Budget gone wrong setup

[eugenee]

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

 

[PunchySunshine]

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)

Welcome to the club!! I just melted our credit cards with all the purchasing. As long as it works, it's worth it!
:D

 

[eugenee]

Welcome to the club!! I just melted our credit cards with all the purchasing. As long as it works, it's worth it!
:D

Thank you for the message!

Things I learned again learning about the solar system are...

1. I gotta waste some money to get better
2. What doesn't kill you makes you stronger
3. What kills you can actually kill you

And I wish I started with 24V

Hope the system works well

 

[MisterSandals]

$149 - 40A Solar Charge Controller (KickAss)
$239 - 40A Solar Charge Controller (Altronics)

Is there a reason you are running all your solar panels in parallel? From your vague specs, it looks like the panels have unusually low voltage (125W / 10A = 12.5V) which should not be enough to charge 12.8V nominal batteries.

What is the max input volts of these 2 SCCs?
What is the panel Voc?

I have more questions and see other areas of interest but lets start here.

 

[eugenee]

Is there a reason you are running all your solar panels in parallel? From your vague specs, it looks like the panels have unusually low voltage (125W / 10A = 12.5V) which should not be enough to charge 12.8V nominal batteries.

What is the max input volts of these 2 SCCs?
What is the panel Voc?

I have more questions and see other areas of interest but lets start here.

Thank you very much for your comment!
I'm combining 4 of 125W panels into a PV Combiner Box (If PV Combiner Box does what I think it does... series combining panels).


If not, then I'd have to find other way to series connect the panels, ? but it is another good learning opportunity!

re: What is the max input volts of these 2 SCCs?

SCC 1 (KickAss) - 100V

SCC 2 (Altronics) - 100V/150V(Optional?)


re: What is the panel Voc?



So the 125W panel is actually 250W panels cut in half since they come connected in series.



Thank you for holding my hands on this dark adventure!
May the Solar be with ya!

 

[crossy]

If I'm reading it right it looks like those panels already have an MPPT controller built in, so no need for additional charge controllers, can hook directly to batteries (hence the big croc. clips on the cables).

Parallel all your panels using the combiner box and link to your battery packs.

 

[eugenee]

If I'm reading it right it looks like those panels already have an MPPT controller built in, so no need for additional charge controllers, can hook directly to batteries (hence the big croc. clips on the cables).

Parallel all your panels using the combiner box and link to your battery packs.

Thanks! The built-in MPPT controller sadly does not support LifePO4 type battery and my batteries are LifePO4 type.

 

[crossy]

Thanks! The built-in MPPT controller sadly does not support LifePO4 type battery and my batteries are LifePO4 type.

Yeah, I read that after I posted.

So, you are removing the built-in beastie and hooking the panels directly to your combiner and charge controllers?

EDIT Can you measure the actual open-circuit voltage of your panels in decent sunshine, your MPPTs will work better with series strings and you can give them up to 90V open-circuit.

 

[eugenee]

Yeah, I read that after I posted.

So, you are removing the built-in beastie and hooking the panels directly to your combiner and charge controllers?

EDIT Can you measure the actual open-circuit voltage of your panels in decent sunshine, your MPPTs will work better with series strings and you can give them up to 90V open-circuit.

I split the 250W panel into 2 * 125W, and each measured 22.90V under full sun!

 

[crossy]

OK that fits with the spec. you posted earlier of 22.3V Voc.

You could hook them up as 3 in series (so 66.9V Voc) and still be well within the specs of both your MPPTs, 2 in series would also work.
If it doesn't get very cold in winter you could also go 4 in series for 89.2V, but watch for cold weather pushing that up over the max of the controller.

With 8 panels I'd probably go 2S2P on each controller (might as well use them as you have them) and see how you do.

 

[eugenee]

OK that fits with the spec. you posted earlier of 22.3V Voc.

You could hook them up as 3 in series (so 66.9V Voc) and still be well within the specs of both your MPPTs, 2 in series would also work.
If it doesn't get very cold in winter you could also go 4 in series for 89.2V, but watch for cold weather pushing that up over the max of the controller.

