Have a recently setup system.
48 v Magnum inverter. Classic 150-SL. 24- 6v T105 Batteries wired 48v and 9- 340w panels.( not yet installed)
System has been setup for weeks now charging and inverting from a gas fired generator. We setup 1 temp 340w panel this week while we build the rest of the ground mount rack system and it’s showing 36-39v IN. “Resting†watts at 0 Should there be watts showing? (it's been cloudy out) Getting the same reading with a volt meter at the combiner. System was recently charged so Batteries were at 49v+. Will I need to hook up another panel to get enough voltage to get the CC out of Resting. Or should a clear sunny day do the trick. I understand voltage IN needs to be greater then battery voltage to get the unit out of resting. Not sure how much these panels put out yet. We’re just looking to keep the system topped off while the property is sitting. No draw yet. Empty property. We only have weekends to work on it. Thanks in advance for any info.
Yes you certainly are going to need another panel in series to get anything happening.
Depending on your setpoints - the Classic will come out of resting when there is enough charge and the voltage is lower than Absorb setpoint. Then it will rise to Absorb setpoint and hold it there by decreasing current - it will stay in absorb until your Absorb time is done and then go to Float. If you have ending amps set then it will end absorb when it gets to Ending amps or Absorb time whichever comes first but not longer than absorb time. You should have Whizbang installed to use End amp if you want it to be a good setting to use. But if you dont' have any loads you could use ending amps without whizbang for now. But for your batteries not being used you will want to either use skip days or set up a long absorb cycle every so often ( set up absorb in Equalize ) . Maybe every 10 days or so to stir up the electrolyte so the acid doesn't stratify in your batteries and cause sulfation. Go to first Forum main page and search for skip days - Vic gave good explanation in the past.
Go on the Midnite web page and use their String calculator for the Classic so you can see what it says for your panels - you can play around setting them up in different configurations.
Larry
Hi Cnormandl Welcome to the Forum.
You are correct, that the PV voltage into the Classic (CC) needs to be above the battery voltage.
Depending on the number of solar cells in each PV, you will need several PVs connected in series, to have enough input voltage, before the CC can wake up, and start to produce power.
What is the brand and model number of the PVs?
Strings of two PVs may not have quite enough voltage to charge Flooded Lead Acid (FLA) batteries.
If your PVs are 60 cells, then strings of three will usually be the best configuration. If the PVs are 72 cells, then strings of two may not quite have enough voltage to allow the CC to find the best operating point for maximum power production, and for some PVs strings of three may have a bit too much voltage.
Use the Classic String Sizing Tool to look at strings of two, vs three:
http://midnitesolar.com/sizingTool/index.php
Later, Thanks, Vic
hey vic we posted at the same time !
Larry
Thanks for the info. We hooked up a second panel this weekend. (Panels are 340w Hansol HS34OUD-AN1). 72 cell.
Now getting about 86vdc in now. Did come out of “restingâ€. IN voltage goes to 54 once it goes into “BULK MPPT†but then cycles in and out of resting every 4-5 minutes. Just briefly hen back to BULK. The system was designed for 3 strings of 3 panels in series.
Quote from: Cnormand on April 06, 2020, 09:08:23 AM
Thanks for the info. We hooked up a second panel this weekend. (Panels are 340w Hansol HS34OUD-AN1). 72 cell.
Now getting about 86vdc in now. Did come out of “restingâ€. IN voltage goes to 54 once it goes into “BULK MPPT†but then cycles in and out of resting every 4-5 minutes. Just briefly hen back to BULK. The system was designed for 3 strings of 3 panels in series.
Hi Cnormand,
Thanks for the info on the PVs, and the behavior of the system with two PVs in series.
Have attached the output of the Classic String Sizer. Do not knw anything about the range of temperatures for your location …
BUT, modern 72 cell PVs can have such a high Vmp and Voc, that strings to two PV may not have quite enough input voltage for the Classic 150 SL, and too high an input during normal operation, when using strings of three, and during cold weather.
In Bulk, seeing the input voltage to the Classic at 54 V, on a 48 V system with strings of two PVs (in good sun) is an indication that the Classic has not found an appropriately high MPPT voltage.
You may want to try using Legacy P & O Mode, which can allow the Classic to operate fairly well with a lower than ideal Vin.
What Firmware revision of Classic and MNGP is your Classic running?
