Wiring for Hyper VOC

[caldoverde]

OOOOopppps !!!!   YES, you are absolutely correct !   I did make a typo.

250V + 24V = 174V max

Sorry about that !

You did it again!!

OK, 260 V is a piece of cake for the 250 so you're good there.

As for dragging the hydro down to 90V, I'm not sure why that is but lets find out what version of software is in your classic
so we can tell what peculiarities it may have in hydro mode.  The very first hydro mode was kind of buggy in a way or two
but we might be able to make it work.

To find the version, go to main STATUS and press the STATUS button a few times until the date of software
comes up for the Classic and MNGP (remote) and note this.

MNGP 901: 01/27/2012
CLASSIC 879: 01/21/2012

Which hydro mode is it in ?  Manual ?  Sweeping every 3 or 4 or 5 minutes ? Twiddle-Dither mode ?

BTW, the latest Twiddle-Dither mode in hydro has been slowed down some but not released yet so you may eventually
want that update if that mode will work good for you.

I would try Manual MPP V  mode first so you can set the operating voltage yourself.  When in Manual MPP V mode,
the Sweep Depth adjustment should go away.  When in other modes, the MPP V  adjustment will still be on
the display, but will not actually mean anything except in Manual MPP mode.

I don't know which Hydro mode it's in. There only appears to be the one! There's a line underneath "Function Hydro" that reads "Custom V input or slow sweep". Pressing the right soft key gives the following values ...

Interval: 3 mins
MPP V: 20.0
MIN V: 10.0
Depth: 10%

I couldn't find any references to Manual or Twiddle-Dither mode in the manual or on the controller. Sorry! Still trying to find my way around.

If it's any help, we need the hydro to handle anything between cut-in voltage (±140V) and the maximum the controller is capable of while we're trialling this high voltage alternator. A 48V model is also in production - we'll eventually select whichever works best in this situation. We're going for the over-voltage + MPPT controller option because it makes the most of the available flow. Normally at this time of year we'd expect the stream to deliver a steady 100-150W - though I'm not sure what's 'normal' any more in these times of increasing climatic variability - with occasional spikes after storms when the stream becomes a torrent.

[boB]

OK, Cal...   You have slightly older software but try this...

In at second menu where you pressed the soft-right key and got...
Interval: 3 mins
MPP V: 20.0
MIN V: 10.0
Depth: 10%

You should notice that Interval: 3 mins  is highlighted....

While it is highlighted, using the down arrow key, bring it down to Manual MPP V
which should be the lowest it will go.

Then, using the right arrow key, highlight the MPP V setting next to it and change that
voltage to something around where you think the MPPT voltage should be.
If it is cutting in at 140 volts, then just set it to something like 100 volts.

The MIN V adjustment is for non-Manual MPP V modes where the Classic is sweeping
above and below the max power point voltage so it should not matter in Manual MPP
mode.  Also, I think that the Sweep Depth %   should disappear when Manual MPP V
mode is selected.  It also doesn't matter for Manual MPP V setting mode because
the Classic should just turn on at your whatever voltage it is sitting at and drag down
to the MPP V setting (100 V in this example).

Press ENTER to have the Classic save it in its non-volatile memory if the power goes
off and back on again so it knows what to do without having to go back in to this
Hydro menu.

After the Classic turns on and loads the hydro down to 100 V (or whatever you
set it to), you can adjust the voltage up and down from the main status menu
using the soft-left (turbine V down) and soft-right (turbine V up) keys to find
the sweet spot.  (MPP V)

Let's try this first and then we can talk about getting your software upgraded so
that the Twiddle-Dither mode can work better, since it doesn't work that great
in the software version that you have now (as far as I remember).  The latest
software works better and I have even better (un-released) software that you
may want to try which slows the automatic sweep down a bit for another hydro
customer we are working with.

Let me know how this goes.  I think the Manual MPP V should be OK in
your version.
Remember that the turbine voltage will  not go below the battery voltage
when it is operating.

boB



If you know what the minimum input voltage might want to be (below the MPP V of 100 volts),
set the MIN V to something high enough that it won't bog down the turbine.

[caldoverde]

OK. Was waiting until the next storm to be able to report back on the results of this.

When the first rain started coming down the stream I did as you instructed. Set the MPP V to 100V. The MIN V stays displayed and the sweep depth % disappears. With the alternator at 150V open circuit, the controller put it under load, registered MPPT BULK and took the voltage down to around 100V. But did nothing with it ... 0000W 0.0A.

When the storm surge hit, the open circuit input voltage went up to 272V. The controller flashed between Hyper VOC and Resting and did nothing. I upped the MPP V to 200V. When the input voltage came down below 250V the controller wouldn't put the alternator under load and was continually switching itself between MPPT BULK and Resting. I put the MPP V back down to 100V. It made no difference - still continually switching back to Resting every time it tried to put the alternator under load. In the brief moments it switched to MPPT BULK, it was registering between 2 and 7W but wouldn't stay on so not knowing what to do with this I switched it off again.

Ideas?

[boB]

I JUST now noticed what you meant when you said "You did it again!!" in the post below !
I must be HyperVoc dyslexic !  Third time is a charm....
250V + 24V = 274V max   Did I finally get it right   I hope so !!

Anyhow, make sure the minimum voltage is set for something lower than your MPP V,
which is probably is already.

