Advice for first time solar options

timothy smith
By timothy smith on Tue, Apr 2, 2013 - 9:59pm

I have recently begun my investigation to solar.  Seem to have a reputable company.  Endless Mountain Solar Services. They have quoted me $12K after rebates Total of 21K for a 3.64 KW solar Pv System.

Trying to determine if this is reasonably priced and also whether there are other options that could be worht exploring that would be more affordable. etc.    Thanks for anyone who may have advice.  Tim

 

14 Comments

treebeard's picture
treebeard
Status: Platinum Member (Offline)
Joined: Apr 18 2010
Posts: 590
Sun Power system

I was just quoted 6.9 kw system, total installed cost is $21,337 after incentives and rebates.  SPR-X21-345 SunPower panels generate 345 watts a panel, but come at a real premium. I have a relatively small roof area so I could get only 20 panels up there and I wanted to max out production.  I do have about an acre and a half of land, but there is not room for a ground mount.

They are selling me a grid tied system, but I have asked to have critical loads on a separate circuit, well pump, refrigerator, and hot water panel pumps.  I want these powered in a grid failure situation, whatever the reason might be.  I have been told that AMS makes an inverter that has a 12a circuit that I can tie to critical loads without battery backup.  Problem is the release of the inverter was supposed to be back in February and now is promised for the third quarter of this year, but now that is expected to be delayed again.

I have told them that supporting the critical loads in power failure mode is critical, that have yet to come back with another option.  I have to wait and see what happens.  If anybody has any advice on the best way to do this let me know.

Tim, for comparison, the first proposal they gave me was for conventional 250 watt panels, grid tied system, 5 kw total,  cost was around 12k.

silvervarg's picture
silvervarg
Status: Bronze Member (Offline)
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Posts: 57
Re: Sun Power system

That's a hefty price increase to go from 5kw to 6.9kw. Going with really high efficiency panels does cost a lot, and is usually not worth the money, so I would think a bit more before accepting such an offer.

I suggest that you really think through what you really need as any extra nice to have things tend to cost quite a lot.

E.g. How many watts do you really need? Can you do without most heating/cooling systems? (really saves on the wattage needed).

What do you need to run when grid is down?

For how long do you need to manage with grid down?

The main reason to go with a grid-tied system is to get a lower total cost due to incentives. That maens you might not be allowed to have a battery bank connected to the system. Still some systems are designs so you could have a battery bank, and usually after a few years you can connect in a battery bank without violating the incentives agreement.

Is it possible to go with a separate battery bank?
That is just charge a few batteries from the grid, so they are not directly connected to solar system.
In the event of a grid down for extended time you could manually connect an inverter to the battery bank and to the things you need to power. This is reather easy if the things you want to power is not permanently connected to the system.
It they are permanently connected you could be ok by cutting the main power switch and then push in power from the inverter to a wall outlet, you better be carefull and know what you are doing if you use this option.

 

jturbo68's picture
jturbo68
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Posts: 207
Battery Inverter.

If you can separate a your critical items onto a dedicated wiring panel, you can use

a Magnum Energy PAE-4448 or 4424 to power the sub panel while the grid is out.

The PAE will recharge the batteries once the grid is restored.

 

John

 

 

Oliveoilguy's picture
Oliveoilguy
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Joined: Jun 29 2012
Posts: 578
AC Coupled System

Probably the most cost effective plan, if you have a small backup load design, is to do a grid tie system (I like the enphase 215 microinverters). and then add an AC coupled inverter with a small battery bank.

I have a DC coupled Outback Radian with Battery backup as one system and on another building 20  250 watt panels with enphase. I like both systems so far.  The DC coupled has a  loss of efficiency with the batteries, but most of the time they are fully charged and the AC current flows right by them. The radian  GS8048 is a great design. With a 48volt system you can use MPPT and gain more efficiency. 

Our electric coop is going to start Demand Billing like commercial billing, so reducing load will get us into a lower category and add another reason to have solar energy. Our goal is to get totally off grid, but we are going a step at a time.

Organic Raw Veggies's picture
Organic Raw Veggies
Status: Bronze Member (Offline)
Joined: Jul 24 2012
Posts: 49
Grid down power out

Get batteries, yes they increase price a lot. If you have no batteries most systems don't give power. Grid down, you down. We put in a 6kw system with 2 to 3 days of batteries, subpanel with well pump, frig, heat circulation pump(hydronic), corn stove, some lights. I can give you component names. System has been in place 2 1/2 yrs, works great. Lost power a few times and things worked great. You can control the amount of power you use and see how fast the batteries are used. If the sun comes out batteries recharge during a grid down. 

