Problem:
- Classic 150 with 1.2KW wired up "was" hunting for voltages on Legacy mode. My neighbor and I watched it for 10 mins under full sun. The PV input voltage would drop to 32v and then ramp up to 95v, hold there (and make the most power)...and then a few minutes later would drop back down to 32v and kill the power/current output. WTF? No weird stuff...panels clean, no shading.
- Switched to "Dynamic" mode and the voltage stayed constant at 95v and power/current remained high. No more ramping up and down (like it was "hunting" for MPPT volts or something)
- What is going on? My other two Classics don't do this...and they are on legacy.
Why a re you using LEGACY and not SOLAR?
I too, use Legacy not Solar, because the Legacy algorithm handles clouds better
Lemme ask this way (see attachments):
Array 1 (Classic 150, 1.8 KW in PV) - Mode "Dynamic". Why does it work better than "Solar"? PV voltages on this Classic "hunt" when in "Solar" mode. While in "Dynamic"...the PV volts stay up and so does current/watts.
Array 2 (Classic 200, 1.3KW in PV) - Mode "Solar". No issues
Array 3 (Classic 150, 1.2KW in PV) - Mode "Dynamic". The voltage on Mode "Solar" ramps up and down "hunting" for voltages. I switch it to "Dynamic" and the PV voltages stay high...current/watts stay up.
What is "Dynamic" mode (engineering/algorithm question...not a 5-word answer please) and why does it work better than "Solar"?
Panels are clean/clear/full sun.
Chris
Hi Chris,
Those images have too few pixels to resolve much, although, have never used the LApp, so those who do may have more abilities.
From the FW 2056 Manual for the Classic (pp 36),
"Dynamic
This is typically used for PV (solar) input sources and tries to follow, on a slow dynamic basis, the changing conditions of the input source. This mode has one user adjustment which is a forced sweep perturb trigger interval for times when the input condition changes do not trigger a dynamic sweep. The interval is in units of minutes."
Believe that Dynamic Mode is to help resolve the situation where Solar Mode would Sweep down to about Vbatt + 5 volts or so, and stay there. This often reduced the harvest to about 60% of what would have been if the Classic used the actual Vmppt. This behavior in Solar Mode was often seen with passing clouds.
The "hunting" that you referred to with Classic 1 in Solar Mode, was probably just the Classic Sweeping, looking for the Vmp for the conditions. In Solar Mode, this Sweeping occurs every three minutes in any MPPT situation. Each Solar sweep appears to take only about one second, or perhaps 1.XX seconds. With a large load change, or with a passing cloud, the Classic might Sweep again before the approximate three-minute automatic Sweep interval ...
The above are neither Engineering Algorithm, nor five-word answers.
Assume that each of the three Classics are on the same battery bank, but are the PVs for each Classic pointing at different azimuths, or do they have different elevation angles, or, some partial Shading conditions?
FWIW, More later, Vic
There is an excellent explanation of how different mppt schemes operate on wiki, google mppt algorithm
Thanks. I switched them back to mode "Solar". Seems to work correctly now. I had some 2/0 battery wiring that needed attention. Not that it related to the dynamic vs solar mode setting...but, all is working fine. My solar panel angles are lousy. Array #3 (1,200w mono Renogy panels) is okay. Set along the fence, gets sun all day, 54 deg (avg for this latitude). Array #2 (1,300w sun knock-offs) sit flat on my pergola...they were cheap...but, in the summertime work fine. Array #1 - 600w in Renogy panels on a "tilter" set now for 54 deg + 1,200w Renogy panels on a pergola extension. They are paralleled in (three strings). The angle on the 1,200w section is maybe 29 deg. Array #1 and #2 angles are horrible. Not going to change Array #2. But, am designing a 1,800w ground mount for Array #1 (tear down what I have and start from scratch). It will be stationary at 54 deg. Bottom line...my backyard is small in Suburbia and shading/space is an issue. Frustrating...but, trying to make it work.
Spoke too soon. Mode is "Solar". Full, 100% sun, clean panels. Classic with 1.2KW in panels is "ramping" and "hunting" AGAIN! Shading loop? The other Classic is steady, staying at around 90v, making great power. The problem Classic goes down to (PV) 32v...about 300 watts. And then it shoots up to 120v and makes 950 watts. There is an occasional indication of "PV Shading" yellow alert. There is no shading. I turned off "PV Shade" on the Classic...no help. The hunting/ramping takes 2 mins 40 seconds. What is going on?
