Battery System HELP


#1

I’m about to purchase 32 solar panels (265 watt). I plan to add more alternative energy producers over the next couple of years…possibly more solar, or maybe wind power. I would like the option to be off grid, but also the option to have the connection to the grid (without the need to use it). I want everything powered by this system, not just a critical panel…so it needs to be able to handle a big load. I have mostly heard about Tesla and Sonnen, but are there any other alternatives that would fit my requirements better? Thank you in advance for your input!


#2

Merry Christmas Allison,

We might need a bit more info behind your motivations in order to give useful feedback. The reason being, if your aim is energy security in the event of a disaster, that is a very different equation to wanting to be carbon neutral for example. Those two goals also compete with each other somewhat.

I’m assuming that you are wanting to do this more for the environmental aspects, but when you mention the ‘option to be offgrid’, that complicates things a little.

Also, can you look on your electricity bill to see how many kWh of electricity you are using per month?

Cheers
Marty


#3

I’m interested in your reply. As I’m in fl won’t solar stored energy work as backup during a hurricane? I was assuming this was the case but after reading this I’m thinking not!
Thanks
CJ


#4

Hi CJ

It depends on the system, and the inverter. It’s not too difficult to get a system that will work in the event of the grid going down (I believe the Tesla Powerwall 2 does this out of the box @Svarky can confirm), but I was thinking more in terms of how much battery storage you will have to use in that event.

If you only size the battery to use for a couple of hours in the evening, then you won’t necessarily have much storage in the case of the grid going down. Although, it could last a while if you are careful.

Have you already got battery storage CJ, or are you looking into it? @Svarky’s article comparing the options is very detailed and useful.


#5

Just looking into it. It wouldn’t be for a couple of hours of power needed. If our area gets hit by a hurricane it can take a week or so to get power back. Tesla doesn’t service Fl I had an appointment with them but they cancelled. Hey, just moved from San Luis Obispo where their offices are I’m sure.

Duke energy is suppose to get me some info but it’s been weeks with no follow up.

Thanks

CJ


#6

I am shocked that Tesla doesn’t service Florida. Thought that would have been their second biggest market.

In Australia we recommend getting three quotes from local solar companies or electricians. Everyone is able to get access to more or less the same brands to install. Is that not possible in Florida? Is there some financing arrangement which makes it easier with the big companies?

@Ekelly234 or @dtbaker61 do you have any insight into that?

Cheers
Marty


#7

Thanks for responding! I really like the idea of both :slight_smile: Hurricanes are an inevitability here (Puerto Rico)…and I wish that was the only time we lost power. The grid here is so outdated that our house loses power about once a week…although usually for less than an hour. We would like the solar system to automatically back up the house without even a couple of seconds of loss of power. This is definitely the priority.

Also, power here is almost double the rate of the US…which is why we would love to use as little grid power as possible. To stay connected to the grid, we would pay $3 a month, which seems like a reasonable price to pay for that extra peace of mind on cloudy days. AND last but certainly not least, we would be doing some good for the environment. There is SO much sun here and it’s just silly not to take advantage of this clean energy!

We typically use less that 2,500 kwh per month. I realize that the 32 panels is just a start to cover our consumption, but we are planning to add more solar or wind power in the next year. Thanks again for your input!


#8

Florida is actually a very UN-friendly market for grid-tied Solar in the US… despite great solar exposure, and high energy needs with air conditioning. The local Utilities have done a good job blocking customer-owned grid-tie Legislatively and with regulatory red tape. Along the same lines, sadly, as Arizona. Utility Laws and management vary widely from state to state, and many are stuck in the ‘old school’ business plan where they think they can only make money by producing the energy, thus work hard to block any 3rd party from feeding in energy to ‘their’ local distribution grid.

Telsa battery wall is quite different than Tesla (Solar City) Solar division. The Solar PV arm has an aggressive marketing and Lead generation engine, selling/installing the cheapest equipment possible, and making their money by Financing the residential deals, with Lease s if the can since that allows them to retain the tax credits. The financing terms are somewhat predatory, and generally only pencil out in markets that have expensive electricity, and reasonable grid-tie regulation. Their Solar division bails out of ‘difficult’ markets, and focuses on high-margin areas… which is why they have no presence in FL, AZ, and recently left NM.

