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diy solar

8 x 415Wp panels. How to proceed?

brandnewb

Going for serious. starting as newb
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So in a stroke of bad decisions I bought 8 x 415Wp panels to start my off grid home adventure.

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Only to realize I know not enough to hook those up to my 16 x raw cell Lifepo4 battery array in series making it a 48V array.

I have an mppt solar charger though but this is what threw me off guard.

Turns our that if one has limited knowledge and just buys what ever seems cheap then one will end up with components that can't be used ;( Or so it seems.

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The goal is to hook up the 8 panels to charge the battery array. I do also have a knock off Daly 16s BMS to go with it if that helps.

But I am willing to see those purchases as a casualty of war and just go for a 3 phase inverter that can happily use those 8 panels now, but my other 44 panels (275Wp) eventually need to be moved from on grid to this off grid system.

Any advice one might have on how to proceed as to quickly DIY a low cost way of not letting the battery cells and panels just sit and do nothing would be of immense help.
 
I chose these panels so I can have some power during overcast days, which are most days here in the NL. the open circuit voltage was around 35V when all 8 panels were in series on a overcast day.
 
Ugh.. that CC won't work for you as you alluded.

You'll want one that is rated for 48v battery and a Max PV voltage voltage of 4 of your modules in series at your lowest temps.

4 x 38v = 168 + some extra for a voltage input.

8 x 415/48 = ~69 AMP

Take a peak at this one from Victron.
 
I have an mppt solar charger though but this is what threw me off guard.
You do? Post a pic and specs on that guy, because that thing in the picture is a 12v/24v PWM controller and not going to accomplish anything useful for you.

The MPPT controller will have a PV Input limit so you'll need to stay under that, most likely with a 4s2p configuration if you get a controller that can take 200v PVInput.

Another option would be getting a pair of 40a controllers that can take a good 150v input (like EPEvers or HQST's or Renogys or the like) and do 2 separate arrays with 2s2p on each controller. Might be cheaper than finding a 80+a controller capable of taking 200+ volts.
 
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You do? Post a pic and specs on that guy, because that thing in the picture is a 12v/24v PWM controller and not going to accomplish anything useful for you.

The MPPT controller will have a PV Input limit so you'll need to stay under that, most likely with a 4s2p configuration if you get a controller that can take 200v PVInput.

Another option would be getting a pair of 40a controllers that can take a good 150v input (like EPEvers or HQST's or Renogys or the like) and do 2 separate arrays with 2s2p on each controller. Might be cheaper than finding a 80+a controller capable of taking 200+ volts.
the photo I shared is all I have my sea faring friend. I can image that it is not actually an mppt device. It's like a said. I just bought what ever felt affordable at the time of purchase. Only to now having to admit that that is a sure way to end up paying more in the long term.
 
Nope. A dead giveaway on controllers is the USB ports and the price. With very, VERY few exceptions nobody makes a proper MPPT controller with USB ports for charging your phone on them. Also, if you paid less than about $100 it's just a PWM.

Once you get a proper MPPT setup between those panels and your batteries you'll be cranking out some good power! If you decide it's not worth it, I can find those panels a good home and my mailing address is... ?

As @OzSolar pointed out, you're going to be capable of pumping out 70-ish amps to your battery if everything lines up straight. It sounds like finances are a concern so I'd point you towards something cheap-but-serviceable like the older impinvt 40a units, or the nothing fancy 60a PowMr's that will take solar DC and turn it into battery DC and not much else. You'd be limited to 2s2p on each of those controllers to use all 8 panels, but at least you have redundancy. For a little more you could get a PowMr 100a SCC or an Impinvt 80a or even step up to a decent EPEver 80a unit and go 2s4p through a combiner box and get all 8 panels cranking through the same controller.

Due to your voltages on the panels the choices of controllers that can handle it aren't great.

Turns our that if one has limited knowledge and just buys what ever seems cheap then one will end up with components that can't be used ;( Or so it seems.
We call that "Tuition" and I've paid more than my fair share. ;)

For the absolute cheapest option that will work right now, get your battery built, BMS and all, and get a pair of the cheap PowMr 60a units. Put 2s2p on each controller, then connect each controller to the battery and system. If one controller dies you've still got 4 panels working. Going 2s2p means you don't need to get fuses and all in your strings. If they both work you've got 8 ginormous panels charging like crazy. Add inverter to power your MargaritaMaster-9000 and you're golden.
 
