Simple 4.5Kwa Daily Need Off-Grid System Diagram

bajamox · August 2020

My last post was back in 2016 and For the last few years I have been enjoying learning about solar power, by trial and error. Luckily not much error . Now it is time to complete my installation of a proper system, that may be increased as needed. There is so much Knowledge and a willingness to help in the members of this forum. I hope this thread is helpful for others starting out with questions of their own .

I have an escape home in Northern Baja, For the last few years I have been enjoying learning about solar power, by trial and error. Luckily not much error . Now it is time to complete my installation of a proper system, that may be increased as needed

I should tell you about my location. I am located 150 miles South of Ensenada In Baja Mexico and my panels face 165 degrees South with unobstructed sun, from sunrise to sunset. Averaging 5.5 Kwh per SQ meter with high of 6.58 July and low 4.13 December, currently. Will need to adjust for winter defiantly

With this small system is it advised to connect a Battery monitor kit ? Or is my battery remote temp to Mate 3 enough?

With my Outback components is a hub mandatory for my simple system? Or, again, is the mate enough?

I'm thinking I should install a combiner box, outback FWPV4-FH600. I only have one 6 panel array but feel it would be simple, clean and safer Can I install my DC disconnect and breaker/fuse between inverter and batteries into my array combiner box, in order tp keep my install as clutter free as possible

Is my charging need for my battery bank larger than the Panels I have? However more panels would be better in cloudy days? Therefor yes on the more panels?

Thanks in advance

Please take time to view System diagram.

Diagram of components:

https://www.smugmug.com/app/organize/Baja/Solar/i-HRnJwxb

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bajamox · August 2020

Woops forgot

System Components:

Outback VFXR3648A-01

Outback Flexmax 60 MPPT

Outback Mate3S

OutBack FWPV4-FH600 Combiner Box

6 Panels 235W, 30V, 7.67 Amp lpm

8 Batteries 12V 180AH sealed AGM

Series/Parallel for 48 V

MichaelK · August 2020

I'm a bit confused about your wiring system. Your link requires a logon password, so I can't just click on it to look at it. You say you have only 1 six-panel array? I'm assuming you don't have it wired in either a 6S1P, or 1S6P configurations, so that leaves 2S3P and 3S2P? With a 3S2P configuration, you don't have to have a combiner box, with with 2S3P you should.

Assuming you have two parallel strings of four 12V batteries, your amphour capacity would be 360AH. Assuming you want to charge them at a rate of about 1/10C, then an optimal solar input would be 360AH X 0.1C X 52V (charging) X 1.2 fudge factor = 2246W. Just call it 2250W.

You could buy three more of your 235W panels, and wire them in a 3S3P configuration to produce about 32-33amps of charging current. If you graduated to larger L-16 batteries, you could scale up to 12 panels, wired in a 3S4P configuration. Assuming your panels put out a Voc of about 38V, then four panels in series would produce >152V, the max for your controller. If it ever drops to freezing, your Voc is likely to go even higher, frying the controller.

bajamox · August 2020

yes Michael a 3S2P

wellbuilt · August 2020

Well it look like you will need more panels , the panels are cheep Now I would add 6 more 225watt for 2700 watts .

You really need a mate to program your inverter charging set points and other information generator size for one .

The mate can plug into one unit with out the hub .

The cc works fine with out the mate .

The fndc battery Monitor can’t be used with out the hub .

I don’t think the battery monitor really works very well , I have one and it’s cool , but you can just check voltage and see where your charging is at .

I would get a mate

bajamox · August 2020

MichaelK said:

you could scale up to 12 panels, wired in a 3S4P configuration. Assuming your panels put out a Voc of about 38V, then four panels in series would produce >152V, the max for your controller. If it ever drops to freezing, your Voc is likely to go even higher, frying the controller.

I am giving thought to doubling the panels to 4 strings of 3. To be safe additional needs. With that It will be close to Maxing the MPPT 60 . As this controller is one of the last components left to purchase I'm feeling upping to am Outback FM80 -150 VDC
Now I'd like to move on to grounding. My PV arrays are about 35' to combiner and charge controller. what is bast, running !0' to new ground post in earth? or running ground along with POS-NEG to the combiner box? Is #10 gauge enough for ground wire on my PV arrays to combiner? All components will connect to ground bar in combiner. From combiner to Existing ground post, in earth, would #6 be sufficient?
Again thanks for your help

MichaelK · August 2020

My technical understanding of proper grounding is that there can be multiple grounding connections above ground, and multiple grounding connections below ground, but the above ground connections should be connected to the below ground connections at one and only one location. So, don't run a second ground wire out to a second ground rod, if it isn't physically tied to the first ground rod. Furthermore, if you do have more than 1 ground rod (some areas require two or more), then they should all be tied together with a single unbroken wire the leads directly to the above ground busbar.

What I see in writting, in my controller manual is that 10gauge ground wire is acceptable for systems smaller than controlled by a 60A breaker, and 8 gauge for larger systems. So, I'd say 6 gauge is more than adequate.

