diy solar

diy solar

Help me diagnose my system

What guage are the wires from the inverter to the battery and back?
 
Got a gut feeling that wiring may be the problem.
Did the panels ever perform to spec?
 
Got a gut feeling that wiring may be the problem.
Did the panels ever perform to spec?


Their volt reading is always fine, but the amps always seems low.

Regarding the wiring, what would you suggest? For instance, on the PV run?
There doesn't seem to be a safe way to size up from 10AWG. But sizing charts say I need larger that 10AWG if I want to stay under 3% loss.
For example. My PV array will output at max 36.76 amps. So I'd need to use at least a 4AWG wire. How do I connect that to the 10AWG that is stock on The panels?
 
I just double check the math.

configuration = 2s4p

45.6 volts * 2s = 91.2 string volts
9.19 amps * 4 strings = 36.76 amps
60 feet round trip
10 awg will give 2.51% voltage drop

This means 10 awg PV rated wire is fine.

Before you spend money on a combiner box or a new solar charge controller we need to verify your panels are ok.
 
The aggregate amperage is a bit high for 10 awg but its well within spec for 10awg wire with insulation rated for 105C.

If the panels are ok I would suggest you get a solar charge controller that can take a higher pv voltage.
Ideally high enough for 4s2p and then you don't need to fuse the individual strings.
 
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I need help diagnosing my system.
It doesn't seem to be putting out the power it should.

System is as follows:
-2,600W solar array ( 8 panels each are 325w-10a-40v panels)
-Renogy Rover 100A MPPT Charge controller
- 12v 600ah lithium battery bank
- renogy 2000W inverter
Wiring is good, oversized slightly. There is almost no loss of power at the charge controller in relation to what is put out at the panels.

My average output for the entire array is about 300w/hour measured at the panels.
This seems way low.
When tested at the panels, they are producing the correct amount of volts but their amps seem low. They only put out 2 or 3 amps per panel and 4 to 6 for the entire array. I have 4 sets of 2 panels (series) wired in parallel. Sorry, I don't know how to better say that.

My orientation and angle is good, there are no obstructions it gets full sun all day.
I have had times where I get 600 to 1200 w generating in the mornings when it is cool.
However that does not last for more than about 40 minutes. The panels heat up significantly and the output drops.

Is it realistic to only be getting 15% or rated output?
I would expect more like 50 to 70%.

I would love any help or trouble shooting tips you guys can give me. I'm happy to send pictures as well

I need help diagnosing my system.
It doesn't seem to be putting out the power it should.

System is as follows:
-2,600W solar array ( 8 panels each are 325w-10a-40v panels)
-Renogy Rover 100A MPPT Charge controller
- 12v 600ah lithium battery bank
- renogy 2000W inverter
Wiring is good, oversized slightly. There is almost no loss of power at the charge controller in relation to what is put out at the panels.

My average output for the entire array is about 300w/hour measured at the panels.
This seems way low.
When tested at the panels, they are producing the correct amount of volts but their amps seem low. They only put out 2 or 3 amps per panel and 4 to 6 for the entire array. I have 4 sets of 2 panels (series) wired in parallel. Sorry, I don't know how to better say that.

My orientation and angle is good, there are no obstructions it gets full sun all day.
I have had times where I get 600 to 1200 w generating in the mornings when it is cool.
However that does not last for more than about 40 minutes. The panels heat up significantly and the output drops.

Is it realistic to only be getting 15% or rated output?
I would expect more like 50 to 70%.

I would love any help or trouble shooting tips you guys can give me. I'm happy to send pictures as well.
 
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The aggregate amperage is a bit high for 10 awg but its well within spec for 10awg wire with insulation rated for 105C.

If the panels are ok I would suggest you get a solar charge controller that can take a higher pv voltage.
Ideally high enough for 4s2p and then you don't need to fuse the individual strings.
Alright. I have confirmed that the panels are good. They are producing at about 70%

I replaced the audio cable and another undersized wire I found. (In retrospect, I should have redone everything instead of keeping the old wiring)

As of now, I have two more questions.

1. I have a 6 AWG wire going from the charge controller to the battery bank. The charge controller is outputting about 80 to 100 amps to the batteries. That 6AWG wire is getting hot. What gauge should I be using? That run is only about 4 ft.

2. As far as a different SCC that could handle more input, what would you suggest? I would like to be able to utilize all of my eight 325w panels.
OR, would it be more cost-effective to get a secondary SCC to use for the second half of panels? I was thinking maybe a renergy 20 amp 100 volt SCC mppt.

3. (I guess I have three questions LOL)
I know that if I wire my battery Bank for 24 volts, my SCC can handle more of an input. Would that be better? I know the WH of a 24 volt bank is the same as a 12 volt bank, but as far as I understand the amp hours is less. Would it make that big of a difference in how long I could run my appliances and lights?


Thanks!
 
