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diy solar

SMA VS AIMS

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No, his loads aren't that heavy. Started out as supplying 240V, 50A just like an RV shore power pedestal. The RV in this case is expected to draw half of that and has 6.5 kW generator. But Inverter should be heavy enough to start A/C, also a well pump (specs TBD)
Put a soft start on both devices ... and for the well pump use a 200 gallon holding tank and have the pump only pump when the voltage gets above a certain point (IOW when nothing else is being used during the day) ...
 
I like the idea of two Sunny Island (want more people to have a system like mine.) I think just one would start motors up to 2hp. Put in two, and if one fails later and can't be replaced because obsolete, a 120/240V transformer can be used instead and the surviving Sunny Island will still do everything.

Single Sunny Island would also do the job if all PV is DC coupled. But I like AC coupling.
I don't understand the DC and AC coupling, this is the first I have heard of that can you explain to me?
Also 1 Sunny can do 240v with a transformer?
 
Where do you look for this second hand? And installation?

eBay, occasionally Craigslist.

I've bought a couple second hand, and quite a few new in the box old-stock.

You can get recent model Sunny Boy 5 to 7.7 kW for around $1200 (may not meet latest codes for some states.)
Earlier models ranging from 3 to 10 kW and prices $400 to $1200.

Of course I do the installation myself. Presumably any skilled electrician/contractor can do hookup given a design with string length, wire size, voltage limits (to test before throwing the switch.) Somebody familiar with Voc etc. needs to design it.

Panels can be had new and used from $0.15 to $0.50/watt. Some have required UL labels, some do not so not for permitted installations, and hopefully not on a roof.
 
I don't understand the DC and AC coupling, this is the first I have heard of that can you explain to me?
Also 1 Sunny can do 240v with a transformer?

Each Sunny Island is 120V, can put out about 50A continuous. They can be stacked in series and parallel, up to 200A at 120V or 100A 120/240V. Also 3-phase 120/208Y 50A.

With a transformer added, one Sunny Island can deliver 6kW 120/240VAC. That's 50A 120V or 25A 250V. (but with transformers that size at least several hundred dollars new, maybe approaching $2000, I'd rather pay $2000 or so for a second Sunny Island.)

Sunny Island generates 120Vac from a 48V battery. It also recharges the battery either from its input (generator or grid), or from its output (if a grid-tie inverter is installed, which is referred to as AC coupled.) In that case, grid tie inverter power and battery inverter power add together. For instance, two 6000W Sunny Boy grid tie inverters and one 6000W Sunny Island battery inverter could produce 18kW continuous when PV panels get full sun.

But for Sunny Island charging the battery (either AC coupled grid-tie inverters or generator), it needs to understand the battery. That is where a BMS is required that speaks its language. Only some models do. The other guys here who use Sunny Island with DIY lithium (rather than select products at high cost) are only DC coupled.

Alternatively, you can connect a normal solar charge controller, "DC coupled". In particular, consider Midnight Classic, because they sell a box that lets it share data with Sunny Island. The PV panels charge the battery, and Sunny Island can make AC from the battery or charge it when generator runs (again, may require the right model BMS if using generator to charge lithium batteries through Sunny Island. Otherwise, use a separate battery charger with lithium settings).
 
Put a soft start on both devices ... and for the well pump use a 200 gallon holding tank and have the pump only pump when the voltage gets above a certain point (IOW when nothing else is being used during the day) ...
Just how much does a "soft starter" cost? the prices I've heard aren't cheap, like several $hundred.
I'd rather have two Sunny Island (paying about $2200 each at today's prices) and I can have 22kW surge for 3 minutes.
I figure if starting current is 5x running, one Sunny Island ought to start a 2 hp motor, but just to be sure ...

But yes, control loads like well pump to only turn on with good sunshine and high battery state of charge.
 
I hate the idea of small battery banks I already have a 15kw bank and im going to keep adding to it. I have already had a week of bad weather that pushed my bank very low. So im going to build it up so that will not happen again.

You already have (or will have) a generator in your RV. So instead of adding batteries, how about a battery charger and signal to start the generator as you approach the maximum DoD?
 
You already have (or will have) a generator in your RV. So instead of adding batteries, how about a battery charger and signal to start the generator as you approach the maximum DoD?
I had to disable that function of my Atkinson GSCM mini-i as it only looked at voltage at the battery and would crank the generator when the inverter had a good load on it. The Sunny Island and the MidNite Classics either can start the generator based on calculated SOC.
 
Most of the pumps im looking at are 120 or 240 I just don't know what the draw will be on them, they don't give that much info on power needs.
The pump will tell you the horsepower. 1HP = 746W. The surge will likely be up to 4 or 5x that, but you can figure out your inverter based on the HP to watt conversion, keeping surge in mind.
 
I don't understand the DC and AC coupling, this is the first I have heard of that can you explain to me?
Also 1 Sunny can do 240v with a transformer?
DC Coupling is simply charging your battery bank with a solar charge controller. AC Coupling is using a grid tied solar inverter, like the SMA SunnyBoy and tricking it into thinking there is a grid with a battery based inverter, like the Sunny Island. It is often used to add battery backup to an existing grid tied system.

I did a video on it here.
 
