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New solar batteries

 
singlefin
(@singlefin)
Trusted Member

Anyone have any experience with these. They sound incredible.

www.teslamotors.com/powerwall

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Topic starter Posted : July 31, 2015 4:19 pm
CruzanIron
(@cruzaniron)
Expert

They aren't even on the market yet, so no one has any experience with them.

They are taking reservations and they will be available 'this summer'.

The cost does not include the inverter, by the way. Add a few more thousand for a good one. And you are charging it with WAPA power unless you have your own panels or wind generator, so with WAPA charging there are no savings.

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Posted : July 31, 2015 8:16 pm
islandtyme
(@islandtyme)
Trusted Member

Nothing wrong with the latest high tech stuff, but cost is always a factor.

Practical Battery needs for storing solar or wind power are different than what is needed for cars. Most important thing here for solar/wind is cost per watt-hour of battery capacity. Normal Lead-Acid batteries are by far the least expensive, even Lithium batteries cost on the order of ten times as much as Lead-acid.

For automotive use size and weight are the main concerns, all this new battery technology is mainly concerned with efficiency as far as watts per pound of battery, not cost per watt.
So for our needs here on the VI as far as Electric generation goes, the old low tech batteries are the way to go unless you just like wasting tons of money.

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Posted : July 31, 2015 8:56 pm
singlefin
(@singlefin)
Trusted Member

I'm still learning about solar options. From what I understand the majority of current systems feed back into the WAPA grid, essentially running your meter backwards (lowering your personal electric bill - Net Metering). The power your generating does not go directly into your electric panel for your homes use. When WAPA goes down, you have no electric.
Having charged batteries to kick in during WAPA power failures sounded good.
I was thinking of having only enough solar panels to run the basics (fridge, water pump, ect) if a long term WAPA disruption should take place.
This system will run independent of WAPA (power to basics) or charge batteries, It doesn't feed back into the grid.

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Topic starter Posted : August 1, 2015 3:45 am
SunnyCaribe
(@SunnyCaribe)
Advanced Member

I have basically the system you describe. I am very pleased with it. My research and long experience on St. Croix persuaded me that the net metering route isn't a smart long-term arrangement. Where is the logic in defying WAPA's horrible service and management by entering into another contractual agreement with WAPA, over which you have no control and the terms of which are subject to change at WAPA's whim? Boy, that'll show 'em.

The Tesla batteries are intriguing and they will develop into a sweet option in a few generations I'm sure. But for now I get roughly twice the watts from a solar lead-acid battery bank costing much less.

Just be sure to invest in a system that is smart enough to accommodate future developments.

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Posted : August 1, 2015 1:33 pm
singlefin
(@singlefin)
Trusted Member

Thanks Sunny,
That's the type of response I was looking for. Your concerns regarding WAPA's deal (net metering) are similar to my own.
I need to get a hold of a reputable, up to date solar guy on STX soon. Solar options keep getting better with all the new technology and having that off-grid option, while still connected, sounds like the way to go. I've heard the stories from older neighbors who went without power after major hurricanes for months at a time. I'm planning new construction in about two years and really want to incorporate the best possible option... without breaking the bank!

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Topic starter Posted : August 1, 2015 3:31 pm
brandonc
(@brandonc)
Advanced Member

I am working on a solar setup for our home here on St. Croix. For our batteries I am using Rolls batteries (48 volts/1104 A/h @ a 20hr rate). For my inverters I went with SMA Sunny Boy/Sunny Island. While my system is capable of being grid-tied, I don't plan on using it that way. I am separating part of my circuits to go on the solar system, and a few high wattage things will stay on WAPA (Stove, Dryer, and main house A/C unit). My goal in to have uninterrupted power in the event of a hurricane as I work from home. To further insure I have internet, I recently got a VSAT system, so I am not reliant on any USVI terrestrial stuff.

I don't yet have as many PV panels as I would like, so I am going to have to keep some stuff off the system for the time being until I grow the array.

So initially will be powering...
- Computers/Internet/Router/Etc
- Refrigerator
- Cistern pump
- Lights/outlets

Once the array is bigger, I will be putting our A/C unit for the bedroom on the system (only run at nighttime)

The SMA Sunny Island battery inverters has features as well so that if you battery charge goes below a certain level you can have it tied to the grid or generator to charge your batteries. I am still debating on using this feature, but could be useful if we have some extended cloudy days or I have to power some unexpected loads.