Charge controllers supply power to subpanel first, then they charge the batteries and then feed the grid running the meter backwards. They also handle periodically running the batteries down to 50% and then recharging.

I put in a generator plug that connects to the batteries. You can recharge the batteries with a generator. I also put in a second subpanel off the batteries with a few extra 120v plugs. 

So much better then a LP or diesel generator. You don't do anything when grid goes don't. You might not even know. We got a state rebate, county property tax rebate, fed tax rebate and green rebates and power credits. Everything helps brings the cost down.

get batteries. They only last about ten yrs, be prepared to get more batteries then, batteries keep getting better.

Oliveoilguy's picture
Oliveoilguy
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Posts: 578
Charge Controllers

I agree with the battery backup importance. We have fridge, freezer, a small minisplit in our root cellar, lights and well pump backed up. We can function on this if the Zombies attack and take out the grid.

The charge controller is on the DC side. It takes DC power from the PV array and controls or regulates the charge going into the batteries. The power then flows from the batteries into the inverter where it is changed from DC to AC and then goes to the loads. First Load priority in my system is the backup load panel, then the loads on the ranch, and then finally if there is more PV power, we "sell back" to the grid.  Also...another charging function can happen through the inverter which can be a charger in reverse. If the batteries get below a SOC (state of charge) set point. (Usually 50%). and there is no sun, the inverter will give prioity to the batteries and invert backwards from AC (grid or generator) to bring the battery bank up to charge so that they don't get damaged. 

Really cool design. 

 

cnbbaldwin's picture
cnbbaldwin
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Posts: 59
Outback Radian with Battery Backup

I would second Oliveoilguy's recommendation for the Outback Radian inverter if you want grid tied with battery backup.  I am running two Outback FX60 MPPT charge controllers with a single Radian inverter that delivers 8000 watts continuous.  My critical loads panel has the entire house on it with the exception of a clothes dryer that is only used for emergency at any time (we use a gas stove).  I am just a little careful of total loads when we are running on batteries and there have been no problems for the year and a half that we have been using the system.  If you need more power, additional Radians can be wired in parallel up to 80,000 watts for a single system so you have a lot of flexibility.  When we loose the grid the switch is so quick we don't even know its happenned.

Good luck.

timothy smith's picture
timothy smith
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Posts: 6
insightful post

Following the posts is helping to refine my thinking at this stage:  And am looking for additional advice.

Hoping to get a starting place for "immediate back up needs"  

Power need would be refrigerator and freezer and energy for fan for woodstove and computer charging.

Have a back-up generator as first line of defense and seems that having a battery system connected to solar could be a long-term solution for power off the grid.  Batteries could be charged from the generator as needed so the generator does not need to run 24/7 and solar could be used to keep batteries juiced up as well.  Where does one look for such set-up advice - particularly for a newbie.  Rely on "professionals" ? websites?  

timothy smith's picture
timothy smith
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Posts: 6
sun power systems

Tree Beard,

Thanks for the input.  It turned the structure of the house (antique) limited the installation options so I am now looking at other options.   My first priority is to have a longer term back up source of power for running the refrigerator and freezer and power for charging computers.   I have a generator that can be run for immediate needs in case of power outage and I'd like to be able to run these items for longer term without the need to run the generator. It seems having a back-up battery system may do the trick.  Batteries could be charged from the grid or from the generator and longer term could be charged off a smaller size solar set up off a single garage roof.  

I am trying to determine how to go about what feels like a daunting task and looking for starting places and how to structure a plan.  Any insight appreciated.

 

GM_Man's picture
GM_Man
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Posts: 74
Sounds like my system

I have a Magnum PAE-4424 (charge/inverter) setup which uses a 24-volt battery setup.  This system provides a pure sine-wave AC from the battery when there is a power disruption.  It works great.  I run a 30-amp 240vAC line from the main power panel through a 40-amp autotransformer.  The autotransformer has inputs from the main power panel and my backup generator.  When power fails the battery pack provides power vis a vis the Magnum 4424.  During daylight the batteries are recharged via 8 solar panels providing about 1600 watts depending on the weather and season.  The solar panels feed an Outback Flexware 60 that keeps the batteries charged when the sun's shining.