The Tesla ‘battery wall’ product is quite separate from PV… it is designed to be ‘ac-coupled’, charge itself during off-peak periods from the grid, and the take the home essentially off grid during peak periods until the internal batteries are exhausted, then re-connect to the grid in the next off-peak period to recharge. Or, serve as a ‘generator’ during grid outage… but can only recharge if the home ALSO has Solar for extended outages. The current battery wall product is designed to be ‘plug and play’ such that multiple units can be added in parallel to increase battery capacity, charge rate and discharge rate (each unit has 12kwhr usable battery capacity, and may be charged/discharged at a max of 5 kw). The company I work for has just signed up to be an authorized Dealer in NM for the battery wall, and the current plan is to sell/install for about $15k USD per unit.

There are at least 3 ‘battery wall’ products to consider if you are looking for either daily use to manage peak/off-peak electric cost, or as grid outage ‘generator’. Tesla, Sonnen, and Panasonic.

For PV, my opinion is that most of the ‘front-sheet collection’, or commodity panel, technology is pretty much the same; yielding the same performance, degradation, and warranty. Choosing between local installers one should look at both price, and local referrals/testimonials to determine how well the installs go. The only outlyer in the PV module market is Sunpower; with significantly different physical design yielding higher efficiency, less degradation and less failures over time enabling a 25 year parts and labor warranty that is unmatched in the industry. Initial cost for Sunpower is usually a little higher because the modules themselves are almost 2x expensive as the cheap ones from China/India/S.Korea… but the long-term value always pencils out higher. Sunpower is not available ‘everywhere’ as they are sold only thru authorized Dealers.


#9

Thanks @dtbaker61, very insightful.

Allison, @BHekman and @Svarky will be able to give much better feedback than myself, but here are my thoughts:

  • having re-read Jason’s article on the Tesla Powerwall, it looks like you do need a bit of extra kit for it to work when the grid goes down.
    https://www.cleanenergyreviews.info/blog/tesla-powerwall-2-solar-battery-review
  • 2500kWh a month is about 80 per day. You would need A LOT of battery to cover you for the grid going down for a week or so (considering as Dan said, 1 Powerwall will give you 15kWh)
  • as Dan says, the battery is quite separate from the solar, in the sense that you can’t rely on the solar when the grid goes down, so you’ll need to size your batteries assuming you won’t get much solar. The solar will on average produce about half your usage (very rough guestimation), but that could vary greatly, especially in stormy whether.
  • Wind could help, but is less reliable than solar, and with your energy use you’d need a lot of wind to supplement.
  • I know you said you want your batteries to cover your entire normal load, but I would seriously consider that. 80kWh a day is an awful lot to cover, if you could identify some big electricity suckers it could make your life a lot easier.
  • realistically, a large diesel generator will be required regardless of your renewables if you want to ensure supply

I hope that helps. I’m curious as to what you are doing currently when the grid goes down all the time, it sounds like a nightmare!


#10

the typical use of a BatteryBackupUnit (BBU) is to backup ‘critical loads’ as long as possible, rather than ‘whole house regular loads’, especially if there are large loads for non-essentials like pool, spa, air conditioning, etc. The typical installation for a emergency BBU would probably suggest some additional electrical service changes to move ‘critical load’ circuits to a new sub-panel, and backup only that sub-panel with the BBU to keep the size and cost down.

With the OP stated use of 80kwhr/day, the first step would be to determine what loads are ‘critical’, and move them to a separate sub-panel so that outages could be handled by a smaller generator… whether it is a normal propane generator, or PV that would normally be grid-tied.

For whole house off-grid or extended outages it is generally ill-advised to backup massive electrical loads… it just gets too expensive for most people. Intending to live off grid generally means to change lifestyle and live on a lot less energy.


#11

Not that I am aware of I don’t know if the state or the utility companies offers some financing


#12

Very interesting discussion. I’m shocked to hear how difficult the utility companies make it to install your own rooftop solar in parts of the US, sounds like they are doing everything to maintain control.