DC Coupling is simply charging your battery bank with a solar charge controller. AC Coupling is using a grid tied solar inverter, like the SMA SunnyBoy and tricking it into thinking there is a grid with a battery based inverter, like the Sunny Island. It is often used to add battery backup to an existing grid tied system.

I did a video on it here.
Then im DC Coupling all the way I will not have grid power so I will only be using solar for the most part and Generator for emergency.

Thank you
 
So it looks like the consensus is that the SMA Sunny Island is the better choice over the Schneider Conext XW Pro 6848.
 
Something else to consider is temperature. How hot does your location get? Will the shed for batteries and inverters be temperature controlled?

The continuous power output of electronics is reduced at high ambient temperature.

SI 6048 specs are:

Continuous AC power at 77°F (25°C) Pnom 5,750 W
AC power for 30 minutes at 77°F (25°C) P30min 7,000 W
AC power for 1 minute at 77°F (25°C) P1min 8,400 W
AC power for 3 seconds at 77°F (25°C) P3sec 11,000 W
Continuous AC power at 104°F (40°C) Pnom 4,700 W
AC power at 104°F (40°C) for 3 hours P3h 5,000 W
Continuous AC power at 122°F (50°C) Pnom 3,500 W
Continuous AC power at 140°F (60°C) Pnom 2,200 W

How much will your power draw be on a hot day? If over 3500W or 2200W for really hot locations, after a while Sunny Island will say, "I think I'll take a nap now", and turn off until it has cooled.
Two of them would put out 4400W continuous even in Death Valley.

 
So it looks like the consensus is that the SMA Sunny Island is the better choice over the Schneider Conext XW Pro 6848.
Depends - I went with one Sunny Island because I have no call for 240V - even my generator is 120V only. To do 240V with the Sunny Island you either need TWO of them or an equally expensive auto-transformer. The Schneider is capable of 240V.
 
I wouldn't go with the Schneider XW, it has grid tied capabilities. Why pay extra for a feature you don't need? I vote Magnum PAE or even one of the Victron Quartros.
 
I wouldn't go with the Schneider XW, it has grid tied capabilities. Why pay extra for a feature you don't need? I vote Magnum PAE or even one of the Victron Quartros.
The Schneider XW Pro has a 10 year warranty with it, the Mag only has 3 that tells me they don't have faith in there product. Im leaning towards the Schneider as its has a 30 min surge of 8.5kw. It also pulls its full 6.8kw at 77°F (25°C) that is an ez temp to maintain with minimal insulation. The others all have lower numbers at 77°F (25°C) im looking more at the power it can give me not extra features. The Schneider XW Pro may even be able to power everything I need off 1 inverter. That would save a good bit of money as I need 240v for my RV and I cant get that unless I get 2 of the others.
 
Magnum PAE also does 240V with 1 inverter. Don't get me wrong, the Schneider XW Pro is a fantastic product, but so is the Magnum. The XW Pro will definitely do everything you want and more.
 
The Schneider XW Pro has a 10 year warranty with it, the Mag only has 3 that tells me they don't have faith in there product.

Or, XW Pro is a grid-tie inverter and California (we lead/drive the nation, you know ;)) now has as law that grid-tie systems installed by a contractor must come with a 10-year warranty. Along with an estimate of power produced, what it will save you, and a hand-written statement from the homeowner saying why the system is in his best interest. (made the last one up, or rather paraphrased it from the requirements to obtain a refinance.)

Me? I don't like warranties. I like reliability.
So the real question is what the track record and failure rate are for XW Pro, Magnum, Sunny Island, Outback ...

I have some data on grid-tie Sunny Boy SWR 2500U. I've had 5 of them for about 15 years. Two died, one in warranty and was repaired for free. I saw a blown up trace on a PC board, which they replaced. The other had a power transistor that blew a crater. It was out of warranty and I rearranged the panels onto remaining inverters, never got around to attempting repair. Have since bought more of later models new and used, to work with battery backup.
 
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Or, XW Pro is a grid-tie inverter and California (we lead/drive the nation, you know ;)) now has as law that grid-tie systems installed by a contractor must come with a 10-year warranty. Along with an estimate of power produced, what it will save you, and a hand-written statement from the homeowner saying why the system is in his best interest. (made the last one up, or rather paraphrased it from the requirements to obtain a refinance.)

Me? I don't like warranties. I like reliability.
So the real question is what the track record and failure rate are for XW Pro, Magnum, Sunny Island, Outback ...

I have some data on grid-tie Sunny Boy SWR 2500U. I've had 5 of them for about 15 years. Two died, one in warranty and was repaired for free. I saw a blown up trace on a PC board, which they replaced. The other had a power transistor that blew a crater. It was out of warranty and I rearranged the panels onto remaining inverters, never got around to attempting repair. Have since bought more of later models new and used, to work with battery backup.
I thought that the XW Pro could be used off grid, did I get that wrong?
 
Im just looking at the continuous power and 30 min suge and the XW Pro smokes the Mag.
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I thought that the XW Pro could be used off grid, did I get that wrong?

Not at all. Work for on grid/backup or off grid. Any of the battery inverters is going to work off-grid.
I'm just saying that they may have made 10 year warranty standard because it is required for some markets.

My original Sunny Boys had 5 year warranty.
Sunny Island now has 10 year warranty standard. Mine had come with the 10 year option offered earlier.
New Sunny Boys have 10 year standard, 15 year and 20 year optional.
 
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