Victron 100/20 Under Performing in a 6S Battery (24V)

[JazzRVwSolar]

How does this not make a difference?



So, you did this manually, with the panel perfectly perpendicular to the sun at high noon?

Is this tool reliable? Have you correlated it to other systems? Have you confirmed panel performance with manual measurements?

To get 330-350W out of a 375W panel this time of year in the northern hemisphere is a tall tale. I have 330W panels tilted at 29° in a cold climate. They only produce about 278W this time of year.




And this was at high noon with the panels perfectly perpendicular to the sun, no shading and clear skies?



Perhaps from your perspective, but many of us on here trying to give advice want to ensure we have a working knowledge of the system.



"Fully programmable" means different things to different people, but in this context, as I indicated, the MPPT is capable of outputting 480W @ 24V.

If your panels are flat on your roof, and you're getting 270-290W out of them, that's fantastic for this time of year assuming you're in the Northern hemisphere.

The wattage and voltage tests were done in July/Aug. Yes, the tester was confirmed against a bench DC power supply up to its max 30V and 10A rating. I have no reason to believe that it would not continue to behave up to its 800W Max. Yes the voltages Voc and Isc were measured. I have no way to produce higher regulated volts/amps.

According to the DC wattage test tool, the panel was producing 330 - 350W. During that time, the MPPT was reporting Max Wattage of 270 - 290.
The 330 - 350W was measure at the point of the wires which go into the SCC. This eliminates all questions about line loss, solar irradiance, tilt, etc. The SCC mode was Bulk. The voltage was low of 20V to high of 24V.

To the best of my knowledge the SCC for bulk is/was set at Bulk charge Voltage of 24V and no limit set to current. In BULK and those parameters I would expect that at a battery voltage of 20 and a charge voltage of 24, for example, there should have been 330W/20V = 16.5A to 350/20 17.5A going to the battery. In reality we were seeing half.

270/330 or 290/350 that puts the SCC at efficiency of 80%. This is 10% below the minimum number claimed, which is 90 - 99%.

The only thing I have every been told by supposed solar professional (who is not a fan of Victron, btw) is that most SCC work best if Solar Voltage is at least 5V above the battery voltage. And efficiency increases, if the battery voltage is not that much further below the optimal tracking point - maybe 2 - 3V. His thought was that if mppt was 37V and battery was 20V, the gap was too big and so the unit was not able to function. I explained that this was programmed and showed him. He said it's too "damn complicated crap," which is why he didn't fool with it.

 

[sunshine_eggo]

The wattage and voltage tests were done in July/Aug.

So, we're talking about something that happened 3-4 months ago?

Summer performance is often penalized by high cell temperatures reducing Vmp, but in perfect conditions, I could see the panels testing in the quoted range.

Yes, the tester was confirmed against a bench DC power supply up to its max 30V and 10A rating. I have no reason to believe that it would not continue to behave up to its 800W Max. Yes the voltages Voc and Isc were measured. I have no way to produce higher regulated volts/amps.

Okay.

According to the DC wattage test tool, the panel was producing 330 - 350W. During that time, the MPPT was reporting Max Wattage of 270 - 290.
The 330 - 350W was measure at the point of the wires which go into the SCC. This eliminates all questions about line loss, solar irradiance, tilt, etc.

Only if the tester is reliable.

270/330 or 290/350 that puts the SCC at efficiency of 80%. This is 10% below the minimum number claimed, which is 90 - 99%.

It was suggested at least a couple times to put both panels on one MPPT. Did you ever try that? If we're talking about something that happened 3-4 months ago, then obviously you didn't. If you observed a single 100/20 MPPT outputting 270-290W with ONE OR TWO 375W panels on it, I would conclude a faulty MPPT if the issue isn't corrected by a reset to factory defaults/firmware update.

 

[JazzRVwSolar]

So, we're talking about something that happened 3-4 months ago?

Summer performance is often penalized by high cell temperatures reducing Vmp, but in perfect conditions, I could see the panels testing in the quoted range.



Okay.



Only if the tester is reliable.



It was suggested at least a couple times to put both panels on one MPPT. Did you ever try that? If we're talking about something that happened 3-4 months ago, then obviously you didn't. If you observed a single 100/20 MPPT outputting 270-290W with ONE OR TWO 375W panels on it, I would conclude a faulty MPPT if the issue isn't corrected by a reset to factory defaults/firmware update.

