Looking for inverter suggestion to set up a critical backup system while cutting utility bill.

MurphyGuy

Solar Addict
yeah and to be fair the box is $595, the $1000.00 is everything pre-wired, but still! Sometimes companies add some time onto the warranty if you buy the extra ad-on but I didn't see anything about that. I like that Outback seems to be willing to sell you just the components that you need.
I'm waiting to see if I can get this from a local dealer at a comparable price as online, if not who is a good supplier?
Got a link to that $595 ??
 

MurphyGuy

Solar Addict
Forget it.. I found it.. Its just a box with bus bars and a shunt... They don't even give you the breakers..

how silly.
 

wattmatters

Solar Addict
It is true that one shaded panel can sink an entire string of them.
Only if they are crap panels and/or a crummy MPPT. Good panels will engage bypass diodes so current from the other unshaded panels is unaffected.

What I meant was to add more panel strings in places where there isn't shade.
If that were the case then wouldn't you'd just put the original panels where there isn't shade?
 

MurphyGuy

Solar Addict
Only if they are crap panels and/or a crummy MPPT. Good panels will engage bypass diodes so current from the other unshaded panels is unaffected.


If that were the case then wouldn't you'd just put the original panels where there isn't shade?

Crap panels? LOL. I have Solarworld and Qcells and they are not "crap panels"..

As for shading, a little known science fact is that the angle to the sun changes as our planet rotates.. its true, not just conspiracy... and this causes objects to create moving shadows on the ground. A spot that is shaded at 11 am in the morning, may be under full sun by 3pm. I know that's mind blowing but its true.
 

wattmatters

Solar Addict
I have Solarworld and Qcells and they are not "crap panels"..
I never said you had crap panels. I said:
Only if they are crap panels
I'm not familiar with Solarworld but Qcells are quality kit, have bypass diodes and also have half cut panels which are even better for helping a string perform well even though one or a few get some partial transient shading.

The old maxim "a one shaded panel ruins a whole string" is just bunkum.

Modern MPPTs and solar panels are very good at extracting production from array which experiences partial transient shading. They can even be as good as a micro inverter system - much depends on the nature of the transient shade.

As for shading, a little known science fact is that the angle to the sun changes as our planet rotates.. its true, not just conspiracy... and this causes objects to create moving shadows on the ground. A spot that is shaded at 11 am in the morning, may be under full sun by 3pm. I know that's mind blowing but its true.
I completely agree in principle that because solar PV is so relatively cheap, often the easiest solution is to just add panels.

But there comes a point when adding one panel more requires a sizeable jump in supporting infrastructure and the marginal cost of extra PV is no longer so nice. e.g. when your MPPT is already at voltage/wattage limits, or available array space is limited such that adding then extra panels isn't always a simple option.

So the first thing to do is place the panels you have in the best solar location for your needs to begin with. Avoid shade where possible, or have it so what shade is cast is when you least need the energy.
 

MurphyGuy

Solar Addict
I never said you had crap panels. I said:

I'm not familiar with Solarworld but Qcells are quality kit, have bypass diodes and also have half cut panels which are even better for helping a string perform well even though one or a few get some partial transient shading.

The old maxim "a one shaded panel ruins a whole string" is just bunkum.

Modern MPPTs and solar panels are very good at extracting production from array which experiences partial transient shading. They can even be as good as a micro inverter system - much depends on the nature of the transient shade.

As someone with Qcells, I can tell you that a shaded panel does indeed drastically reduce power to the whole string.

This is why they sell optimizers.. although, in my opinion, its better to just buy more panels since they're so cheap.
 

MurphyGuy

Solar Addict
Then maybe you need a better MPPT?

Have a look at this post and the video showing results using a good MPPT.
Better than an SMA SunnyBoy SB series inverter??? LOL

I'm going on 5 years with my array and I'm quite aware of how shading affects solar output. I have both 60 cell panels (SolarWorld) and 72 cell split panels (Qcells). During certain months, my array is subject to some shading and I know how panels and strings behave under various conditions.
I don't need some youtube expert to tell me what I already know through experience.

What solar system do you have?
 

wattmatters

Solar Addict
What solar system do you have?
I have two.

