Size of MPPT Charger

[jnchavez]

I'm buying two solar panels at 305 Watts, with a Max V of 32.3V. I'll link them in parallel... if I am doing the math correctly... would I need an MPPT controller of 40A? I've attached the solar panel info

 

[FilterGuy]

would I need an MPPT controller of 40A?

Please read the controller manual closely so you know what the Amp rating actually is.

The following describes the Victron Line of SCCs. Other brands may be different.
The Victron MPPT solar controllers are listed with a voltage and current: Example Smart Solar 100 | 50.

• The 100 is the absolute max voltage that can be applied to the PV input connections (100V in the example).
• The 50 is the maximum current the SCC will generate on the battery output connections (50A for the example.

So, for your 2x305=610 watts, we need to know the system voltage so we can calculate the current at the output.

1. 12V system
   610W/12V=50.83A
   
   
2. 24V system
   610W/24V = 25.41A
   
   
3. 48V system won't work. (The PV voltage is too low).

 

[Forbisher]

I'm buying two solar panels at 305 Watts, with a Max V of 32.3V. I'll link them in parallel... if I am doing the math correctly... would I need an MPPT controller of 40A? I've attached the solar panel info

If your battery is 12V
610 watts at 12V is 50A MPPT

You could connect in series or parallel on a 100V max input MPPT.
The Vmp has nothing to do with the amps needed on a MPPT SCC.
How far is the SCC from the panels?

 

[jnchavez]

Please read the controller manual closely so you know what the Amp rating actually is.

The following describes the Victron Line of SCCs. Other brands may be different.
The Victron MPPT solar controllers are listed with a voltage and current: Example Smart Solar 100 | 50.

• The 100 is the absolute max voltage that can be applied to the PV input connections (100V in the example).
• The 50 is the maximum current the SCC will generate on the battery output connections (50A for the example.

So, for your 2x305=610 watts, we need to know the system voltage so we can calculate the current at the output.

1. 12V system
   610W/12V=50.83A
   
   
2. 24V system
   610W/24V = 25.41A
   
   
3. 48V system won't work. (The PV voltage is too low).

It's going to be a 12V system... thank you for that breakdown as well... this definitely helps me understand it a little more.

 

[jnchavez]

If your battery is 12V
610 watts at 12V is 50A MPPT

You could connect in series or parallel on a 100V max input MPPT.
The Vmp has nothing to do with the amps needed on a MPPT SCC.
How far is the SCC from the panels?

The SCC will be no more than 25ft away, it'll be for my Transit Van Conversion.

 

[snoobler]

Also watch out for very cheap MPPT controllers. They don't exist. Go with something from here:

DIY Off Grid Solar Charge Controllers

Building a vehicle mounted solar power system? Let me help.

www.mobile-solarpower.com