No - we are taking two. Each dedicated to 375W (measured output at 330 - 350W). Each SCC reporting numbers between 270 - 290 range. So, both could be duds, hard to believe. All equipment was updated as of July/Aug when tests were done.

We originally thought (and blamed) the solar manufacturer for selling us defective panels. We did Voc and Isc like their engineer requested. It was within their spec. Still insisting, given output we were told it was line loss, bad connections, or MPPT.

He told us how to sort out including suggestion we get a tester so to compare mppt against tested reference - Voc and Isc are not Vmp and Imp and without that we had nothing. He then told us that the problem was in mppt and he also did not believe we were using 8AWG or there was still bad connection (see warning post about buying wire with jacket label of 8AWG, which now is known to be 10AWG).

He told us to test for "hot spots" and we found none which is when he said either we were mistake or it wasn't 8AWG. Checking the wire with wire gauge he proved himself cause it measured 11AWG not 8AWG (he told us how to measure and he also said 11AWG is 10AWG).

 

[sunshine_eggo]

No - we are taking two. Each dedicated to 375W (measured output at 330 - 350W). Each SCC reporting numbers between 270 - 290 range.

I fully understand this.

As part of your troubleshooting, did you ever attempt to put TWO panels on ONE MPPT? That would have conclusively established if the "290W" was an arbitrary controller limit or not.

So, both could be duds, hard to believe.

Yep.

All equipment was updated as of July/Aug when tests were done.

So you're troubleshooting an issue that occurred 3-4 months ago for which you can take no corrective/investigative action?

Why? I mean what the hell is the point?

Yeah. I saw your other thread that from which you pretty much just disappeared. Two posts on the first page, then you just ignored subsequent questions.

 

[JazzRVwSolar]

I fully understand this.

As part of your troubleshooting, did you ever attempt to put TWO panels on ONE MPPT? That would have conclusively established if the "290W" was an arbitrary controller limit or not.



Yep.



So you're troubleshooting an issue that occurred 3-4 months ago for which you can take no corrective/investigative action?

Why? I mean what the hell is the point?

Yeah. I saw your other thread that from which you pretty much just disappeared. Two posts on the first page, then you just ignored subsequent questions.

It was a public service announcement to all buyers check wire gauge before installing. I was not going to tell anyone who the seller is and while I've been asked to, I've decided against it.

You have a foolish notion of not taking action. Do you think all the effort to make all measurements, discuss with panel manufacturer, and others is non action?

If this is such a good idea, which it's not, why do you think a solar engineer who works for major brand didn't suggest it?

The reason why you are so keen on this is you are unfamiliar with the test tool. Unlike you, he was aware and familiar with his panel, how the test device works, and was sharp enough on all this to tell us over the phone that we were mistaken when we told him we had 8AWG. Based on just numbers and reading we were giving him off the test tool he could tell it couldn't have been. Indeed he was right -- it wasn't.

I think if this was necessary and as good an idea as you seem to believe, he would have suggested it. He gave us plenty of help including how to look for hotspots, check panel, when and how to connect the tool etc. Not to mention how to properly measure wire gauge, which I passed on.

I am totally impressed that just off numbers from the tool, he spotted the wire. And I'm totally impressed by the number of hours he spent on this. He was sharp and would have told us to put panels in series. In fact we talked about getting optimizers and he told us don't waste the money. The problem is in mppt or well past the point where anything on the roof would help.

 

[BuffaloTrace]

Any flaws or alternatives? Has anyone encountered this? What solution?

Members here answered your questions, made suggestions, and tried to get clarification by asking you questions as well. You don't understand a lot of what people have said here and are unable to answer many of the clarification questions, in regards to your first post.

It seems like you've got it figured out pretty well based on the replies I've seen
Do you have any other questions?

My perspective is a lot of these components are designed with the best case use in the average scenario. One will get different efficiencies out of these mppt units at different voltage ranges while charging different chemistries. And you're system parameters and their needs combined with the combination of components being used could very well be yielding less than what the real potential of your particular solar charge controller combined is able to output.

 

[Checkthisout]

Panel mount etc makes no difference. We tested the optimum tracking point with a test tool and it showed the panel to produce 330 - 350W. The SCC was only delivering 270 - 290W while in bulk. The charge voltage was set to 24V there was no restriction put on charge current.