Please look at the attached String Sizer output, to get an idea of what your environmental conditions may have on your system.
More later, Thanks, Vic
I have looked at the string sizer and unfortunately don’t quite grasp it. Not sure how to figure / calculate Environmental conditions. We are in Shapleigh, Maine. In the Northeast USA. If that helps. If strings of three are potentially two much voltage I should then go to strings of two. Should I purchase another panel and do 5 strings of two? We have a six slot combiner. MNPV6.
Next is I’m unsure of how to get the firmware revision of the CC and the MNGP are running. Please advise.
I’m not sure what was meant about the comment
“In Bulk, seeing the input voltage to the Classic at 54 V, on a 48 V system with strings of two PVs (in good sun) is an indication that the Classic has not found an appropriately high MPPT voltage.â€
What does that mean classic has not found an appropriate High MPPT voltage? Is this some sort of learned setting?
I did put the CC in Legacy P&O mode as suggested. It was in resting and went to Bulk once enabled. Though after a few minutes it did go to “Resting†again. It was cloudy and snowing a bit. Voltage IN was from 60.9 to as low as 49.1 and no matter the unit goes into Resting every few minutes. (Same as last day of testing in full sun.) CC reads 80.7 IN when in Resting. Also When in Bulk watts show 0-30 and Batt amps at .8. But these readings fluctuate up and down continuously. Is that normal in any way?
Another question is how to calculate the total battery amp hours to enter into the inverter charge settings. Factory setting is 600. Batteries are Trogen Motive -T105’s. 24 of them.
Are we just coming up with these odd issues because I’m not running the complete system? Cart before the horse. Trying to get it temporarily going while we finish the ground array on weekends. Not as plug and play as I had hoped. Wish I could get someone to look over the entire system now that it’s physically installed. See what I’m missing or do I have an issue with a component or installation.
Any suggestions ? thanks all.
Sorry for all the questions.
On the String sizer tool http://midnitesolar.com/sizingTool/index.php
it asks for the highest and lowest temperatures for your area. It uses those as one of the calculations to know how many PV panels you can put in series before it is too high a voltage that would damage your Classic.
You can put all the values in for your PV panels - and then change it from 2 in series to 3 in series and a change the amounts of series strings so you can see how best to optimize the Classic.
I think what Vic meant was that you have to have a certain voltage above the battery voltage in order for the MPPT to work correctly .
The string tool should help with that.
Larry
Hi Cnormand,
I did run your PV through the Classic String sizer, and did attach the output to Reply #5, at the bottom.
I guessed that your coldest temperature might be about 20C, IIRC. The Sizer data indicated that with strings of three of your PVs, the Classic would cease operation, at about +3 degrees C. This is about 37.5 degrees F.
SO, strings of three are really out of the question in ME. With those existing PVs, you really have little choice. Think that you should consider strings of two.
BUT, we need to figure out the reason for Resting.
Below, is a Link that describes how to read the Classic's Reason For Resting (RFR):
http://midniteftp.com/forum/index.php?topic=2034.0
If you push the small round button on the left of the Classic display panel (the MNGP), about six times, the display should show the Classic and MNGP firmware versions.
Regarding the comment about the Classic NOT finding a high enough MPPT voltage, when the Input voltage had been taken down to around 54 V, was just a reference to the fact that the CC cannot produce much power, with the Vin that low. And, with two PVs in series, that a good input voltage should be around 70-75 V, in good sun, depending on the outside temperature.
Are you able to place a load on the batteries, like an electric heater on the output of the inverter, and watch the charging behavior of the Classic?
EDIT: The 74 Cell PVs that you have are just on the edge of running well with a 150 V CC. Three strings are definitely not going to work too well in your Winters, and even in warm WX, the high input voltage will result in more CC heating than you would want. AND two PVs, especially in warm weather may not produce quite enough input voltage for the Classic to produce as much power as you might expect from an array of the size you will have.
AND, believe that the Classic will display, on the main Status page, something like Hyper Voc, or, perhaps Hi Voc, on the lower right part of the MNGP display, when the CC is resting due to excessive input voltage. But with only two PV in that string, this is not the reason for resting ...
More later, Vic
Thanks for the information in layman terms. Im starting to understand most of it.
I will look into the “RFR†When I am back at the property. I made note of the process. That should shed some light.