Hi @Alison, as @dtbaker61 stated it makes sense to setup the system to backup the ‘critical’ loads only during a blackout. This means the inverter and battery size will be much smaller, 80kWh a day is very high and would cost a small fortune in batteries.
The best bet is too consult an experienced solar system designer. The systems and inverters are complex and need to be configured properly. I recommend using the Schneider Electric Conext XW+ multi-mode inverter or outback radian series. Also if available the SMA sunny island or Victron Quattro inverters are also very good for larger scale off-grid/hybrid systems but i depends on what your installer is experienced with?

I have written several articles about the different options available… https://www.cleanenergyreviews.info/blog/2015/7/1/hybrid-interactive-and-solar-inverter-combination


#13

Hi Allison,
I just added a more detailed reply about sizing a system but just wondering do you have an experienced system designer or installer who could size and configure a system for you? A system of this size and complexity will need an experienced electrical professional to setup and install correctly or you could end up with all sorts of faults and even a potential fire hazard.
What brand or make panels are you thinking about purchasing?


#14

Hi everyone! You guys are seriously amazing for providing so much helpful information! I have been researching solar for almost a year now, but the options are a bit overwhelming and I still struggle to wrap my head around everything…unfortunately the local providers have not been very helpful, so I’ve been trying to figure everything out on my own.

For the past couple of years, we have been backing up our power with a 23kW Generac Generator (propane). This has helped our power situation significantly…but we do still have that 14 second gap in power once the grid goes out. Such a short period of time wouldn’t be such a big deal if we didn’t work from home and have a “smart” house. My husband is all about the tech and all the lights (among other components) in our house become very stupid once the power cuts out. This type of technology was just not designed to have to go through power outages on a regular basis, so we are hoping to have continuous power and not have to deal with this issue much longer. We did buy the original house with small solar system that use to fill the gap between the grid and generator, but that system flew away during Hurricane Maria :frowning:

@Marty @Svarky Is it possible to have the BBU connected to only the critical loads for when the grid goes out, but have the solar panels feed the entire house and even sell back to the grid when there is solar production? It seems like we will also need to keep our generator just in case we have any longterm outages like we did after Maria. So, essentially our system would function like this:

-Solar panels (and future energy producers) would feed the house and BBU during the day. Any excess energy produced would be sold back to the power company.

  • At night, the critical panel would be powered by BBU, while the rest of the house is powered by the grid (or generator if the grid goes out). Generator also set up to turn on automatically and power the BBU if backup is depleted.
    -In the event of a longterm outage, the generator would kick on to recharge the BBU whenever it runs out of the solar energy production. We could also use the generator to power the entire house (as it is currently setup to do)…if this was automatic, that would be ideal…but we could also just manually turn it on for the whole house function. Is it possible to set up the generator to do these 2 functions automatically?

I import a lot of materials for my business here in PR, so I am importing these 265 watt solar panels (32 panels, just over 16% efficiency) to blend with our terra cotta roof: http://www.lofsolar.com/Standard-PV-Module#5
We realize that aesthetics will cost us slightly in efficiency, but that is a compromise we are willing to make. I will be putting the order in for these panels in the next week…do you foresee any problems with these panels?

The 2 battery systems that I have heard of being frequently used here (and quoted for) are the Tesla and Sonnen Battery. I have actually seen more Sonnen systems installed around here…but I’m not really sure why. I will end up buying the battery system through an experienced solar/electrical professional and have them setup and install our entire solar system. @Svarky Can you briefly explain why you recommend the Schneider Electric Conext XW+ multimode inverter or outback radian series above the Tesla and Sonnen battery systems for our specific circumstances?

