edit: March 10, 2006, 11:04:15 PM by Chiron »

commanda

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Re: New system voltage options and total costs inv
« Reply #5 on: March 11, 2006, 01:38:13 AM »
Chiron,


Sounds like you're on almost the same path I am. Only difference is I'm using high-voltage generation & transmission, then down-converting it at the batteries. Having worked in Telecoms, I'm very aware of just how dangerous 50 volts dc can be. Please be very careful with that 200 volts dc.


Amanda

« Last Edit: March 11, 2006, 01:38:13 AM by commanda »

erichtopp

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Re: New system voltage options and total costs
« Reply #6 on: March 12, 2006, 02:13:09 PM »
Yes, 220 VDC can really bite you. Trust me, I know from experience (especially in water).
« Last Edit: March 12, 2006, 02:13:09 PM by erichtopp »

Chiron

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Re: New system voltage options and total costs inv
« Reply #7 on: March 12, 2006, 09:44:04 PM »
Amanda,


Thanks for the caution about working with 200VDC. Since I cut my teeth (so to speak)on old tube based TVs and radios I'm quite aware of the hazards of high voltage DC current. Got my first nasty shock/burn when I was about 9 exploring the mysteries of a Hallicrafter's (S110?) radio.


Wether AC or DC is more "dangerous" is something that's debatable. Each has thier own hazards. My personal rule about working on a circuit that might carry enough voltage to hurt me is "Short it out first". Fuses and circuit breakers are cheap insurance.


Ever see what a 460VAC 1000A circuit does to a screwdriver? My partner told me the circuit was "cold". Everyone makes mistakes and luckily that mistake only cost a screwdriver (and a 200' climb down with soiled shorts).


What I'm aiming at is to keep current as low as possible until the point of use. One reason is to minimize losses. Common Romex type wiring can be used saving up front costs. Lower current/higher voltage also has less risk of overheating and fire at junctions and in the wire runs themselves. Soldering then wirenutting joints also makes arcing/fire less likely. I only use Copper wire, Aluminum is for beer cans....


The main problem with DC is arcing. Don't use a switch designed for AC in a DC circuit. Industrial DC motors and servos use a very different kind of connector for a reason. I'm still looking into the best options for outlet/plugs to use.


The eventual goal is an (almost) fully RE house and it will probably be a converted mobile home. I'm a bit "shy" of mobile homes because I nearly died of smoke inhalation when the Aluminum wiring in it caught a wall on fire so I'm leaning very heavy on safety.


Other reasons for using the higher voltage battery bank is the ease of controlling charging it from the mains if I have to. Heat in winter would be WMO/WVO, propane backup since I have sources for both. Summer without AC is pretty much inconcevable to my mate and a driver/inverter to run AC is simplified if you start with a higher voltage.


My Lady is a programmer who can telecommute 4 out of 5 days a week so the system for the computers/communications would have to be reliable and redundant. Scream if you want but probably mains connected with commercial UPS systems and using the RE for backup.


Oh well, I'll keep working on it.

« Last Edit: March 12, 2006, 09:44:04 PM by Chiron »