Multiple MPPT Solar Charge Controllers to the same battery bank

Andrewr05 said:

Not trying to be an asshole here, But I think that you just fundamentally do not understand what we are trying to say.

You've said the same thing like three or four times now and I legitimately think that you just aren't willing to be wrong. You are so stuck on the thought that you have to be right that you aren't stopping for like four and a half seconds to actually think about what you're typing and to comprehend what you're reading in a way that lets you actually pay attention to what we're saying.

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You can be an asshat, I won't care.

I'll keep repeating what I am saying and maybe by the 20th time, you might understand.

Zwy said:

X number of panels only have X potential yield.

Where do you source these magic panels that produce more yield just because you overpanel a SCC compared to underpaneling an SCC?

Does the panel morph into super yield production just because it is one string where the SCC is overpaneled?

Please share your source.



Say what???




Say what??




I never worry about charge current. I have a bank large enough that even if I had 120A of charge current, each 16S battery in a bank of 4 will only have 30A of charge current. 160A would be 40A.

I'm not anywhere even close to 1C.


3C? Really, you are using that spec as an argument?

1200A on just one 48V battery would take something like 60Kw of PV yield.

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You are determined that you are right (despite being wrong)- overpanelling doesn't make each panel do 'magic' and make more power- but in an array where the charge controller is the limiting factor- overpaneling allows the charge controller to make its full output WHEN CONDITIONS ARE POOR -- and panels don't make their full output...

In overcast condition, the power from a single panel may drop 50% or more- so in places where you have extended periods of bad weather- overpanelling allows your controller to still be at full output in those conditions, rather than being stuck at half its rated output also...

By having 50% more panels than 'you need'- you still get full charge in poor weather conditions, and in good condiotions the controller limits the current to the battery to its maximum output (hopefully in a well designed system, below the maximum charge current)- where if you had 'more charge controllers' so you didn't 'overpanel' you could exceed the battery banks safe charge limit- and well- time to open the wallet up and buy new batteries...

It is a common and well understood (by most) way to maximise your poor weather production when you live in an area that warrants it...

Quite simple really...

Zwy said:

You can be an asshat, I won't care.

I'll keep repeating what I am saying and maybe by the 20th time, you might understand.

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Maybe you are the one who isn't understanding- ever thought of that???

Texas-Mark said:

Nobody is arguing that.

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At least I am now making progress.

Texas-Mark said:

If you don't understand that X+2 panels will produce more than X+0 panels off peak or when cloudy, then I don't know what to tell you.

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Sorry but my mounts only take X number of panels. And I will capture all of the potential those X number of panels can produce. Doesn't matter if sunny or cloudy, I harvest all of it.

You asked the question, "Please explain how this is better than overpanneling for cloudy days."

I explained it.

Now you make the argument of adding more panels. Of course one can get more yield by adding more panels. Duh!

I'm adding more panels this year. I'll get more yield from those panels too.

Those panels will be on their own MPPT's.

Zwy said:

You can be an asshat, I won't care.

I'll keep repeating what I am saying and maybe by the 20th time, you might understand.

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And like I said before, I don't think that any of us are arguing that in a perfect situation you either shouldn't ever have to over-panel or you just have the budget for quadruple your required battery system instead.

Nobody is saying that your alternative is wrong either.
We are just saying that an alternative opposite end of the spectrum concept exists and you are the one who is saying that it actually doesn't work (???) and that what you're proposing is the only way it should be, or that's what it seems.

Zwy said:

I know I'm correct, you did the same thing for 4 decades and seem stuck in that mindset.

We have an industry saying, "40 years of experience or is it 40 years of the same experience?"

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Sighs- now you are really trying to be the 'asshat' in this conversation aren't you???

If that was the case, I'd still be pushing flooded lead acid crap with PWM voltage matched arrays...
Seriously- have YOU ever thought- 'maybe I'm wrong, maybe there is a good reason'???

Nope, like a stuck record, just keep repeating the same outdated nonsense...
Overpaneling on 'yea oldfashioned' voltage matched PWM systems simply didn't work (probably why you are so stuck on the idea) but on modern high voltage MPPT systems, it works- and works well...

Zwy said:

Now you make the argument of adding more panels. Of course one can get more yield by adding more panels. Duh!

