Adding 4 more solar panels to my existing 4x 320 watt 24 volt string

[john95]

Hi, It's been almost a year since I installed my 1280 watts solar system which is working fantastic.

Not a single problem, very reliable, these components are very easy to work with, I'm very happy with my solar system.

Mission Solar 4x 320 watt 24 volt 9 Amp (6 Amp real life) solar panels (harvesting about 864 watts max per hour out of 1,280)
Outback FlexMax 80 Charger
Go Power 1,500 Watt 24 Volt Inverter
Interstate 8x Golf car 6 Volt 225 Ah batteries 24 Volt battery bank 10.8 kWh

My loads are below 700 watts for less than 3 hours a day and want to increase to 1 kWh for more extended hours a day.

I want to add 4 more panels to my setup, which would be the best way to connect the additional 4 panels to my existing 4 solar panels?
Should I have to buy a 2nd Outback FlexMax 80 Charger to handle more watts from the solar panels? I'm estimating another 864 watts for a total of 1,728 watts still under the 2,000 watts mark for my existing charger.

Also, I want to place the next 4 solar panels facing the opposite side to collect the morning sun light.

Thanks in advance for your help.

[Mike90250]

if your proposed new panels will closely match the voltage of the existing string of panels, placing them in parallel to the existing charger would work great.

What's the spec and configuration of the existing PV's ? Proposed PV's ?

[john95]

Mike90250 thanks for replying to my questions.
Yes, the 4 panels that I want to add are similar to the specs that I already have. See the attachment for the specs and configuration for the ones that I already have.

They don't have anymore of the ones that I purchased but they have some that are 340 watt 24 V and the vendor says that they will work perfectly with the ones that I already have.

[john95]

I found the specs for the 4 panels that I want to add, please see the attachment:

[Mike90250]

YES.

You sketch shows your existing panels are wired 2S2P (2 in series, 2 parallel) and 36.1V 2nd attachment shows 36.1V also, so they are a fine match to create another 2S2P array and wire it in parallel to the existing creating a 2S4P overall array. The only "gotcha" is the 4P, more than 2 strings in parallel, and you need to install a series fuse on each string. The label on each panel will list the Max Fuse size to use in each string, 4 strings, 4 fuses.
Since each array is pointing a different direction (so you say) you won't easily overload your existing charge controller, and it should be just fine.

[john95]

This is great! Thanks for your info.
My major concern was to make sure not to overcharge the FlexMax 80 charger, that's why I came with the idea of pointing the 2 arrays to different directions. Also I noticed that I get only 6 Amps max (best conditions) from a panel out of 9 Amps which each panel is rated. So however I configure the 2 arrays I'll be getting 864 watts per array, 1,728 watts between the two arrays.

I have an 80 Amp fuse before the charger and of course I'll put those 4 fuses that you recommended me for every string. The existing 4 panels string recommends a 15 Amp fuse and the 340 watt 24 Volt recommends a 20 Amp fuse for the series.

Also, I have installed fuses on the battery bank and on the inverter.

The FlexMax 80 reports that panels are harvesting 4 ~ 5 kWh a day. By doubling the panels I'm expecting another 4 ~ 5 kWh or more a day. I'm very exciting waiting for the summer to see how much the 2 arrays would harvest.