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What is the reasoning for epevers pv voltage recomendations?

Scph9002

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In the manual of epevers ssc they for example recomend 3x38 voc panels but states 4x38 voc is max. This is for 200v/48v ssc.

Why isnt max amount of panels recomended?

Im using only 2x40 voc panels which gives around 64volt max power voltage which is perfect for a 48v lifepo4 bank (58v max)

Also for those rare occasions when ssc hangs around in pwm mode the panel voltage isnt to far away from battery voltage
 
Why isnt max amount of panels recomended?
The input voltage is the critical metric that must be adhered to for the electronics inside. Violating the max input voltage often lets the magic smoke out.

The "max amount of panels" makes it sound like the panels push the current when its the charge controller that pulls the current.
Im using only 2x40 voc panels which gives around 64volt max power voltage which is perfect for a 48v lifepo4 bank (58v max)
I am assuming your EPEver is an MPPT charge controller that accepts an input voltage range well above the battery voltage. Its the job of the MPPT to convert this to a battery charge voltage.
Thinking that 64V is perfect to charge a 48V battery is more how one would talk about if you have a PWM charge controller.

What is the input voltage range and (optimal) MPPT voltage range of your SCC? This is what you should be looking at achieving with your array. And NOT violating the max input voltage, ever.
 
I would assume the most optimal mppt voltage would be battery voltage+2 lol. Guess you indirectly answered my question. 3x<38 voc panels seem to be the optimal mppt voltage range if charging a 48 bank. so around 90-100 volt. Although i am easely pulling 100% of rated pv power during normal weather with 64 volt and in rare occasions when panels was cold and sun came out from clouds i got 130% of rated power lol
 
I would assume the most optimal mppt voltage would be battery voltage+2 lol.
The SCC is optimized with hardware and software for a specific voltage range. If should say what this optimal range is in your manual.
3x<38 voc panels seem to be the optimal mppt voltage range if charging a 48 bank.
Why does this "seem to be optimal"?
when panels was cold and sun came out from clouds i got 130% of rated power lol
Yes, this can be calculated with your panel thermal coefficient (possibly on the panel label). The Voc will increase by your panels' thermal coefficient (probably around .3-.4%) for each degree C drop.

So if your temp drops 10 degrees C (below 25C), your Voc would increase like this:

10 deg x .003 x 38Voc = 1.14V increase.

But the MPPT likely quickly adjusts charging and pulls it down close to the Vmp. Nonetheless, the spike is often a killer for electronics in the SCC. Thus the max input voltage and temp compensation.
 
The SCC is optimized with hardware and software for a specific voltage range. If should say what this optimal range is in your manual.

Why does this "seem to be optimal"?

Yes, this can be calculated with your panel thermal coefficient (possibly on the panel label). The Voc will increase by your panels' thermal coefficient (probably around .3-.4%) for each degree C drop.

So if your temp drops 10 degrees C (below 25C), your Voc would increase like this:

10 deg x .003 x 38Voc = 1.14V increase.

But the MPPT likely quickly adjusts charging and pulls it down close to the Vmp. Nonetheless, the spike is often a killer for electronics in the SCC. Thus the max input voltage and temp compensation.
would this line where it says mpp range be the optimal range?

Reason why i said 3x38voc would be optimal is because that setup was listed under "best" in a chart in the manual
 

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would this line where it says mpp range be the optimal range?

The MPP range is just anywhere from a minimum to charge the battery (set voltage +2), to the maximum that the charger can safely handle.

Reason why i said 3x38voc would be optimal is because that setup was listed under "best" in a chart in the manual

3x 38v, after an allowance for temperature, is probably a safe configuration. 4x38v would be "on spec", as a maximum, but is a bit close to the line for me, as the charger can actually only handle 180v at an operating temperature of 25*c.
 
The MPP range is just anywhere from a minimum to charge the battery (set voltage +2), to the maximum that the charger can safely handle.



3x 38v, after an allowance for temperature, is probably a safe configuration. 4x38v would be "on spec", as a maximum, but is a bit close to the line for me, as the charger can actually only handle 180v at an operating temperature of 25*c.
alright yeah makes sense =)
 
What is this? You've both mentioned it. Is it in the pic or manual?

I see "Vbat2 + V". What am i missing?

For solar charging a battery, "head room" its normally around 5V above battery voltage for an SCC to function.
the ssc wont start charge until pv gets 2 volt above battery volt
 
How did you come up with 2 volts? Thats what i cannot see in your pic (it could be there, i cannot search a pic nor can i see it).

If it's any help, and remembering that this was probably translated from Chinese at some point, I read "Vbat2+V" to mean the battery voltage +2
 
For solar charging a battery, "head room" its normally around 5V above battery voltage for an SCC to function.
I do agree that 5v headroom is actually much more helpful =) The norm i've seen is that if the voltage is close to the limts where the scc will kick in, its likely that input voltage will drop below the range as soon as the panels go on load.
 
vbat2 is battery volt plus 2. And as i understood it the line where is says mpp voltage was just the mppt range. so for a battery that is at 50v the mppt range was 52v to 196v(vbat2+144) or 52v to 180v if at 25 degree c
 
If it's any help, and remembering that this was probably translated from Chinese at some point, I read "Vbat2+V" to mean the battery voltage +2
vbat2 is battery volt plus 2. And as i understood it the line where is says mpp voltage was just the mppt range. so for a battery that is at 50v the mppt range was 52v to 196v(vbat2+144) or 52v to 180v if at 25 degree c
Okay, at least you are both in agreement, i still dunno what "Vbatt2+V" means. Especially for MPPT range.

The head room is normally where the SCC will start charging (battery voltage + headroom). What this means in terms of the MPPT range, i am not sure i even have a guess.

Shouldn't really matter though, i was just trying to learn something that i did not understand.
 
yes translations are really bad sometimes.

In the pc software there is an option that enables or disables "oilengine controlsignal"
Try figuring out what that means lol :D

it is relay switch to start diesel generator
 
Okay, at least you are both in agreement, i still dunno what "Vbatt2+V" means. Especially for MPPT range.
The controller needs at least battery voltage +2V coming in from solar to charge the batteries. I've seen some controllers that say battery voltage +5V to start charging and battery voltage +2V to maintain charging.
 
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