I recently added a second 2700 watt array with a second Classic. I've noticed that the Classic shows it's input current from this array intermittently spiking down to zero for very brief moments several times a day. Each instance it drops to zero for less than a minute. There are no passing clouds or other shading during this time. My other array/Classic does dose not do this. I can be watching them both simultaneously on the local app while in full sun and only the new one does this. I've attached screen shots showing the current and wattage drop to zero while the voltage spikes. Any ideas why this is happening?
Quote from: mtdoc on October 21, 2012, 04:22:06 PM
I recently added a second 2700 watt array with a second Classic. I've noticed that the Classic shows it's input current from this array intermittently spiking down to zero for very brief moments several times a day. Each instance it drops to zero for less than a minute. There are no passing clouds or other shading during this time. My other array/Classic does dose not do this. I can be watching them both simultaneously on the local app while in full sun and only the new one does this. I've attached screen shots showing the current and wattage drop to zero while the voltage spikes. Any ideas why this is happening?
Interesting. The Classic WILL drop the input briefly but should be less than 1 second or maybe even less than 1/2 second
while it does its sweep.
You might want to export that data (via the export button) as the CSV output has a sample rate of 2 seconds and
the display on the Local App itself does not. At worst case, the Classic may have found a wrong power point.
It was most likely something else but not sure of course.
It looks like your battery voltage is low enough that the other classic is most likely not in absorb or float ??
If the battery is near full, then the classic will necessarily put out lower power and bring the input to higher
PV voltage to regulate the battery voltage. Maybe the Classic went to "Resting" during that time ???
boB
Well I went through the CSV file and counted at least 50 episodes of this happening in todays data! Each occurs for 10-12 data points (?20-24 seconds?).
This has been happening on other days as well. I just happened to notice it a few times the last few days.
My battery voltage is low because I am grid tied and am selling to the grid. So my Classics never come out of Bulk with my Sell RE set point on my GVFX3648 set at about float voltage.
Definitely something strange going on. If it was a loose connection someplace it doesn't seem that it would be happening with such regularity - each time for almost the exact same duration.
Any ideas? I'd attach the CSV file but it is too large.
Thanks for your help boB!
Add - here's a screenshot of one example from the CSV file. All 49 others look almost identical.
I have an idea... Maybe...
Let's check the Reason for Resting code... From the MNGP main status screen,
Hold down the LEFT-ARROW key and tap the ENTER key. You will see a screen
with a bunch of numbers on it. The ones I am interested in is the TOP-MIDDLE
number and the LOWER RIGHT number. RFR code is the top middle number
and will stay current until the Classic goes to Resting again which will change
the reason for resting code. During the day, that number should reflect
the reason yours is doing this. At night, the reason will usually be because of
low light so won't help then. During the day it should.
It is stopping for about 20 seconds which is a clue ! I will wait to hear what that
number is.
boB
Ok great. I won't be home during the day until Tuesday - so I'll try it then.
Question- do I need to do this during one of the 20 second periods that it goes to zero - or anytime during the day?
Quote from: mtdoc on October 22, 2012, 01:52:28 AM
Ok great. I won't be home during the day until Tuesday - so I'll try it then.
Question- do I need to do this during one of the 20 second periods that it goes to zero - or anytime during the day?
If it goes to resting, that number will be good until next time it goes to resting, in which
case it will probably go to resting for the same reason so hopefully that number will
be good no matter when. It would be best to check it anytime after you know it
went to resting for 20 seconds.
It you started having rain or dark clouds, the reason for resting would most likely
be overwritten with a low light RFR code as it will do during the night.
Anytime you manually turn the MPPT MODE to OFF, it will also change the RFR code.
Whatever reason the Classic last went to resting, that number will still be in there.
boB
Got it. Thanks.
Quote from: boB on October 22, 2012, 02:00:03 AM
It you started having rain or dark clouds, the reason for resting would most likely
be overwritten with a low light RFR code as it will do during the night.
Well here's my forecast - so we'll see. Gotta love PNW weather :P
Quote from: boB on October 22, 2012, 01:34:50 AM
I have an idea... Maybe...
Let's check the Reason for Resting code... From the MNGP main status screen,
Hold down the LEFT-ARROW key and tap the ENTER key. You will see a screen
with a bunch of numbers on it. The ones I am interested in is the TOP-MIDDLE
number and the LOWER RIGHT number. RFR code is the top middle number
and will stay current until the Classic goes to Resting again which will change
the reason for resting code. During the day, that number should reflect
the reason yours is doing this. At night, the reason will usually be because of
low light so won't help then. During the day it should.
