Quote feedback please?

[chicagoandy]

Hello,

I was hoping to get some feedback on a quote from a custom installer.

Inverter	Sol-Ark 15K
Optimizer	26 X Tigo TS4-A-O + monitoring & shutdown
Panels	26 X REC 420AA Pure 2	Total System Price - REC : $34,725.60
or	26 X QCells Q.PEAK DUE BLK ML-G10 + 410	Total System Price - QCells : $32,513.00

Installation is on the roof of a 3,600 square foot two story house in north suburban Atlanta.

They also estimated an expensive Homegrid battery system, instead I plan on adding my own Ruixu 10-rack of 48v100ah, or 48,000WH battery.

18 Panels mounted South
8 panels mounted west

Total Georgia Power consumption in 2023 was 20,447 kwh, using the EV TOU rate. ($.08/kwh overnight, $.32/kwh peak afternoon). Annual spend in 2023 was $2,904, $.142/kwh avg.

They will include a Bi-pass Transfer Switch (instead of a fused disconnect), but do not plan on any combiner boxes or fuses on the PV wire.

I'd love to hear anyone's thoughts on this proposal.

Thanks.

 

[solar8484]

Is this an off-grid system? If yes, you can probably pick an off-grid inverter and save money. If no (i.e. on-grid), it would be unlikely that you can legally use a DIY battery bank in an on-grid system due to UL compliance requirements.

 

[MisterSandals]

rack of 48v100ah, or 48,000AH battery.

You are getting 480 100Ah batteries?

 

[chicagoandy]

Is this an off-grid system? If yes, you can probably pick an off-grid inverter and save money. If no (i.e. on-grid), it would be unlikely that you can legally use a DIY battery bank in an on-grid system due to UL compliance requirements.

Interesting. It is grid-tie. The Ruixu batteries are UL listed under 1973. Can you point me to more information on UL requirements?

You are getting 480 100Ah batteries?

No. 10 100ah 48V batteries, so 48,000 WH. My bad.

 

[glandpuck]

I'm in So Cal. Looking at your system, roughly speaking the hardware costs are about 16.4K and the remainder is labor, permitting, passing inspection, etc.

As for batteries, a UL listed 40 kW system should cost you no more than 14K plus maybe 2K for installation. This is based on say using 8 Pytes batteries which are UL listed high quality. They can be viewed at: www.pytesusa.com. Plus this forum has many others. www.stackrackbattery.com also sells UL listed indoor and outdoor cabinets for the batteries.

To total this all up, I think about 50K for the system installed with the batteries and either solar panel would be a decent price before the Federal tax credit.

What I don't understand is why you want to spend 50K on a PV system and battery when you have such cheap energy from your utility company? The payback period doesn't seem to make any sense.

Would you invest any money up front knowing that you would need to wait 8-10 years to get a return on your investment?

Plus solar panels on the roof can cause insurance rates to go up.

An alternative may just be to install a powerwall type system (there are several to choose from) without any solar panels, charge the batteries at night when the rate is cheap and use them during emergencies.

 

[MisterSandals]

10 100ah 48V batteries

That is a big batch of batteries. Do you have a plan on how to connect them in a balanced manner?

Read the first 4 posts in this thread to get an understanding of the issues:

Calculation of parallel string battery currents

Hi, everybody! I'm a retired EE. I didn't want my EE skills to fade away after retirment, so I exercise them when I can. Whenever I see a non-trivial circuit analysis problem on one of various forums I frequent, I challenge myself to solve it. Recently I watched Will's video about current...

diysolarforum.com

 

[Quattrohead]

EG4 18k plus 3 PowerPro batteries will set you back around $17,000 and are fully ul and permit capable.

 

[solar8484]

Interesting. It is grid-tie. The Ruixu batteries are UL listed under 1973. Can you point me to more information on UL requirements?

UL9540 is required. Make sure the battery sticker clearly show the specific UL compliance. There appear to be battery vendors that claim UL compliance but the actual battery systems don't actually have the necessary UL compliance markings to pass inspection.

 

[glandpuck]

If you are familiar with Pytes batteries, the Ebox is scalable to 245.6 kW.

In my system, I use 2 cabinets, each containing 4 Ebox batteries. One of the 8 batteries is designated the master and the canbus cable goes from this battery into the Sol-Ark inverter. The master battery also has the DIP switches set to recognize Sol-Ark. then the remaining 3 batteries in the cabinet art linked with ethernet style cables in series. The last battery in the cabinet has a connection cable that runs to the first battery in the second cabinet and then these 4 are connected for communication in series.