Alright. I have confirmed that the panels are good. They are producing at about 70%

I replaced the audio cable and another undersized wire I found. (In retrospect, I should have redone everything instead of keeping the old wiring)

As of now, I have two more questions.

1. I have a 6 AWG wire going from the charge controller to the battery bank. The charge controller is outputting about 80 to 100 amps to the batteries. That 6AWG wire is getting hot. What gauge should I be using? That run is only about 4 ft.
4 awg pure copper with 105C insulating with a 150 amp fuse.
Since its right off the battery the fuse needs 10000 amps breaking capacity or better.
2. As far as a different SCC that could handle more input, what would you suggest? I would like to be able to utilize all of my eight 325w panels.
OR, would it be more cost-effective to get a secondary SCC to use for the second half of panels? I was thinking maybe a renergy 20 amp 100 volt SCC mppt.
As much as I'm not a fan of vendor lockin I have to point you toward Victron.
Good selection of stuff that works.
The bluetooth is the icing on top.
Morningstar is also good.
3. (I guess I have three questions LOL)
I know that if I wire my battery Bank for 24 volts, my SCC can handle more of an input. Would that be better? I know the WH of a 24 volt bank is the same as a 12 volt bank, but as far as I understand the amp hours is less. Would it make that big of a difference in how long I could run my appliances and lights?
If you change system voltage you will need a 24 volt inverter.

You 2000 watt inverter needs 2/0 awg with a 300 amp fuse with a breaking capacity of 10000 amps or better.

I suggest a fused busbar for the positive leg and a regular busbar for the negative leg.
It just makes things more serviceable and extensible.

I'll make you a drawing if you want.
12 volt 24 volt?
 
Alright. I have confirmed that the panels are good. They are producing at about 70%

I replaced the audio cable and another undersized wire I found. (In retrospect, I should have redone everything instead of keeping the old wiring)

As of now, I have two more questions.

1. I have a 6 AWG wire going from the charge controller to the battery bank. The charge controller is outputting about 80 to 100 amps to the batteries. That 6AWG wire is getting hot. What gauge should I be using? That run is only about 4 ft.

2. As far as a different SCC that could handle more input, what would you suggest? I would like to be able to utilize all of my eight 325w panels.
OR, would it be more cost-effective to get a secondary SCC to use for the second half of panels? I was thinking maybe a renergy 20 amp 100 volt SCC mppt.

3. (I guess I have three questions LOL)
I know that if I wire my battery Bank for 24 volts, my SCC can handle more of an input. Would that be better? I know the WH of a 24 volt bank is the same as a 12 volt bank, but as far as I understand the amp hours is less. Would it make that big of a difference in how long I could run my appliances and lights?


Thanks!
Great, glad that kinks are being worked out, for 80-100 amps at 24v x 48in I would not go below a 2AWG pure copper, welding wire is great, BUT.... if you want you can go with heavier gauge, depending on your budget, you could, freaking copper is expensive! Sometimes when I need a heavier gauge and I don't have it I will double up on a lighter gauge, so if I need 2AWG and I have 4AWG I just cut to even length and do a nice crimp (a must) and use that temporarily until I get the correct gauge. Had to do that not long ago because somehow I lost a lug. As far as your SCC the one you have seems to be the correct one for the energy you are producing, as long as your panels are below the max SCC input rating! But if you still want to get another one to split the input you can do that, there are some advantages to that setup. I would try to stick with the same model you already have if available. But yeah you can run 2 MPPTs at the same time and they will share the task nicely. As far as your extra question, the wh remain constant, the only thing that changes is the voltage and ah. Example, 4 batteries in series parallel at 48v 100ah each will give you the same wh as 4 X 100ah each batteries in parallel at 12v, but you will end up with 400 ah instead of 200ah on the 48v setup, but you will have the same "capacity" on both configurations. Please someone correct me if I'm wrong, I'm just learning this stuff too, but that is what I understand. I'm not good with formulas but I'm pretty sure someone here knows it by heart! I have 8X12v each 100Ah batteries hooked up in series parallel for 48v and according to my research they have the same capacity. The higher the voltage the lower gauge wire you can use, and some say the system will be more efficient! Cheers! I use 2AWG pure copper on all my cables except the panel input cables which are 10AWG pure copper, and the AC input and output which are also 10AWG pure copper, but I really don't run that much current on my system, 25 amps is the average so it stays cool!
 

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You 2000 watt inverter needs 2/0 awg with a 300 amp fuse with a breaking capacity of 10000 amps or better.
Even though the inverter came with 4AWG cables?

And where do you suggest I find these fuses? My local places don't carry them.

I'd LOVE a drawing.

I think I'll stick with 12v. 24v inverters are more pricey than another SCC.
 
Even though the inverter came with 4AWG cables?

And where do you suggest I find these fuses? My local places don't carry them.

I'd LOVE a drawing.

