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diy solar

20kW Solar and 40kWhr battery plan. Need feedback.

jazclrint

New Member
Joined
Mar 20, 2022
Messages
9
Location
Port Charlotte, FL
Hello all,

I am brand new to this forum.

Here in FL they have decided to phase out net metering and in the same week, FPL (my power company) raised the cost of electricity by almost 25%.

Now my power bill is apparently WAY bigger than it should be given the size of my house. We did what we thought was the right thing and refinanced the house and had all new windows put in. The old windows looked to be original. We were told we'd save a ton on both our power bill and insurance. Both have turned out to be completely untrue. I am just not interested in spending any more money on efficiency at this point. Frankly, it gives me the excuse to put on a system big enough to take care of our needs plus a bit. Then, as we save money we can invest in making the house more efficient and selling the excess back to FPL. And if they complain we are selling too much back we have the power consumption bills to prove it.

Also, I am not convinced my AC is the culprit. We were gone last summer for 5 weeks. It lined up perfectly with our power bill cycle. My Mom house sat and my nephew visited. The pool pump ran a LOT as they did not maintain our pool. And they used only 1598kWhrs for the month of July. June we used 2688kWhrs. And September we used 2817kWhrs. But for August, when we got back we used 3936kWhrs!!! I feel this proves my family is just really wasteful beyond my current control.

I did just see that last year my monthly average consumption was 2471kWhrs. and this year has been 2320kWhrs. Even though the cost has gone up almost $20/month.

Anyway, I'm done spending money on anything other than a self-sufficient solar system. I'm not even sure I am in a position to get a loan. But I'd like to get a solid system down on paper that is accurate.

So far in my plan, I've spec'd 4 MPP LV6548 inverters. 60 LG375Q1C-V5 panels for 22.5kW. How does everyone feel about LG panels now? And 8 SOK 48V server rack batteries. DIY of course.

Also, someone has already suggested an energy survey and to buy more efficient appliances, etc. I am confident that doing that would not generate the saving to make such purchases worth it. Also, besides having a house in SWFL and AC bill to match, I have an EV. I was averaging about 13-16kWrs a day commuting. But we have started door dashing and consumption has gone up. Not sure how much yet as we have just started. Also, we will have an EV truck sometime in the (distant?) future. So any perceived "oversizing" of my system to some is simply future-proofing to me.

Now, my biggest frustration is finding out how to have my solar and batteries working during a power outage. The idea of my panels shutting off just because the power goes out is infuriating. As a matter of fact, if I could have the grid disconnected unless my battery pack is full and there is access power to be sold, I'd be happy with that. But I need a solution that disconnects from the grid in case of a power outage for safety, but that I don't notice in my house. My panels keep powering the house and charging the batteries. And, I see no sense whatsoever in buying and wiring up a separate panel for "essentials". I can unplug things myself. It's this part of the project that keeps me up at night. I want my inverters to power my main panel. KISS.

One thing that I just now thought of, and have no idea how to integrate into this system, is 3 or 4 500w wind turbines. I know I'll never get 500w out of any of them. But I am maybe a mile from the ocean and not a lot of tall trees at all in my area. And having them on the top of my house surely wouldn't hurt anything.

Thoughts, ideas, suggestions, concerns?

Thank you for your time,
Richard
 
If you wish to be grid-tied with the ability to sell back to the utility company MPP Solar Inverters will not work. As far as I know all major utility companies require UL1741SA inverters. The LV6548 does not have Sell Back capability, the LV6048 apparently does but its not UL compliant.
Take a look at Outback, Schneider, SMA, Sol-Ark. These are higher end, full featured Inverters with internal disconnect switches to separate your house from the grid in a power out situation.
Also important is to understand the difference between AC coupling and DC coupling. Its possible to one or the other or both.
 
