Victron 100/20 or 100/30?

[kaid]

Hello, I will be installing 360 watts of solar (3 x 120) on my camper - it's a small camper and this is what will fit. They'll be mounted flat and I understand I should expect to see 50-60% of rated power. I'm trying to decide whether I should get a SmartSolar MPPT 100/20, with support for up to 290 watts of solar @ 12v or the 100/30 with support for 440 watts.

I don't want to leave power on the table but with the flat mount I really should expect to see less than 290 watts and the 100/20 should be fine right? I like that it's a bit less expensive and that it has load outputs.

 

[sunshine_eggo]

Flat mount varies widely throughout the year. In summer, you may see 80%. In winter you may see only 40%.

 

[Ranger Rick]

The Key number for determining the size of a SCC is the VOC of your panels. The PV's total VOC (if the PVs are in series, one adds all the PV's VOCs) cannot exceed the SCC's voltage rating. The second number refers to the amperage that your SCC will charge your battery bank. Higher is better.

 

[kaid]

Flat mount varies widely throughout the year. In summer, you may see 80%. In winter you may see only 40%.

Got it, thanks. So even at 80% output, it's just at the maximum output of the 100/20. And I'm fine being slightly over paneled in best case scenario.

The Key number for determining the size of a SCC is the VOC of your panels. The PV's total VOC (if the PVs are in series, one adds all the PV's VOCs) cannot exceed the SCC's voltage rating. The second number refers to the amperage that your SCC will charge your battery bank. Higher is better.

Yea, the panels have a VOC of 40v so I would be wiring in parallel to stay under 100v on the SCC.

 

[Martijn]

Here's an excellent solar power calculator that will output which Victron device to use.

Solar Charge Controller Calculator

www.explorist.life

 

[sunshine_eggo]

Got it, thanks. So even at 80% output, it's just at the maximum output of the 100/20. And I'm fine being slightly over paneled in best case scenario.


Yea, the panels have a VOC of 40v so I would be wiring in parallel to stay under 100v on the SCC.

Then they will need to be in a 3P configuration

Here's an excellent solar power calculator that will output which Victron device to use.

Solar Charge Controller Calculator

www.explorist.life

I'd go to Victron direct:

MPPT Calculator - Victron Energy

Use our Online MPPT Calculator for PV sizing calculations.

mppt.victronenergy.com

 

[kaid]

Thanks folks. This interesting tidbit from Victron re oversizing panels: "Generally total energy harvested from a 130% panel oversizing results in less than 1% annual energy loss."

Given that the panels will be flat mounted and the best I might achieve is 80% rated capacity, I'm feeling pretty confident in using the 100/20.

The

I'd go to Victron direct:

MPPT Calculator - Victron Energy

Use our Online MPPT Calculator for PV sizing calculations.

mppt.victronenergy.com

This is really slick!

 

[Martijn]

I'd go to Victron direct:

MPPT Calculator - Victron Energy

Use our Online MPPT Calculator for PV sizing calculations.

mppt.victronenergy.com

Oh, that one is very nice too

 

[Ranger Rick]

Thanks folks. This interesting tidbit from Victron re oversizing panels: "Generally total energy harvested from a 130% panel oversizing results in less than 1% annual energy loss."

Given that the panels will be flat mounted and the best I might achieve is 80% rated capacity, I'm feeling pretty confident in using the 100/20.

The

This is really slick!

Because you will be wiring your panels in parallel, you will need to fuse them.

 

[kaid]

Because you will be wiring your panels in parallel, you will need to fuse them.

Yes! Thanks for the reminder. And a breaker before the parallel string goes into the SCC.

 

[Supervstech]

Keep in mind, that the panels you have NOW will be a little overpaneled,
You might need more solar in the future, and sizing the controller and wiring for more would mean all you’d need to do is attach a ground mount to the setup in the future…

Of course, you could also just get an additional controller with the new panels…