My grid tied system is a 10kW Fronius Symo 3-phase inverter with 11kW of Trina 275W panels in 4 x 10 panel strings, with 2 x 10 in parallel into each MPPT. Not half cut panels, just regular with the usual 3 bypass diodes.

I get shading, particularly in the Winter from a row of Jacarada trees on the sun side of our home. Having them strategically lopped earlier this year improved our Winter production by 34% over the previous year.

Strategic placement of optimisers is not an option anyway since I have paralleled arrays. Optimisers are only an option for single strings, unless of course you put them on every panel.

I don't need some youtube expert to tell me what I already know through experience.
Perhaps not, but always keep in mind that YMMV. IOW one can't always extend their personal experience as being universally applicable.
 

MurphyGuy

Solar Addict
I have two.

My grid tied system is a 10kW Fronius Symo 3-phase inverter with 11kW of Trina 275W panels in 4 x 10 panel strings, with 2 x 10 in parallel into each MPPT. Not half cut panels, just regular with the usual 3 bypass diodes.

I get shading, particularly in the Winter from a row of Jacarada trees on the sun side of our home. Having them strategically lopped earlier this year improved our Winter production by 34% over the previous year.

Strategic placement of optimisers is not an option anyway since I have paralleled arrays. Optimisers are only an option for single strings, unless of course you put them on every panel.


Perhaps not, but always keep in mind that YMMV. IOW one can't always extend their personal experience as being universally applicable.
3 phase inverter? On a business or something?
 

Short_Shot

Photon Sorcerer
1000 watts of solar panels isn't going to be enough to run a chest freezer, family sized fridge, and a well pump.. I don't know what size fridge you have, but mine pulls 3.6kWh/s per day.. My small basement chest freezer pulls 600.
My less than year old rather large French door fridge with icemaker in the fridge part, which is about the last efficient design possible, pulls about 1.2kwh/day.

There's something wrong with yours or it's pretty old.

My chest freezer draws about the same 600wh.

1kw of panels should get you some 4kwh during the summer but during the winter will come up pretty well short of needs.

As you said, getting a killawatt meter to understand actual needs is invaluable information.
 

Short_Shot

Photon Sorcerer
I have one, the freezer and fridge draw about 130W each continuous.
I also remeasured the well pump, the MAX amps my Fluke meter is picking up is 6.3A from one leg of the 240V pump. I noticed it increased from 2A to 4A to 6A over a second or so which makes me hopeful it is a soft start pump?
If you have that meter you should know kwh/day.

Much more valuable information for solar installations than instantaneous draw.

If your fridge is pulling 3kwh/day (130w continuous for 24 hours) I'd consider buying a new fridge, depending how much time you want to run it on batteries it may be cheaper to do so.

Same goes for the pump. Average kwh/day consumption during normal use.
 

MurphyGuy

Solar Addict
My less than year old rather large French door fridge with icemaker in the fridge part, which is about the last efficient design possible, pulls about 1.2kwh/day.

There's something wrong with yours or it's pretty old.

My chest freezer draws about the same 600wh.

1kw of panels should get you some 4kwh during the summer but during the winter will come up pretty well short of needs.

As you said, getting a killawatt meter to understand actual needs is invaluable information.

Our side by side fridge is 28 CuFt with icemaker, and an 8 year old that opens the door and stares at the food.. I think it was built in 1998.. Yup.. 3.6kW.. although, to be honest, I think that was a summer measurement..

Checking online, it looks like I'm in good shape form this 2018 article.

On a side note: As a prepper, these energy loads are part of my calculations.. especially since we lose grid power almost every other month or two.. If it came right down to it in the winter during the solar horror months, we could put food outside.. let mother nature save us the energy if we got that desperate without grid power.
 

Short_Shot

Photon Sorcerer
Ours is 27 cubic feet, and we have an 8 and 10 year old that does the same lol

Blows me away the numbers other people see from their fridges. That article is borderline nonsense citing "wattage times 8 hours per day" and then assuming it draws 780w, and was obviously written by someone who has never measured power in their life.

If mine pulled 6kwh I'd ask who left it open all day.

