620w panels in parallel on DSSR20

[Dan Karau]

Hello

Well, I can't leave well enough alone.   Upgrading my RV to a Forks RV 40' Continental Elegance.

Old system had 16 x 280Ah cells (2P8S) and 8 x 330v panels on 4 x DSSR20s...which of course won't all fit on the new RV with the Vent/AC layout.  

Soooo...looking to put 2 x 620v panels and 2 x 500w panels on a pair of DSSR20s and then find other smaller panels for the other 2 DSSR20s.

Want to ensure that the DSSR20's will handle a pair of 620w panels in parallel.  Specs are:

Voc - 52.77

Isc - 14.85

Wmp - 44.33

Imp - 13.99

Thanks

Dan K

[Dacian Todea (electrodacus)]

Dan,

The DSSR20 is designed for 20A max so two of those 620W modules in parallel will put out around 30A 50% over the DSSR20 spec.

Also the Wmp is to high and will be very inefficient. Those two 620W panels about 1240W total spec will only output around 30A * 28V = 840W

Look for 60 cell (120 half cells) and not 72 cells (144 half cells) modules.

Not sure about the spec of those 500W modules but likely only one can be used with DSSR20 and not two in parallel.

The DSSR50 can handle 3 of them not 4.  

[Dan Karau]

The 620w panels are 72/144 cell panels.  I meant to say connected in series to keep the amps below 20a.

They are the Longi LR7-72HGD-620M Bi-facial panels.

The 500w once are the Longi JAM-60D51-500W panels. These are 60/120 cell panels.

[Dacian Todea (electrodacus)]

Connecting them in series (either the 500W or 620W) will exceed the voltage rating of the DSSR20.

The 500W panels is best for charging a 24V battery using DSSR20 or DSSR50 if you need energy most in hot summer days.  Else if you need most of the energy in colder days (cloudy or winter) then even the 54 cell (108 half cell) models will do even better.

Not sure if bi-facial panels will offer any advantage if installed on the roof of your RV here is an example of 108 half cell panel LONGi LR8-54HGBB-500M  You can expect about 16A from that panel at STC it may peak at 18A in some conditions so it will be a good choice for one DSSR20.

I still have a few DSSR20's if you need more than 4 I just do not have the spacer PCB's (can order a few of those but will take time).

[Dacian Todea (electrodacus)]

Since you will be in a hot climate 60 cell panels will be best. So that JAM60D41-500 I think you already mentioned.

Each DSSR20 can handle one of those 500W modules. If you need more you can either get a few more DSSR20 or the DSSR50. Each DSSR50 can handle 3x 500W modules.

Will you have the same battery or similar ? 8S2P ? 

[Dacian Todea (electrodacus)]

Those 120W panels are 68 cells and will output around 3A each so 10 of them will be just around 30 to 33A max so either two DSSR20's or a single DSSR50 will handle them with no issues.   Up to 16 of those all in parallel can be connected to a DSSR50.