While using the sizing tool I read the note at the bottom stating
“To insure proper startup and MPPT operation, the minimum initial PV input should be at least 30% higher then the highest expected battery voltage.â€
Being as 64.8 is the equalize set point, +30% = 84.2 V at the input. If I’m reading that correctly I don’t believe the input has been at that level. That’s with the 2 panels. I noted 80.7 V this weekend in full sun. Temp was 50*F. Thoughts on this ?
Thanks.
Hi Cnormand,
YES good that you saw that Note when using the string sizer.
This is the issue that some of the modern 72 Cell PVs. Mine are 72 cells, but date from 15 years ago. So their Vmp is 35.4 V. Yours are 38V, IIRC. Our climate is mild, yours is NOT. The highest Vin, to the Classics is about 141 V.
The RFR will still be an important piece of info. So, hope that you can get that, and the Firmware versions for the Classic and MNGP.
You might try setting the Classic's Mode to Legacy P & O, during the night, and leave it that way, for the next day's charging. Legacy P &O should allow the Classic to make better use of your lower string voltage.
Sometimes, when changing the Mode twix Solar and Legacy, it seems to hang up the CC for a while, and can cause low power production, Vin too low (close to battery voltage), etc.
Also, the PVs should be facing South-ish, and at an elevation so they are close to being at right angles to the sun, when you are doing your testing. Also, any shading on any PVs, will significantly reduce the amount of power available from the PVs.
Good luck, Vic
I did leave the classic in Legacy P&O mode yesterday after poking around a bit. I calibrated the battery bank to the Inverter yesterday also. Charge controller was right on but the Magnum was off .6 Volt. Also set the battery charge setPoints in the inverter remote
We do have the 2 panels facing and angled correctly. No shading at all. Open sun. .
Havnt yet tried the RFR thing yet. Will get back soon with more info.
Thanks.
Hi Cnormand,
Thanks for the update.
Did not mention this, but with multiple charge sources, the Classic can go to Resting, when any other charger's voltage exceeds the setpoint in the Classic. Had not mentioned that previously, as it seemed that you probably did not have any other charge source, at that time.
Good on your PVs, sounds like you are doing fine, in that regard.
As an experiment, you could try adding a third PV to the existing two, to see if that allows the Classic to continue to charge (without any additional charger). But if the WX is cold, the Classic could go into Hyper Voc, however.
Good luck, Vic
Cnormand,
Trying to check the data used to input the Temperature Coefficient of the Voc (Open CIrcuit Voltage). Used the Default value for this value, which may not be correct.
Do you have a Hansol data sheet for your 340 Watt PVs??
Could not find this online, but there is a database of PV info. This value noted on the following site shows a very low value (-- 0.149V per degree C). If that value is correct, then, perhaps strings of three of your PVs might not be a problem with Hyper Voc on COLD days. Although during normal operation, the high PV input voltage of strings of three into the Classic would make run warm, to hot, even under light loading of the CC output.
Here is a Link to that data on that noted site:
http://www.solardesigntool.com/components/module-panel-solar/Hansol/4154/HS340SE-V01/specification-data-sheet.html
This is a bit in the technical weeds, but good info will help guide your decisions about string configuration, etc.
Thanks, Vic
RFR was #5. “ Too Low power and VBatt below set point for 90 seconds. “
I guess that says it.
I forgot to get the firmware revision. Can someone remind me how to get that from the Controller and the MNGP? I thought it was mentioned above but could not find it.
Thanks again. You have all been awesome with my issues.
Conrmand,
That RFR, seems to say that there is too little PV power available to do any charging.
You had mentioned that you have had no shading of the PVs, and that you were running two PVs in series, etc. So, perhaps this RFR was early or late in the day ? Do you recall the solar conditions at the time that you looked at that RFR?
The Firmware versions are found on the MNGP display, by pushing the left small round button about six of seven times.
Good luck, Vic
Quote from: Cnormand on April 14, 2020, 06:22:03 AM
RFR was #5. “ Too Low power and VBatt below set point for 90 seconds. “
I guess that says it.
I forgot to get the firmware revision. Can someone remind me how to get that from the Controller and the MNGP? I thought it was mentioned above but could not find it.
Thanks again. You have all been awesome with my issues.
Just press through the screens on MNGP - firmware version is on one of them.
Larry
Commnd, You may do better with a Classic 200 due to your panel output and weather stats...