Grid tie system with well pump backup

[oakhilltop]

I am considering a solar PV system to tie to the grid. I'd also like to be able to run a well pump when the grid goes down. Our well pump is 25 years old, so a replacement pump is not out of the question. I'm not sure how long we should wait before replacing a well pump.

Typically, we lose power for a few hours, up to a day or two. In general that is not a problem, other than we have no water for toilets, brushing teeth etc. We usually are aware of the possible loss of power and fill the bathtub to have a supply of water for flushing. And there is some water in the pressure tank. During the past few years, we have had a couple of instances where we were without power for 4 to 6 days. We have a shelter, a wood stove for heat, hurricane lamps for light, but no source of water. I have not given in to buying a generator yet. I really don't want another internal combustion engine to maintain, just to use once or twice a year.

If we do install a solar PV system, it just seems logical to use that power during outages. Even if it is just to refill the pressure tank once per day. I'm aware of the turn on current problems of the well pump, although I haven't figured out what my pump's current would be. I've done some research on pumps with soft start, such as the Grundfos SmartFlo. If these would work and my current pump is an issue, I would consider replacing my 25 year old well pump to have water during outages.

I'm posting to draw on the experience of this forum. I've been lurking here for awhile now. Trying to get informed, but I feel like I'm spinning my wheels. I do have an installer coming next week to discuss whether the site is suitable for solar. I would have to remove some trees for sure. I hope the installer can give me some guidance.

Is what I'm thinking of reasonable?
Would the backup add a large extra cost to the system?
Should I be spending more time investigating a new well pump?

Some info on the well pump and water system.
* Pump: Goulds 10EJ05412 1/2 HP 230V 1PH. Well is 275 feet deep.
* Franklin Electric Submersible Motor Controller
Model 2801054910. S.F 1.6 S.F Max Amps = 5.9
* Pressure Tank: Well-X-Trol by Amtrol. WX203

[oakhilltop]

I forgot a few things, including more questions

My plan would be to have the battery bank trickle charge off the grid while the grid is up. So the batteries would be fully charged when the grid goes down. I could manually disconnect from the grid then, connect the batteries to the inverter. The idea being, I would begin the outage with enough charge to run the pump a few times.

I have not been able to find out estimates of battery life when they are just being trickle charged most of the time and only used a couple of times per year. Does anyone have info on the life of batteries in an application like this?

[Sunking]

Well here is the deal. What you ask for is two different systems. Not very economical or practical.

However chew on this:

1. Install a Grid Tied system as large or small as you want, it is not needed to do what you want to do.

2. For the water well just buy you an inexpensive AC powered battery charger, battery, and an inverter to run the pump in the rare event the commercial power fails. Size it correctly and you should be able to pump water for a several days. No expensive solar system is required.

[peakbagger]

http://www.simplepump.com/

One of these might work. The website is short on details but they indicate that you can install the pump in the well casing along with your existing pump and have it discharge into your pitless adaptor in the casing. That means in theory you can use the hand pump to charge up the existing house piping and expansion tank. They offer a DC motor and solar option but that would probably be overkill for most folks.

I would like one but it would be hard to justify. Worse case is I have an old surface well so all I need a a rope and bucket. I have had a generator in my garage for 12 years in northern NH and have never had to use it but the folks down in southern NH do seem to need them on occasion.

[oakhilltop]

I appreciate the replies.

I am in the Seacoast region of NH. We had the October storm last year, I think, and a few years ago we had a December ice storm. We lost power for a few days during both. The December one was especially annoying since it was right around the solstice and it would get dark at 4:30 PM. That one lasted 5 days. I'd like to find a way to get some 12V DC LED lights distributed around the house and run them off a battery when the power goes down.

We are thinking of getting a grid tie system just because we think having solar would be a good thing. Depending on what the costs end up being. We were thinking that it could provide some backup power for the well and perhaps some lights etc, when the sun came out. That would have made the cost of PV more attractive. Its looking like that doesn't work out so well. Still seems strange to me that with a grid tie system, someone doesn't have a manual way of switching it over to a backup system mode. I mean, I have the panels, inverter and could add a few batteries to give me some power.

Given the grid tie system would not be a backup, the hand pump looks cool. But the $1600 price surprised me. So, I looked at some inverters to run the well. What I saw is that I need a minimum of a 1.5K watt inverter to run a 1/2 hp pump. And the inverters are in the $1500 range. I would still need some batteries. Now the $1600 hand pump isn't looking so bad, and it is not dependent on anything.

I will have to see what info I get from the installer. I believe they have a fish eye camera and can feed the pics into software which can calculate the benefits of removing certain trees. Yet another cost for the solar. It may turn out that my site isn't suitable for solar, and I won't have any decisions to make.

[billvon]

Still seems strange to me that with a grid tie system, someone doesn't have a manual way of switching it over to a backup system mode. I mean, I have the panels, inverter and could add a few batteries to give me some power.

