How to add/connect more panels

[Wicked]

I hope this is posted in the right section

I am fairly new to solar and mainly use it for camping/expedition use on my truck for extended stays away from traditional camp sites. I use my solar to keep my AUX battery (100ah group 31) charged up to run my 600w inverter, ARB fridge and other accessories.

I purposely overbuilt my system so i can add/support more panels later. Here is my current setup that i worked with Amsolar to build:

100w GS100 panel
25ft 10g wire (allows me to park truck in shade and move panel to sun)
this extension wire goes from the panel and then plugs into my truck bed (via MC4 connectors) where there is about a 6' run of 8g wire to my Blue Sky Solar Boost 2512iX-HV MPPT
I use the Blue Sky IPN PRO Remote Meter to monitor everything

I have questions on adding additional panels.

While 100w is typically enough, I find there are times i need some more power on some trips. I am thinking of adding a 100w foldable panel - essentially 2 50w panels connected nicely like this:



I have been reading about connecting the panels and wanted to see if I am doing this correctly.

I was going to terminate the output of the 2 50w panels with MC4 connectors (vs going to the charge controller in the image) then using MC4 multibranch connectors to run my single 100w panel to the folding panel in parallel like this:



Would this be a correct way to set this up? I want to use the multibranch so i can bring in the additional panel as needed (vs a more permanent combiner box). I have been reading about the use of bypass diodes - are they necessary in this setup?

I also feel i am getting close to the limit of my 25ft 10g extension cable but I think it will suffice for a 4-5% loss.

Any comments or suggestions are welcome - thanks!

[SunEagle]

I hope this is posted in the right section

I am fairly new to solar and mainly use it for camping/expedition use on my truck for extended stays away from traditional camp sites. I use my solar to keep my AUX battery (100ah group 31) charged up to run my 600w inverter, ARB fridge and other accessories.

I purposely overbuilt my system so i can add/support more panels later. Here is my current setup that i worked with Amsolar to build:

100w GS100 panel
25ft 10g wire (allows me to park truck in shade and move panel to sun)
this extension wire goes from the panel and then plugs into my truck bed (via MC4 connectors) where there is about a 6' run of 8g wire to my Blue Sky Solar Boost 2512iX-HV MPPT
I use the Blue Sky IPN PRO Remote Meter to monitor everything

I have questions on adding additional panels.

While 100w is typically enough, I find there are times i need some more power on some trips. I am thinking of adding a 100w foldable panel - essentially 2 50w panels connected nicely like this:



I have been reading about connecting the panels and wanted to see if I am doing this correctly.

I was going to terminate the output of the 2 50w panels with MC4 connectors (vs going to the charge controller in the image) then using MC4 multibranch connectors to run my single 100w panel to the folding panel in parallel like this:



Would this be a correct way to set this up? I want to use the multibranch so i can bring in the additional panel as needed (vs a more permanent combiner box). I have been reading about the use of bypass diodes - are they necessary in this setup?

I also feel i am getting close to the limit of my 25ft 10g extension cable but I think it will suffice for a 4-5% loss.

Any comments or suggestions are welcome - thanks!

It looks like your Blue Sky charge controller is good for 25 amps so connecting 4 x 50 watt panels should be ok.

You do not need any fusing on the panel wiring if you only connect 2 panels in parallel just like that folding panel system you show in your photo.

Once you add more panels in parallel you will need to add fusing on each panel wire. This is why you will need a combiner box or fuse box of some kind.

There is a type of fuse box made by Blue Sea System Marine Fuse Block that allows you to use those 12volt auto fuses.

Or you can build the combiner box like I did. Of course my box is designed for up to 5 x 90 watt panels but I only have 4 wired as of today. Each of those black wires are terminated with MC4 connectors which then allow me to plug them into to my panels. I do use those multi branch or Y connectors on the negative wire but each positive wire goes to a fuse in the combiner box.

Oh. The Negative wiring is also connected to that green "ground" wire which has a stake on the end to ground the system. Not shown in this picture is my grounding wire for each panel frame. They are all connected to the same ground wire.

[Wicked]

It looks like your Blue Sky charge controller is good for 25 amps so connecting 4 x 50 watt panels should be ok.

You do not need any fusing on the panel wiring if you only connect 2 panels in parallel just like that folding panel system you show in your photo.

Once you add more panels in parallel you will need to add fusing on each panel wire. This is why you will need a combiner box or fuse box of some kind.

There is a type of fuse box made by Blue Sea System Marine Fuse Block that allows you to use those 12volt auto fuses.

Or you can build the combiner box like I did. Of course my box is designed for up to 5 x 90 watt panels but I only have 4 wired as of today. Each of those black wires are terminated with MC4 connectors which then allow me to plug them into to my panels. I do use those multi branch or Y connectors on the negative wire but each positive wire goes to a fuse in the combiner box.

Oh. The Negative wiring is also connected to that green "ground" wire which has a stake on the end to ground the system. Not shown in this picture is my grounding wire for each panel frame. They are all connected to the same ground wire.

