Budget gone wrong setup

[eugenee]

And photos, we need photos of your setup

This section of the forum is after all "Show and Tell".

I came to the Show and Tell forum too early! will move to the newbie section hehe..

 

[MisterSandals]

I came to the Show and Tell forum too early! will move to the newbie section hehe..

Phew, i was worried that you actually implemented it that way.

Where are you in building your array? All 8 panels in parallel will be a train wreck in full slow motion with voltage below your battery voltage.

 

[Nobodybusiness]

View attachment 123594

This weird thing started when I purchased 3000W inverter at Adventure Kings shop with 2 * 200Ah batteries and 4 * 250W panels.
My knowledge was very limited so I had to rely on the dude at the shop telling me his mate built his setup using what I'm buying. also gave me a tip that I need to buy 2 * 40A Charge Controllers. 1kW panels!

Sweet.
that's all I need.
I think it was about this time that I started buying things without much thinking.

Then I ran to a shop nearby, bought 1 * 40A charge controller cuz I wasn't confident enough about wiring.

then I got stuck cuz other wires, and terminals were not available anywhere +1hr drive away.
Since I didn't have any diagrams so I gave up after a few meaningless shopping trips.
Then I saw this PV Box on Youtube and thought it was amazing so I waste some more money on buying 2 * PV BOX. It came with a nice panel and circuit breaker!

I started watching Will's video seriously then I realised that I don't know where I'm at with my gears and I should have planned my system from the start.
It was too late to go back anyways so I just finished ordering things on Ebay.

I wasn't planning to use 3000W continuously but at purchase time I didn't know what I was doing/thinking.
I'll keep updating once the items arrive.

$ AUD
$1450 - 2 * 200Ah LifePO4 (Adventure Kings)
$780 - 4 * 250W with MPPT (Adventure Kings / not compatible with LifePO4)
$400 - 3000W Inverter (Adventure Kings)
$149 - 40A Solar Charge Controller (KickAss)
$239 - 40A Solar Charge Controller (Altronics)
$325 - 2 * 4 strings PV BOX 15A each string (Ebay)
$140+ - wires
$20 - Battery Switch (Ebay)
$100 - Battery Shunt/Monitor (Renogy)
$50 - Fuses (Ebay)
$150 - Tools (Ebay)
$340 - Lynx Distributor (Victron)

Total (so far) $4100~$4400

We call it tuition.

It’s Better if you can determine what you want to run, How much power that is going to use, then design for worst case scenario before buying anything.

You have some stuff you can reuse but you are limited to your inverter size at this point.

 

[eugenee]

Phew, i was worried that you actually implemented it that way.

Where are you in building your array? All 8 panels in parallel will be a train wreck in full slow motion with voltage below your battery voltage.

The modification I need here would be
turning 250W / 20A / 22.9VoC panels (2 * 125W in parallel) into 250W/45.8VoC panels (2 * 125W in series)
with something like the below...



I don't think I understand "Where are you in building your array?" hehe.. do you mean like back of the panels or should they be contained some panel box?

 

[crossy]

Spot-on old bean!

 

[MisterSandals]

I don't think I can understand "Where are you in building your array?"

Sorry, i was asking what progress you have made.

Spot-on old bean!

But this is not correct. Combining panels in series adds the volts while amps remain the same. So i think this diagramed 2S string should be 22.9V and 10A. (What are panel Voc and Isc numbers? 11.45V and 10A? seems wrong)

 

[crossy]

Sorry, i was asking what progress you have made.

View attachment 123775
But this is not correct. Combining panels in series adds the volts while amps remain the same. So i think this diagramed 2S string should be 22.9V and 10A. (What are panel Voc and Isc numbers? 11.45V and 10A? seems wrong)

Yeah, he should be ending up with 10A x 22.3V (roughly 250W).

It's difficult to know exactly what each half-panel is from the available info.

Best bet is to hook it up as drawn and verify what's actually coming out before connecting the SCC.

 

[MisterSandals]

Best bet is to hook it up as drawn and verify what's actually coming out before connecting the SCC.

And given that his panels do not have MC4 connectors, he has options. Maybe remove alligator clips and combine at (already purchased?) combiner boxes. Or utilize the awesome Anderson connectors somehow (not cheap to buy the connectors but many folks love them).

Quite a bit may depend on distances required between array, combiner boxes and the SCCs. Hopefully this is working out.

 

[crossy]

It's at times like this you just want to jump in the car and go and fix it! If it took an hour to sort, I'd be surprised.

Sadly, he's in the wrong country

 

[crossy]

And given that his panels do not have MC4 connectors, he has options. Maybe remove alligator clips and combine at (already purchased?) combiner boxes. Or utilize the awesome Anderson connectors somehow (not cheap to buy the connectors but many folks love them).

Quite a bit may depend on distances required between array, combiner boxes and the SCCs. Hopefully this is working out.

He says it's being installed in a garden shed, but when an Aussie says "garden shed" he means something like this: -



Or maybe: -

 

[eugenee]

Sorry, i was asking what progress you have made.

View attachment 123775
But this is not correct. Combining panels in series adds the volts while amps remain the same. So i think this diagramed 2S string should be 22.9V and 10A. (What are panel Voc and Isc numbers? 11.45V and 10A? seems wrong)

Yeah, he should be ending up with 10A x 22.3V (roughly 250W).

It's difficult to know exactly what each half-panel is from the available info.

Best bet is to hook it up as drawn and verify what's actually coming out before connecting the SCC.

The factory default of the panels is 250W / 10A/ 22.9VoC.
So currently I have 4 * 250W / 10A / 22.9VoC (22.3 in user manual) panels.
It was my mistake to assume the output of the solar panel was 20A when the "built-in" SCC is 20A.

