diy solar

diy solar

2400 sqft cabin - Need advice

??????? those solar guys are funny .
I was thinking the same thing. I only put up 9 panels with XR100, but it was so easy. The hardest part was carrying the panels up the ladder by myself. I actually just balanced them on a six foot ladder, climbed up, and then pulled the panels up one at a time. They are only 40lbs, so it is not terrible. Google just updated their images for my area, so I am official I guess... $2800 later I can generate 10kwh a day on a good day and have 6kwh of storage...

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I got the below quote for my system which seems quite good....though there is about an 18% import tax on that.

Based on my energy audit, with AC running 12 hours a day (mini split), and the rest of the loads, I calculate peak usage at just under 7kW and daily usage at about 36 kWh (I did go very aggressive on my energy usage, so assume actual will be less).

Based on my location and roof pitch I should be producing 53kwh on average in summer and about 32kwh in winter based on 50x250w panels or roughly 12kw worth of panels (using pvwatts).

Does this all seem reasonable to everyone?



Rosen Quote.jpg
 
The price looks good , but I have no clue what the equipment is?
It would all depend on if the equipment is any good?
A UL listing would be a must in my area .
Pretty much you could get any 8k inverter for 4K out back magnum snider ?
I would rather have a separate charge controller for the extra 1k ?
my 2 cents
 
I like the thought of ease of installation for these all-in-one systems. To the best of my knowledge (and I should probably check with my contractor), I do not have to have UL listed equipment.... I'm out in the middle of nowhere in oklahoma.

the inverter is a DEYE 8k which from my understanding is the parent manufacturer of the Sol-Ark 8k?

links to spec sheets below

Deye 8k inverter

200aH powerwall
 
Item 2 seems to good to be true? 10kw for $2200 is $0.22 a watt. I don't know the brand, but if it turns out to be a solid 10kw power wall I think that is a smokin deal.
 
I like the thought of ease of installation for these all-in-one systems. To the best of my knowledge (and I should probably check with my contractor), I do not have to have UL listed equipment.... I'm out in the middle of nowhere in oklahoma.

the inverter is a DEYE 8k which from my understanding is the parent manufacturer of the Sol-Ark 8k?

links to spec sheets below

Deye 8k inverter

200aH powerwall

"Operating temperature range -20 ~ 50[C]"
"Life cycles > 6000"

Don't believe 6000 cycles. A third-party test of dozens of lithium batteries had only a couple that reached 3500 equivalent 100% cycles (ending with about 80% of original capacity.) Sony was one of the those. 95% of the units tested failed, needing replacement or repair. Many showed much more degradation, like to 50%, and many reached or were projected to about 2500 or 1000 cycles.

How much will you draw at night? If 35 kWh or 87% DoD, then you will need 3650 cycles to last a decade. If 10 kWh then only 900 equivalent cycles. Normally for off-grid people thing of 3 days operation without sun. Generator lets you go smaller. Sized for one night would be the minimum. I favor more PV, less battery, but my use is grid-backup.

The temperature range is OK for discharge. Not mentioned here is charge, which can't occur below 0 degrees C. Keep battery warm, and BMS ought to have low-temperature disconnect to prevent charging below that temperature (try to find that in documentation.)

Your 12kW (STC) array will produce about 10 kW, and with 40 kWh of battery that's 0.25C
Discharge is shown as 1.0C max, charge is probably 0.5C max (at nominal temperature.)

Some cell brands show charging 1.0C OK at room temperature, cut in half to 0.5C or 0.7 degrees C
With 0.25C available (half my presumed max charge rate for this battery), I suggest setting low-temperature charge disconnect at 15 degrees C, or at least 7 degrees C; don't let it charge that fast down towards zero degrees C.


Deye vs. SolArk - appears both began as same design, but thought Deye wasn't supposed to sell in US? For a higher price, SolArk may have better support. There is a 12 kW (PV) SolArk, but it's AC output is about 8kW or 9kW max. It supports AC coupling of grid-tie PV inverters that have frequency-watts; moving some PV panels to such an inverter could allow more AC power during peak sun.


What are your loads? Any big induction motors like a well pump or air conditioner? Starting surge is about 5x the nameplate rating, so an 8kW inverter should start up to 1500W load (my small air conditioner for 1000sf house is bigger than that.) If inverter has a surge rating to higher wattage for multiple seconds, use that. It is possible to reduce the surge with a soft-start, or 3-phase inverter drive motors have no surge. There are several top-name low frequency inverters known to run motor loads well. Make sure what you select will meet your needs.

