Unimpressed by PV production, what am I doing wrong?

[zanydroid]

Haha yes very good point... With great difficulty! (And an LPG generator), little wind turbine to make some power would help, it's windy here

What most people do is cut their power use to the bone ,

it's only really Oct, Nov, Dec, Jan, Feb, that are a problem.. . The rest of the year is brilliant lol

I need my creature comforts too much for that (I’m in Northern California, around 37N. I’m doubling my panels right now to 20kW (terrible site conditions, I get 50% solar access so my setup is double the size / half the ROI of normal people), and that’s theoretically capable to cover me off grid in the winter apart from heating. With heating added in, forget about it.

After April I should be pushing a crazy amount of power into the grid.

 

[zanydroid]

I'm maxxed out with 32 panels across the 4 inverter inputs.

If you just need more winter output why not overpanel with 2p. Sure you will clip but you might anyway be generating more than you can consume in the summer.

 

[Farm Boy]

I was never really impressed with my system of 8-390w facing south in 2 strings to combiner box then run 175' through 224 triplex to inverter. The voltage was usually there but the amps were all ways lower than I thought. The other day, I hooked up my 220v wellpump, tankless water heater and softener to the system and wow!. Now my pv system is impressive to before showing the amps draw from the pv much higher. Go's to show as others have said, you need to have the draw or a place to put that power your pv can produce before it will show up on the meter.

 

[SamDeleted]

I need my creature comforts too much for that (I’m in Northern California, around 37N. I’m doubling my panels right now to 20kW (terrible site conditions, I get 50% solar access so my setup is double the size / half the ROI of normal people), and that’s theoretically capable to cover me off grid in the winter apart from heating. With heating added in, forget about it.

After April I should be pushing a crazy amount of power into the grid.

What do you think your 20kw will produce summer / winter ?

 

[zanydroid]

What do you think your 20kw will produce summer / winter ?

Right now I produce about 6kWh per day in winter, after doubling that it will be 12kWh best case, but because of orientation details it might be 9kwh. A lot depends on how much my prioritization of the best solar access parts of the roof for panels gets me.

I believe our rule of thumb is 3x summer to winter. However because I have tree issues => geometry is hard, it’s very nonlinear so to speak what will happen. And one of the new roof planes is useless for 5 months but relatively amazing for 7 months.

I am heating dominated so this system will be really awkward in 20 years when net metering is sunset for me.

 

[SamDeleted]

Right now I produce about 6kWh per day in winter, after doubling that it will be 12kWh best case, but because of orientation details it might be 9kwh. A lot depends on how much my prioritization of the best solar access parts of the roof for panels gets me.

I believe our rule of thumb is 3x summer to winter. However because I have tree issues => geometry is hard, it’s very nonlinear so to speak what will happen. And one of the new roof planes is useless for 5 months but relatively amazing for 7 months.

I am heating dominated so this system will be really awkward in 20 years when net metering is sunset for me.

20 yrs here's hoping SHTF before then!

Can't you install a log burner for heat? Kill two birds with one stone, solve your tree problem and your heating problems

 

[zanydroid]

20 yrs here's hoping SHTF before then!

Can't you install a log burner for heat? Kill two birds with one stone, solve your tree problem and your heating problems

I would rather avoid SHTF, too much juicy infra at my house for people to raid.

I’m in the inner suburbs.

These are holy old growth trees that are sacrosanct. You can’t remove them legally speaking (and possibly morally speaking, they grow very slowly and there’s only a few left).

Wood fire burning is not allowed on many days because the pollution gets trapped by our winter meteorological conditions. I converted the fireplace to gas for that reason, and because I would need a pretty nicely encapsulated wood stove for my own health as well.

 

[SamDeleted]

Wood fire burning is not allowed on many days because the pollution gets trapped by our winter meteorological conditions.

They're trying to do the same thing here, trying to stop us burning wood, ridiculous when we're still burning gas / dirty nuclear to make power.

In my opinion wood is a renewable energy

Anyway that's enough hijacking @30362 's thread !

 

[saen]

Since each PV input can only support max 500v, I'm maxxed out with 32 panels across the 4 inverter inputs. I have space to add more, but I'd need to add another inverter or two...

Other brand inverters support up to 1500v. ex: Growatt
My Growatt MOD-9000TL3-X is 1100V
But in this case spec of panels need to support 1500v.
Most panels support up to 1000v.

 

[30362]

Anyway that's enough hijacking @30362 's thread !

No! I'm really enjoying the discussion, it's helping me with expectations. When I originally talked to SS I was getting the 455w per panel X 4-5 hours of sun in the summer and 2-3 hours in the winter, but I think I was only hearing what I wanted to hear. When I finally got my PV connected I was worried that the underperformance (200w for 4 panels at noon on a sunny day) was going to be it, and I was really upset. Someone rightfully pointed out that I need a load to see more (for some reason I assumed the inverters would show the total, not just what it was using) and so adding a load helped, but I was still getting substandard performance, about a 500w peak when my 4 panels should have been 1.8kW. I added another string of 4 panels to the other PV input and was equally unimpressed so still worried.

