Solar Panel add on to existing system

[tnscad]

I have a working system that I would like to add two more 100 watt panels to the current 2-100 watt panels. And I'm not stuck on adding 100watt panels only, will consider other options. I'm Looking for the most efficient way to upgrade the current system. Attached is my poor drawing of my current system. I'm getting confused with the voltage and current requirements for adding 2 more panels. I'm also not sure which would be more efficient series or parallel for the PV.
Eventually i plan on adding a small A/C unit that draws 8.4 amps to the system. I think the 1Kw inverter I have might work, if not I will bump to a 2Kw inverter. the MPPT is a DR3210N Epever Duoracer 100V 30A charger Max PV open circuit voltage: 100V @minimum operating temp, 92V @25c temp. MPP voltage range (battery voltage +2V)-72V, House battery rated charge current 30A, rated charge power 390W/12V, Have I left anything out ??


current PV panels: RNG-100D
open circuit voltage 22.5V
optimum operating voltage 18.9V
optimum operating current 5.29A
short circuit current 5.75A
Max system voltage 600VDC
Max series fuse 15A

PV panels I plan on adding:
Open circuit voltage 24.3V
optimum operating voltage 20.4V
optimum operating current 4.91A
short circuit current 5.21A
Max voltage 600VDC
Max series fuse 15A

 

[DIYrich]

2s2p, with each series being one old panel, and one new panel.
Each string would be 39.30v (sum of two voltages) at 4.91a (lower of the two amps), or 193 watts. Volts is well under 100Voc.
Parallel two strings for 9.82 amps, or 385.93 watts. Just below the max of the inverter. It didn't list a max Isc, but I would guess that 10a is not a problem.

You could do 4s1p (all in series), but then you are at 93.6Voc, without adjusting for temperature. Really close to the 100v max (at min temp), and above the 92v @ 25c.

 

[tnscad]

I thought all in series was really close to the max voltage, but everyone says that you loose 25% so it's ok.

 

[kmin]

but everyone says that you loose 25% so it's ok.

You loose 25% of voltage? How? Keeping them permanently above 100 'C

 

[tnscad]

Would i fuse the whole series or each panel?

 

[tnscad]

sorry fuse each parallel series?

 

[DIYrich]

I thought all in series was really close to the max voltage,

it is.

but everyone says that you loose 25% so it's ok.

??? not that I am aware of. But, assuming you are in the FL Keys, the record low was 41f (5c) in Key West, so you might be ok. Assuming a temp coefficient of 0.3%, that would put 4s at 99.2v at 5c (41f).