Different Size of Solar Panel Limitation?

[TheGoldenPanda]

Due to limited roof space and shape, I am planning to install two different sizes of solar panels on the RV.
The first one is a 255W CanadianSolar CS69-255P, which has a 30.2V operating voltage, 8.43A operating current while VoC is 37.4 V, short circuit current is 9A.
The second one is a 100W Rich Solar RS-P100, which has 18.5V voltage, 5.41A operating current, Voc is 22.6V, the short circuit is 5.86A.
The panels will be connected in series and the travel distance is about 12 feet to the MPTT.
The MPTT is Renogy ROVER LI 40 AMP MPPT SOLAR CHARGE CONTROLLER, (Max Solar Input Voltage: 100VDC)
The batteries are two Renogy 100 AMP Lithium batteries.
I am within the limit of the MPTT but would like to understand the limitations of mix-size panels. Almost every system I saw uses the same size panels. Any specific reasons for that?

 

[MisterSandals]

In series the panels will produce 38.7v but will be clipped by the lowest amperage (5.41a):

38.7v x 5.41a = 209w

You'd be better off with just the 250w panel!

How about getting a second smaller SCC like a Victron 75/15 for the 2nd panel? Its $120 for the bluetooth model (bluetooth absolutely recommended). This would give you a bit of redundancy for the added expense.

Just for kicks, if you wired in parallel:
Amps would be 8.43a + 5.41a = 13.84a
Volts would be clipped to lowest (18.5v):

13.84a x 18.5v = 256w better than in series but not much better than just the 250w panel alone.

 

[time2roll]

Those two panels are so mismatched you need separate controllers regardless of series or parallel.
If you are charging LFP batteries make sure the controllers have user adjustable voltages.

 

[TheGoldenPanda]

In series the panels will produce 38.7v but will be clipped by the lowest amperage (5.41a):

38.7v x 5.41a = 209w

You'd be better off with just the 250w panel!

How about getting a second smaller SCC like a Victron 75/15 for the 2nd panel? Its $120 for the bluetooth model (bluetooth absolutely recommended). This would give you a bit of redundancy for the added expense.

Just for kicks, if you wired in parallel:
Amps would be 8.43a + 5.41a = 13.84a
Volts would be clipped to lowest (18.5v):

13.84a x 18.5v = 256w better than in series but not much better than just the 250w panel alone.

Thank you very much for the answer. I will just use one 250W panel.

 

[MisterSandals]

Thank you very much for the answer. I will just use one 250W panel.

You might be able to use the smaller panel as a carry out panel for when you park in the shade or want to catch some late afternoon or early morning sun. You set it up so you could use the 100w on ~25' wires instead of the RV's shaded 250w without a lot of effort and wiring.

 

[TheGoldenPanda]

You might be able to use the smaller panel as a carry out panel for when you park in the shade or want to catch some late afternoon or early morning sun. You set it up so you could use the 100w on ~25' wires instead of the RV's shaded 250w without a lot of effort and wiring.

That's a great idea. My Lance 1685 does come with a side mount solar port. Thank you again.