All this talk of series panels and cell count are non-issues -- at least they are suppose to be in a fully programmable SCC.

Guy, stop.

The SCC's are hitting their charging amperage limit of 20 amps (probably 22) at the given voltage.

Your battery voltage is too low for a 24 volt system.

 

[JazzRVwSolar]

Guy, stop.

The SCC's are hitting their charging amperage limit of 20 amps (probably 22) at the given voltage.

Your battery voltage is too low for a 24 volt system.

Please point to Victron manual as others have said it could be defective MPPT.

And I'm still of mind that there is some kind of configuration problem as Victron sales guy did not agree with your assessment. I have passed on that 24v, actual, is too low and is he certain that it's not. He told me no. It should work.

And how can voltage be too low? 330W - 350W in at worst case of 20V, means 16A to 17A, well below the rated 20A. The battery lowest voltage has been 20V.

Maybe the watt equation isn't making sense to you? There are only two possibilities left: configuration or Victron MPPTs are still not fully programmable and despite manual and despite supposed program ability, they are still tied to antiquated notions of cell count from days when we used lead acid batteries.

 

[Checkthisout]

We have two 100/20 MPPTs dedicated to two 375W LG Panels. In other words, each panel has a dedicated MPPT. Also in the system is a custom 6S battery with nominal high voltage for around 24ish volts. We operate between low of 20 and high of 24. There is an inverter as well in the system. We are not seeing the expected production.

A solar tester was use to verify that the panels are meeting spec. They appear to be. Even called manufacturer to confirm the numbers the tester was saying because it was a bit lower than rated. However, their explanation was plausible and within limits of the solar tester. At mid day, the tester was showing 350W at the point where the wire feeds the MPPT. This accounts for any line loss from panel to MPPT. (In fact, this how we discovered that 8AWG wire was not 8AWG but 10AWG). But that discounted, the MPPT is still not performing any where close to the tested 330 - 350W.

On the other hand both MPPTs are way under performing what the solar tester shows. Instead of getting the 350W - 330W, the tester says (tested using the same wire that is going into the MPPTs), the two Victron MPPTs always max out at 290W (each).

At first, we though there was some kind of load balance going on or some kind of interference between the two MPPTs. We removed one MPPT out of the system. And ran everything with just one Solar and one MPPT. Same thing. The MPPT is maxing out at 290W.

Upon checking the specs and manuals, I noticed that the max rating for one of these (100/20) is 290W. I also noticed that this was for a 14.5V battery, which Victron calls 12V. And what Victron calls 24V specs is actually for a 29V battery. Thus the 24V of our battery falls far short of the Victron expecting a 29V, as their nominal 24V.

Our thinking now is that the MPPT despite being told behave as 24, is still going with 12V and limiting to max of 290W. The gap between 29V and 24V is too big for the Victorn 100/20. So, it is automatically downshifting to 12V (14.5V) and limiting to 290W max.

Any flaws or alternatives? Has anyone encountered this? What solution?

Did you read the manual and go in check these settings?

 

[Checkthisout]

Yes. It is manually set to 24V. However, because it is a 6S some of the charge parameters have been reduced accordingly. But your point is well taken. I will upload the all current settings shortly.

Wait a minute. What settings did you reduce?

What is your Max Charge Current and Voltage currently set at?

Post a screen shot.

And, post a screen shot of the charger in action. I.E. I want to see the output current and voltage when it's limiting input wattage to 290 watts (it's 12V charging system limit)

 

[Checkthisout]

Yeah...so for now, give us a screen shot of your max charging voltage and current limit settings.

I'm going to go eat some paint chips and huff some glue while I wait. Thanks.

 

[Crowz]

Yes. It is manually set to 24V. However, because it is a 6S some of the charge parameters have been reduced accordingly. But your point is well taken. I will upload the all current settings shortly.

You lowered the charge parameters and your complaining about it not charging enough?????

 

[mikefitz]

3.4 is the max per one cell

Different cell chemistries have different nominal voltages.

Your oddball battery setup is the problem

More details about the battery pack would be useful, cell type , new or used, tested cell performance, sucessful charging with alternative chargers, battery construction method, battery capacity and performance test, picture of battery , BMS type and setting, ( although I suspect there is no BMS).

Mike

 

[JazzRVwSolar]

Did you read the manual and go in check these settings?

