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Epever charge controller dropping out of MPPT mode

morningcoffee

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I have 2 Epever 40 amp tracers panels are connected in series per controller (2x300w panels) charging a 400amp Lifpo4 battery bank.
Its cloudy today sometimes the sun comes out from behind the clouds but it seems when the light dims they will drop back from MPPT mode to PWM mode, once I disconnect them from the solar and reconnect them they go into MPPT mode giving 50% more energy but poorly as they are not hitting the peak VMP(around 60v) rather staying at the VOC (69v)
Am I missing something both controllers have the same behaviour.
 
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How do you define mppt mode and pwm mode?

Clouds will cripple solar production.
Correct clouds do been living off grid on and off for years I know the basics :p
PWM mode is when the solar controller drops the panels down to the battery voltage (just above 14v) and charges rather than staying at VMP understandable in some situations but not in these conditions.

I have just disconnected both of them from the batteries and solar (in the correct order) for around a minute and reconnected them they are both now operating correctly sitting at close to 60v (VMP for my panels) producing far more power.
The pack is sitting at around 85% currently just lost the morning solar production that is some what irritating I wonder what cause this error on both solar controllers? Might have been because all the batteries BMS's DCed yesterday maybe in an odd order due to being full and this caused some odd glitch.
 
I would often see 27v on cloudy/rainy days (66voc/24v system) with my 4210AN. I thought nothing of it, i thought that was just the maximum power point at the time.
 
I would often see 27v on cloudy/rainy days (66voc/24v system) with my 4210AN. I thought nothing of it, i thought that was just the maximum power point at the time.
Depends when the sun comes out would it increase the voltage and output?
One of my controllers just went to VOC again just dced it again and reconnected it and it seems happy again going from producing less than 1amp to producing 10amp (12v system)
 
I have 2 Epever 40 amp tracers bot are connected in series to a 2 300w panels charging a 400amp Lifpo4 battery bank.
Its cloudy today sometimes the sun comes out from behind the clouds but it seems when the light dims they will drop back from MPPT mode to PWM mode, once I disconnect them from the solar and reconnect them they go into MPPT mode giving 50% more energy but poorly as they are not hitting the peak VMP(around 60v) rather staying at the VOC (69v)
Am I missing something both controllers have the same behaviour.
How do you connect the two SCC in series?
Are they Epever Tracer AN or BN series? Both of them are MPPT, I have never see or heard of these model can perform PWM solar charging mode.
 
Without knowing battery voltage cannot say much.

First suspicion is MPPT controller does not have enough overhead voltage above battery voltage.

Dropping back to PWM mode indicates it does not have enough PV overhead voltage from panels above battery voltage to definitively determine MPPT point.
 
How do you connect the two SCC in series?
Are they Epever Tracer AN or BN series? Both of them are MPPT, I have never see or heard of these model can perform PWM solar charging mode.
I ignored that statement believing he meant two panels in series to each controller (four total panels). Putting two MPPT controllers in series would be too absurd to believe.
 
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How do you connect the two SCC in series?
Are they Epever Tracer AN or BN series? Both of them are MPPT, I have never see or heard of these model can perform PWM solar charging mode.
As in the solar panels are in series, model of the epever c/c is 4210AN. I think practically all MPPT controller can go into PWM mode
 
Without knowing battery voltage cannot say much.

First suspicion is MPPT controller does not have enough overhead voltage above battery voltage.

Dropping back to PWM mode indicates it does not have enough PV overhead voltage from panels above battery voltage to definitively determine MPPT point.
Its a 12v system
It was an error with the charge controller should be fixed by disconnecting them from the batteries either that or the charge controller where overheating its about 27 degrees C here at the moment

To give you an idea it was sitting the panels at 14v producing 4-5amps into the batteries, once I dced the solar controller (from the batteries and panels) and reconnected it in the same conditions the panel voltage was sitting at 59v and putting 20amps into the batteries (per controller).

We just had a big downpour here with very dark clouds the panels where sitting at 55v and putting 6amps into the batteries more than in the better conditions.
Downpour has finished the sun is still behind some light clouds and I am getting 30amp into the batteries (per controller)
 
I wonder if its a weird thresholding issue. Often in the design of various systems, they don't want to switch from one operational state to another state unless conditions significantly exceed some threshold. This is done for various reasons, but one of the reasons is to prevent rapid switching back and forth between the 2 states when conditions are just barely on the edge. For example, if they wanted to switch to PWM when voltage is < 14, and back to MPPT for voltage >= 14, then when voltage is near 13.99999 you may rapidly switch back and forth, causing mayhem. So they may switch to PWM when v < 14, but refuse to switch back to mppt until v > 16 or something like that.