If anybody has any questions about my experience so far or any further details, I would be glad to answer.

Thanks,
Brandon

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Posted : August 2, 2015 1:59 am
vicanuck
(@vicanuck)
Expert

I have a 7.5 kw net metering system here on STX. A decent diesel generator as back up power is still much cheaper than batteries at this point. The net metering deal we have now is pretty generous at 1:1.

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Posted : August 3, 2015 11:51 am
CarlHartmann
(@CarlHartmann)
Advanced Member

We live at Coakley Bay Condos -- which has a VERY strong commitment to infrastructure solidification and upgrades. A few years ago -- before the Board added full-time, full-coverage electrical backup -- we did an experiment with such a system. Back then it was called "whole house backup" by GAIA, a company was selling a "total" 220v system for about $14,000 that would power an average 1400 sq.ft condo for about 8 hours when line power was lost. It could also be charged by either gasoline generator or solar panels -- all automatic.

Our condo was used as the test unit. The backup unit and dual 110v invertors was located after the WAPA meters and before the condo. It was in place (and VERY successful) after Omar. It was never used for solar....but after Omar, the batteries could be charged by generator during the day, and then run through the night without noise.

The switching is almost instantaneous. We still have it in place and it acts like a huge Computer BU battery for the once weekly exercising of the new generators.

The batteries are deep cell marine units that fit with the inverters and control unit inside a unit about the size of a small fridge. It is in the storage unit under the building.

Several years ago, the Board decided to go with three automatic diesel generators which come on within 5 seconds of line failure. (It has fuel for 14 days and is triple redundant rather than relying on one huge unit.) It has worked almost perfectly for the years that have been in operation -- and Coakley has since buried its main supply lines out to the road as well -- to further harden the system. But my wife and I still love having that big backup unit there and the fact that our clocks stay on when the generators exercise weekly. Also, although the three generators are housed and muffled, if they run through the night, the condos closest to them still get some noise. (They are sufficient to run all power including A/C.)

I would strongly recommend such a setup for a single home -- especially if supplemented by a small generator and some solar ! I have not priced them recently, but the three new power pack units that have been announced -- along with 220v inverters and a control unit will have to be much cheaper today. Just keep in mind two things -- the hot weather tends to shorten battery life somewhat, and there i9s a slight power hum from the inverters. But no generator noise while sleeping !!

ps. We are now moving to put our water system on solar power !

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Posted : August 3, 2015 3:27 pm
vicanuck
(@vicanuck)
Expert

Wow, that great Carl. Now that I have a rooftop solar system, I've been investigating water making systems recently. Making water is much more expensive than making electricity.

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Posted : August 3, 2015 4:00 pm
CarlHartmann
(@CarlHartmann)
Advanced Member

I know....great isn't it ? So many of the daily irritations on living in the Caribbean relate to glitchy, high cost power. (Notice I said Caribbean.....This is NOT just in the VI.) Once you have that solved -- the rest seems much, MUCH easier. Add in Sat TV, virtually overnight mail-order and far-better than ever internet.....and it has changed a lot.

(BTW, I first lived here in 1959 as a boy, and have lived on STT and in FL as well a more northern climes like NYC and DC.. The "new" arrivals (anyone after 1989) who complain about these things have NO IDEA about how good it is now by comparison. It is like living in a dysfunctional suburb of a major city except for the lack of big malls and presidential voting.....I know people complain but with the right improvements like reliable electricity and solar hot water the VI can't even begin to compete with Northeast cities for other annoyances like snow, crowding, crooked legislators or a challenged local govt. The NY legislature makes ours look like a brilliant group of angels)

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Posted : August 3, 2015 5:06 pm
singlefin
(@singlefin)
Trusted Member

Thanks Carl.
Great info.
It does seem that options keep getting better all the time. I've often wondered how difficult it must have been before things like the Internet and modern power options were available. It's always encouraging to hear from people who have been on-island for decades. Its always great to hear that even though they have been through some incredibly difficult times (hurricanes, ect...), they have chosen to remain, determined to rebuild and continue living on these beautiful islands.

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Topic starter Posted : August 3, 2015 5:57 pm
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