But I am willing to see those purchases as a casualty of war and just go for a 3 phase inverter that can happily use those 8 panels now, but my other 44 panels (275Wp) eventually need to be moved from on grid to this off grid system.
Why do you need 3-phase power? That's pretty much an industrial thing. Do you mean split phase?
 
Why do you need 3-phase power? That's pretty much an industrial thing. Do you mean split phase?
No brother, I am from the wrong side of the pond and here in the NL we have 3 phase as a standard for new constructions starting as far back as 2006 if I am not mistaken.

My house, that I designed and built my self saw the light of day at around 2011 in terms of planning. By then 3 phase what not an option. It was the demand.
 
You could use a maximum of 6 of those panels in parallel with that PWM scc for a total of 84.36a short circuit current.

Rule of thumb with PWMs is to size the short circuit current of the array to 80% that of the scc (100a in your case).

Unfortunately it will be incompatible with your 16s Daly knock off BMS :)
 
No brother, I am from the wrong side of the pond and here in the NL we have 3 phase as a standard for new constructions starting as far back as 2006 if I am not mistaken.

My house, that I designed and built my self saw the light of day at around 2011 in terms of planning. By then 3 phase what not an option. It was the demand.
Wow! I work on ships built to EU 220v standard and it's still single phase. The only difference I've found between ship wiring and land wiring from my EU co-workers is that on ship we're 120v-120v and on shore it's 220v-0v. Just kinda surprised. :oops:
 
Wow! I work on ships built to EU 220v standard and it's still single phase.
Nah borther, it's only single phase because that is easy to supply to internation single phase ships. It's all about ease. DO know that meanland NL is going to 3 phase quite fast. I am among them already.
 
ohh and although completely off topic, I am open to suggestions on how to make this breaker cabinet a bit less wild west.

Do know though that how ever wild west it might seem, this is working out great. No noticeable temperature build up, no noise from that 50 Hz one can get, all in all it's a pretty stable setup that I think can only be improved on on the way connections are being made. There lies room for improvement.

And of course there is room for improvement in where I did not see yet where improvements should be made.
 
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So I guess now is no longer time to buy cheap no name stuff as I am worried that things will just break without any support far too easy.

I have taken a look at the suggestions and the closest I found is
a max PV of 150V or 35A.

So if I get 2 of those I can have 4 x panels in series resulting in 4*38VOC = 152 on each of the charge controllers.
Only a tiny bit oversized should be no problem yes?
Or better to opt for a 2s2p configuration per controller? that way both the amps and voltage is well within their capacity.
 
But since we are no longer really only looking at the price of certain components then I could go for a hybrid inverter


my price as a small scale 'professional' installer would be 1182 euro after VAT.

Please note the quotes I used to make sure everyone knows I am no where near professional when it comes to this aspect of going off grid.

So the hybrid inverter is quite a bit less affordable yet comes with good warranty, backed up by a trustworthy supplier. And it will mean a single inverter that can handle 3 phase and charge my battery array.
But how ever much I plow through the spec sheets and manual I just can't seem to confirm if this particular model will play nice with a 16s Lifepo4 array.
It states somewhere that the battery should be matched with the inverter what ever that means in this context.

So let's for the time being assume I am willing to spend a little more on reliability what could you recommend?
 
Ok after some thought I have narrowed it down, I think, to not going for anything super specialized like the victron mppt products can do. Even when going full vicrton even their lineup does not seem to cover my use case.

I think I am better suited going for more like the growatt route. although that opens up a whole new world of uncertainty

ohh I almost forgot @Rednecktek I assume you were joking yes? And that you can get panels like these over on the good side of the pond.

If not I am willing to, as a sign of good gesture, deliver you said panels when you hit a port of call that is either Amsterdam, or Amsterdam ;)
Sorry. Rotterdam is just too far away for me and my trailer ;(

I think with these kind of panels one is kind of traversing ahead of the curve, which is a bi*(tch when you want to find components to go along with it.
 
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