These are all just hypothetical numbers. I'm just explaining the concept. There may be other factors besides voltage taken into account when deciding when to use PWM vs MPPT mode.

I wouldn't be surprised if they required a large threshold to get back into mppt mode. My reasoning is that they may figure that the low voltage (or other conditions) which caused PWM mode are very likely caused by clouds. And a cloudy day is likely to stay cloudy for some non trivial amount of minutes, and so they may be leery of jumping back to mppt too soon for fear another cloud is just a moment away. So they may want to see strong sun for some sustained period of time before going back to mppt. I would imagine reconnecting things will force it to abandon any such thresholds and immediately go into whatever state appears optimal at that instant.

But if I read you correctly, to me it sounds like you said sometimes even after you reconnect to force it back into mppt, it then chooses a voltage far above VMP. Is that correct? During and after you reconnected, when v was ~69 instead of the expected 60, was the sun strong the entire time, or were there periods of clouds or panel shading (perhaps caused by your body)?
 
I wonder if its a weird thresholding issue. Often in the design of various systems, they don't want to switch from one operational state to another state unless conditions significantly exceed some threshold. This is done for various reasons, but one of the reasons is to prevent rapid switching back and forth between the 2 states when conditions are just barely on the edge. For example, if they wanted to switch to PWM when voltage is < 14, and back to MPPT for voltage >= 14, then when voltage is near 13.99999 you may rapidly switch back and forth, causing mayhem. So they may switch to PWM when v < 14, but refuse to switch back to mppt until v > 16 or something like that.

These are all just hypothetical numbers. I'm just explaining the concept. There may be other factors besides voltage taken into account when deciding when to use PWM vs MPPT mode.

I wouldn't be surprised if they required a large threshold to get back into mppt mode. My reasoning is that they may figure that the low voltage (or other conditions) which caused PWM mode are very likely caused by clouds. And a cloudy day is likely to stay cloudy for some non trivial amount of minutes, and so they may be leery of jumping back to mppt too soon for fear another cloud is just a moment away. So they may want to see strong sun for some sustained period of time before going back to mppt. I would imagine reconnecting things will force it to abandon any such thresholds and immediately go into whatever state appears optimal at that instant.

But if I read you correctly, to me it sounds like you said sometimes even after you reconnect to force it back into mppt, it then chooses a voltage far above VMP. Is that correct? During and after you reconnected, when v was ~69 instead of the expected 60, was the sun strong the entire time, or were there periods of clouds or panel shading (perhaps caused by your body)?
It was an issue with the charge controller itself going into some odd mode, once I dced it from the battery bank and reconnected it one stayed at VMP the entire day the other had to be disconnected from the battery bank a few more times so I have left it unplugged for awhile for it to hopefully reset itself properly.
 
I think practically all MPPT controller can go into PWM mode
Never heard of a MPPT controller pretending to be a PWM controller - have you got a link?

The Vmp is a panel characteristic and not the voltage the controller will attempt to maintain. (the controller knows nothing about your panel/s and will track the I-V curve for the current conditions)
 
Never heard of a MPPT controller pretending to be a PWM controller - have you got a link?

The Vmp is a panel characteristic and not the voltage the controller will attempt to maintain. (the controller knows nothing about your panel/s and will track the I-V curve for the current conditions)
Its when the controller pulls down the panels to just above the level of the batteries
Been talked about on here before
 
Been talked about on here before
If you continued reading as far as post 16, you'd see a contradictory quote
"I’m sorry, but this is nonsense. MPPT charge controllers have no ‘PWM mode’."

Can you quote a reputable source?

If you follow the link in that thread (and read to the end):
Sounds like a problem with the controller.
Seems like this was it. The "MPPT" Part had failed. And Interestingly it reverted to PWM style Operation rather than Shutting down or Throwing up and error code.
I do not have an MT 50 :)
Get the USB cable - you can configure way more from the PC software
 
cheaper too.

I actually got the cable first but couldn't figure out how to make my laptop recognise the scc ... so I gave up and bought the mt50
 
cheaper too.

I actually got the cable first but couldn't figure out how to make my laptop recognise the scc ... so I gave up and bought the mt50
Hmm .. yeah, it can be uncooperative.
If the USB drivers don't load automatically, you've got to find your own.

Once it's running, it gives you a lot of control.
 
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