Those "SanTan" white-label panels are cheap, but put out less power per unit area. Big question is whether they degrade faster than others; panels vary greatly in quality/durability. I understand these were originally Trina, who makes good panels today but replaced a bunch under warranty in the hpast. Without UL labels, could be a problem for fire insurance. You can pay more for premium quality and 50% higher output in the same area.

Your 2400 sf "cabin" is 2.5 times the size of my house. But I have a huge PV system (just because I can.)
 
It is preferable, though not required, for battery to have a BMS that talks to inverter/charger.
If cells become imbalanced and one starts to run away from the others near fully charged, this lets BMS request lower charge rate so it can take the time to bring the runner into balance. If one runs away too far, BMS has to disconnect which shuts off the system.
 
Thanks everyone....

Don't believe 6000 cycles. A third-party test of dozens of lithium batteries had only a couple that reached 3500 equivalent 100% cycles (ending with about 80% of original capacity.) Sony was one of the those. 95% of the units tested failed, needing replacement or repair. Many showed much more degradation, like to 50%, and many reached or were projected to about 2500 or 1000 cycles.

At the price quoted, I'm not overly concerned on whether or not they meet 6000 cycles or not.... I kind of assume whenever I buy something from China directly, that the specs are exagerated.

How much will you draw at night? If 35 kWh or 87% DoD, then you will need 3650 cycles to last a decade. If 10 kWh then only 900 equivalent cycles. Normally for off-grid people thing of 3 days operation without sun. Generator lets you go smaller. Sized for one night would be the minimum. I favor more PV, less battery, but my use is grid-backup.

I'm estimating about 15kWh at night (again, that's being conservative...probably less). I am guessing that I will need more batteries eventually, but my thought was I could always add more later.... of course if I'm ordering from China, it would be better to get them all at once, so maybe I'll start with 6 200aH powerwalls.

The temperature range is OK for discharge. Not mentioned here is charge, which can't occur below 0 degrees C. Keep battery warm, and BMS ought to have low-temperature disconnect to prevent charging below that temperature (try to find that in documentation.)
Everything will be hooked up in the home in a separate room. I can always put a little space heater in there that will turn on when there is excess solar. I haven't even considered using a BMS yet.... I'll have to do some research on that, and would appreciate any recommendations. I guess I kind of assumed that since the inverter and the powerwall themselves are all connected by network cables, that the management is done by either the batteries or the inverter/

Deye vs. SolArk - appears both began as same design, but thought Deye wasn't supposed to sell in US? For a higher price, SolArk may have better support. There is a 12 kW (PV) SolArk, but it's AC output is about 8kW or 9kW max. It supports AC coupling of grid-tie PV inverters that have frequency-watts; moving some PV panels to such an inverter could allow more AC power during peak sun.


So Rosen claimed they could not get the Deye 12k for me in US specs (only EU) (maybe because of this non-compete), but no problem getting the 8k. I have to say, the support from Rosen so far has been good. they sent me a wiring diagram for everything, and have been quite helpful with exceptionally good english. They are also arranging all the shipping etc.

What are your loads? Any big induction motors like a well pump or air conditioner? Starting surge is about 5x the nameplate rating, so an 8kW inverter should start up to 1500W load (my small air conditioner for 1000sf house is bigger than that.) If inverter has a surge rating to higher wattage for multiple seconds, use that. It is possible to reduce the surge with a soft-start, or 3-phase inverter drive motors have no surge. There are several top-name low frequency inverters known to run motor loads well. Make sure what you select will meet your needs.

I'm planning on a mini-split AC, so will have to check what the surge load is. They do say peak power is 2x max power for 10s. so peak power is 8kw for each inverter, so peak power would be 32kw I'm assuming with my 2 inverters.


Those "SanTan" white-label panels are cheap, but put out less power per unit area. Big question is whether they degrade faster than others; panels vary greatly in quality/durability. I understand these were originally Trina, who makes good panels today but replaced a bunch under warranty in the hpast. Without UL labels, could be a problem for fire insurance. You can pay more for premium quality and 50% higher output in the same area.

I've got plenty of roof space, and lots of space to add panels on my inverter... so I'm all into getting best bang for the buck.... I know Rosen also sells new panels at a very good price, so I'll check with them as well.
 
SanTan also has new top rated panels (probably extras from installs) closer to $0.50/W but in more limited quantities. Use multiple orientations if possible to spread power over more hours.


Sounds like surge capability is good. The inverter-drive mini-split should have no surge, and vary pump speed to match cooling requirements.

The batteries will have a BMS inside. It is necessary to monitor individual cell voltages, balance them, and disconnect if anything out of spec. Several brands of BMS that could be used, or custom by the battery vendor. Some support CAN and other busses, with protocols compatible with SMA, SolArk, others. Better system performance if they do talk, and more important if available charge current is higher in proportion to battery capacity.