With 8 panels I'd probably go 2S2P on each controller (might as well use them as you have them) and see how you do.

Thanks!

does it mean
3 * 125W => MPPT
would output almost same as
4 * 125W => PV Combiner Box => MPPT
? or simply PV Combiner Box isn't actually suitable in my situation. I just wanted to utilise since it's impossible to return them haha..

Here the temperature goes below 0 degrees here during winter but I'm installing the system in garden shed.
Fun adventure!

 

[crossy]

Not really, 4 panels will always generate more peak power than 3. But longer series strings will start generating earlier and stop generating later, so you actually get a bit more overall energy.

I would do 2 panels in series x 2 back to the combiner (the combiner box will parallel the strings) then to your MPPT. Same on the other MPPT.

It's the panels you need to watch in cool temperatures, they are specified at 25C but the Voc goes up as the temperature drops and you could over-volt your controller (which tends to let out the Magic Smoke) on a cold morning. 2S2P isn't going to give you any issues at all. Could you get another panel so you can go 3S2P on one controller and 3S on the other?

How are you mounting your panels, will they be easy to get at if you want to re-configure / add more in future? I've found our system is constantly evolving and it all being mounted on the car-port makes changes easier than if it was on the house roof. I've got space for another 6 x 340W panels which could well get installed sooner rather than later with the potential electricity price hike in January.

It's all good fun, and the feeling of those first free Watts firing up the TV etc. is contagious. We started with 4 x 300W panels a few years back, my wife was sceptical until she saw the reduction in our energy bill, we now have 10.6kWp of panels!

Our 10.6kWp grid-tie hybrid system in sunny Thailand.

So as a noob here I suppose a bit of showing and telling is in order. So this is our recently upgraded system. The 6kW grid-tie system on the left was our original install, the 5kW hybrid on the right is new. Like much of the world anything labelled as "solar" means the price gets...

diysolarforum.com

 

[eugenee]

Not really, 4 panels will always generate more peak power than 3. But longer series strings will start generating earlier and stop generating later, so you actually get a bit more overall energy.

I would do 2 panels in series x 2 back to the combiner (the combiner box will parallel the strings) then to your MPPT. Same on the other MPPT.

It's the panels you need to watch in cool temperatures, they are specified at 25C but the Voc goes up as the temperature drops and you could over-volt your controller (which tends to let out the Magic Smoke) on a cold morning. 2S2P isn't going to give you any issues at all. Could you get another panel so you can go 3S2P on one controller and 3S on the other?

How are you mounting your panels, will they be easy to get at if you want to re-configure / add more in future? I've found our system is constantly evolving and it all being mounted on the car-port makes changes easier than if it was on the house roof. I've got space for another 6 x 340W panels which could well get installed sooner rather than later with the potential electricity price hike in January.

It's all good fun, and the feeling of those first free Watts firing up the TV etc. is contagious. We started with 4 x 300W panels a few years back, my wife was sceptical until she saw the reduction in our energy bill, we now have 10.6kWp of panels!

Awesome story! I hope my wife is happy without running a generator soon too.


Here I attached the spec of the PV Box.
Initially, I simply calculated it like "hmm 250W panel produces 20A... Not sure about wiring.. so why not split it in half then that should be 10A... I don't want to place circuit breaker my self so why not get this fancy PV box that has everything"
But it sounds like that's not how it's calculated.
I only thought that Each Single PV Array will produce 10A * 4 strings = 40A output from the PV Box and that can be wired to SCC!

Does SCC prefer higher voltage with low amp than low voltage with high amp?
Cheers!

 

[crossy]

Generally, the higher the string voltage, the better with an MPPT controller (but watch Voc!). Higher volts also means that the same power is transmitted using lower currents (W = V x A). Lower current means you can use thinner wires (save $$$).

Hook up your panels how you think they should be (put the two halves of a 250W set in series for 10A and more volts), verify that the Voc is well within what your controller can do, and start making all that lovely free energy.

 

[MisterSandals]

Thanks! The built-in MPPT controller sadly does not support LifePO4 type battery and my batteries are LifePO4 type.