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Wow, he finally gets it.

Zwy said:

Those panels will be on their own MPPT's.

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What you are missing is that that may not be the optimal solution in every case.

Texas-Mark said:

Wow, he finally gets it.



What you are missing is that that may not be the optimal solution in every case.

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But still doesn't get that in order to push production up in poor conditions, you have to limit it in good conditions...
Sighs (and I don't expect he ever will...) old dog, new tricks etc...

Bop said:

You are determined that you are right (despite being wrong)- overpanelling doesn't make each panel do 'magic' and make more power- but in an array where the charge controller is the limiting factor- overpaneling allows the charge controller to make its full output WHEN CONDITIONS ARE POOR -- and panels don't make their full output...

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If the charge controller is the limiting factor, add more charge controllers and maximize yield.

When conditions are poor as you put it, you will still harvest maximum potential of the array.

Bop said:

In overcast condition, the power from a single panel may drop 50% or more- so in places where you have extended periods of bad weather- overpanelling allows your controller to still be at full output in those conditions, rather than being stuck at half its rated output also...

By having 50% more panels than 'you need'- you still get full charge in poor weather conditions, and in good condiotions the controller limits the current to the battery to its maximum output (hopefully in a well designed system, below the maximum charge current)- where if you had 'more charge controllers' so you didn't 'overpanel' you could exceed the battery banks safe charge limit- and well- time to open the wallet up and buy new batteries...

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Bop said:

It is a common and well understood (by most) way to maximise your poor weather production when you live in an area that warrants it...

Quite simple really...

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You just might understand what I have said but on second thought I don't think you will.

Go back and read what I have written in this thread thus far, you might be able to understand it after a few times.

The ecoflow Delta 2 max actually has two mppt charge controllers built in and they work together giving two separate charge inputs.
You can use both for solar or one for solar one for charging from another source.

Texas-Mark said:

Wow, he finally gets it.

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It's a dumb argument. Of course adding panels will produce more. One can configure strings to take advantage of extra panels, add more SCC's and harvest any potential yield instead of part of it.

You're trying to make it sound like you won some argument, well, you haven't. I stand by my statements.

Texas-Mark said:

What you are missing is that that may not be the optimal solution in every case.

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You obviously did not read thru any of the links. 3 weeks with 20 minutes of sun is one example. How would overpaneling help that situation? If the sun shined at peak power for 20 minutes in a week, heck I'll even give you 1 hour, would the SCC capture more yield with overpaneling than it would if the SCC was underpaneled?

Answer that question. I shall return after lunch to discover your answer.

And NOPE- he still missed the point completely...

You STILL missed that your battery bank has a LIMITED amount of current it can accept- if you have the array set to a safe limit in the good conditions, then it will make LESS in POOR conditions...
If you experience POOR weather conditions a lot of the time, then you are losing charging capability- when you need it the MOST...

By overpanelling- you are trading generation capability in the best conditions, (a few hours a day in good weather, none in bad weather) for MORE charging ability in the poorer conditions (ie early morning/late afternoon in good weather, all day in poorer weather)

It WORKS...

Bop said:

But still doesn't get that in order to push production up in poor conditions, you have to limit it in good conditions...
Sighs (and I don't expect he ever will...) old dog, new tricks etc...

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Why limit yield?

You must be an old dog, said you had 4 decades of the same experience and haven't learned the new tricks.

Zwy said:

Go back and read what I have written in this thread thus far, you might be able to understand it after a few times.

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We can say the same.

You are the one who initially claimed overpanneleing will never exceed an underpanneled system. If you still believe that, so be it.

You remind me of the guy who claimed we have all been charging our batteries wrong. LOL

Zwy said:

If the sun shined at peak power for 20 minutes in a week, heck I'll even give you 1 hour...

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Zwy said:

would the SCC capture more yield with overpaneling than it would if the SCC was underpaneled?

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Of course it would.

I don't even know how you come to the logic that it couldn't.

If I stick two pieces of paper towel on some water that I spilled, won't the two pieces of paper towel absorb more water?

I think you're somehow conflating what we are saying to mean that we are trying to imply that you can extract more power than exists.