Thanks for the reply. I wont have 4 x 50watts. I will have my 100w panel (single GS100) and the fold-able (2x50w already paralleled as pictured). My hope was that I could run a single lead from the 2 paralleled 50 watt panels to a multibranch that would connect to the 100w parallel then into the charge controller. I hope I am explaining this clearly. I may draw it out then post a picture of it

[Naptown]

Thanks for the reply. I wont have 4 x 50watts. I will have my 100w panel (single GS100) and the fold-able (2x50w already paralleled as pictured). My hope was that I could run a single lead from the 2 paralleled 50 watt panels to a multibranch that would connect to the 100w parallel then into the charge controller. I hope I am explaining this clearly. I may draw it out then post a picture of it

please post the specs for the existing and new panels.

[Wicked]

Pic of proposed setup:

existing panel:
Pmax = 100 watts @ maximum power
Vmpp = 17.7 volts @ maximum power point
Impp = 5.7 amps @ maximum power point
Voc = 21.2 volts @ open circuit
Isc = 6.10 amps @ short circuit

New Foldable 100w (2x5ow):
Peak power: 100W
Maximum power voltage: 17.5V
Maximum power current: 5.7A (2x2.85A)
Open circuit voltage: 21.6V
Short circuit current: 6.2A (2x3.1A)

[SunEagle]

As Naptown has suggested you need to post the panel specs.

Depending on how much Vmp they are rated you may be able to wire them in series but I don't think that Blue Sky CC can handle more than 35VDC input.

If you can't wire them in series then you will still have to add fuses if you wire all 3 panels in parallel.

[inetdog]

Pic of proposed setup:

existing panel:
Pmax = 100 watts @ maximum power
Vmpp = 17.7 volts @ maximum power point
Impp = 5.7 amps @ maximum power point
Voc = 21.2 volts @ open circuit
Isc = 6.10 amps @ short circuit

New Foldable 100w (2x5ow):
Peak power: 100W
Maximum power voltage: 17.5V
Maximum power current: 5.7A (2x2.85A)
Open circuit voltage: 21.6V
Short circuit current: 6.2A (2x3.1A)

Since the Vmp and Imp values of the old and the new panels are so close, you can put them in series or in parallel without any concerns about power loss.
With an MPPT controller series would be better, up to the Voc limit of the CC.
or for PWM CC you can put them all in parallel up to the maximum input current of the CC.

[Naptown]

In your case you would wire the two 50W in parallel and then wire them in series with your 100W

Looks like max voltage is 50

[SunEagle]

In your case you would wire the two 50W in parallel and then wire them in series with your 100W

Looks like max voltage is 50

Good catch on the CC spec. I was looking at the 2512i which only has a max voltage of 35VDC. The 2512iX-HV goes to 50 VDC.

[Wicked]

In your case you would wire the two 50W in parallel and then wire them in series with your 100W

Looks like max voltage is 50

from the 2512i-HV spec sheet: 50VDC absolute maximum (Recommend maximum VOC at STC ≤40VDC)

In your case you would wire the two 50W in parallel and then wire them in series with your 100W

Looks like max voltage is 50

Thanks for the help guys. Any reason not to run the 2 50w panels in parallel then run them in parallel to my 100w (vs. parallel to series as suggested above)? Sorry if this is a dumb question as this is new to me.

I should have stated that my goal of adding an additional panel would be to increase the amp output to charge/recover my battery as quickly as possible. I currently get 6-7amp/hr charge with my 100w panel and hope is to bump that up to 12amp/hr

[Naptown]

By running the series parallel it will reduce amps to the charge controller and therefore voltage drop

[Wicked]

By running the series parallel it will reduce amps to the charge controller and therefore voltage drop

maybe its because its monday but your answer has added some confusion. this is what i understand on parallel vs series:

In parallel amps and watts add, voltage is unchanged.
In series voltage and watts add, current is unchanged

so in adding the proposed panel (100w + 2 50w in parallel = 200w total)

hooking it to my existing 100w panel in:
series is 200W @ 42.8v open circuit with 5.7amps
parallel is 200w @ ~21.4 open circuit with 11.4amps

Is this correct? Which scenario will charge the 100amp/hr battery the quickest and most efficiently?

Also can the blue star handle the series when from the 2512i-HV spec sheet: 50VDC absolute maximum (Recommend maximum VOC at STC ≤40VDC)

[Naptown]

Both will be equal charging the battery
By running higher volts and lower amps you will have less voltage drop ( read power loss) to the controller

[Wicked]

Both will be equal charging the battery
By running higher volts and lower amps you will have less voltage drop ( read power loss) to the controller

Makes sense. Seems parallel is the only option as going in series would be above the current recommendation from blue star. It stats absolute max of 50VDC but recommend you divide it by 1.25 (to get 40VDC) as a max to build in head room for spikes.

[Naptown]

spikes are a function of temperature
If you only camp when warm (above 0) you will be OK