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AC Turbine with battery bank

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  • whitcity3
    I am new to this forum. Hello to all. I am preparing to install a small off-grid hydropower system in Chile. I have head and flow for about 2kw; however, the
    Message 1 of 66 , Jan 1, 2008
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      I am new to this forum. Hello to all.

      I am preparing to install a small off-grid hydropower system in Chile. I have head and
      flow for about 2kw; however, the location of the turbine is a 300 feet from where the
      power is needed. I have a choice between 1) a DC turbine with a lot of line loss (or inch
      thick wire) or 2) An AC turbine.

      An AC turbine solves the transmission problem; however, it creates other problems as the
      invertor/chargers are not designed for AC systems.

      Anybody out there know the best way to use an AC turbine with a battery bank and
      invertors?

      Thanks

      Charles
    • Jeffe & Carrie Aronson
      Okee dokee....I get all of this...except the last part with the ballast load on the hydro before the first controller...how does that work? (If you¹ve already
      Message 66 of 66 , Jan 17, 2008
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        Okee dokee....I get all of this...except the last part with the ballast load
        on the hydro before the first controller...how does that work? (If you¹ve
        already discarded that idea...or it¹s not a likely one on your list, don¹t
        worry or waste your time...)

        Jeffe


        On 1/8/08 11:51 AM, "nando" <nando37@...> wrote:

        >
        >
        >
        >
        > After so many suggestion that have come along for Jeffe to implement in his
        > hydro I am making public what I said to him via direct mail.
        >
        > I know Jeffe for years and I know his system well until recently when the
        > latest technical people made an electrical mess that has two power source
        > (solar panel and hydro) with several ( more than two) charge controllers that
        > are not synchronized or regulated between themselves.
        >
        > Jeffe problem has two solutions for a cleaner wiring and good battery
        > controlling.
        >
        > The over charge of the battery can be solved in an easier way , since the
        > system has a Pure sine wave inverter ON all the time, the system can use this
        > power source to control the battery voltage by detecting the battery voltage
        > and triggering a TRIAC or SSR to turn a water heater resistance with a power
        > about 30 to 40 % higher power than the generated power and in addition a
        > secondary loop when the water heater over temperature thermostat opens the
        > load to re-route the power to other ballast load -- this way all the excess
        > power to heat water for home use ( I have done something like that to heat a 5
        > cubic meter tank for shower and / or home ambient heating).
        >
        > The ideal case would be a PWM TRIAC controller to have the battery at fixed
        > maximum voltage level with no battery peak fluctuations.
        >
        > The other solution is to have a ballast load on the hydro before the hydro
        > charge controller to maintain a high safe voltage, this way the ballast does
        > not load the battery bank and 2 charge controllers ( mppt type ) do not
        > overcharge the battery bank, a simpler MosFet ballast controller.
        >
        > He has other issues that need resolution for proper system health which we are
        > taking care of.
        >
        > Nando
        >
        > ----- Original Message -----
        > From: k1hop
        > To: microhydro@yahoogroups.com <mailto:microhydro%40yahoogroups.com>
        > Sent: Tuesday, January 08, 2008 8:08 AM
        > Subject: [microhydro] Re: AC Turbine with battery bank
        >
        > Hi... thought I'd jump in here with a suggestion... though perhaps
        > you've already considered it. Would seem quite simple to rig up a
        > precise voltage sensing circuit that turns on a MOSFET (or other)
        > transistor across the panel/hydro output (to ground). This would act
        > as a "shunt regulator" and continuously dump excess energy to ground.
        > It would maintain whatever precise voltage output you set, no relays
        > to wear out, no clunking noises, no hysteresis, etc. It is a LINEAR
        > regulator (with very high gain) not a "bang-bang" digital type like
        > your relay, so hysteresis is not needed. The more the voltage rises
        > above the set-point, the harder the transistor turns on to shunt it
        > back down. If the voltage drops below the set-point, the transistor
        > is not turned on at all, and on dumping occurs.
        >
        > While you're talking a bit of power, there are many BIG, powerful, yet
        > inexpensive transistors around these days. With a good size heatsink
        > and perhaps a fan to help out, it could readily dissipate the excess
        > power. And, since it is constantly functioning, there is no big
        > buildup of excess power needing to be suddenly dumped... it's more
        > gradual, continual, and thus easier on the whole system.
        >
        > Hope you find this useful.
        >
        > Russ
        > --- In microhydro@yahoogroups.com <mailto:microhydro%40yahoogroups.com> ,
        > Jeffe & Carrie Aronson <jeffe@...>
        > wrote:
        >> >
        >> > Hi, Dave. Thanks for your input (pun intended):
        >> >
        >> > Actually, I¹ve tried various hysteresis settings, large and small
        > (.4 to 2).
        >> > Problem is (I THINK!)...that when the sun is shining, the panels are
        >> > producing as much as 16 amps (at 24v = 380 watts), plus the hydro
        > going at
        >> > about as much. With my wonky system the installers went with 2
        > controllers,
        >> > one for the solar, one for the hydro, and they¹re not synchronized. The
        >> > panel one reads battery voltage as up to .5v less than the hydro one.
        >> > Consequently, the panels keep charging for a small amount of time
        > after the
        >> > dump relay is turned on by the hydro, jamming in excess of 700 watts
        > into a
        >> > 400 watt dump load. I¹ll be changing this system soon, however, in any
        >> > case...if you¹re input is high, even with one controller with a high
        >> > hysteresis, with no or small household loads during the day and
        > significant
        >> > input from the sun, you very well might be jumping a relay rapidly
        > anyway.
        >> > Mine (with the unsynched controllers and during a sunny day) goes
        > from 29.4v
        >> > (battery state of charge) to 27 in a matter of a second or two, then
        > crawls
        >> > rapidly back to its high within 15 or 20 seconds. That¹s with a 2v
        >> > hysteresis. That¹s a lot. Thus, it seems that even with no solar,
        > you could
        >> > see a cycling of the relay in 30 to 40 seconds. No?
        >> >
        >> > Jeffe
        >> >
        >> >
        >> >
        >> >
        >> > On 1/7/08 11:39 AM, "dave_festing" <dave_festing@...> wrote:
        >> >
        >>> > >
        >>> > >
        >>> > >
        >>> > >
        >>> > > Sounds like you haven't got any hysteresis on what ever is controlling
        >>> > > the relay.
        >>> > >
        >>> > > For example, relay closes when the voltage is 15.0 Volts and the relay
        >>> > > opens at 14.0 Volts. You should be able to find a point where the
        >>> > > relay cycling period is lower without "wasting" too much of the
        >>> > > stored power in the batteries.
        >>> > >
        >>>>> > >> > I have a relay and solenoid to fire the ³dump², or resistive load
        >>> > > instead of
        >>>>> > >> > through the internal load of the controller...and when the power
        >>> > > input is
        >>>>> > >> > high, the relay clunks on and off repeatedly, dumping, then
        > letting the
        >>>>> > >> > batteries reaload, etc. when we¹re not using large household
        loads.
        >>> > > Consider
        >>>>> > >> > the noise, but also consider that relays are mechanical, and
        > they will
        >>>>> > >> > probably eventually fail. You should have a backup so that if
        > the relay
        >>>>> > >> > fails open or closed, you do not harm the batteries or
        > overspeed the
        >>>>> > >> > turbine....just a thought.
        >>>>> > >> >
        >>>>> > >> > Jeffe
        >>> > >
        >>> > >
        >>> > >
        >> >
        >> >
        >> >
        >> >
        >> > [Non-text portions of this message have been removed]
        >> >
        >
        > [Non-text portions of this message have been removed]
        >
        >
        >




        [Non-text portions of this message have been removed]
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