Of course if you don't have AC that figure will go up. I guess I can't say it's an impossible number by any means.

And it can't hurt to plan for extra power capacity.
 

MurphyGuy

Solar Addict
Ours is 27 cubic feet, and we have an 8 and 10 year old that does the same lol

Blows me away the numbers other people see from their fridges. That article is borderline nonsense citing "wattage times 8 hours per day" and then assuming it draws 780w, and was obviously written by someone who has never measured power in their life.

If mine pulled 6kwh I'd ask who left it open all day.

Of course if you don't have AC that figure will go up. I guess I can't say it's an impossible number by any means.

And it can't hurt to plan for extra power capacity.

I have a buddy with a fridge similar to mine.. just a tiny bit smaller. I think I'll measure his and see what he gets. I think he bought his in 2010 or around there..
I have so much solar power that the large power draw doesn't bother me... and I love my fridge, even though its showing some signs of rust.. but I'm curious now.
 

wattmatters

Solar Addict
3 phase inverter? On a business or something?
Just our home but we have 3 buildings, two homes and a large mancave. We have 3-phase supply. I'm down under, not in USA.

Reckon I could use some more but connection limits.

I put together my first DIY project this year - that's a 2.22kW off-grid array (6 x 2nd hand 370W Longi panels) feeding a generic 4kW AIO inverter with 18kWh of pre-loved data centre SLA batteries (380Ah 48V). It's out outage backup system, plus a generator if needed. Tested it the other night and running 8 hours overnight still was >80% state of charge. During the day it runs the pool pump.

When the time is right I can start looking at moving more loads to (mostly) off-grid with more DIY set ups.
 

wcpastures

New Member
I have two.

My grid tied system is a 10kW Fronius Symo 3-phase inverter with 11kW of Trina 275W panels in 4 x 10 panel strings, with 2 x 10 in parallel into each MPPT. Not half cut panels, just regular with the usual 3 bypass diodes.

I get shading, particularly in the Winter from a row of Jacarada trees on the sun side of our home. Having them strategically lopped earlier this year improved our Winter production by 34% over the previous year.

Strategic placement of optimisers is not an option anyway since I have paralleled arrays. Optimisers are only an option for single strings, unless of course you put them on every panel.


Perhaps not, but always keep in mind that YMMV. IOW one can't always extend their personal experience as being universally applicable.
What do you mean by "loopped"? Is that the same as paralleled?
I can pick up some inexpensive used panels here: https://store.santansolar.com/product-category/solar-panels/
Do most newer panels have diodes built in? This is something I need to learn about, I am only familiar with optimizes which seem to cost about as much as the panel itself if using the low cost source above.
 
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wattmatters

Solar Addict
What do you mean by "loopped"? Is that the same as paralleled?
I said lopped, not loopped.

I was talking about the trees (jacarandas) along the sun side of our home. I had them lopped, i.e. branches cut/removed/trimmed to thin them somewhat and reduce their overall height. They needed it for their own health, for safety as it reduces the risk of branches or trees falling and of course the benefit of letting more light through to both the solar panels on the roof and the house in general during Winter.

I can pick up some inexpensive used panels here: https://store.santansolar.com/product-category/solar-panels/
Do most newer panels have diodes built in?
Yes. I'm talking about the residential scale panels, 60 cell, 72 cell size units (and larger).

You'd need to check the specifications for the specific panel but the panels/brands on that page all look like modern panels which would have multi-diodes built in. I think you'll be fine!

I am only familiar with optimizes which seem to cost about as much as the panel itself if using the low cost source above.
Honestly I wouldn't bother with optimisers unless you have a very specific need for them. They can always be fitted later in any case.

Shading is just a fact of life and an optimiser doesn't make light, just helps (sometimes) reduce losses in a string. That said they may not be any better than a panel using its own bypass diodes for that purpose. It depends on the nature of the shading. Watch the video I posted earlier comparing how in real life a string inverter system and a micro-inverter system manage different shading scenarios.

Set stuff up to minimise shade in the first place and don't let seeking "perfect" be the enemy of good.

