Hi Daniel
My view is keep it simple I still do not know your pipe line length? I've assumed 1000 ft (300m) Flow 4L /s, static head 6.5m, cable length 1000 ft. I would recommend you install a farm grade plastic pipe of 75mm OD 65mm ID. This is very common in NZ and costs about $5 NZ ($3.5 US /m) Using this pipe your running head would be about 30m at a flow rate of 4 L/s. The output power from the turbine would be 570 Watts. If you can get a power cable that has a cross sectional area of 25-30 mm^2 per conductor then you will have less than 10% loss in the cable. The turbine voltage will be about 5 volts higher than your battery voltage due to the cable loss. Cost of cable in NZ from a cable surplus yard is about $5-6NZ/m ($4 US). You can also use house wiring cable, in NZ the 3 conductors add up to 7.5mm^2 and it costs $1 NZ /m. So doing it this way would cost you $8 NZ/m ($5.5 US). Find a large surplus roll of cable if you can. Power delivered to the batteries would exceed 500W. To prevent battery over charging simple install a C40 with resistive element in your hot water tank or air resistive element. Cost in NZ would be Turbine $1000 Cable $1800 C40 and water element $450 Plastic pipe 300m long $1500 Intake strainer (make yourself) $200 Total equipment cost = $5000 NZ = $3500 US. So your budget of $6,000 is ample and will allow for some labour assistance in getting the pipe and cable in. We can supply the turbine, we have a deal for overseas customers where if you buy two turbines we will pay the airfreight - 2 year warrantee on turbine. You then have a spare or can sell it to you neighbor. Regards Michael Lawley Renewable Energy Engineer EcoInnovation EcoInn/EcoBach 671 Kent Road R.D.1 New Plymouth New Zealand Phone: (NZ) 06 752 2765 Fax: (NZ) 06 7522768 Web site: www.ecoinn.co.nz email: [EMAIL PROTECTED] ----- Original Message ----- From: "Daniel Kim" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Thursday, February 17, 2005 9:22 PM Subject: Re: [microhydro] AC vs. DC microhydro Okay... just went through all of the email thread -- I really really appreciate all of you (some of you quite passionately) posting to help me out.. Now, I am getting a little bit more sense of what is necessary here.. and what kind of parameters / limitations I need to consider... Well, as mentioned before, here's a list of parameters that I have to work with: 1) completely off-grid system 2) a big main battery bank (48V @ 1700AH) hooked up to 15KW LP generator for peak usage backup 3) a rack of Trace (or Xentrax) inverter/charger is hooked up between the LP generator and the battery bank. It can handle up to 120amps. 4) main battery bank will eventually be hooked up to 3 cabins (one of them being a 2500 square feet residence!). 5) weekend usage only, but we can assume that it's almost every weekend. Assume that during the weekend, we'll be using something like 40-50KWH. 6) creek is 800-1000ft away from the battery bank, 120ft head w/ 60-70GPM flow 7) we're willing to spend up to $6,000 on the hydro system, if it can fully charge the batteries (which would be able to store about 40KWH of usable power - at 50% discharge limit) during the weekdays. I think having these parameters will actually help narrow down the choices a bit... Basically, we're hoping that with the hydro charging the batteries throughout the week when no one is there, we won't need to use the LP generator (especially with the skyrocketing price of propane these days) as much. So, it is not an option for me to run directly off of the AC hydrogenerator... it has to charge up the battery bank (b/c of the high usage during the weekend). And because of the high storage of the battery bank, we would like to get as much power out of the stream as possible (i.e., minimize power loss). Now, many of you guys are talking about rectifiers and transformers and alternators and induction motors, etc... I'm sorry, but I have a hard time understanding that.. (please have patience, I'm a newbie!) So far, I've basically figured out what an inverter/charger does... I understand AC & DC, and I understand the basic way that voltage and amperage works. But I don't know what a rectifier does... does it convert AC to DC?? But wouldn't my inverter/charger do that for me? What's an alternator? Anyway, for that reason, I am having a bit of a hard time understanding what is actually being suggested by many of your postings. Hopefully, with the parameters that I listed above set, it will narrow down the range of possibilities... It seems like some of you were being very creative with what I could do! That's great, and I really appreciate that.. but the reality is that my range of possibilities isn't that wide... so with my parameters, perhaps all those ideas with rectifiers and alternators would not be applicable?? Not sure. Now, moving onto the things that I DO understand... I see that some of the postings have suggested that I just get a DC hydrogenerator and just get thick #2 wires to transmit the power up to the battery bank 800-1000ft away. That's an idea that I at least understand. I also understand that DC current is safer than AC. But I also understand that DC current doesn't travel as well as AC -- even with a #2 wire, wouldn't the power loss be pretty significant? Even at something like 48V, wouldn't the loss be significant? And the added cost of a #2 wire is also something that I'm concerned about, as it will add about $700 more to the wiring, right? But I'm open to suggestions. If DC generators are cheaper than AC generators and the power loss over #2 wires is not that much, maybe I can buy into that... Any thoughts on this? Another posting suggested that I get a DC hydrogenerator powering a small battery bank, and then use an inverter to convert it to AC and make it travel... that's something that I also understand... And I DO have a small battery bank (just a 1KWH storage system)... so that idea sounds intriguing. Basically, I would put the small battery bank and the extra cheap inverter down at the stream next to the DC hydrogenerator, and let the hydrogenerator charge the batteries, and let the inverter convert the battery voltage to AC and push it for 1000 ft, right? Now, I'm just wondering what advantage this particular system would have over me just getting an AC hydrogenerator to begin with (since it looks like this system is basically "simulating" an AC hydrogenerator). Wouldn't it be simpler to just buy an AC hydrogenerator? Or maybe there's some nice advantage to having this DC->batteries->inverter->AC system that I'm not seeing? Anyway, this is sort of where I'm at here.. Hopefully that gives you a better idea of my knowledge level and my situation. When there's all these parameters & limitations, sometimes the job becomes easier - and hopefully this is one of those situations where the limitations that I have @ my site actually makes the job easier. Thank you again for all your postings, it has been tremendously helpful.. although at times I didn't really understand what all those terms meant... Please have patience with me, I'm learning as fast as I can. Thank you again, I really appreciate it. --Daniel --------------------------------- Do you Yahoo!? Meet the all-new My Yahoo! - Try it today! [Non-text portions of this message have been removed] Does your company feature in the microhydro business directory at http://microhydropower.net/directory ? If not, please register free of charge and be exposed to the microhydro community world wide! NOTE: The advertisements in this email are added by Yahoogroups who provides us with free email group services. The microhydro-group does not endorse products or support the advertisements in any way. More information on micro hydropower at http://microhydropower.net To unsubscribe: send empty message to [EMAIL PROTECTED] Yahoo! Groups Links ------------------------ Yahoo! Groups Sponsor --------------------~--> What would our lives be like without music, dance, and theater? 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