Photowhit · August 2020

Well, I looked at your diagram, I assume your words are correct and not the diagram on the panel wiring, diagram shows panels wired in pairs. I'm impressed at your minimal use of electric, 1 hour a day TV and 1 hour Laptop, even the 2 hours air conditioner! I'd guess you could likely 'hide' the energy used with the floor heater as you likely wouldn't need air conditioning on days you need the floor heater.

I, personally would worry much about topping out the 60 amp charge controller. I think you can limit output tp 60 amps and because of how charging works you may never approach the upper limits, even doubling your array.

bajamox · August 2020

MichaelK said:

What I see in writting, in my controller manual is that 10gauge ground wire is acceptable for systems smaller than controlled by a 60A breaker, and 8 gauge for larger systems. So, I'd say 6 gauge is more than adequate.

Thanks, I'll stick with the Existing ground pole only and the #6 from combiner to pole

bajamox · August 2020

Photowhit said:

Well, I looked at your diagram, I assume your words are correct and not the diagram on the panel wiring, diagram shows panels wired in pairs. I'm impressed at your minimal use of electric, 1 hour a day TV and 1 hour Laptop, even the 2 hours air conditioner!

Yes, not a real TV viewer when down south in Baja. Generally working on the house (under generator power) and surfing.

1 hour on laptop is for charging then unplugged from system. AC is a small split system used to chill One 200 Sq Ft bedroom. This of course only on hot sunny days so on in full solar availability.

Thanks for the heads up on improper wiring of panels . I'll be checking for proper wiring diagram. thought I had it figured out

bajamox · August 2020

Photowhit said:

Well, I looked at your diagram, I assume your words are correct and not the diagram on the panel wiring, diagram shows panels wired in pairs.

Thanks for not only viewing but studying & also correcting the panel wiring.

please view what the change was

bajamox · August 2020

I am looking to double my solar array

I currently have six panels that are 230 W, 37VOC, 7.67Amp

I can pick up 6 panels, at a great price, that are not the same specs but close

They are 230W, 36.8 Voc 7.78A

I am thinking that they match close enough to wire one from each group in series then parallel to create a six panel string then do that again for the next string. I should not just add the six new mismatched panels together to create a new string. Would this confuse the Charge controller or is the difference so little that the controller will cope?

would I need a combiner box for these strings or could I use example C and parallel the two strings straight to the controller

Image: https://us.v-cdn.net/6024911/uploads/editor/pv/xuejo7vz8u0r.jpg

mike95490 · August 2020

What voltage is your battery bank ?
Using 1 controller or 2 ? ( I see 45amps Imp from 6 panels , will be more with MPPT controller )

bajamox · August 2020

mike95490 said:

What voltage is your battery bank ?
Using 1 controller or 2

the bank is wired for 48volts, controller Outback MPPT60, using only one.
i believe if i mix panels in array power/current will be reduced to that of weaker panel. not much of a difference however. could I parallel the strings in example C then take them straight o charge controller or would utilizing a combiner box be a better solution. thinking of making all wiring connections in Combiner : shutoffs, temp shunts etc

mike95490 · August 2020

C is not going to work for charging a 48V bank. All the panels in parallel ( 33V ) , will not be able to charge a 48V bank
which needs 64V for EQ 1.3x 64V = 83.2 V ( using Vmp ) from the PV array.

More than 2 panels in parallel, requires (for safety) a combiner box, using 1 fuse/breaker, for each panel (or series string) with the "Series Fuse" spec from the label on the PV panel.

for a 48V battery, you need to use your panels Vmp spec, and you will likely need 3 panels in series to meet or exceed the required 83V

Then you use the Voc spec, to insure you never overvoltage the CC on a cold winter morning (of 3 panels in series

bajamox · August 2020

mike95490 said:

C is not going to work for charging a 48V bank. All the panels in parallel ( 33V ) , will not be able to charge a 48V bank
which needs 64V for EQ 1.3x 64V = 83.2 V ( using Vmp ) from the PV array.

for a 48V battery, you need to use your panels Vmp spec, and you will likely need 3 panels in series to meet or exceed the required 83V

Thanks Mike. yYu were helpful in getting my mind going here's what I have ended up with I'm adding 6 more panels.

I do have this posted elsewhere

mike95490 · August 2020

That looks much better
Vmp will be about 90V
Voc will be 112V @ 70F Now run your calcs for your Voc when it's cold and make sure it wont fry your controller

bajamox · February 29

Hi Mike, Well Things slowed down for me so I'm getting ready to install my new system. I did get a better battery . I'm thinking my latest configuration and wiring is now correct. please give it a review. The setup is located in Baja and rarely gets below 45 degrees. Thanks

Image: https://us.v-cdn.net/6024911/uploads/editor/oj/78ablrz3uv9t.jpg

BB. · February 29

Just an FYI... Mike passed around 1 year(?) ago. And our condolences to his widow.

In remembrance.
-Bill

bajamox · March 1

Oh Bill, I am so sorry to hear this news. Mike was so Help-full over the years with me, as were you. Condolences go out to his family and to all Group members that he has helped

BB. · March 1

Mike is greatly missed.

-Bill

Simple 4.5Kwa Daily Need Off-Grid System Diagram

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