That is quite doable - but you have to design that in from the beginning. You will use what's called a hybrid inverter, one that can feed power back and switch to independent operation once the power goes out. For example the Outback GTFX 2524 will give you that functionality, although it's pricey ($2000 or so.)

[peakbagger]

The reason I recommended the hand pump is that I have gone thru the numbers quite a few times and everytime it wins compared to a PV backup. Given that you can pick up a generator for $500 its hard to compete. There is another pump company, Bison, in Maine that competes with Simple Pumps and the prices are about the same. I expect both firms are small machine shops that build them as people order them or keep a small inventory so there isnt a lot of economy of scale. They aslo market to the prepper community who seem to be immune to high prices when they decide to feed their irrational habit.

The NH solar rebate http://www.dsireusa.org/incentives/i...H32F&re=0&ee=0 is generally best applied to a straight grid tie system as if the size of the system gets very large the $3,750 cap will kick in pretty quick. Then again the federal rebate is 30% of the entire system so you can get the fed to pay at least 30% of the extra costs for the battery backup. Realisitically, the firms that do business in the state have figured out the "sweet spot" where they can get the maximum rebates for the minimum owner cost and thats what they will try to get you to install if they are setting up a solar lease.

Good luck on the site survey. NHs rebate is only given to sites with reasonable solar potential, if the proposed installation doesnt meet that criteria, then the installer is just trying to make work and have the fed subsidize a portion of it.

[oakhilltop]

The Outback inverter looks like it would do what I want. I wish the websites would have a category for hybrids. I did find the Outback for under $1800, which doesn't seem like that much more than the standard grid tie inverters I looked at. Solar needs a website like Newegg is for electronics. Newegg makes it much easier to narrow down the search.

Like I said in a previous post, I'd like to have a few batteries trickle charging on the grid and be able to get a few runs of the well pump from them. With the possibilty of recharging the batteries if the sun is out. We often have the Montreal Express come through after a winter storm. When the storm goes into the Atlantic, it draws cold, clear, high pressure air out of Canada with bright winter sun.

Is there info avail to tell me the size of the batteries needed to run the well pump?

If the cost of the batteries is beyond what I want to spend, can a 2 to 4 KW solar panel with inverter system drive the well pump without batteries?
Depending on the inverter I end up with, I might need a step up transformer also.

It would be nice to be able to run the fridge even if it is just when the sun is out. Our fridge will stay cool for a day or so. Sometimes I go out and buy a bag of ice, put the ice in plastic containers, and put a bunch in the fridge. Being able to run the fridge while the sun is out with a few container of ice, would probably save the food for days.

Thanks for all the feedback

[Mike90250]

Is there info avail to tell me the size of the batteries needed to run the well pump?

Well pumps have 2 power specs, running amps or watts, and starting or Locked Rotor amps or watts. The inverter (and batteries) have to be able supply the power needed for starting the pump (about 5 seconds), and then the amount of time you can run the pump, depends on the battery capacity. Don't forget, to use the locked rotor amps, when calculating the DC wire gauge, or the inverter will shut off from low voltage, before the pump spins up.

Mike

[oakhilltop]

An installer came by to look at the site. I attached the measurements of the site. He says the site will work if I remove a few trees, which is obvious from the SunEye picture.

He came back with 2 proposals. The second is larger in order to run an electric water heater, and there is also an option for a electric water heater with a heat pump. They are specing a ACCELERA© 300 HEAT PUMP WATER HEATER for an additional $650.

He also mentioned that there is a Sunny Boy inverter coming out which will provide power during outages, but only when the sun is out. It is a Sunny Boy 4000tl-us inverter

Will the inverters run the 1/2 hp well pump when the sun is out? Is it better to have a buffer of a few batteries to run the pump for a short period if a cloud comes over? It would be a plus if during an outage, I can look outside, see the sun is out, go down to the basement and fill up the pressure tank. Or run some water into a bathtub to use for flushing toilets.

Even if I don't start with batteries, I think I would like to have the option of adding batteries (perhaps I should say storage) in the future. Just in case there is significant progress made in the coming years.

The first system
The system features these major components:

• (20) 245 watt Monosilicon Canadian Solar photovoltaic panels; CS6P-245M or equivalent
(www.canadian-solar.com)
• (1) SMA Sunny Boy 5000 US grid-tied solar electric inverter (www.sma-america.com)
• (135) Feet of Iron Ridge extruded aluminum solar mounting rail with hardware
• (1) Flashed Metallic Junction Box

The second system:

• (26) 245 watt Monosilicon Canadian Solar photovoltaic panels; CS6P-245M or equivalent
(www.canadian-solar.com)
• (1) 85 gallon super-insulated Marathon solar hot water storage tank with electric element backup
• (1) SMA Sunny Boy 6000 US grid-tied solar electric inverter (www.sma-america.com)
• (175) Feet of Iron Ridge extruded aluminum solar mounting rail with hardware
• (1) Flashed Metallic Junction Box

[inetdog]

An installer came by to look at the site. I attached the measurements of the site. He says the site will work if I remove a few trees, which is obvious from the SunEye picture.

