8 x 415Wp panels. How to proceed?

[brandnewb]

@Checkthisout I realize that it's work in progress. I just don't really respect or understand why the HAHA.

I am learning as we speak. would you please elaborate?

 

[DJSmiley]

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

Amazon.nl

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.

4*38 is 152V, but at 25 celcius

Those panels have a temp coefficient of -0.29%/C, so at -10 that would be +10%, thus near 168V.

So no, 4 won't work on a 150V controller.

I personally would opt for a VE.CAN MPPT, which makes it a lot easier to expand your setup in the future and run/monitor everything using a rPI, Cerbo or similar.

If you want a hybrid, a Growatt SPF5000ES might be a (affordable) option.
Disadvantage is those don't allow feedback to the grid.


A Victron Multiplus is the best option, altough expensive. Those allow backfeeding any excess into the grid (salderen) once the battery is full.

They also support various integrations, so you can, with a flexible contract, charge in the low-tariff hours, and feedback during expensive hours for example.

 

[Checkthisout]

@Checkthisout I realize that it's work in progress. I just don't really respect or understand why the HAHA.

I am learning as we speak. would you please elaborate?

You seemed to be making a tongue-in-cheek remark about your abilities so I haw hawed.

 

[brandnewb]

You seemed to be making a tongue-in-cheek remark about your abilities so I haw hawed.

yes indeed. sometimes I am a bit insecure is all ;(

 

[brandnewb]

but I do know that there is a lot to be improved upon though, so please hang in there

 

[brandnewb]

4*38 is 152V, but at 25 celcius

Those panels have a temp coefficient of -0.29%/C, so at -10 that would be +10%, thus near 168V.

So no, 4 won't work on a 150V controller.

I personally would opt for a VE.CAN MPPT, which makes it a lot easier to expand your setup in the future and run/monitor everything using a rPI, Cerbo or similar.

If you want a hybrid, a Growatt SPF5000ES might be a (affordable) option.
Disadvantage is those don't allow feedback to the grid.


A Victron Multiplus is the best option, altough expensive. Those allow backfeeding any excess into the grid (salderen) once the battery is full.

They also support various integrations, so you can, with a flexible contract, charge in the low-tariff hours, and feedback during expensive hours for example.

Completely off topic!

If I may be so blunt to ask. Why, based on your video, did you opt for Home Assistant rather than OpenHab?

I chose for OpenHab as to be able to run the software in visual debug mode using an IDE as to be able to far faster dig into where potential problems lie.

I might have missed some facts though in where this is perfectly possible with HA as well.

It only goes to show that even though I have an IT background does not mean i know everything ;(

 

[brandnewb]

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

so as a quick fix, which is what I originally asked for, this could work?

I mean better to have things working rather than having things sit idle all this time.

 

[pollenface]

so as a quick fix, which is what I originally asked for, this could work?

Not with your bms.

 

[brandnewb]

The BMS I am willing to categorize as a casualty of war. How to proceed?

 

[brandnewb]

I meant that It;s ok, although it will hurt, to leave out that BMS. we can spend more and get better suited products.

 

[missingegg]

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.

This comment is a key piece of information that should inform your system design. Given your location, it's desirable to have maximum string length (panels in series), and minimal numbers of parallel strings, because that will increase the chance that you're supplying a high enough solar voltage to enable your charge controller to generate the voltage necessary for charging a 48v battery bank. If you were running 2 panel strings, your voltage would presumably have been down around 9V, which won't do you much good. Unfortunately MPPT charge controllers that can accept high panel array voltages are more expensive. But if you can afford it, then a 1P8S panel array to a high voltage charge controller would seem advisable.

Another thing to consider is whether or not you really want a 48V battery built out of your cells. A 24v battery would be chargeable when the 8S array is producing 35V, although presumably a bit slowly.

 

[brandnewb]

btw, did you find that egg?

I am in awe how creative people can be when choosing their nickname

 

[brandnewb]

This comment is a key piece of information that should inform your system design. Given your location, it's desirable to have maximum string length (panels in series), and minimal numbers of parallel strings, because that will increase the chance that you're supplying a high enough solar voltage to enable your charge controller to generate the voltage necessary for charging a 48v battery bank. If you were running 2 panel strings, your voltage would presumably have been down around 9V, which won't do you much good. Unfortunately MPPT charge controllers that can accept high panel array voltages are more expensive. But if you can afford it, then a 1P8S panel array to a high voltage charge controller would seem advisable.

Another thing to consider is whether or not you really want a 48V battery built out of your cells. A 24v battery would be chargeable when the 8S array is producing 35V, although presumably a bit slowly.

choices choices.

So could I make 2 x 24V Lifepo4 arrays and then hook up the 8 panels.
Or should I dig a little deeper and get another 8 panels and then hook them up to a single 48V array?

Options options, I am rather confused.

 

[brandnewb]

getting extra panels I have considered but I am worried about then when the sun does get to radiate directly on those panels.

The power would be massive, possibly wrecking up a poorly designed system.

I am renowned for poor designs.

 

[pollenface]

The BMS I am willing to categorize as a casualty of war. How to proceed?

I've had a few casualties myself :D

I think put the cheap PWM charger on the shelf and get a good quality MPPT which you can program accordingly for your 48v lifepo4 bank.

I'm in the process of putting together a 48v system, I'm using a Victron 100/20 and 8*45voc panels in 2s4p

 

[brandnewb]

But then let's get into specifics.

I know by now that the MPPT chargers from victron only need a surcharge of 5 volts, over the battery array voltage, to trigger the battery charging. Once triggered a surcharge of 1 volt is enough to keep it going.

However. Their maximum range is only 250/70 if I am well informed. meaning a max input of 250 volts and a max charge of 70 amps.

This does not seem to cover my use case when all 8 or maybe better all 16(I am still considering getting extra panels) are being fully blasted on by the sun. We do have some sun here from time to time and when it happens I don't want to have things melting, or catching fire, in my technical room.

 

[pollenface]

You only need 2 in series to charge your 48v bank.

 

[brandnewb]

@pollenface may I please ask you to be a little bit more verbose?

2 of what you mean in this instance?

2 panels in series would indeed make for enough voltage to get charging going on on a sunny day but it would leave 6 of the panels out of use.

I am not sure I get what you meant.

 

[brandnewb]

ahh you are still in the getting things done quick and dirty modus operandi are you? in that case yes. thank you

 

[missingegg]

You only need 2 in series to charge your 48v bank.

Unfortunately only true when there's direct sun on the panels. As the OP is in a far north location with lots of overcast days, then more than 2 in series is called for.