I think I'll stick with 12v. 24v inverters are more pricey than another SCC.
I'll jump in here for a sec, can you verify the amperage going into the inverter? I know the voltage is 12v right? 80-100 amps at 12v is a lot of current, do we still talking 80-100 amps? If so John's comment above is correct, quote "You 2000 watt inverter needs 2/0 awg with a 300 amp fuse with a breaking capacity of 10000 amps or better". For a fuse Amazon got these ones, they are excellent but expensive! Hope that helps!

Go Power! FBL-300 300 Amp Fuse Class T with Block , Black​

For battery to inverter cables these are very good for the price.

2/0 Gauge 2/0 AWG 5 Feet Red + 5 Feet Black Welding Battery Pure Copper Flexible Cable​

 
4 awg pure copper with 105C insulating with a 150 amp fuse.
Since its right off the battery the fuse needs 10000 amps breaking capacity or better.

As much as I'm not a fan of vendor lockin I have to point you toward Victron.
Good selection of stuff that works.
The bluetooth is the icing on top.
Morningstar is also good.

If you change system voltage you will need a 24 volt inverter.

You 2000 watt inverter needs 2/0 awg with a 300 amp fuse with a breaking capacity of 10000 amps or better.

I suggest a fused busbar for the positive leg and a regular busbar for the negative leg.
It just makes things more serviceable and extensible.

I'll make you a drawing if you want.
12 volt 24 volt?
I'm also curious about the science behind over paneling.

My SCC can accept 1300 W when on a 12 volt battery bank. My understanding is that if I go over that it simply limits it and only uses what it needs. As long as I stay under the 100 amp 150 volt SCC limit, there is not a problem.

First off, is that correct?

Secondly, where does that extra wattage go?

And thirdly, my panels are producing about 2,600 Watts and my SCC displays the status "limiting current"
I'm assuming that is due to the over paneling of watts, am I correct in assuming that nothing unfortunate will happen if it is left as is?

I definitely want a second SCC to make use of those unused watts. But will I get in trouble leaving it as is over the next few weeks?
 
I'll jump in here for a sec, can you verify the amperage going into the inverter? I know the voltage is 12v right? 80-100 amps at 12v is a lot of current, do we still talking 80-100 amps? If so John's comment above is correct, quote "You 2000 watt inverter needs 2/0 awg with a 300 amp fuse with a breaking capacity of 10000 amps or better". For a fuse Amazon got these ones, they are excellent but expensive! Hope that helps!

Go Power! FBL-300 300 Amp Fuse Class T with Block , Black​

For battery to inverter cables these are very good for the price.

2/0 Gauge 2/0 AWG 5 Feet Red + 5 Feet Black Welding Battery Pure Copper Flexible Cable​

Yes. 12v
The 80-100a is what the SCC is pushing to the batteries.
I'm not sure what the inverter is pulling. I assumed it just does it's own thing with the 12v bank.
I'm curious to see. I'll let you know what that reading is.
 
Hello, I think you are correct, I think another SCC is in line, then you can split the input and they will share it nicely. Will have a good video on this topic if you want to check it out. Humm, you mentioned your amps were low, but your wires are OK? I have a Victron SCC and is a little older than Mr. Growhat? and in occasions it has limited the input, (they are smart enough to lower the current) but mostly during real cool/sunny days, panels love cool and sunny and they can output lots more current. But so far it's been working for over 6 years without any issues. My 2 little PV systems can't compare to yours, most of my energy from solar is generated by the Grid-Tied Enphase IQ PV system and that's only 5kw of panels, on a daily basis it can generate around 25-35Kw give or take. But I use one little system for emergencies and one to supplement the central AC unit which consumes a lot of energy specially during hot days! Hope that helps. Cheers!
 
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Yes. 12v
The 80-100a is what the SCC is pushing to the batteries.
I'm not sure what the inverter is pulling. I assumed it just does it's own thing with the 12v bank.
I'm curious to see. I'll let you know what that reading is.
Me too, that is a lot of power! Are you powering the hold city?:ROFLMAO:
 
Even though the inverter came with 4AWG cables?
Yes the cables the come with inverters should almost always been discarded with the packing peanuts.
2000 ac watts / .85 conversion factor / 10 volt low cutoff = 235.294117647 service amps
235.294117647 service amps / .8 fuse headroom = 294.117647059 fault amps
That means pure copper 2/0 awg wire insulation rated for 105C and a 300 amp fuse.
see the ampacity limits table here https://baymarinesupply.com/calculator
And where do you suggest I find these fuses? My local places don't carry them.
Amazon or https://www.waytekwire.com/ or similar.
Exactly which kind is to be determined by other factors which we will get to before I make you a topology diagram.
I'd LOVE a drawing.
Give me a day or two.
Will you have any non alternating current loads?
In other words do you want to add a dc distribution block?
What size are the studs on the battery?(UPDATE: I see they are m8)
What size are the studs on the inverter?
I think I'll stick with 12v. 24v inverters are more pricey than another SCC.
Gotcha.
 
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