@zanydroid comment about 1x panels in the winter seems about right, now that I've actually got the system in and running and PV finally attached and I'm seeing real numbers.

I was able to cover the panels and rewire the 8 of them in series (versus 2 separate 4 panel strings to each PV input), and I'm seeing far better results, even today when it's much cloudier than yesterday, so I'm a bit happier. Looks like I just need to get the other 24 panels in place before I can really get a sense for my PV production... and of course time is passing, and it's been slow going getting the ground mounts installed and panels attached working solo, so solar angle is increasing daily and I'm sure that by the time I have all 32 in place it'll be another 6-8 weeks...

 

[30362]

If you just need more winter output why not overpanel with 2p.

Not sure what you mean by 2p? And how would I handle this in the summer, PV disconnect at the string of additional panels? or are you talking about parallel and combiner box?

 

[zanydroid]

Not sure what you mean by 2p? And how would I handle this in the summer, PV disconnect at the string of additional panels? or are you talking about parallel and combiner box?

Yes, start paralleling the strings. I mostly am familiar microinverters, but with 2 parallel (and not higher) you can take advantage of some special cases to simplify fusing. I think you just need a fuse after the combiner matched to the max amps draw of the MPPT and the wire between combiner and MPPT. You may need to upsize this wire too.

All this is needed in the winter too to be code compliant. Everything needs to be sized according to worst case analysis per NEC.

AIUI, you don’t need to handle it in the summer. In normal operation the MPPT will only draw up to its rating. The fuse(s) will provide the necessary protection during a fault.

 

[zanydroid]

One thing to consider to help with debugging/understanding solar is to add panel-level monitoring devices into your string, I believe these will measure voltage, amps, and power.

It’s probably $20-30 per panel and $300-500 for the gateway to read off the data. You may be able to skip panels too, though I think once you go in on this approach might as well go all the way.

You can also get the kind with RSD (AFAIK not needed for ground mounts) if you want the ability to drop the string voltage quickly during service. I’m not sure if they’re meant to support this use case though, I haven’t seen people talk about the modules this way. This adds an additional point of failure and way to increase the complexity of starting the system in the morning.

 

[SamDeleted]

(200w for 4 panels at noon on a sunny day) was going to be it, and I was really upset.

You yanks are just too excitable lol



Your setup will work out I am sure,

take life one day at a time, just like Jesus said at Matthew 6:25-34

 

[EPicTony]

I'm looking at the bottom of page 8, solar input, and I'm not sure what info there says that my second string of 4 panels are useless. When I discussed this with SS it was recommended 8 panels in series on PV1 and 8 panels in series on PV2, then the same on the 2nd inverter, for a total of 32 panels. 8 panels max per string so the input voltage didn't exceed 500v per PV input...

I have the same inverter and panel, 8 per string is the max.

 

[EPicTony]

Yes, start paralleling the strings. I mostly am familiar microinverters, but with 2 parallel (and not higher) you can take advantage of some special cases to simplify fusing. I think you just need a fuse after the combiner matched to the max amps draw of the MPPT and the wire between combiner and MPPT. You may need to upsize this wire too.

All this is needed in the winter too to be code compliant. Everything needs to be sized according to worst case analysis per NEC.

AIUI, you don’t need to handle it in the summer. In normal operation the MPPT will only draw up to its rating. The fuse(s) will provide the necessary protection during a fault.

Be careful with parallel panels on the EG4, it only handles 18a max. per string. The Solever 455w panels deliver 11a so you do not want to parallel them (2x11=22amps = BAD)

 

[saen]

I have the same inverter and panel, 8 per string is the max.

8 panels but what panels 60V model?
I save some CdTe panels with 87.5v Voc / 59.7 Vmp

Be careful with parallel panels on the EG4, it only handles 18a max. per string. The Solever 455w panels deliver 11a so you do not want to parallel them (2x11=22amps = BAD)

bad is when is over voltage not over amperage
Your phone charger is connected to 10+ A fuse, but use less then 1 A why nothing happens?

He just will lose this extra 4 amps

 

[zanydroid]

Be careful with parallel panels on the EG4, it only handles 18a max. per string. The Solever 455w panels deliver 11a so you do not want to parallel them (2x11=22amps = BAD)

That’s why I said to fuse after the combiner at a level where the fuse won’t blow from the max draw that the inverter will pull. Preferably matching the published fuse rating on the inverter.

 

[30362]

Dumb question - if I only care about leveraging PV to charge the batteries, can I just get another MPPT SCC (eg. Victron) and connect one or more strings into that MPPT and then wire the output from that MPPT SCC to the battery bank so that both this MPPT and the 2 EG4s are connected and charging the batteries?

 

[timselectric]

Dumb question - if I only care about leveraging PV to charge the batteries, can I just get another MPPT SCC (eg. Victron) and connect one or more strings into that MPPT and then wire the output from that MPPT SCC to the battery bank so that both this MPPT and the 2 EG4s are connected and charging the batteries?

Yes, as long as the total charging amps don't exceed the battery specs.