Each battery cabinet has only 2 Pytes batteries connected together for the + and -. The top of the cabinet contains the buss bars for + and - and ground. The + buss bar then has a battery fuse added. The cabinet exits in metal conduit containing the ground wire, and + and - battery cables into the Sol-Ark barttery connections. Both of the sol-Ark battery connection terminals are used, each supporting one cabinet of batteries. The BMS of the master battery communicates with all 8 batteries and handles the balancing. Remember, only 2 batteries are ever connected in series together. If more than 8 batteries are needed, the BMS of the master on the Ebox can handle 16 batteries directly. If more cabinets used, then an external battery buss bar would be used between cabinets and the Sol-Ark battery terminals.

 

[Solar Guppy]

They also estimated an expensive Homegrid battery system, instead I plan on adding my own Ruixu 10-rack of 48v100ah, or 48,000WH battery.

NEC2020 requires UL9540 listed ESS systems ( paired inverter and battery ) no other ( legal ) options, which GA is one of:

Learn where the NEC is enforced. | NFPA

Discover which edition of the NFPA 70, National Electrical Code® (NEC® ) is enforced in your state.

www.nfpa.org

 

[Hedges]

Hello,

I was hoping to get some feedback on a quote from a custom installer.

Inverter	Sol-Ark 15K
Optimizer	26 X Tigo TS4-A-O + monitoring & shutdown
Panels	26 X REC 420AA Pure 2	Total System Price - REC : $34,725.60
or	26 X QCells Q.PEAK DUE BLK ML-G10 + 410	Total System Price - QCells : $32,513.00

Total Georgia Power consumption in 2023 was 20,447 kwh, using the EV TOU rate. ($.02/kwh overnight, $.25/kwh peak afternoon). Annual spend in 2023 was $2,904, $.142/kwh avg.

Hard to justify $32k ~ $35k, plus batteries, minus tax credit, when power costs you $2900.
Payback is basically never, better places to invest money. Unless you're a gambling man.

Is net metering available, and if so what terms?
If so, you might install primarily GT PV, optional small battery backup.
Also consider DIY labor.
I figure turnkey GT PV costs $3/W and $0.10/kWh. DIY costs $1/W and $0.025/kWh (more or less, those two sets of numbers don't quite agree.) Battery adds $0.05/kWh.

 

[ksmithaz1]

Hard to justify $32k ~ $35k, plus batteries, minus tax credit, when power costs you $2900.
Payback is basically never, better places to invest money. Unless you're a gambling man.

Is net metering available, and if so what terms?
If so, you might install primarily GT PV, optional small battery backup.
Also consider DIY labor.
I figure turnkey GT PV costs $3/W and $0.10/kWh. DIY costs $1/W and $0.025/kWh (more or less, those two sets of numbers don't quite agree.) Battery adds $0.05/kWh.

Yea, I'm all in with batteries at about $40K for ~$3K/yr of savings. Rates just went up here, I expect them to rise again. The problem is whatever you have it's never enough. Sometimes it's not about the ROI. . . But sticking the middle finger to the man can be a bit pricey.

 

[chicagoandy]

That is a big batch of batteries. Do you have a plan on how to connect them in a balanced manner?

Read the first 4 posts in this thread to get an understanding of the issues:

Calculation of parallel string battery currents

Hi, everybody! I'm a retired EE. I didn't want my EE skills to fade away after retirment, so I exercise them when I can. Whenever I see a non-trivial circuit analysis problem on one of various forums I frequent, I challenge myself to solve it. Recently I watched Will's video about current...

diysolarforum.com

Interesting read. I am planning on using a busbar setup with each battery having an independent, equal-length 4/0 connection to bus bar, then the bus-bar connected to inverter at diagonals via 4/0 cable. All of that is provided out-of-the box from Ruixu.


I'm not sure how I'd adapt the mid-point connection method to 10 batteries. My intuition is that with good bus-bars, independent battery connections, and oversized cable, that gets close enough and they should stay in-balance. That approach does seem to be commonly used, and I've seen testimonials that they stay well in-balances. Any concerns?

Hard to justify $32k ~ $35k, plus batteries, minus tax credit, when power costs you $2900.
Payback is basically never, better places to invest money. Unless you're a gambling man.

