Controller input rating question

[Glots222]

Putting together a small system. Playing around and trying to learn. Still really sizing. This is just a controller question so won’t go into other things. I have a Renogy rover 40A controller. At this time I have 4 100 watt panels.
Planning on expanding.
In researching controllers they all have voltage input rating. Totally understand that.
Just looking at the specs and it says maximum solar INPUT 520W.
Looked at a couple other brands data sheets after seeing this and don’t see any mention of input other than voltage.
All info and advice I could find was always related to voltage. Again, I really don’t remember ever even seeing this mentioned.
Something doesn’t seem right. This seems like a pretty important piece of information that should be stated.
If I get 1000W of panels I need another controller?
How do you determine that since no one seems to state it?
Or maybe it’s staring me in the face and I don’t see it.

 

[Forbisher]

Putting together a small system. Playing around and trying to learn. Still really sizing. This is just a controller question so won’t go into other things. I have a Renogy rover 40A controller. At this time I have 4 100 watt panels.
Planning on expanding.
In researching controllers they all have voltage input rating. Totally understand that.
Just looking at the specs and it says maximum solar INPUT 520W.
Looked at a couple other brands data sheets after seeing this and don’t see any mention of input other than voltage.
All info and advice I could find was always related to voltage. Again, I really don’t remember ever even seeing this mentioned.
Something doesn’t seem right. This seems like a pretty important piece of information that should be stated.
If I get 1000W of panels I need another controller?
How do you determine that since no one seems to state it?
Or maybe it’s staring me in the face and I don’t see it.

13V x 40A is 520 watts max production.

1000 watts panels ÷ 13V is 77A

 

[Glots222]

13V x 40A is 520 watts max production.

1000 watts panels ÷ 13V is 77A

Thanks. Im still missing something. For example 3000 watts of panels would require 230 amp controller? Sounds big. (3000/13 =230). I’m seeing $900-$1000 controllers rated at 100 amp.
Theres gazillions on Amazon but not much over 100A.
A 100A controller would be limited to 1300W?
Just seems like you would be seeing lots of them well beyond 100.
Maybe they are out there and I haven’t found them.

 

[Forbisher]

Thanks. Im still missing something. For example 3000 watts of panels would require 230 amp controller? Sounds big. (3000/13 =230). I’m seeing $900-$1000 controllers rated at 100 amp.
Theres gazillions on Amazon but not much over 100A.
A 100A controller would be limited to 1300W?
Just seems like you would be seeing lots of them well beyond 100.
Maybe they are out there and I haven’t found them.

When your 12V battery system has a lot of panels you would either use multiple SCC's on the same array.
Or upgrade to a 24V battery which halves the amps of the SCC.
48V battery is quarter of the amps.
EDIT: Higher VOLTAGE uses smaller and cheaper wires too.

Larger inverter wattages will need a 24V battery too.

 

[Glots222]

When your 12V battery system has a lot of panels you would either use multiple SCC's on the same array.
Or upgrade to a 24V battery which halves the amps of the SCC.
48V battery is quarter of the amps.
Higher amperage uses smaller and cheaper wires too.

Larger inverter wattages will need a 24V battery too.

OK starting to understand it. very helpful.
edit
Actually I still missed something. Why do the batteries have anything to do with it?
It is the SOLAR POWER INPUT wattage rating from panels.

 

[Forbisher]

OK starting to understand it. very helpful.

EDIT: Higher VOLTAGE uses smaller and cheaper wire.
I said amperage by mistake to test you. Lolz

Where are you installing your 100w panels? Unless its an RV with limited space the recommendation is to use larger and much cheaper panels.

 

[Glots222]

EDIT: Higher VOLTAGE uses smaller and cheaper wire.
I said amperage by mistake to test you. Lolz

Where are you installing your 100w panels? Unless its an RV with limited space the recommendation is to use larger and much cheaper panels.

This whole thing is a learning experience. This is not an “installation”. Panels at this time are mounted on fold up angle supports so they can be easily moved around. Permanent mounting area is limited.
When I really understand how it works I will decide exactly what to do.

 

[HRTKD]

Looked at a couple other brands data sheets after seeing this and don’t see any mention of input other than voltage.

The model names used by Victron are fairly obvious once you "get it". The MPPT 100/50 has a maximum voltage input of 100v and will output a maximum of 50 amps. Their datasheet (see below) will list two different wattage "limits" depending on if you have a 12v or 24v battery system.

https://www.victronenergy.com/upload/documents/Datasheet-SmartSolar-charge-controller-MPPT-100-30-&-100-50-EN.pdf

 

[chrisski]

Your manual may have a blurb with at a 12 volt system 520 watts and at 24 volt system 1040 watts. This is pretty common with the SCCs I look at.

Remember 40max in and 40 max out.

You can use math and see 40 amps at 18 volts from the solar panel is equivalent to around 46 amps at 14.6 charging volts. However, your charge controller is limited to a 40 amp output.

With my example I gave, I have a mppt SCC, and overpaneling is OK to an extent. Not sure with a PWM.

 

[Glots222]

Your manual may have a blurb with at a 12 volt system 520 watts and at 24 volt system 1040 watts. This is pretty common with the SCCs I look at.

Remember 40max in and 40 max out.

You can use math and see 40 amps at 18 volts from the solar panel is equivalent to around 46 amps at 14.6 charging volts. However, your charge controller is limited to a 40 amp output.

With my example I gave, I have a mppt SCC, and overpaneling is OK to an extent. Not sure with a PWM.

Sorry guys maybe I’m not saying it right. Forget the batteries and system voltage and anything going out. This incoming.
It states the maximum SOLAR PANEL INPUT WATTAGE 520W at 12 volts, 1040 at 24V
This sounds like you want the highest voltage (not exceeding input) to maximize panels.
‘So if I have a bunch of panels say putting out 100 volts/12=8.333 x 520 =4333 maximum watt input?

 

[HRTKD]

Sorry guys maybe I’m not saying it right. Forget the batteries and system voltage and anything going out. This incoming.
It states the maximum SOLAR PANEL INPUT WATTAGE 520W at 12 volts, 1040 at 24V
This sounds like you want the highest voltage (not exceeding input) to maximize panels.
‘So if I have a bunch of panels say putting out 100 volts/12=8.333 x 520 =4333 maximum watt input?

Yes, that is true. Most MPPT solar charge controllers work this way. The higher the system voltage, the more watts the solar charge controller can handle.

 

[Glots222]

Yes, that is true. Most MPPT solar charge controllers work this way. The higher the system voltage, the more watts the solar charge controller can handle.

Thanks! Another piece of the puzzle figured out.

 

[HRTKD]

You can over-panel (more watts than the controller is rated for) as long as the total panel Voc doesn't exceed the controller's max input volts.

 

[the_colorist]

You can over-panel (more watts than the controller is rated for) as long as the total panel Voc doesn't exceed the controller's max input volts.

Very true. The only limit to that is there is usually a maximum short-circuit current limited listed for a given controller. That combined with the max VOC is your max over-paneling/over-provisioning limit for the input.