Force Bulk

[Sweet Taterman]

Other than having Mode set to ON and input present, what conditions need to be met for the force BLK function in the TWEAKS menu to work? I tried this I think for the first time and the controller acknowledges the command but just keeps on resting. I'd tell you the version of the firmware but I've forgotten how to extract that info and the means is not evident from the menu or manual. It is whatever version that was current in Dec of 2012.

[Westbranch]

you can read the firmware dates by pressing the lower left soft key on the MNGP repeatedly to cycle through several screens...

[boB]

Try looking at the "Reason For Resting"  (RFR)  number in the secret screen from the main status menu...

In main status, hold down the LEFT-ARROW key and then tap the ENTER key.

This should bring you to a screen with a bunch of numbers on it.  Top left should say IN and
the top right should say OUT or BATT.   Look for a number on the top line in-between IN and OUT.
That will be the RFR.   Let us know what it says.

If that area is blank, we'll try something else but it should give you a number.

boB

[Sweet Taterman]

I've checked the RFR under several sequences and get inconsistent results. Sometimes with Vbatt at 13.5 and Vin at 15.7 with 300W potentially available it is resting with RFR code 5. On other occasions with the conditions as above the RFR field is blank even though resting. I did a forum search for RFR and code 5 [Power too low] doesn't make sense. FWIW, LOMAX is on which as I understand it implies that the controller should do OK with only a couple of volts I/O difference provided adequate power is available which is the case. Adding to the inconsistency, I did get the force BLK to work once but that was starting from FLOAT status, not RESTING. So perhaps the real question here is why the controller is not exiting the resting state once input power is available.

[Vic]

Hi Sweet,

Out of curiosity,  does this Classic have an End Amps value set?

And,  when you say that there is "300W potentially available",  do you know just how much power is actually available at the time that you are observing this Resting conditition?

Thanks,   Vic

[Sweet Taterman]

@vic
End amps is set to 10A.
Your second question, ...do I know... Yes.

[Vic]

S T,

The following observation probably has nothing to do with the RFR question.  However,  there two ways that I have been able to Force Bulk when the Classic is delivering less output current than the EA setting;  one is to create a DC load current that exceeds the EA value that is set.  In my case,  just turn on an AC electric heater,  command the Force Bulk,  and then turn off this large load.  The other way is to set the EA value to 00 (at least in my case).  Otherwise,  the CC APPEARS to ignore the FB command.  Would bet that the CC either tests the CC output current,  and if below EA,  does nothing,  or it starts the Bulk,  immediately test the output current,  notices that is is below the EA setting,  and returns to Float,  all so quickly that it appears to have done nothing.

Since,  in your case the CC is Resting,  the CC may not choose to try to deliver this amount of current.

Glad that you know the amount of input power that is available when the Classic is Resting.  This amount of power (and therefore) charge current will probably not exceed the 10 A EA setting (anyway).  But secrets are a good thing.  Vic

[boB]

I've checked the RFR under several sequences and get inconsistent results. Sometimes with Vbatt at 13.5 and Vin at 15.7 with 300W potentially available it is resting with RFR code 5.

AHA !!   Maybe that 15.7 V in is the culprit !

First, RFR = 5 (low power) is the LAST reason that the Classic WENT to Resting from running...   There is
another reason that it could be STAYING in Resting and not waking up again and that might be
because your input voltage is too low.

When you said input voltage was 15.7 Volts, was that Voc  (input voltage when it was Resting)   ?

If so, you need higher input voltage.  Your PV modules may be hot and bringing the voltage down
too much.   The Classic requires   battery voltage + 1/3 of that Vbatt minus 2.0 volts on its input
to turn on.

If your battery voltage is 13.5 volts, then the Classic will require at least

13.5 + 13.5 * 0.33333  - 2.0   =  16.0 volts input to turn on.

15.7 volts is barely too low for the Classic to turn on.  Can you wire your PV
in series  maybe to get higher voltage ?   In series would make it around 31.4 volts
which would be perfect.

Also, the  SOLAR mode does not work as well when the input voltage (Voc) is so low even
if it is slightly above that 16V minimum.   You ~might~ want to try the Legacy MPPT mode
just in case when it wakes up again.

Solar mppt mode should work much better with 30+ volts input, too.

I think I better add a message to the Status screen that says when the input voltage
is just shy of being able to turn on like this, if that 15.7 volts is Voc that is.
It's not really a RFR but a reason for not waking up, like when the sun goes down and
the input voltage falls below battery voltage.  There is NO power available from PV
when the PV Voc is right around battery voltage.  MPP voltage is around 80% (or less)
of Voc usually so in your case MPP V would be  15.7 * 0.8 = 12.56 volts, below battery
voltage and the power from the PV falls off more rapidly on the high side of the MPPT
voltage curve.

Wiring the PV in series may increase your available power by quite a bit and is at least
worth trying if you can.

boB

[Sweet Taterman]

@boB. Thanks for the explanation. That 15.7V on the input was being supplied for testing purposes from a stiff power supply that does not start to significantly begin to foldback the voltage until a load of ~340W is reached.

[boB]

@boB. Thanks for the explanation. That 15.7V on the input was being supplied for testing purposes from a stiff power supply that does not start to significantly begin to foldback the voltage until a load of ~340W is reached.

Ahhh...  OK.   Just raise the voltage a wee bit then if it is from a large, low impedance source power supply.
Another volt or two should work fine.  Maybe 20V input but you will not want to use SOLAR  because that
mode does not track power supplies well at all.

Try Legacy mode or Hydro mode or maybe Hydro mode in Manual MPP V input mode.

boB

[Sweet Taterman]

@boB
I've since applied the info you have provided and sure enough the controller will exit resting within 100mV of the value calculated from the formula you have provided. Thanks!