Having a built in LiFePO4 charging profile is not required for an MPPT SCC. If these controllers have a user defined battery setting, and that setting allows for turning equalization off (or equalization time to 0 hours), they will more than likely work.

Can you post a make and model and a close up pic with hopes somebody has experience with them? Thats not required but it might prove handy.

 

[MisterSandals]

Here I attached the spec of the PV Box.

Sorry for being absent, crossy has advanced this nicely.
If you have not already purchased the combiner box, or can return it easily, you really don't need it. It would be far easier using a pair of Y connectors for each 4 panel (2S2P) array.

If you're set on using your 2 new SCCs, as crossy recommended, a 2S2P array for each SCC would be pretty good.
To do this, starting with the 2 panels shown above with the blue SCC, remove the SCC and connect the 2 wires (a + from one panel and - from the other) and you have a 2S array. Do this for another pair of panels. With a $15 Y cable pair (i'll try to remember a link below), connect the 2 pairs' + wires, and connect the 2 pairs' - wires into a single + and single - that go to your SCC.

Repeat with the other 4 panels and the other SCC. This is likely your optimal charging configuration and by far the easiest and cheapest to implement.

Ha! I didn't forget... (get 2 pairs of these. $7.99 is a great price!)

https://www.amazon.com/BougeRV-Connectors-Branch-Parallel-Adapter/dp/B0753X68PS/

 

[eugenee]

Generally, the higher the string voltage, the better with an MPPT controller (but watch Voc!). Higher volts also means that the same power is transmitted using lower currents (W = V x A). Lower current means you can use thinner wires (save $$$).

Hook up your panels how you think they should be (put the two halves of a 250W set in series for 10A and more volts), verify that the Voc is well within what your controller can do, and start making all that lovely free energy.

Wela'lin!
Free energy here I go!

 

[MisterSandals]

With a $15 Y cable pair (i'll try to remember a link below), connect the 2 pairs' + wires, and connect the 2 pairs' - wires into a single + and single - that go to your SCC.

Hmm, is quoting yourself a bad sign?

After reexamining the panel/SCC pic, i see you DO NOT have MC4 connectors as I assumed when recommending the MC4 Y cables. Looks like there is a really nice anderson connector that could be put to use. Though I am not seeing an Anderson Y connector and making one would not help the "budget gone wrong" aspect of things.

You could put MC4 connectors on your panels and use the cheap MC4 Y connectors (they're waterproof and a sturdy connection and cheapish).

Maybe I'm back to recommending seeing if you can get your existing SCCs to work with a user defined battery profile (much easier than it sounds!).

 

[crossy]

And photos, we need photos of your setup

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

 

[eugenee]

Having a built in LiFePO4 charging profile is not required for an MPPT SCC. If these controllers have a user defined battery setting, and that setting allows for turning equalization off (or equalization time to 0 hours), they will more than likely work.

Can you post a make and model and a close up pic with hopes somebody has experience with them? Thats not required but it might prove handy.

It was too late when I realised the built-in MPPT does not have any buttons... it has factory settings for Lead Acid battery!
But it was a fun learning!

Sorry for being absent, crossy has advanced this nicely.
If you have not already purchased the combiner box, or can return it easily, you really don't need it. It would be far easier using a pair of Y connectors for each 4 panel (2S2P) array.

If you're set on using your 2 new SCCs, as crossy recommended, a 2S2P array for each SCC would be pretty good.
To do this, starting with the 2 panels shown above with the blue SCC, remove the SCC and connect the 2 wires (a + from one panel and - from the other) and you have a 2S array. Do this for another pair of panels. With a $15 Y cable pair (i'll try to remember a link below), connect the 2 pairs' + wires, and connect the 2 pairs' - wires into a single + and single - that go to your SCC.

Repeat with the other 4 panels and the other SCC. This is likely your optimal charging configuration and by far the easiest and cheapest to implement.

Ha! I didn't forget... (get 2 pairs of these. $7.99 is a great price!)

https://www.amazon.com/BougeRV-Connectors-Branch-Parallel-Adapter/dp/B0753X68PS/

Ahhh here the big $325 is being thrown in the air!
Thank you for the detailed explanation. I'll upload updated photos!