The assembled "Powerwalls" you're looking at are at a price we would pay to DIY with individual cells and BMS, so very good so long as the batteries are good, especially for (relatively safe) LiFePO4.

With 16 kW of inverters and multiple 10kW (max discharge) batteries, the current doesn't even need to be very well balanced to stay within maximum rate. Most people with smaller battery are closer to maximum.
 
I guess if you don’t carry Insurance on the property a u l listing is not important ?
I know i would not forgo insurance on my place to have sub par equipment and void the coverage .
 
I guess if you don’t carry Insurance on the property a u l listing is not important ?
I know i would not forgo insurance on my place to have sub par equipment and void the coverage .
Good point.... but I did check and they do claim to be UL listed.

I also don't automatically assume they are "sub-par" since the vast majority of electronics these days are manufactured in China. Deye is a pretty big company that has been selling inverters since 2017. Here's a write up in PV-magazine. They have a reputation to uphold, and are listed on the SSE and as such will not purposely sell crap... this is as opposed to companies that make "knock-offs". Chinese knock-offs are notorious for putting in junk or undersized components to save a buck where they can.

In the end.... I think there is a risk importing directly from China, but at half the price, it's a risk I think I'm willing to take. I would not take the same risk if I was only saving $4-5k.
 
I’m a little old school , and I have no experience with the latest and greatest supper WAMO all in one inverter /chargermppt solar controllers gizmos .
I started off grid on a 36’ sail boat in 1990 with magnum equipment from alt energy .
This system is still working to day .
5 years a go , there where not a lot of all in one systems .
There have been a lot of changes , this site was not available 5 years ago .
every time I use equipment that is not name brand , it dies 10 days out of warrantee .
Then there is no parts and no repair. ☹️
I end up buying name brand equipment any way , I was not saving any money ☹
my neighbor has had out back equipment running for 21 years in his basement with only 3 battery changes .
and some up grades .
 
I end up buying name brand equipment any way , I was not saving any money ☹
my neighbor has had out back equipment running for 21 years in his basement with only 3 battery changes .
and some up grades .
I got this from my sister-in-law. "You remember the quality long after the price is forgotten".

It applies equally well to reloading supplies. I get tempted to go cheap, then a month or two later I'm paying again for the quality brand.
 
Yep that is for sure mike , that a good line to remember , I’m going to use that.
I just got a big box of back ordered reloading supplied from Dillon for my 550 press .
A bunch or projectiles and a box of primers .
I only ordered it in November ?
 
2800 sq ft...All Electric, 3 ea 5.5 tons of 14, 16 and 20 SEER HP Systems...20,000 W array, two solark 12k’s, 12 ea 48V 280 aH batteries. $60K DIY.
 
2800 sq ft...All Electric, 3 ea 5.5 tons of 14, 16 and 20 SEER HP Systems...20,000 W array, two solark 12k’s, 12 ea 48V 280 aH batteries. $60K DIY.
Wow. That’s one heck of a system! But if my cost goes above about $25k then it’s not worth it to me. Main reason I’m going solar is because the cost to run grid power is about $17k.

Sol-Ark 8ks are $6100+tax and shipping. The Deye 8k is about $2600 which includes shipping and import tax. So to me it’s a question of risk. Should I pay 2.5 times more for a unit with the exact same specs but I’ll get significantly better support and a much better warranty? That is worth something but not $4000 dollars to me.
 
Sol-Ark 8ks are $6100+tax and shipping. The Deye 8k is about $2600 which includes shipping and import tax. So to me it’s a question of risk. Should I pay 2.5 times more for a unit with the exact same specs but I’ll get significantly better support and a much better warranty? That is worth something but not $4000 dollars to me.
I'd recommend what I've got, the Schneider XW+ 6848. It has fantastic surge capacity, and I've had it running my well-pump, a cement mixer, and a circular saw, all at the same time. Sol-Ark cheats in their XW price comparison. They mate the Schneider with two of their very expensive charge controllers. I'm using a single Midnight200, which is a far cheaper solution.
 
Hay, scorch for 17k it probably going to be better to jump on the grid .
They quoted me 42k to bring the wire up to the edge of the property
I still had to run a 350’ under ground service to get to the house.
and repair on the 2500 foot power line to the top of the Mountain was on my dime .
 
Hay, scorch for 17k it probably going to be better to jump on the grid .
They quoted me 42k to bring the wire up to the edge of the property
I still had to run a 350’ under ground service to get to the house.
and repair on the 2500 foot power line to the top of the Mountain was on my dime .
It’ll definitely cost more to try to go full off-grid. But I like the idea of not having an energy bill. I also have a few other reasons why I’d like to go this route, so it’s more than just a $/kwh calculation.
 
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