6 used 260 Watt 30.6v 8.5A panels and a large imagination beginning to get me in trouble

[Jeff From NJ]

I have a shading issue, so it seems like 2S3P (do I not use an entire panel, seems wasteful since I own it already?)

As for the controller, do you agree I should get rid of the 2 - 40 AMP Rovers and replace them with 1 Epever 6415AN (60 Amp)?

If this is all affirmative, then I just need to find a 2000 Watt pure sine inverter and I'm golden.

 

[MichaelK]

In the real-world you are likely to never see 100% output. For most calculations I use 85%. Most of the panels that I bought that are similar to yours have been output tested and 85% holds up pretty well.

So, what you are likely to actually see is {(260W X 6 panels)/25V charging } X 85% = 53amps.

Remember, whenever you have more than two strings of solar panels they are required by code to be protected by fuse/breaker. With about 8A of current flowing, a 12A fuse/breaker is what's appropriate.

One thing you might try if you want to stick with 2S3P is align string #1 SE, string #2 South, and string #3 SW. It will tend to dampen you noon amperage peak, but spread the lower peak more broadly over the course of the day.

Dampening the noon peak would be a way to still use one of your Rover controllers, but me personally would still get the Epever 6415.

 

[rmaddy]

2S3P is 6 panels. Put two in series. Put another two in series. Put another two in series. You now have 3 pairs of panels in series. Put these 3 series strings in parallel using a combiner box and fuse each string.

With a 24V system you can use the 2 40A Rovers with 3 panels each. The three panels would need to be in parallel. Those controllers can't handle 3 of those panels in series. So you would have 3P on one controller and 3P on the other controller. Lots of parallel panels. That's great if you have shading issues. But a Voc of 38V on a 24V system means you won't have very good low light handling.

One controller is simpler than two.

But ultimately your shading issue(s) will determine the best option. If you go with the one controller and have the panels in 2S3P you must ensure that each pair of panels in series together will rarely, if ever, be partially shaded. So if you can arrange the 3 pairs of panels so a given pair is rarely partially shaded then that's probably the best option. If you can't do that and you would get better results with 6 panels all in parallel then stick with the two existing controllers.

 

[Jeff From NJ]

Shading is always going to be an issue for me since I'm placing the panels low to the ground in my back yard, lots of tall trees. I also don't want to have panels facing different directions visually.

Seems like the advice then is to keep the two 40Amp Rovers, run 3 panels in parallel to each Rover, and connect the 2 Rovers to a single 2000W inverter

 

[rmaddy]

and connect the 2 Rovers to a single 2000W inverter

Not really. There would be bus bars. The batteries connect to the bus bars. The inverter connects to the bus bars. Each charge controller connects to the bus bars. Any other charger connects to the bus bars. Your DC fuse box (if any) connects to be bus bars. See the pattern yet?

Oh, and each thing connected to the bus bars gets its own fuse/breaker.

 

[Jeff From NJ]

Not really. There would be bus bars. The batteries connect to the bus bars. The inverter connects to the bus bars. Each charge controller connects to the bus bars. Any other charger connects to the bus bars. Your DC fuse box (if any) connects to be bus bars. See the pattern yet?

Oh, and each thing connected to the bus bars gets its own fuse/breaker.

I admit I was being overly simplistic, my point was only that I need to buy one more major component, the inverter.

 

[Nickatnyt]

Also, look at Will's low end 12v LiFePo4 review videos on Youtube. Amazon supplied 100ah are down to $400.

Now at low $300s !

 

[pollenface]

Any thoughts on the best configuration to accomplish this goal based on the starting point of what I have, 6 panels and 2 controllers.

Easy. 3 panels per controller. It may seem overkill but it will do you justice on rainy days.

If you're using prebuilt lifepo4 batteries, be mindful of their instantaneous discharge current limits. e.g. a 3000/6000w inverter can have a 300a surge in 24v. (6000/24/0.85)

I've had ZERO dramas buying from china and I live in Australia. Things often take 2-3 months to get to my door but Chinese vendors will often bend over backwards to help you get your parcel, or compensate you if you don't.

 

[Jeff From NJ]

If you're using prebuilt lifepo4 batteries, be mindful of their instantaneous discharge current limits. e.g. a 3000/6000w inverter can have a 300a surge in 24v. (6000/24/0.85)

I read that I should get the smallest inverter that handles the voltage put out by my panels. For me, I am putting out 1560 V, so going with a 2000W inverter is the sweet spot for efficiency. You mention 3000W, was that just an off the cuff comment, or did you think I should be "sizing up" on my inverter size?

 

[MichaelK]

I read that I should get the smallest inverter that handles the voltage put out by my panels. For me, I am putting out 1560 V, so going with a 2000W inverter is the sweet spot for efficiency. You mention 3000W, was that just an off the cuff comment, or did you think I should be "sizing up" on my inverter size?

I personally would not agree with that. I think that caution is a response to otherwise poor system design. An important issue with inverter size is that in general the inverter always consumes some power (idle load) just being left running, even if it is powering nothing, and the size of the inverter is proportional to the size of the idle load. With other small-system DIYers here, I've seen their low-budget inverters as being the single largest load on the systems over a 24hr period.

This appears to be the most problematic with newer low-budget AiO inverters, which self-consume hundreds of watts per hour, with 24hr consumption values in the 3-7kWh range.

With your system, with 1500+W of solar, I don't think you'll be having any problems with background consumption. I'll recommend the inverter that I myself am using.