If the Classic is bringing the input (hydro) voltage down, then it MUST be putting out
power close to what the hydro could be providing.  If not, then the Classic would
be get VERY hot, because the power has to go somewhere.

Do you have a clamp on DC ammeter you can measure the input and output current with ??

It could be that there just isn't much current available (and power) from the hydro at 100 Volts.
Another way to check the output power would be to load the hydro output down with a
power resistor and measure the voltage across it, OR just see if that power resistor
gets warm or hot.

If you had a 100 Ohm resistor and it brought down the hydro voltage to 100 Volts,
that would be  100V X 100V / 100 Ohms  = 100 watts.

By the same load, the DC current into that 100 Ohm resistor for 100 watts of
power (voltage wouldn't matter for this calculation), you would have
I^2 X R = W  which means that I (current) is  square root of (watts/Resistance)
So, if 100 watts and 100 Ohms, you would measure SQRT(100/100) =
SQRT(1) = 1 amp.

Let's see if that hydro is putting out much current when you load it down.
That will help to trouble shoot this.

boB

PS, another problem that can cause this to happen is a bad connection somewhere.
If so, that connection can get very hot.   But, the Classic will still bring its input
voltage down.

[caldoverde]

We'll won't be able to try this until the next lot of rain as the stream is back down to a trickle again.

The best indication I can give at the moment of the output potential of the alternator is that 150V open circuit through the Outback FlexMax 80 made 21W. We hooked it up when we first got the alternator installed before the Classic arrived. However, the FlexMax can't handle voltages higher than 150V, hence the Classic 250.

[caldoverde]

Just had another brief rainstorm so I had the chance to try the controller again.

I had my clamp meter ready then discovered the batteries were out ...

In Hydro mode, the controller won't take the input until it drops below 250V. It flips between signalling Hyper VOC and Resting. Thinking about this, it could be a problem once (if ...) we get water back in the stream as I went to take a close good look at how much we had coming down in the first rush and it's not even a flow rate we would consider 'normal' for winter. This presumably means that the normal operation of the wheel will have the open circuit voltage input above the level at which the controller will accept it? Once the alternator is under load, the voltage comes right down, of course ...

I waited until the voltage hit 250V to see what happened and again the controller was flipping on and off continually and not accepting the input, so I switched it over to wind mode again. It accepted the input with no problems. The water surge didn't last much longer than 15  minutes but in that time I was able to observe that the input voltage was being kept to roughly 90V while the amps, and hence watts slowly declined until the open circuit input fell below 140V at which point the controller went into Resting state again. That would be expected since the cut-in voltage of the alternator is around 140V. So all well and good.

I'm thinking that next time we get some rain that I'll just switch the controller on in wind mode and see what happens? Would you recommend that? Given that these alternators are primarily designed for wind applications, would I be as well leaving the controller in wind mode? Or is there a way to get the hydro setting to emulate the default wind settings but just sweep less frequently? I don;'t know if that makes sense? I'm still trying to get my head around how this controller is working and what each of the parameters are designed to do. Without an understanding of that I'm just playing with numbers in the dark and feeling I'm not contributing much to the process of getting it set up right.

Another thing ... I noticed the Classic was reading the battery voltage at 23.9V while the Outback Mate said 24.4V. That's quite some difference! The previous unit we had also showed a different voltage to the Mate as well but the difference wasn't anything like as large - only 0.1-0.2V which, given the Mate only reads in increments of 0.2V seemed close enough to be accurate.

[boB]

Hi Cal...

Wind mode can work fine I suppose especially since your water flow varies... Kind of like
the wind does, only slower.

To help bring down the input voltage below 250V, you could add a load resistor just big
enough to draw it down below 250V.  I don't know what value that would be, but if
your max power point voltage is much below 250V, then you should not lose too
much power by doing that.

As far as battery voltage discrepancy, the OB meter takes its measurement at
a slightly different place in the system that the Classic measuring at its
terminals so ~maybe~ that's where the difference is coming from....  Or not...

If you have a handheld DC voltmeter, measure the battery voltage where the
Outback senses it and again at the Classic's battery terminals and see how far
off it reads to see if it is the Classic reading wrong or something else.

Thanks !
boB

[djsharpe]

I have built and installed a series regulator for a Classic 150 48v system that has 4P4S 230W  60 cell Canadian Solar Monos. The reg is based on  a 200A  IGBT that tries to maintain 150V on its output via 150V zener reference. There is a 4-5V drop across the IGBT when in its active op. A temp probe attached to the underside of one of the lowest module drives a temp controller such that when a predetermined temp is reached around 20degC 12V DC is applied to the IGBT gate which then goes to about 0.5 V VCE Sat and a relay closes same time such that V drop is then zero and power flows straight thru. Power losses in this mode is around 2-3 Watts. The relay is equipped with steering diodes and a 470uF 200V cap such that ii will never interrupt high DC V in case of failure. 12V power is sourced via a DC -DC converter direct from the incoming PV array Volts. This is needed for the temp controller, DC injection to the gate, 12V relay and a 12V fan which only runs at 60 deg C. The whole lot is built into an H section heat sink so the fan is prob not need. The controller sits on top of the H. The benefit is of course that you will get power when otherwise hypervolts would prevent op. It works well but we havent seen very cold weather yet being in southern Aus. The probe indicates that the panels heat up to 20-25 deg above ambient as predicted.
I built the reg from scrap parts (my cust encouraged me to recycle equipment)
I can send pics and cct diagram if anyone is interested. David