Switching to Legacy P & O instead of solar keeps things stable.
So, what gives? "Solar" mode works on the other two Classics.
Chris
Hi Chris,
So, Is it correct, that all of these Classics are on the SAME battery?
Are all of the Classics running the SAME version of Firmware?
Are you using FollowMe?
I assume that the Classic that needs to run Legacy P&O produces the expected amount of power in this Mode (?).
Thanks, Vic
Quote from: Vic on April 12, 2016, 02:45:08 PM
Hi Chris,
So, Is it correct, that all of these Classics are on the SAME battery?
Are all of the Classics running the SAME version of Firmware?
Are you using FollowMe?
I assume that the Classic that needs to run Legacy P&O produces the expected amount of power in this Mode (?).
Thanks, Vic
Same battery bank (24v)
Classic 1 and 2: FW1923 (both in "Solar" mode and run fine), Classic 3: FW2079
Follow Me: Yes
Legacy P&O expected power? Yep...runs stable. In "Solar" mode...it "loops, ramps, hunts".
Quote from: Jacotenente on April 12, 2016, 04:34:58 PM
Same battery bank (24v)
Classic 1 and 2: FW1923 (both in "Solar" mode and run fine), Classic 3: FW2079
Follow Me: Yes
Legacy P&O expected power? Yep...runs stable. In "Solar" mode...it "loops, ramps, hunts".
Did you know, that to use FollowMe, it has been said that using identical FW Versions, that support FollowMe, need to be used on each Classic in the FM loop? This may not be your specific issue, but believe that this has been stated by MN ... will look for that reference in the Classic Manual ...
EDIT: OK Chris, found this in the Rev G 2056 Version of the Classic Manual on pg 18,
"WARNING: ALL FIRMWARE SHOULD MATCH ACROSS ALL CLASSICS"
Again, this may not be your exact issue, but it IS a Warning << end edit <
More later, Thanks, Vic
Thanks Vic. Appreciate it. Everything is stable now and the three Classic's seem to be working correctly in "Follow Me" mode (bulk-absorb-float cycles fine). Blue lights are all blinking (per Ryan's video).
1) Should I update the firmware for Classics #1 and #2?
2) Should I revert down to REV1923 on Classic #3?
3) Leave everything as is because everything is stable now?
Pretty impressed running the three Classics in Follow Me. When in "Float" the Master Classic (#1) essentially throttles back and takes a break while #2 and #3 maintain the float charge. Really like that.
Chris
Hi Chris,
Thanks for the info.
Since the Classic manual notes that the Firmware should match, and it was a WARNING, I would try very hard to get the FW versions to match ... all that I know, is what I have read in the Classic manual, on this Forum. Cannot say what are the downsides/risks of having mismatched FW.
Since (tell no one) I am running the venerable FW 1849 on all the Classics here, I cannot advise which version might be best for you ...
Have you ever Updated any Classic FW? If so, is the computer used for those updates still available for your use?
Others may have advice on which FW may work best in your situation.
As an aside, getting equal current-sharing between charge sources, when CCs are in a voltage-regulating stage (Absorb, Float, EQ) can be difficult. That Classic #1 is taking a break now, but, probably, if a large load comes along while in Float, that Classic will contribute something, especially if the other two have trouble maintaining Vfloat. Glad that you are happy with that ...
More later. Good Luck, Vic
Thanks Vic - I did have a "solid red" fault on Classic #3. Communications related? IDK. All my computers are Windows 10...and I have heard that the latest firmware has issues. So, am reluctant to update (esp when everything is working now). As for the "master" Classic #1 taking a break...when a load comes across the inverter/batteries (like vacuuming, microwave, window AC)...she increases her wattage to maintain float. My partial off-grid system has been running my house 24/7. The 240v side in on-grid...which I sparingly use. Saw 4,000 watts coming in yesterday. ~happy~
i had that "pumping" action in solar mode as well as described by jacotenente. 3 panels in series only and clear sunny day. so i changed to legacy P&O and it was not doing it anymore. i have not checked this after installed the latest firmware.
Jaco,
How do you have your trojans wired up?
Do you use a buss bar for the charging and inverter draw?
Russ
I switched to Legacy P & O and power is back up and it is not "solar looping" anymore. Power stays up instead of "hunting and ramping" up and down.