After reading all the information you guys have provided, it seems like our best bet is to stick with a smaller battery system to start (critical panel) and rely on the grid and the generator when not generating enough of our own power. I am a bit weary of the process of creating a critical panel with the electric already contained within concrete walls. We have a very wonky electrical system due to the fact that our property was constructed in various stages (some before we moved in and have no electrical plans for). So that part should be interesting! Anyway, that’s a more thorough breakdown of our specific situation…with your help I feel like I am getting much closer to finding our end solution for this system. Thanks again for all the information! You guys are great!! :smiley:


#15

Hi Allison,

Thanks for your feedback. I will try to keep my answers relatively simple. My recommendation to go with a dedicated off-grid/hybrid inverter such as the Schneider Electric Conext XW+ or Outback radian series above the Tesla and Sonnen battery systems is because the Schneider and Outback systems are designed to operate continuously in off-grid mode and control multiple energy sources such as generators, grid, solar… plus they can be both DC and AC coupled which provides a more robust backup UPS system.

On the other hand the Tesla Powerwall 2 and Sonnen ECO are relatively simple AC batteries designed for typical grid connected homes (with infrequent blackouts) and have limited surge power rating and no backup generator controls. Don’t get me wrong they are great products but not really suited to your particular circumstances. Although Tesla have recently announced a new backup gateway which may have off-grid control features such as generator control.

If you were in Australia I would recommend the Selectronic SP PRO but I believe it is not available in the America’s. The Victron Quattro multi-mode inverter is also a powerful system designed for hybrid and off-grid use with UPS backup. It may come down to your solar professional and what products they are familiar with, good service and support will be required to get the system configured correctly.

Hope this helps,
Jason


#16

Forgot to mention I have some concerns with the ‘lof solar’ panels you selected. I had a look at the link and they are an unfamiliar brand with a very short 5 year warranty. All reputable brands I know of have ‘at least’ a 10 year product (manufacturers) warranty together with a 25 year performance warranty.

I know asthetics are important for some installations but I would recommend using a well known brand with a good track record and at minimum standard 10 year product warranty. The ‘all-black’ panels available from many manufacturers do look pretty slick.

For example… https://www.trinasolar.com/au/product/honey/honeymplus-dd05a08ii


#17

@Svarky Thank you for your feedback. Your information on the hybrid inverters makes a lot of sense and is very helpful!
I really don’t know why the LOF site says that on the main page…I will have to question that one. However, I actually have the contract already and it states: “10 year limited warranty for PV modules (power performance warranty: 90% in 12 years and 80% in 25 years)” and the products warranty is backed by EU insurance group of Munich Re. LOF invented and developed the technology, but they work with many module manufacturers to produce the panels. Our panels will be manufactured in Vietnam by GREEN WING SOLAR TECHNOLOGY CO.,LTD because there MOQ could support our small order. This is the company that will also be responsible for the warranty previously mentioned. Have you by any chance heard of this company?

The reason why I have taken so long to pull the trigger on our solar, is because my husband was just as concerned with aesthetics as function. The black panels are looking better and better, but he had something very specific in mind. We would have loved to go with the Tesla Terra Cotta Tiles, but that is a long way from being available to us in Puerto Rico…and would be ridiculously expensive. This option seems to provide us with the best of both worlds…although I do understand your skepticism. I have tried to be as thorough with my research on the panels as possible to alleviate as much risk as I can.


#18

Do you have the securespace for your power needs ? I mean land free from thievery or a very sturdy ample roof? You are talking at least80 panels


#19

My Choice is SimpyPhi ( USA ) with Victron multi plus 2 ( DUTCH )
Compare SimpyPhi and Sonnen they are both Lithum Fe Phosphate and 10000 cycle warranty

Now the difference is Sonnen battery modular expandable in 2 kw per module
The SimpyPhi is a 3.4 Kw battery only

Sonnen is a i integrated solutions while Simpliphi will have to be integratied with Victron
( That Not Complicated ) There are sio many Victron Professional and better pricing
It much easier to change things around and do upgrade , to customized your need
eg I can choose the size of inverter
I am choosing Victron Multi plus 2 which is Off Grid as well as Grid Connect

I welcome other view


#20

@jvilella4 Our panels would be secure on our second and third story roof.

Any thoughts on using the Solar Edge system with LG Chem batteries? I just had a solar professional come to the house and he recommended this product for our specific needs. He claims this option will work best because we want to install some panels on roofs that don’t necessary pitch toward direct sunlight and this system allows each panel to preform independently to reduce power loss.