The best option is to position panels to minimise shading in the first place, or to move/remove objects which are casting the shade. Don't worry as much about shade early/late in the day. It's shade during peak production hours (the 2-3 hours either side of solar noon) you want to keep a check on.

This is the impact of reducing the shading cast by our trees. Shown below is the PV output from my system (expressed as kW output per kW of installed panels), comparing a nice day close to Winter Solstice this year, and a day with similar conditions the year before.

Screen Shot 2021-09-24 at 6.34.08 am.png

You can see how much my tree lopping helped solar PV output this Winter compared with last Winter, especially during the middle portion of the day.

Even so, I was still getting good useful output when I had the extra tree shading and the panel diodes and MPPTs did their job in extracting what energy they could.

Optimisers for me would be a total waste of money. As I said, they can't make light.

They don't work with paralleled arrays unless fitted to every panel so in my case adding A$4k worth of optimisers to improve production worth about an extra $100 year would not be particularly smart.
 

SolarPrep

Solar Enthusiast
Ok good, yeah I think I will put together my own panel, save some $, and I can customize it the way I want. It almost seems the "Load Center" makes it more complicated.
Outback publishes their install manual for the Radian which is helpful at seeing how this will go together:

I am really starting to get excited about Outback, beats Sol-Ark hands down on price and they are not made in China like Sol-Ark now is.
The only thing I can see Sol-Ark 5k having that the Outback Radian does not is the charge controller integrated, but I would still prefer to have those components separated for serviceability.
WC: Don't rely on that information about Outback not being made in China. I'm not pushing any brand in this discussion, and in fact am looking at many of these same brands for our projects. Many of these units are made in China, Victron in India, etc. Magnum is still made in the USA, and Exeltech. The new Midnite Solar DIY are Chinese. And then there is the fact that even if they are partially assembled in the US, where do the parts come from? For the most part, China.
 

wcpastures

New Member
I said lopped, not loopped.

I was talking about the trees (jacarandas) along the sun side of our home. I had them lopped, i.e. branches cut/removed/trimmed to thin them somewhat and reduce their overall height. They needed it for their own health, for safety as it reduces the risk of branches or trees falling and of course the benefit of letting more light through to both the solar panels on the roof and the house in general during Winter.


Yes. I'm talking about the residential scale panels, 60 cell, 72 cell size units (and larger).

You'd need to check the specifications for the specific panel but the panels/brands on that page all look like modern panels which would have multi-diodes built in. I think you'll be fine!


Honestly I wouldn't bother with optimisers unless you have a very specific need for them. They can always be fitted later in any case.

Shading is just a fact of life and an optimiser doesn't make light, just helps (sometimes) reduce losses in a string. That said they may not be any better than a panel using its own bypass diodes for that purpose. It depends on the nature of the shading. Watch the video I posted earlier comparing how in real life a string inverter system and a micro-inverter system manage different shading scenarios.

Set stuff up to minimise shade in the first place and don't let seeking "perfect" be the enemy of good.

The best option is to position panels to minimise shading in the first place, or to move/remove objects which are casting the shade. Don't worry as much about shade early/late in the day. It's shade during peak production hours (the 2-3 hours either side of solar noon) you want to keep a check on.

This is the impact of reducing the shading cast by our trees. Shown below is the PV output from my system (expressed as kW output per kW of installed panels), comparing a nice day close to Winter Solstice this year, and a day with similar conditions the year before.

View attachment 65982

You can see how much my tree lopping helped solar PV output this Winter compared with last Winter, especially during the middle portion of the day.

Even so, I was still getting good useful output when I had the extra tree shading and the panel diodes and MPPTs did their job in extracting what energy they could.

Optimisers for me would be a total waste of money. As I said, they can't make light.

They don't work with paralleled arrays unless fitted to every panel so in my case adding A$4k worth of optimisers to improve production worth about an extra $100 year would not be particularly smart.
Thank you for this chart, it is helpful to visualize when the peak output is, and since I now plan to purchase and use the hybrid features of the Outback Radian I will be taking full advantage during those peak times.
Yeah I don't think optimizers would make sense in most situations. It seems that running them parallel will achieve similar results in partial shade.
 
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