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Solar with battery systems for home

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robertomartinezsr

Hello all:

I am looking for any recommendations on a solar panel / battery company in Puerto Rico.  I purchased a home in July and would like to move off the grid as much as possible, with solar and battery configuration, to power home in the event of a LUMA outage.


Thank you!

Roberto Martinez

William Cameron

Big topic. Planet Solar, Windmar… many others. Costco uses Planet Solar. Windmar is huge. They have relationships with local “banks” cooperativas. You can get financing up to $75K at about 5.5% for 15-20 years. The banks will require batteries, don’t ask me why.


Assume batteries are about $25k for two and about $3k per Kilowatt so a 10Kw system with 2 batteries will be about $50-60,000.


As for grid tied, you can stay tied up to 25kw. Assume you use about 40-50Kw per day ($400-500 per month). A 10Kw system should produce about 40-50Kw per day, enough to cover the use but, it generates it all during the day. LUMA will “net” the day’s usage so your bill should be very small.


If you go off grid you will need to understand your low light and nighttime usage. Tesla batteries have about 11-12kw usable power each. It goes fast if you use them for cooking, a dryer or electric hot water. I would stay grid tied until you have the hard numbers. You can always cut the cord down the road.

robertomartinezsr

William,

Thank you very much.  This information is greatly appreciated!


Roberto

Fred

If I may suggest an option.

Full off grid systems are expensive because the batteries cost an absolute fortune. However, an emergency system that will keep lights, charge phones, and run other small items is far less so.

I put a small system together that runs 12v lights and phone chargers, but also has a small inverter in so I can charge laptops.

Something a little larger will keep your fridge running for a few hours.


Another possibility is a charger/invertor. These charge whatever batteries from the mains and cut to battery power if the mains dies, essentially a large UPS.

William Cameron

Just 1 addition, if you are grid tied and LUMA goes down, your system will be shut down, because sending electric current back over the LUMA lines could endanger workers and people.


if you have batteries, they close the loop and your solar panels will continue to provide electricity to the house during daylight hours even when LUMA is down.

wpotvin

I just had a system put in by Power Solar.  I was very happy with the work and service.   A few suggestions.


  1. I had an existing diesel generator at a vacation house I rent out, and they installed the panels to work with my backup generator without any problem.   
  2. On a 22kw diesel generator, I have gotten seven days of power on a standard fuel tank.
  3. I was offered batteries, but the cost was about $40k, which would power the house for a max 2 days if we dramatically reduced power usage, i.e., no AC, reduce hot water, etc.  The high-end generator cost $12k and keeps everything going as normal, like pool pumps and washers/dryers. etc. 
  4. Don't over-panel.  My roof held 30 panels and cost $30k.  It is saving me $500 to $700 a month.  An excellent return.  If you put in more panels than the power that you use in any  24 hours, you don't get your money back for that power. 
  5. Don't lease!  Along with battery sales, these are where the companies make the most of their money. Pay cash or borrow from a bank.  It is like leasing a car, sounds good but it is good only for the dealer.

robertomartinezsr

@William Cameron


William,

Thank you very much.  The information you have provided is valuable!


Roberto

robertomartinezsr

@wpotvin


Thank you!

shapeyoursuccess

Hi all,

My question is about general approvals/licensing etc PR & Luma require for a DIY weekend warrior. We are considering still connecting the home to the grid and working with Luma - so I am wondering what I, as a home owner will be allowed to do by myself with solar.


Background:

After covid and code delays, we are in the process of building our home in Cabo Rojo - first floor walls are going up this week!

We are in the early phases of deciding on the solar system and I am leaning towards buying a kit and installing it myself.  We will have a staircase leading directly to the roof, and all of the mechanicals are provided in the plan, so I should be able to drop the wires straight towards the inverter/battery in the garage.  I  wired my own home in Minnesota & was able to pass the electrical inspection with a pretty fastidious inspector.  So these are my "qualifications".


After having several initial conversations with PR solar contractors, I am finding they are trying to (a) sell me more of a system than we will need and (b) do not seem to have the latest/most optimal panels.

I can talk about part (a) later bc it gets complicated, but part (b) is pretty straightforward: to optimize the available roof space, I'd want to go with the 540W panels, so that if we end up with a 10KW system, we'd need fewer panels & less of a footprint.  Folks I talked with on the island seem to push 330W or 400W.


In any case, before I plan too far, will Luma be OK with me doing my own solar install from a kit?

Will someone have to sign off on it like a master electrician? Will need permitting? Will it need inspections?

No financing, no banks involved.


Thanks!

techdispatch

Hello SYS: I would take a walk or drive down to the Luma office and get the information needed directly from them, they may even have procedure on print for you. You don't want to guess or get any second hand information for what you have in mind. That's all I have to say.

Charlie Vega

@shapeyoursuccess

Hello Shapeyoursuccess,

Techdispatch gave your key of success, if you want to hook up with LUMA. Maybe, they have the requirements online and you would be saving a trip there. I'm on the same situation and no Windsolar, no solar gurus, no loans, but more important to me "NO LUMA". Everybody is gouging their knowledge of solar energy. The ROI is stupid ridiculous for a whole system which you already mentioned it on part (a) it's obviously more than most people need. I'll share where I got my system and it is working perfect.  signaturesolar.com/complete-all-in-one-off-grid-solar-kit-kit-e0000

shapeyoursuccess

TechDispatch, Charlie,

Thank you both.

We are still in MN, and will be during most of the PR construction. I will try reaching out to Luma over the phone and see how far I can get.  When we were in their Mayaguez office last fall, we did find them an easier utility to work with than the water/AcuaductosPR. 


Charlie,

While I am waiting for your link to post, I can tell you that I did do an energy audit using a sizing excel spreadsheet tool from a DIY solar forum. We are looking at <2KW daily with 1.7KW surge power usage.

Estimating PV production at 20W/ft2, I am figuring on a little over 500ft2 of solar panel area. To fit our available roof space, it looks like we will have to go with a combo of 540W, 400W & 330W panels. I am thinking AXITEC panels & a Solar Edge SE11400A inverter (11.4KW).


I will post our progress on this, if anyone cares, as we move forward. It is unlikely the house will be ready for the solar install until the coming winter, based on our construction speed thus far.


Thanks again to both of you for your help.

Charlie Vega

@shapeyoursuccess Great research. 13.5kW inverter/solar controller is enough for me. Sounds like you'll need a little more, but you'll need a hybrid controller to support LUMA also. PR avg 4.3 hrs/day of sunlight, (it was the number we were given) so you can use that to calculate the number of panels. I'd shoot for the big 500+ watts panels.

Water with acueductosPR is another story, we had a master plumber sign a certificate that AcueductosPR require before installing the meter. Good luck.

shapeyoursuccess

Charlie,

Thanks,  Great link - these folks seem better prices than I've seen at most suppliers to DIY folks.


They are out of stock on a bunch of stuff at the moment (particularly the hybrid kits) but we won't be ready for delivery for several more months at least.   I am looking forward to connecting with them tomorrow to start the discussion on our specific needs.  I am also looking at their solar-specific AC mini-splits.  Those look pricey, so I am curious as to their additional benefits.  Is is lower surge wattage draw?  Hopefully will learn tomorrow. 


Can I ask you what the freight ended up costing you to PR from them in TX?


Also, took a while but we ultimately won the AcueductosPR battle last year.  Our prize?  A brand new bill we just paid over the internet 1f602.svg


Thanks again for the link.

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