View attachment 177491

While I cannot recall this. The safest voltage is 24V and that is the Bulk. No current limit other than the default 20A. So, it should be able to deliver 24x20 = 480W, assuming the input watts is available. We believe at time(s) of test input available was 330 - 350W range (mid-day). This is based on measurement of voltage and current going into the MPPT.

The battery voltage was 20 - 24V. For sake of argument assume the voltage was low, all that would mean is amps would rise to 16A. If volts was high, amps would be lower, so more like 15A. Because watts in have to be watts out (less inefficient MPPT).

All reported numbers are from when MPPT was in bulk mode. Absorption mode was a bit lower as the charge voltage is a bit lower.

We never saw over about 7A. Half of what we expected. With that kind of performance, we might as well have bought 75/10 and not the nearly twice as as expensive 100/20.

 

[Supervstech]

I am about to lock this thread.

You request assistance for an issue.

All attempts to help you ignore, and all requests for specs and pictures you ignore.

Please state in simple answers what you want to know to help.

The point of a 100V controller is to allow you to send maximum voltage of 100V to the controller, and let the controller adjust output to the battery charge voltage.

If you tie a single panel to a single controller keeping the output voltage of the panel limits... you will not achieve desired results.

Please.

If you are having problems. Requesting help.

Accept the help. Produce requested information.

 

[Supervstech]

Clean slate time

You appear convinced the panels are outputting a specific wattage.

They are not.

Controller can only output what is being drawn from the loads.

Specific voltage batteries draw volts of change until full charge is achieved.

I am guessing you have LiNMC chemistry batteries. Where 6s would be 22.2v nominal, and 25.2 maximum voltage.

If panel output voltage is above 30V under load you should be able to achieve over 400W with the controller, but the panel needs to be able to produce that wattage.

A single 375W panel at a fixed angle, isnt going to produce above 300W but at very specific sun angle and irradiance levels.

 

[JazzRVwSolar]

Please lock the thread.

It is indeed pointless when you claim that people need to know battery chemistry and size of cells etc when they have nothing to do with the voltage and current going into a battery. It makes NO difference.

Questions like exact Voc - do they need the decimal point? A .2V is not going to make a beans difference.

If you believe the panel was not producing 330 - 350W at midday with sun direct and clear, I cannot change your opinion. The chemistry of a battery makes no difference to how many amps at what volts it can consume. It either can or cant. What's next blame the fact that this is a 60 cell solar panel and not conventional 72 cell panel?

The Multiplus has a charger, at 20V battery voltage, we have set charge of 30A and the battery absorbed it just fine. So that means battery voltage, chemistry has nothing to do with this. It has to be MPPT.

If you claim that MPPT does not take watts in and delivery all watts up to the max rated amps available to the load/battery that makes no sense. Why the world would anybody engineer such a thing?

I myself am weary of this and was just looking around to see if I could stop comments. So, please lock it.

Thank you in advance for doing this.

 

[Brucey]

Why are people not badgering joesolar who has same 24V 6S request for help?

Because he posted on August 2nd, someone asked for more info then he never replied back. Next post in the thread was yours. If he had continued posting without providing the requested info people would be badgering him as well.

 

[JazzRVwSolar]

Then that kills this thread also.

 

[Supervstech]

Please lock the thread.

It is indeed pointless when you claim that people need to know battery chemistry and size of cells etc when they have nothing to do with the voltage and current going into a battery. It makes NO difference.

Questions like exact Voc - do they need the decimal point? A .2V is not going to make a beans difference.

If you believe the panel was not producing 330 - 350W at midday with sun direct and clear, I cannot change your opinion. The chemistry of a battery makes no difference to how many amps at what volts it can consume. It either can or cant. What's next blame the fact that this is a 60 cell solar panel and not conventional 72 cell panel?

The Multiplus has a charger, at 20V battery voltage, we have set charge of 30A and the battery absorbed it just fine. So that means battery voltage, chemistry has nothing to do with this. It has to be MPPT.

If you claim that MPPT does not take watts in and delivery all watts up to the max rated amps available to the load/battery that makes no sense. Why the world would anybody engineer such a thing?

I myself am weary of this and was just looking around to see if I could stop comments. So, please lock it.

Thank you in advance for doing this.

Yup, the scc should output 20V at 20A...

If 400+W are reaching it from the panel...

Since you have a single 375 panel imcapable of outputting 400W...

I will blame the panel areangement.