Author Topic: Does this look correct for my Midnight 150 & 600 watt panels? 16 amps charging  (Read 302 times)

73-GMC-RV

  • Newby
  • *
  • Posts: 13
I have 6 panels, with the following specs..


Sunny Day, Los Angeles CA

does these number look correct for my system?

1)
Would I get the same charging Amps if I tried wit wire these differently?
I have 3 panels in series and 2 strings of those currently as in the diagram.

The photo with the 16 amps was at lunch today with High sun for April...

Now I see 51-Volts since I am now in Float mode, sun is going down now at 4.30 PM

Confusing as the "Volts in" Increases on the display, when I would have thought the number would be going down here at at end of the day.

If these look correct I will proceed. I assumed I would be getting more charging AMPS than 16. 
« Last Edit: April 13, 2018, 07:27:21 PM by 73-GMC-RV »

Vic

  • Hero Member
  • *****
  • Posts: 1948
Hi 73-GMC..

Since your application is an RV,  with PVs mounted flat (no elevation),  morning sun will not produce will not produce significant output.

Solar noon,   when the sun is directly overhead should be a good test of your system.

In the pic of the Classic's display,   the input voltage is low  for three PVs in series,   but,  this  is probably also due to a low sun angle.

AND,   any shading of any PV in your array can reduce output of the array.  On RVs,  when the sun is not directly overhead,   shading can be a factor from vents,  antennas,  A/Cs,   etc.

It is about solar noon-ish,  how is the output now,  if you are around to observe.  Otherwise,   the Log can help you tell,  as will the MidNite Local App,   or Graham's Android App.

Thanks for any additional info. Vic
« Last Edit: April 13, 2018, 07:07:01 PM by Vic »
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!

Vic

  • Hero Member
  • *****
  • Posts: 1948
Will add,   that you might typically expect a maximum output current from the Classic of around 35 Amps in Bulk from your 600 W array,  given normal de-rating from the published ratings of your PV array.

More later,   Vic
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!

73-GMC-RV

  • Newby
  • *
  • Posts: 13
Thanks, The most I have ever seen was 16 Amps.

So I need to do some testing,  this sounds like half the expected power then.

Thanks

Vic

  • Hero Member
  • *****
  • Posts: 1948
OK GMC-..,

When you have the chance,  it would be interesting to see what in the input voltage to the Classic at about solar noon in a clear day,  during Bulk charge,  if possible.   If your system is never in Bulk by noon-ish,  then a heavy load (like a heater,  hair dryer etc),  to show the maximum power available from the PVs should do it.  Also,  it would be nice to know the approximate outside temperature at that time.

And,  a couple of  other things;  if you could disconnect one string of PVs,   and note what is the change in the output current from the Classic.  It would be nice to know what is the difference in production.

Also,  PV heating is an important factor in PV solar production.   Do your PVs have any space between the frame and the roof of the RV?   Some space is nice to help reduce the effect of heat that could be trapped under the PVs.   Is there any inclination in the PVs,  at all?   This helps ventilation quite a lot.

The Voc seems a bit low in the output of the Classic String Sizer  ...   this may just have been a bit of a guess on your part,  but;

What is the manufacturer and model number of your PVs?

Thanks,   Vic
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!

73-GMC-RV

  • Newby
  • *
  • Posts: 13
The 1st photo of the screen was at noon today, in Bulk mode. with the 29.4 volts, it started off as 54 v, then changed to 29 when it went to bulk mode.

I will unplug one sting tomorrow and see what the difference is.

I mounted the panels on top of these Polycarbonate Greenhouse Panels, that way there is Air between the RV and the solar panels.
« Last Edit: April 14, 2018, 12:04:24 AM by 73-GMC-RV »

73-GMC-RV

  • Newby
  • *
  • Posts: 13
Here is the specs on the panels,  todays temps were 75 degrees.

Thanks for the reply. Love this product and the forum.



OK GMC-..,

When you have the chance,  it would be interesting to see what in the input voltage to the Classic at about solar noon in a clear day,  during Bulk charge,  if possible.   If your system is never in Bulk by noon-ish,  then a heavy load (like a heater,  hair dryer etc),  to show the maximum power available from the PVs should do it.  Also,  it would be nice to know the approximate outside temperature at that time.

And,  a couple of  other things;  if you could disconnect one string of PVs,   and note what is the change in the output current from the Classic.  It would be nice to know what is the difference in production.

Also,  PV heating is an important factor in PV solar production.   Do your PVs have any space between the frame and the roof of the RV?   Some space is nice to help reduce the effect of heat that could be trapped under the PVs.   Is there any inclination in the PVs,  at all?   This helps ventilation quite a lot.

The Voc seems a bit low in the output of the Classic String Sizer  ...   this may just have been a bit of a guess on your part,  but;

What is the manufacturer and model number of your PVs?

Thanks,   Vic

Resthome

  • Hero Member
  • *****
  • Posts: 1100
The PV IN voltage in Bulk has something wrong it should be more like what is shown in Float if the panel all have clear sun and no shadows.

Get ride of those ege crate panels if you are flush mounting the solar panels on them you are trapping the heat on the under side of the panel. They should be mounted at least 1" or more off the roof of the RV. You need to have the air be able to flow under the panels. The hotter the panels get the less they produce.

I still think the problem is with the Low PV In shown in Bulk at high noon.

What is your Absorb set point voltage. Are the Classic setting at the factory default?  What kind of battery bank are you charging?
« Last Edit: April 14, 2018, 02:10:45 AM by Resthome »
John

10 x Kyocera KC140, Classic 150 w/WBJr, Link10 Battery Monitor, 850 AH @ 12v Solar One 2v cells, Xantrex PROwatt SW2000
Off Grid on Houseboat Lake Don Pedro, CA

73-GMC-RV

  • Newby
  • *
  • Posts: 13
I found part of my problem.

2 strings of 3 panels

I measured volts when I was installing these panels, and did not check the amps side during installation.

One of my panels on one string was not putting out any amps, just the correct volts.  Is this a common problem to get past on a new panel.

Also I checked underneath the panels and the heat was extremely high.  I will have to redesign my panel mounting to give more air between the roof and back of the panels.

Thanks for those who commented and got me checking things again.

:)

Vic

  • Hero Member
  • *****
  • Posts: 1948

   ...   One of my panels on one string was not putting out any amps, just the correct volts.  Is this a common problem to get past on a new panel   ...
:)

Hi GMC,

No,   this neither good,   nor normal.

So you measured each PV individually for Isc  and Voc,  with you multimeter?

I finally did look up the PVs on the manufacturer's site (they might be out of business,  now).   I did not that they were semi-flexible PVs.

Good luck with coming up with a better way to mount them.   Vic
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!