The output from the Magnum feeds a small power panel with 8 circuit breakers.  These circuits cover most of my home's needs including the fridge and freezer.  My water is gravity fed so the water pump is not-essential.  I generally turn off the freezer or the fridge during the day, running only one of the appliances.  Microwave, dish washer, washing machine, and dryer are either grid tied or not available on battery power due to their excessive drain.

The generator handles everything on the small power panel including the freezer and fridge and microwave.  It also recharges the batteries via the Magnum 4424.  Two hours or so during the morning and two hours at night does the trick on really crummy days.

I also have two smaller panels providing 480 watts into a small, Chinese manufactured grid-tied inverter.  Just so that I can watch the meter run backwards.  

silvervarg's picture
silvervarg
Status: Bronze Member (Offline)
Joined: Mar 28 2010
Posts: 57
Compare goals to costs

Most of us want quite a bit to work on solar, but then things like costs, really cloudy days, few sun-hours per day in winter etc makes things complex.

If you just have loads of money burning in your pocket this might not be much of an issue, but that is usually not the case for most of us.

For every item you want to run from your batteries list the device, average power usage in 24 hours and for heavy power draw items also list what starting power you expect it to have.

E.g. running a microwave or electric water kettle for 3 minutes every 24 hours will not require much in therms of watt-hours, but it requires a lot of peak effect from the inverter. The freezer is similar, but often hard to know how high the power spike to start it is (1500W peak for less than 1 second is a good guess).

If you want to avoid the risk of having issues in the winter or with many consequtive heavy could days you might want a backup power source, like wind-based or a generator. This will limit your worst case and results in less solar panels and smaller battery bank. From a cost perspective this might be really appealing, especially if you don't expect the noise from the generator to be an issue or inconvinence.

Remember to consider that the same system completely without solar panels might give you the same short term solution as with solar panels. If you expect a really long scenario you will eventually run out of fuel to the generator.

Consider cutting back on usage as an option. E.g. if I have a battery bank that can run my essential needs for 24 hours and I could use a generator once a day to top up the battery bank I would say that is pretty good.

If we are in for a year long power outage or so or the generator stops working then I would be willing to cut my needs to allow a smaller array of solar panels to provide the charging. E.g. No freezer (but still run refrigerator), no electric water kettle, fewer lights, fewer hours of computer use etc.
It is often possible to cut the usage to a fraction when thinking like this. E.g. freezer power usage is often 10 times the refrigerator power usage.
A lower usage also means a much cheaper charge controller for the solar panels and a smaller and much cheaper inverter etc.

You might also think a bit outside the box. E.g. I will get the least solar power per day in the winter, but then I am likely to be able to easily freeze water in plastic containers outside and put them inside the refrigerator to keep temps down even without any electric power use. By cutting the usage more when I have the least solar power I can further reduce the needed solar panels.

Then one thing that is really easy to forget is redundancy.
Lets say you plan on managing through a long grid down in a remote cabin (lets say a month), then what will happen if your expensive inverter breaks down?
Is it better to have a slightly smaller system and have a backup inverter? Perhaps not as good and expensive as the primary inverter.
There is also other options, like you could have a refrigerator and freezer that can run both on electricity and on propane (these are commonly available). It could turn out to be a lot less expensive solution.

Craig Severance's picture
Craig Severance
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Joined: Aug 2 2010
Posts: 7
Less Expensive Option with Off-Grid Capability

We installed a grid-tied 4.4 Kw solar array with net metering and did not incur the costs of a battery bank.

For Off-Grid capability our system has a SunnyBoy inverter which has a dedicated circuit that provides up to 1500 watts of daylight time power whenever the grid would go down. We had this circuit brought through the wall from outside where the inverter sits, to an interior wall plug that is right next to our critical loads.

We don't really need electricity for very much should the grid go down as we heat the house entirely with passive solar and a wood stove. So for us our critical loads are the refrigerator, freezer, and washing machine.

Our refrigerator has 3" of insulation and will keep food cold for three days of being shut off, so I'm sure we can get by running it and the freezer and washer only in daylight hours should the grid go down even for an extended period.

We could also easily keep our cell phones charged. We would need to cook over the wood stove if winter, or grill, campstove and solar oven if summer, but again no big hardship.

I don't yet have a system other than windup flashlights and kerosene lamps for nighttime lights but again I'm not too concerned with grid failures lasting very long. There are lights available that run from battery charging of a lantern that could upgrade our capability.

My point here is that although if I wanted to burn a lot of money I could have purchased a battery bank, charge controller, backup generator etc. However I felt it better to keep our electricity needs very modest in the first place with super efficient appliances and house, so that the SunnyBoy daytime Off-Grid 1500 watts is a very comfortable amount of Off-Grid capability for no additional cost whatsoever.