It is stopping for about 20 seconds which is a clue ! I will wait to hear what that
number is.
boB
Ok - not much sun here today but enough to check this I believe. Output has dropped out to zero a few times with V in spiking up for 20 second intervals as before.
The top middle number is 5. The lower right number bounces around between 550 and 560.
BTW my other classic which is not showing this behavior shows the same numbers.
Hope this helps! Thanks.
Quote from: mtdoc on October 23, 2012, 05:46:28 PM
Ok - not much sun here today but enough to check this I believe. Output has dropped out to zero a few times with V in spiking up for 20 second intervals as before.
The top middle number is 5. The lower right number bounces around between 550 and 560.
BTW my other classic which is not showing this behavior shows the same numbers.
Hope this helps! Thanks.
Well, it's not what I thought it might be. The bottom right number looks like it is just
showing your battery voltage but without the decimal point, which would be correct.
You DO have a 48V battery system, right ?? i.e. around 55 to 56 volts ?
The Reason For Resting being "5" just means that you have low light. Maybe today
with the weather such as it is, that it is a different reason than when you have lots
of sun and lots of power. RFR = 5 will come up in solar mode if the power output
drops below 20 watts or so for 90 seconds. But if your output power was higher
than this, then maybe we can still do something about it.
Let's wait until you have lots-o-watts again and then check that RFR number again.
On my way up to Guemes Island for an SEI hydro class thing.
boB
Quote from: boB on October 23, 2012, 05:54:40 PM
You DO have a 48V battery system, right ?? i.e. around 55 to 56 volts ?
Yes - that's right.
Quote
Let's wait until you have lots-o-watts again and then check that RFR number again.
On my way up to Guemes Island for an SEI hydro class thing.
boB
Ok - will do. Thanks. I really appreciate the service!.
Ooooh Hydro- my next project and Classic purchase... ;D
If you updated the firmware then you should do a VMM. That's what solved the similar problem I was having:
http://midnitesolar.com/smf_forum/index.php?topic=720.0
QuoteVMM = This is where you hold the LEFT and RIGHT arrow keys down as the MNGP (remote)
is re-booting (power up) until you see the selection screen SOLAR--WIND--HYDRO come up.
Have been reluctant to add my 3 cents on this, BUT ...
I had a very similar resting situation, but never did get to do the RFR to see why.
In my situation, reloading the same FW version, BUT waiting a number of minutes after the loader (from Win7) said it was "done, or 100% complete" for it to completely finish, and also doing the VMM did correct this issue, and have not seen the Pause or Rest during Bulk for about three weeks.
Realize that mtdoc may have not ever updated the FW in the CC that has this similar issue, but these two things seem to have eliminated this stutter during Bulk, and so on.
Just my unscientific experience, Good Luck, Vic
stephendv and Vic - Thanks for this. Somehow it's reassuring that others have seen this and resolved it. I did update my firmware to the 6/29 version on this Classic shortly after installing it a few weeks ago.
A bit more sun this am and after a few of the same "stutters", the Classic is still showing RFR=5.
I'll give the VMM a whirl.
Live Long and Prosper... ;)
Yes I have seen that exact issue as well and a VMM fixes it.
Ryan
could it be an improper vmm from others? you must use all of your fingers for a good meld. ;D
poop to live long. ??? :P
if you guys dislike my humor feel free to hit it with your phasor.
Well I did a VMM earlier and so far it looks like it cured the problem. Even with relatively little sun today , since doing the VMM I've had no more stutters. :)
Quote from: niel on October 24, 2012, 05:28:29 PM
could it be an improper vmm from others? you must use all of your fingers for a good meld. ;D
Ha Ha!. The origin of using VMM to describe this procedure did not occur to me until I actually did it. Holding those 2 keys in does put ones hand in a very Spock-like position. I could almost feel the tips of my ears tingling and the Classics modbus registers rolling over..
Thanks all!
Quote from: niel on October 24, 2012, 05:28:29 PM
could it be an improper vmm from others? you must use all of your fingers for a good meld. ;D
poop to live long. ??? :P
if you guys dislike my humor feel free to hit it with your phasor.
Niel
No worries here we all have an interesting sense of Humor ::)