Based on your excessive electrical consumption, I would suggest you should not overlook further investigation into efficiency improvements. A Pentair or Hayward permanent magnet, variable speed pool pump will help quite a bit as will a 20 SEER variable speed AC system. The advantage of variable speed devices is that eliminate those very large inrush currents which are NOT compatible with High Frequency Inverters.
Last but not least, just because the electrical meter is SUPPOSED to be calibrated to some kind of standard doesn't mean its working properly. You should absolutely get something like an Emporia energy monitor. Their base model with 2 CT's for the main L1 & L2 is only $70. Accuracy is claimed to be + or - 2% which isn't too bad for the price. I'm speaking from experience, a few years ago I used a Brueltech meter to capture NET metering data. It took a couple of months to get their attention, but they finally admitted the meter was malfunctioning. They replaced it and rebated 1 month of the Bill.
 
As far as the wind turbines, they would tie into a solar system via their own Charge Controller connected directly to your batteries. This is why its important to research the details of AC vs. DC coupling.
 
If you wish to be grid-tied with the ability to sell back to the utility company MPP Solar Inverters will not work. As far as I know all major utility companies require UL1741SA inverters. The LV6548 does not have Sell Back capability, the LV6048 apparently does but its not UL compliant.
Take a look at Outback, Schneider, SMA, Sol-Ark. These are higher end, full featured Inverters with internal disconnect switches to separate your house from the grid in a power out situation.
Also important is to understand the difference between AC coupling and DC coupling. Its possible to one or the other or both.
I just found the new MMP LVX6048WP will be UL1741 compliant.
 
I just found the new MMP LVX6048WP will be UL1741 compliant.
That is good news if true, adds another product that can be used in the US. I'm curious where that information came from. Looking at the downloads from MPP Solar on that product I don't see UL1741SA listed anywhere.
 
As far as the wind turbines, they would tie into a solar system via their own Charge Controller connected directly to your batteries. This is why its important to research the details of AC vs. DC coupling.
I'll definitely look into it.

I was looking at the MMP material (https://www.mppsolar.com/v3/catalogs/LVX6048WP.pdf) and noticed it looks like there is a bus bar between the batteries and inverters. So I feel like I am thinking in the right direction. If that's the case the micro wind turbines would have their own charge controller, rectifier, brake controller, etc., and just wire it into the battery bank's bus bar. I wish that if the pack is full then the excess wind energy would be sold to the grid as well. But, I feel like I'm just being greedy at that point. And if the turbines are doing their thing when there isn't much light I doubt the pack would be full.
 
Ya, you are correct, the product brochure does list UL1741. Funny the installation manual didn't seem to mention UL1741 in the specs. It seems like MPP Solar makes super good value products. If you can use it in FL, that's great.
Note that UL1741 is the older standard.
In some states like CA the inverter has to be UL1741(SA), sometimes called Rule 21, compliant which is a newer version with added functionality. Before spending money make sure you ask your local building department AND utility company what is required for grid-tie permitting
 
Ya, you are correct, the product brochure does list UL1741. Funny the installation manual didn't seem to mention UL1741 in the specs. It seems like MPP Solar makes super good value products. If you can use it in FL, that's great.
Note that UL1741 is the older standard.
In some states like CA the inverter has to be UL1741(SA), sometimes called Rule 21, compliant which is a newer version with added functionality. Before spending money make sure you ask your local building department AND utility company what is required for grid-tie permitting
Ahh, see these are the details I was hoping to find out. I'm not buying anything soon. I plan to have the whole thing planned out before financing anything. Thank you very much for the head's up.
 
Ahh, see these are the details I was hoping to find out. I'm not buying anything soon. I plan to have the whole thing planned out before financing anything. Thank you very much for the head's up.
I would suggest you work closely with your power company. There are a lot of specs, rules, compliances floating around, but ultimately it will be your power company that makes the call, even if your system meets every requirement on earth, if your power company doesn't like it, you are not getting it... Flip side is if the power company is ok with you standing there holding two wires together with your teeth, it might not be correct or safe, but if they sign off on it, you can do it.
 
I would suggest you work closely with your power company. There are a lot of specs, rules, compliances floating around, but ultimately it will be your power company that makes the call, even if your system meets every requirement on earth, if your power company doesn't like it, you are not getting it... Flip side is if the power company is ok with you standing there holding two wires together with your teeth, it might not be correct or safe, but if they sign off on it, you can do it.
Ya, its interesting that the utilities have their own electrical specs and requirements and are not required to follow NFPA 70 and they are free to adopt almost any local rules that they wish as long as their system is electrically compatible with the larger grid.
 
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