Incidentally I'm not pushing the SunnyBoy brand particularly. Others have mentioned other brands but I'm simply saying this was the most cost effective solution for our family.

Amanda Witman's picture
Amanda Witman
Status: Peak Prosperity Team (Offline)
Joined: Mar 17 2008
Posts: 409
Thanks for telling us about your system, Craig

Would you be willing to share what the price tag was on your system?  It sounds like the basic sort of thing I'll be interested in, when the time comes, and cost-effectiveness will be very high on my list.

What has your experience been with the SunnyBoy inverter?  I have heard about this (and it seemed like the perfect solution to not wanting a battery bank but still wanting power in an outage).  Am I understanding correctly that when the grid is up, yours is just a regular, sell-it-back-to-the-power-company system, and when the grid is down, it supplies your home (via that one outlet) directly with power (but only when the sun shines)?  Is that right?

How long have you had it, and is there anything you'd do differently were you to get a second chance at installing it from scratch?

So can you run fridge, freezer, washing machine, and...can you also run one electric light?  What about a laptop?  Or would you switch something off to run the washer?  I'm not clear on what 1500 watts can handle...

Craig Severance wrote:

We installed a grid-tied 4.4 Kw solar array with net metering and did not incur the costs of a battery bank. For Off-Grid capability our system has a SunnyBoy inverter which has a dedicated circuit that provides up to 1500 watts of daylight time power whenever the grid would go down. We had this circuit brought through the wall from outside where the inverter sits, to an interior wall plug that is right next to our critical loads. We don't really need electricity for very much should the grid go down as we heat the house entirely with passive solar and a wood stove. So for us our critical loads are the refrigerator, freezer, and washing machine. Our refrigerator has 3" of insulation and will keep food cold for three days of being shut off, so I'm sure we can get by running it and the freezer and washer only in daylight hours should the grid go down even for an extended period. We could also easily keep our cell phones charged. We would need to cook over the wood stove if winter, or grill, campstove and solar oven if summer, but again no big hardship. I don't yet have a system other than windup flashlights and kerosene lamps for nighttime lights but again I'm not too concerned with grid failures lasting very long. There are lights available that run from battery charging of a lantern that could upgrade our capability. My point here is that although if I wanted to burn a lot of money I could have purchased a battery bank, charge controller, backup generator etc. However I felt it better to keep our electricity needs very modest in the first place with super efficient appliances and house, so that the SunnyBoy daytime Off-Grid 1500 watts is a very comfortable amount of Off-Grid capability for no additional cost whatsoever. Incidentally I'm not pushing the SunnyBoy brand particularly. Others have mentioned other brands but I'm simply saying this was the most cost effective solution for our family.

Craig Severance's picture
Craig Severance
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Joined: Aug 2 2010
Posts: 7
Affordable solar electric system with Off-Grid capability

Your characterization of my system is spot-on accurate. It is a basic grid-tied system except with this feature we also can activate a feature to pull 1500 watts of power off the solar panels when disconnected from the grid.

Another feature of our particular system is we have three angles we can set the panels. Flush with our roof is about 22 degrees which we will use in summer. There are also legs we can swing into place to tip up the panels at either 45 degrees (for spring and fall) or 60 degrees (for winter). It takes my son a couple of hours with two socket wrenches to change the legs out four times a year, about 6-7 weeks ahead of the solstice or equinoxes that are the official beginning date for each season.

The adjustable tilt has really helped and we are getting very good KWh production throughout the year. Not much added cost since they are simply two different leg lengths we can use or lay flush.

Our total system all inclusive was about $16,000 before tax credit and our REC has no dollar rebate, just net metering. However I'm not sure of actual retail price since we bought from the solar company where my son works.

The system was just installed and turned on in early October so we are going through our first winter with no chance to build up banked Kwh in better more productive months, and so far up till today we have used about 125 total Kwh over what we have fed into grid.

I haven't put a Kill-a-Watt meter on my critical appliances yet to know how much each one draws so can't answer yet what we can handle with 1500 watts maximum draw. However I'm not concerned if we have to stage them since we have such efficient refrigerator for instance. It is an old Cold Miser brand which I'm not sure is still in business but SunFrost has similarly efficient refrigerators today.

Yes of course up to 1500 watts you can plug in whatever you wish. I mentioned that I think some lantern s exist which have their own battery so that might be a way to charge some lights for use at night when grid is down.

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