If you have a 400 watt solar panel and there's so little sun out on a given day that it's only producing 80 Watts of power and then next to it you also have a 400 watt solar panel, that other solar panel would also be in taking in 80 watts of power.

So, literally during inclement weather the more solar panels you have, the more power you were able to extract.
That's like the basic 101 of householder panels work on any day, not just a shitty weather day.

Peak sun hours to me are largely irrelevant, because I know that total all day long at least some form of wattage is going to be coming in.

Bop said:

And NOPE- he still missed the point completely...

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I haven't missed anything.

Bop said:

You STILL missed that your battery bank has a LIMITED amount of current it can accept- if you have the array set to a safe limit in the good conditions, then it will make LESS in POOR conditions...
If you experience POOR weather conditions a lot of the time, then you are losing charging capability- when you need it the MOST...

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Yep, old dog that "learned" with lead acid.

Put in a bigger bank and maximize yield from PV and get back to me. It is possible you might learn some new tricks.

Bop said:

By overpanelling- you are trading generation capability in the best conditions, (a few hours a day in good weather, none in bad weather) for MORE charging ability in the poorer conditions (ie early morning/late afternoon in good weather, all day in poorer weather)

It WORKS...

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No need, I have a large enough battery bank plus dump loads to handle days of high production and capture all potential yield on days of poor production.

It WORKS......

Zwy said:

It WORKS......

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Unless I've missed one of the posts, I don't believe anybody so far in any way has said anything to the contrary.

We are just also saying that something else is also possible.

Andrewr05 said:

Of course it would.

I don't even know how you come to the logic that it couldn't.

If I stick two pieces of paper towel on some water that I spilled, won't the two pieces of paper towel absorb more water?

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I never stated that more panels would not produce more power. We all know they will. What some have tried to claim is that X number of panels will produce more power by just overpaneling the SCC instead of underpaneling. In actuality, the yield will be less long term due to clipping.

Andrewr05 said:

I think you're somehow conflating what we are saying to mean that we are trying to imply that you can extract more power than exists.

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There you go. You get that part.

Some are trying to confuse the argument by claiming I said more panels won't produce more power. Never said it. It's a strawman argument on their part.

Zwy said:

I never stated that more panels would not produce more power. We all know they will. What some have tried to claim is that X number of panels will produce more power by just overpaneling the SCC instead of underpaneling. In actuality, the yield will be less long term due to clipping.

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Again how many bad weather days we are talking about.

Nobody here has argued that it isn't a wasteful method.
From the get-go, I think those of us that are talking about this have fully understood and made it aware that we understand that on a normal day the extra current is being wasted.

I think we can all agree that that's the reality of over-paneling.

Andrewr05 said:

Again how many bad weather days we are talking about.

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It isn't just about bad weather days. We can take today as an example. Sun shined for about 15 minutes this morning at about 9 am, then went behind heavy cloud cover. My battery bank was down to under 40% as the heat pump ran all night and yesterday the sun went behind the clouds at about 2 pm. Very little production with the heavy cloud cover. There was very little PV to power loads.

The sky cleared at a little after 11 am today. It is now clear but it almost looks like late afternoon it might cloud back over.

Would overpaneling my SCC's lead to increased yield for the day or would underpaneling? We are talking peak sun hours here so overpaneling will lead to clipping as the sun is bright now and I'm pulling close to 100% from my array. My bank has plenty of capacity to allow for capturing any potential yield from PV. By underpaneling, I can capture all those photons and put them to use by underpaneling.

Many days here this time of year are clear skies until late in the day, then cloud cover. Or cloud cover in the morning with clear skies later in the day. By harvesting all potential yield mid day at peak sun, I can put that energy into my batteries for later use, such as heating my house overnight.

Andrewr05 said:

Nobody here has argued that it isn't a wasteful method.
From the get-go, I think those of us that are talking about this have fully understood and made it aware that we understand that on a normal day the extra current is being wasted.

I think we can all agree that that's the reality of over-paneling.

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I look at it this way, I'd spend the money on a SCC before overpaneling. The EG4 MPPT is $399. I can capture all yield and use it, the excess yield can pay back the $399 fairly quickly. Today I will charge my bank up enough in a short time frame that I can heat my house overnight for free.