35K minus tax credit, so $24,000 / $3000 = 8 year payoff. Which isn't' great, but I also am looking for a backup power system as we get a lot of blackouts. The alternative is a whole-home generator, and the financial payoff for a generator would be zero. And yes, rates have increase 3 times in the last year. With Georgia Power building the first nuclear plant in the last 40 years, future price increases are a safe bet.

Is net metering available, and if so what terms? If so, you might install primarily GT PV, optional small battery backup.

It is not available, which is what brings the big battery. The state of Georgia has basically zero net metering.

Also consider DIY labor.

Given my steep and high roof, self-installing the panels would be a unsafe choice for me. I'm happy to do the battery myself. And I don't think I can do a grid-tie inverter myself. Regardless, the Inverter install is a small portion of the install price.

NEC2020 requires UL9540 listed ESS systems ( paired inverter and battery ) no other ( legal ) options, which GA is one of:

Learn where the NEC is enforced. | NFPA

Discover which edition of the NFPA 70, National Electrical Code® (NEC® ) is enforced in your state.

www.nfpa.org

This surprises me. Doing some googling, I believe this may only be true in California. Can you point to a reference for this?

 

[MisterSandals]

That approach does seem to be commonly used, and I've seen testimonials that they stay well in-balances. Any concerns?

Sounds like you understand the issues. Keep a close eye on the connections and current flows as much as possible until you are confident that things are working.

Good luck! Keep us posted on what you learn.

 

[chrisski]

It is not available, which is what brings the big battery. The state of Georgia has basically zero net metering.

If that $2.9k you spend every year, how much is electric vs fees?

-I might have $360 per year in fixed fees.
-My state forces me to a different rate fee that charges me a solar connection fee. I think this may be around $400 per year.

 

[Mark-]

Hard to justify $32k ~ $35k, plus batteries, minus tax credit, when power costs you $2900.

If you live far out in the country and reliable grid power is a problem, it is easy to justify.

 

[chicagoandy]

If that $2.9k you spend every year, how much is electric vs fees?

-I might have $360 per year in fixed fees.
-My state forces me to a different rate fee that charges me a solar connection fee. I think this may be around $400 per year.

Good question! In the state of Georgia, most of the fees are still based on usage.

For example:

Nuclear Construction Cost Recover Fee: "All bills rendered subject to the NCCR Schedule shall be respectively increased in an amount equal to 3.8130% of their base bill calculations which exclude Real Time Pricing (RTP) incremental usage revenue. NCCR shall apply to 65% of the base bill calculations for bills rendered on the Fixed Pricing Alternative (FPA) and the Electric Arc Furnace (EAF) tariffs."

or,
Environmental Cost Compliance Recovery Fee: "All bills rendered subject to the ECCR Schedule shall be respectively increased in an amount equal to12.7680% of their base bill calculations which excludes Real Time Pricing (RTP) incremental usage revenue. ECCR shall apply to 65% of the base bill calculations for bills rendered on the Fixed Pricing Alternative (FPA) and the Electric Arc Furnace (EAF) tariffs"

If you live far out in the country and reliable grid power is a problem, it is easy to justify.

Even in the cities of Georgia, with so many tall pine trees to get knocked down during storms, reliability is a major concern. Atlanta is 20 degrees hotter now than in the 1980's, summer Air Conditioning is now a life-safety function, just like winter-heat up north.

 

[Hedges]

Rather than all cable lengths being the same, Positive + Negative the same should be sufficient. That could cut in half total length and cost.

So long as any communication is isolated, i.e. BMS is grounded to chassis not Bat+ or Bat-.
If battery allows both positive ground and negative ground, that should be the case.

 

[Solar Guppy]

This surprises me. Doing some googling, I believe this may only be true in California. Can you point to a reference for this?

It is part of NEC2020 code which Georgia adopted so you have to have UL9540 listed for battery backup

 

[chicagoandy]

It is part of NEC2020 code which Georgia adopted so you have to have UL9540 listed for battery backup

View attachment 208738

Yes, Georgia is NEC2020. I've seen other threads here which indicate that UL9540 is only required in California, and UL9540A (batteries alone) is the national standard.

Here's one example: https://diysolarforum.com/threads/paired-vs-non-paired-ul9540-requirement.68238/#post-861979

Hence my question, if someone can point to where NEC2020 requires UL9540.

Anyways, thanks for raising this - I'll bring it up with my installer and ensure it gets put into the permits.