But it's actually
Solar [10A*22.9 = ~250W] => MPPT [20A*12V = ~240W] => Battery

As far as I understand, I can convert
4 * 250W / 10A / 22.9VoC
into
2 * 500W / 10A / 45.8VoC
2P * (2S)
And each array will be connected to the pair of SCC!

But to do that (2S2P), I'll have to connect
2 * 250W / 10A / 22.9VoC
into
1 * 500W / 10A / 45.8VoC
using MC4 Y connectors.

I have 10 * Anderson connectors but I'm not really sure if they could be any help
Cheers

He says it's being installed in a garden shed, but when an Aussie says "garden shed" he means something like this: -

View attachment 123784

Or maybe: -

View attachment 123785

Of course, it's the later one!



Edit
The Amp for panel in this post is wrong.
It shouldn't be 10A (the 10A was calculated off the builtin SCC that should be removed from the system)
The actual spec is posted below.

 

[crossy]

And each array will be connected to the pair of SCC!

That won't work, one array / string to one SCC.

You can't connect strings with different Voc (number of series panels) in parallel.

You've done some decent diagrams, better diagram exactly what you want to do.

We are getting close to a workable solution

 

[MisterSandals]

have 10 * Anderson connectors but I'm not really sure if they could be any help

I incorrectly recommended the MC4 Y connectors because 98% of panels have them. Yours do not.

You can use your combiner boxes the join 2x 250W into a 500W in parallel. Then from combiner to one SCC.

If you can make Y cable with your Anderson’s that works too. But you will want a disconnect switch inline too.

 

[eugenee]

That won't work, one array / string to one SCC.

You can't connect strings with different Voc (number of series panels) in parallel.

You've done some decent diagrams, better diagram exactly what you want to do.

We are getting close to a workable solution

My brain started getting some wake-up shorts with all the positive solar energy.

You can use your combiner boxes the join 2x 250W into a 500W in parallel. Then from combiner to one SCC.

If you can make Y cable with your Anderson’s that works too. But you will want a disconnect switch inline too.

On the using combiner box (I love the idea I don't have to waste them haha!)





Given the spec of the PV Combiner Box,

I guess I have two options here

1. 250W split in half to meet the PV Combiner Box specs
that'd make 4 * 125W panel (22.9V VoC / 18.2V Vmp / 6.87A Imp) for each SCC
producing 500W (22.9V VoC / 18.2V Vmp / 27.48A Imp)
which will be the initial diagram, where 125W / 10A panel drawing is misleading since that calculation was based off the "built-in" MPPT SCC.

It should have been this!


2. double the Voltage by modifying the 250W panel
since the 250W panel is 125W * 2 parallel connected at the back of the panel, if I connect them in Series then
that'll make VoC 22.9V * 2 = 45.8V which is within the 40A SCC specs.

Then (125W * 2S) * 2 will be
45.8V VoC / 36.4V Vmp / 13.74A Imp
And I can forget about PV Box and just connect it to the SCC with MC4!

I incorrectly recommended the MC4 Y connectors because 98% of panels have them. Yours do not.

Not an incorrect recommendation at all! I have some MC4 connectors and soldering/wiring tools(on the way)! I should be able to reuse some cables and do the required job! (unless it's not recommended)

Thank you for all the positive comments!

 

[MisterSandals]

Given the spec of the PV Combiner Box,

What is the spec of the combiner box?
The solar blanket spec is NOT for a combiner box.

Can you post a link?
Or pic of the box innards so we can see the breakers?

 

[eugenee]

What is the spec of the combiner box?
The solar blanket spec is NOT for a combiner box.

Can you post a link?
Or pic of the box innards so we can see the breakers?

My bad! should have posted this earlier?

Edit
The solar blanket spec was for the 4 * 250W panels, somehow they call it a blanket hehe..

 

[MisterSandals]

The pic shows 32A breakers coming in from the array. Is that what is in your combiner box?
Do you have a 63A output breaker as pictured?

 

[pollenface]

Mate, when i started out I threw 3 brand new charge controllers in the bin for overcharging my camper trailer battery before i learned that I was supposed to connect them to the battery first (not the solar panel).

I then killed 2x 50ah lifepo4 batteries with a cheap single stage pwm charger which held them at 14.6v all day, everyday for about 12 months until they died.

I then killed 2x 100ah agms in the same manner.

The last few years have gone well though. I learned about the importance buying quality mppts. Same batteries for about 3yrs and no noticeable capacity loss yet

 

[eugenee]

The pic shows 32A breakers coming in from the array. Is that what is in your combiner box?
Do you have a 63A output breaker as pictured?

It comes with 15A fuse installed in it!

 

[eugenee]

Mate, when i started out I threw 3 brand new charge controllers in the bin for overcharging my camper trailer battery before i learned that I was supposed to connect them to the battery first (not the solar panel).

I then killed 2x 50ah lifepo4 batteries with a cheap single stage pwm charger which held them at 14.6v all day, everyday for about 12 months until they died.

I then killed 2x 100ah agms in the same manner.

The last few years have gone well though. I learned about the importance buying quality mppts. Same batteries for about 3yrs and no noticeable capacity loss yet

That gave me a flashback to blowing one of the 200ah LifePO4 batteries with the cheap PWM SCC because I didn't read the user manual and connected PWM controller to solar panels first...
I'm still not sure if I blew up the battery completely. I can only check once AC-DC charger arrives.
But on that, do you think I should get a new 200ah LifePO4 battery? because I had 2 * 200ah and use 1 of them for testing/using and I might have possibly damaged it due to the above (flashback again) reason.