I forgot to mention one basic thing in the last email...
I mentioned how the CC reduces the output current and output voltage
but what I didn't mention is that when the battery gets fully charged,
and/or
the battery side can not use the power from the solar or hydro or wind
source,
the controller opens up the input letting the turbine free-wheel.
It may either raise the input voltage as high as it can go to keep the
battery voltage
and current in check, OR in your case it went above 250 volts and then
to Resting which is OFF.
The primary purpose of the CC is to keep the battery voltage from rising
above
the charging set point and to give the battery maximum power/current when
it needs charging.
Most MPPT charge controllers operate this way.
boB
On 3/19/2015 11:57 AM, b...@midnitesolar.com wrote:
Jeff, I am sorry you did not get a proper answer from tech support to
a very basic question like this.
I don't know who you talked with so we will flog all of them equally.
I am glad that particular sentence was removed from the manual as it
was not correct. You can only
keep the charge controller ON if it is safe for the batteries to do so.
The reason that the Classic goes to resting is because raising the
input voltage is (usually) the only way to
reduce battery voltage and current on its own. Insomnia will not keep
the Classic operating above 250 volts
input... What "Insomnia" does is to keep the Classic from going to
Resting due to low power output (< ~20 watts).
It won't help when the batteries are full or over full.
Since you are VERY slightly over 250 volts when free-wheeling, the
first thing I would try is to turn OFF
the Classic mode and adjust the nozzles or flow to the turbine until
it drops below 250 volts. Then no
matter what, it will turn on... That is, as long as the water flow
does not increase too much to cause
the voltage to rise above 250 volts again when nobody is looking.
Another thing that can be done, or in addition to reducing the free
running Voc is to lightly load the
turbine with a resistor. Better yet, use 2 or 3 resistors to load
the AC side a wee bit. This works well
especially if the Max Power Point voltage is quite a ways below the
Voc so these resistors don't have
to dissipate all that much power. I would think that this method
would not be necessary though.
NEXT thing to do is to adjust the Classic's battery charge set point
voltage to somewhat higher
than that of the FM charge controllers so that the Classic is almost
always charging (when not in Float).
OR, adjust the FM60/80 charge voltages slightly lower than the
Classics' set point voltage.
Or, a compromise, one slightly higher than wanted and the other
slightly lower charge voltage
to give both systems that "distance" between them. This way, the FMs
will always be helping out
in MPPT modes and Absorb/Float just won't matter much where that
current comes from.
This method will mean that the Classic is always loaded some except
for those times when the
charge current required from it is zero or very close to zero.
Roy Rakobitsch also has a good idea which is closer to being a Clipper
by using a 3-phase AC SSR,
(3 Triacs), connecting all 3 phases of the turbine together. Doing
this on the AC side is important.
You don't want to short out the rectified DC input to a charge
controller for various reasons.
If you go this route, the best control is to use Aux 2. Be sure to go
to Clipper mode to make
sure it is set to AC mode. You could then use Clipper mode or PV ON
HIGH mode using
higher frequency PWM activation of the SSR. I like the Teledyne
3-phase triac SSRs personally
if you decide to go this route.
First, just turn down the flow slightly to reduce that free running
Voc. That is probably the
quickest, simplest and cheapest method.
boB
On 3/19/2015 10:26 AM, Windsine Inc. wrote:
You could use a triac to feed AC from turbine directly to the dump
load just before HyperVOC using the Aux relay in classic to fire the
Triac. Then program the Aux logic to revert to normal when turbine
voltage/RPM drops from dump load loading.
Kinda like an Aux triggered bypass circuit
Roy Rakobitsch
NABCEP Certified Small Wind Installer®
NABCEP Certified Solar PV Installer®
NYSERDA eligible Small Wind installer
Certified Advanced Tower Climbing, Safety & Rescue
Wind/PV Design Engineer
Windsine LLC
631-514-4166 <tel:631-514-4166>
www.windsine.org <http://www.windsine.org/>
On Thu, Mar 19, 2015 at 11:53 AM, Jeff Oldham <starpowe...@juno.com
<mailto:starpowe...@juno.com>> wrote:
Finding this application quite frustrating - Harris 120Vdc 1kW
turbine, Classic 250, 48V batt., 1200W load dump. The manual
downloaded just before purchase stated: "This mode will NOT go to
resting even when the input has been disconnected and will always
stay awake so the turbine has the least chance of over-spinning."
It now seems that this is not the case and this sentence is no
longer in the manual. My installer cannot get Midnite to confirm
one way or the other and they have been guessing for over a month
on how to keep the CC from going into RESTING that open circuits
the hydro and puts the CC into hyperVOC at 253V and will never
reconnect. To complicate things there is also ~4kW of PV on
FM60's, when they drive up batt V. to above what the Classic
wants it drops into RESTING and back into HyperVoc. Midnite has
been very responsive and have suggested every possible setting
and combination and my installer has made the 3 hour RT drive far
too many times to only find the most recent "suggestion to try"
another approach not working. INSOMNIA does not do as the name
implies and still allows the CC to step out if external charging
elevates the V above what the Classic wants. i.e. FM60 in Bulk,
Absorb or EQ. when the Classic wants to Float.
I fully realize that the Clipper will deal with this for a
considerable amount of money, but I've heard of several folks
using a Classic or Outback w/o a Clipper to deal with turbines
w/o allowing freewheeling and runaway VOC. If the turbine is not
dropped by the Classic the VOC will never exceed 120Vdc. Is there
anyone of you out there that knows:
1) Is there a way to keep a Classic from ever moving into
RESTING, a true INSOMNIA? If it will not do as originally stated
in the manual I need someone to step up and say so, so we can
stop guessing and wasting time.
2) If so what is the secret, please?
I really like all of Midnite's products and they are better than
most with reasonable prices, support has always been 1st rate.
This application oddly seems to have all of us at a loss pulling
our hair out and losing money.
With much appreciation for all input.
From the Solar, Wind and Hydro powered office of Jeff
Oldham/Regenerative SOLutions
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