Schneider Electric Conext SW4024-120/240 Inverter/Charger - RES Supply

Free Shipping! Schneider Electric Conext SW4024-120/240 Inverter/Charger, 4000W, 120/240VAC, 50/60Hz, 30A Transfer, 24VDC, 90A Charger, RNW8654024

ressupply.com

Being a quality, low-frequency inverter, it supports the starting surges of all my power tools, and it has a idle consumption of only 11W. Note though that this inverter is designed to be hard-wired directly into your electrical panel, so it does NOT have NEMA sockets.

 

[Jeff From NJ]

I personally would not agree with that. I think that caution is a response to otherwise poor system design. An important issue with inverter size is that in general the inverter always consumes some power (idle load) just being left running, even if it is powering nothing, and the size of the inverter is proportional to the size of the idle load. With other small-system DIYers here, I've seen their low-budget inverters as being the single largest load on the systems over a 24hr period.

This appears to be the most problematic with newer low-budget AiO inverters, which self-consume hundreds of watts per hour, with 24hr consumption values in the 3-7kWh range.

With your system, with 1500+W of solar, I don't think you'll be having any problems with background consumption. I'll recommend the inverter that I myself am using.

Schneider Electric Conext SW4024-120/240 Inverter/Charger - RES Supply

Free Shipping! Schneider Electric Conext SW4024-120/240 Inverter/Charger, 4000W, 120/240VAC, 50/60Hz, 30A Transfer, 24VDC, 90A Charger, RNW8654024

ressupply.com

Being a quality, low-frequency inverter, it supports the starting surges of all my power tools, and it has a idle consumption of only 11W. Note though that this inverter is designed to be hard-wired directly into your electrical panel, so it does NOT have NEMA sockets.
View attachment 78430

That inverter is out of my price range, but thanks for clarifying my understanding regarding wattage/size. One of the inverters Will suggests, GIANDEL 24 Volt 2000W Pure Sine Wave Power Inverter, costs $369. That's where I am currently leaning, and anticipate purchasing an inverter later today.

 

[MichaelK]

That inverter is out of my price range, but thanks for clarifying my understanding regarding wattage/size. One of the inverters Will suggests, GIANDEL 24 Volt 2000W Pure Sine Wave Power Inverter, costs $369. That's where I am currently leaning, and anticipate purchasing an inverter later today.

OK, but remember, with solar, you get what you pay for. I wouldn't even consider it for my own use. It's idle consumption will be ~50W per hour or 1150W per day, about 4X what the Conext consumes.

 

[wiseacre]

That inverter is out of my price range, but thanks for clarifying my understanding regarding wattage/size. One of the inverters Will suggests, GIANDEL 24 Volt 2000W Pure Sine Wave Power Inverter, costs $369. That's where I am currently leaning, and anticipate purchasing an inverter later today.

I have a 3500w inverter. While my loads don't usually exceed 2000w loads I feel it's better to have the extra in case I need it.
I also feel it's better to run an inverter at lower draws instead of pushing a smaller inverter to its limits and running it hot.
Heat is not good for components.

I think the Giandel (2000w) has around 20w idle draw
my inverter is 25w idle draw
https://www.eco-worthy.com/collecti...d-pure-sine-wave-inverter-12v-24v-48v-to-110v

It's not a tier 1 but has proven to be reliable without any problems.
If I had to buy again would I purchase it again - Yes

 

[Jeff From NJ]

I have a 3500w inverter. While my loads don't usually exceed 2000w loads I feel it's better to have the extra in case I need it.
I also feel it's better to run an inverter at lower draws instead of pushing a smaller inverter to its limits and running it hot.
Heat is not good for components.

I think the Giandel (2000w) has around 20w idle draw
my inverter is 25w idle draw
https://www.eco-worthy.com/collecti...d-pure-sine-wave-inverter-12v-24v-48v-to-110v

It's not a tier 1 but has proven to be reliable without any problems.
If I had to buy again would I purchase it again - Yes

Same price as the Giandel, so I'll take a look at yours now.

 

[pollenface]

You mention 3000W, was that just an off the cuff comment, or did you think I should be "sizing up" on my inverter size?

just an example for you

 

[GLC]

My Giandel 4000 watt 110 inverter uses only 4 watts in idle mode with nothing on or drawing power. My Sigineer 6000 watt 110/220 uses 45 watts at idle. I only turn it on when I need 220 power.

 

[MichaelK]

My Giandel 4000 watt 110 inverter uses only 4 watts in idle mode with nothing on or drawing power. My Sigineer 6000 watt 110/220 uses 45 watts at idle. I only turn it on when I need 220 power.

Is it 4W? The Giandel manual I checked stated 2A, so at 24V that would be 48W?

 

[GLC]

Is it 4W? The Giandel manual I checked stated 2A, so at 24V that would be 48W?

That is on a their 24 volt 4000/8000 inverter. I recently checked because with another inverter that I placed in operation was pulling the system down pretty quick with nothing on. With meters on both units and everything off, Giandel was at 4 watts and the Sigineer was at 45 watts. Yep the manual states one thing but the meter shows a totally different reading. Very impressed with a 4 watt idle consumption.

 

[Jeff From NJ]

Could I use something like this hybrid inverter to connect to my batteries and also to the grid for net metering?

161.68US $ 14% OFF|3kva Pure Sine Wave Hybrid Solar Inverter 24v 220v 110v Built-in Pwm 50a Solar Charge Controller And Ac Charger For Home Use - Inverters & Converters - AliExpress

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www.aliexpress.com

I'd love to be able to charge my batteries and then sell back power when the batteries are full. Then, in a power outage, have the inverter draw the house power from my batteries, disconnecting from the grid.

 

[MichaelK]

Hmmm, would even Harbor Freight want to sell this bottom rung item?