He came back with 2 proposals. The second is larger in order to run an electric water heater, and there is also an option for a electric water heater with a heat pump. They are specing a ACCELERA© 300 HEAT PUMP WATER HEATER for an additional $650.

He also mentioned that there is a Sunny Boy inverter coming out which will provide power during outages, but only when the sun is out. It is a Sunny Boy 4000tl-us inverter

1. As far as DWH goes, if you cannot use Solar thermal panels and have to use electric rather than Natural or LP gas, then the most economical way to heat the water is with a heat pump. This assumes that you do your homework and look at where the heat pump will be sucking heat from. If it gets the heat by cooling down a space that is in turn heated by electric resistance heating, it will be a winner in the summer and a big-time loser in the winter.

2. Quote from the preliminary brochure:

One of many unique features to the TL-US
residential series is its innovative Emergency
Power Supply ability. With most grid-tied
inverters, when the grid loses power, so does
the solar-powered home. SMA’s solution
allows daytime energy to be isolated from
the grid and be fed directly to the home
via a dedicated power socket, providing
residents with access to power as long as
the PV system generates electricity.

Sounds promising. It gives you power out to the grid tie when the grid is up and a separate dedicated output circuit for when the sun shines and the grid is down. It needs some more examination of things like surge capability (with no batteries it might be very limited) and what happens to your connected emergency loads when a cloud goes by. I am open to convincing!

It is also an optional feature, so we shall see what the cost is.

[bstedh]

I have a similar situation as yourself. What I did was find a used 2000W UPS/Inverter with dead batteries and wired 3 AGM 12V batteries in Parallel to give me a full day of back up on my sump pump. This was my biggest worry as the basement was already flooded once due to power outage during a large storm a couple of years ago. All of the water came in through the sump! I am currently looking for a 220V inverter to run my well and will do the same for it. I am looking at something like this for the well with a custom battery string. I have to figure out the amperage draw for the well first before I decide on what to buy.

I go with the UPS option for the sump so that I don't have to worry about it if I am out of town for the weekend.

I have fuel oil hot water so as long as I can keep water pressure I am golden. You could even add an oil back up water heater and just run it in parallel to the existing one for cheaper than anything else for hot water if that is a big concern.

Ed

[Wy_White_Wolf]

An installer came by to look at the site. I attached the measurements of the site. He says the site will work if I remove a few trees, which is obvious from the SunEye picture.

He came back with 2 proposals. The second is larger in order to run an electric water heater, and there is also an option for a electric water heater with a heat pump. They are specing a ACCELERA© 300 HEAT PUMP WATER HEATER for an additional $650.

He also mentioned that there is a Sunny Boy inverter coming out which will provide power during outages, but only when the sun is out. It is a Sunny Boy 4000tl-us inverter

Will the inverters run the 1/2 hp well pump when the sun is out? Is it better to have a buffer of a few batteries to run the pump for a short period if a cloud comes over? It would be a plus if during an outage, I can look outside, see the sun is out, go down to the basement and fill up the pressure tank. Or run some water into a bathtub to use for flushing toilets.

Even if I don't start with batteries, I think I would like to have the option of adding batteries (perhaps I should say storage) in the future. Just in case there is significant progress made in the coming years.

The first system
The system features these major components:

• (20) 245 watt Monosilicon Canadian Solar photovoltaic panels; CS6P-245M or equivalent
(www.canadian-solar.com)
• (1) SMA Sunny Boy 5000 US grid-tied solar electric inverter (www.sma-america.com)
• (135) Feet of Iron Ridge extruded aluminum solar mounting rail with hardware
• (1) Flashed Metallic Junction Box

The second system:

• (26) 245 watt Monosilicon Canadian Solar photovoltaic panels; CS6P-245M or equivalent
(www.canadian-solar.com)
• (1) 85 gallon super-insulated Marathon solar hot water storage tank with electric element backup
• (1) SMA Sunny Boy 6000 US grid-tied solar electric inverter (www.sma-america.com)
• (175) Feet of Iron Ridge extruded aluminum solar mounting rail with hardware
• (1) Flashed Metallic Junction Box

No. The inverters will only work when the grid is working. No grid -> no power.

[inetdog]

No. The inverters will only work when the grid is working. No grid -> no power.

A perfectly good answer except if the inverters in question are current hybrid inverter models or the upcoming SMA SunnyBoy TL-US series with the Emergency Power option added. More details are anxiously awaited.

[Wy_White_Wolf]

A perfectly good answer except if the inverters in question are current hybrid inverter models or the upcoming SMA SunnyBoy TL-US series with the Emergency Power option added. More details are anxiously awaited.

The inverter numbers as listed are grid tie only.

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