# Large solar power system. (Kit, or pieces?)



## thestartupman (Jul 25, 2010)

I am looking to install a 4-5 Kw solar power system on my place. This system will be off grid. I am trying to do research about piecing my own system together using the best prices I can find, or to go with a kit from http://www.wholesalesolar.com/, sunelec.com, http://www.bluepacificsolar.com/, or another company that I have yet to decide on. To start with, I understand that when you look at each of the companies websites, you are not comparing apples to apples. Each one has different types of equipment, and also different items may or may not be included. Any thoughts or ideas from those that already have put systems in would be great. Any specific websites or equipment recommendation would be great also. Anything to watch out for would be great too. Please don't start off with, you need to figure out how much power you are going to need. That is what I am finalizing right now.


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## TnAndy (Sep 15, 2005)

I'd go 48v, for sure. Smaller wire required, allows more panels per charge controller, etc.

You plan to ground mount, or roof mount ?


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## lynnemabry (Dec 28, 2013)

We used a local company. That way if and when we have trouble we can take in the box in for troubleshooting. 
We can also use their knowledge and experience. 
Plus, it keeps more of the $ in our local community.
They helped us plan a 5 kW system that we bought and installed over a couple years.


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## thestartupman (Jul 25, 2010)

It will be a ground mount system.


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## TnAndy (Sep 15, 2005)

Lot of kits include the racking. If you're ground mounting, I'd use pipe and galvanized angle like I've done....lot cheaper.

I don't see any real advantage to "kits", I guess. I'd about bet they won't have every single thing you need (like in the way of disconnects, lightning arrestors, etc)...so you'd still have stuff to buy.


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## SteveRobertson (Aug 27, 2015)

I agree with TnAndy, 48V gives strong advantages over lower DC voltages. Even if you plan to hire someone to perform the work, having a basic idea of what it's all about can be beneficial for you. If you want an idea of how to calculate your own requirements, I have a primer here:
https://www.youtube.com/playlist?list=PL881BEC0EFE5870D4


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## MichaelK! (Oct 22, 2010)

I'm in the process myself of designing my second-generation system for my mountain home. This is a kit I'm looking at from Renogy.

http://www.renogy-store.com/3600W-24V-Polycrystalline-Solar-Cabin-Kit-p/kit-cabin3600p.htm

My plan is to couple this to a power center like this one.
http://www.wholesalesolar.com/14400...r/magnum-single-ms4448-w-no-charge-controller

Lastly, I want to be running it at 48V, so add 8 Trojian L16 batteries.

Ideally, I want something that can handle the 1.5hp 240VAC Grunfos well pump I have. I really, really want to get away from running my generator to pump water.


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## JeepHammer (May 12, 2015)

The inverter switch, switching from battery to generator is a good idea, but can be complicated.
When I run my generator/welder it charges batteries, it powers the home/shop, it pumps water, ect.

With my water, to run minimum batteries, is on a timer, pumps during peak sun.
I can run the pump in the dead of night off batteries if I need to, but I'd rather use a little larger holding/pressure tank and run during peak sun so a small battery bank isn't deep cycled.
During peak sun (10am to 2pm generally) I have enough panel to run the pump and charge batteries, even on a partly cloudy day.

During peak sun, I can also run the washer and dryer at the same time without issues,
Add in the dishwasher and water pump, and I'm pushing it, but that just means I have the panels fairly well balanced with the load I'm using.

I have a golf cart that runs on a 48 volt battery string,
Plugging in the golf cart when we aren't using it adds about 1/2 again as much battery reserve. 
No sense in letting all that battery power sit idle when you aren't using it for transportation or work!


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## tonyaboggs (Sep 1, 2015)

The Greatest kit I have found and LOVE because I can buy as I need or money allows its great with kids growing up using more and more power >LOL. But really here a link you can check it out. Everythingsolarpower.net


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## TnAndy (Sep 15, 2005)

Yeah, a one post wonder raving about a 'kit' with 200w of panels, 35amphr battery, and a 1500w inverter. Your typical "solar generator" by another name. What a pile of spam.


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## SteveRobertson (Aug 27, 2015)

MichaelK! said:


> I'm in the process myself of designing my second-generation system for my mountain home. This is a kit I'm looking at from Renogy.
> 
> http://www.renogy-store.com/3600W-24V-Polycrystalline-Solar-Cabin-Kit-p/kit-cabin3600p.htm
> 
> ...


The setup you're talking about is nearly identical to mine. I run a 240VAC pump at 280' deep well, and it works fine. My batteries are similar to L16 but are the FullRiver AGM type. My inverter is the Magnum Magnasine 4400 watt pure sine wave inverter. It's a good setup. I also have 4.8kw solar panels and a 48vdc Thermodyne wind turbine. The pump usually kicks on a couple times each night when we take showers/baths.


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## AndrewD (Nov 24, 2015)

I imagine that you could save a lot of money by buying separate pieces and putting together a system by yourself. It might even make for a fun project if you&#8217;re mechanically adept. At the same time, a kit could save you many headaches. I suppose it depends on how mechanically inclined you are versus how much money you&#8217;re willing to spend. You could look at Solar to the People, which is a really good site that lets you compare quotes on different systems. This link takes you to a page where you can compare different quotes: http://solar-to-the-people.com/solar-quote/ 

Solar to the People doesn&#8217;t really do kits, where you&#8217;re getting all the parts and then constructing it by yourself, but you could always use it to compare the price of a full system to the price of a kit. There are many great websites that can help guide you through the process of deciding what works for you. There&#8217;s one site called PVWatts ( http://pvwatts.nrel.gov/index.php ) that can help you figure out how much energy you&#8217;ll be able to produce with your system. Another good site is the photovoltaic pricing trends document issued by the U.S. Department of Energy: http://www.nrel.gov/docs/fy14osti/62558.pdf 

This document is a bit complex, but it does offer some good information on the prices of solar energy across the U.S. Lastly, here&#8217;s an FAQ that I think you might find helpful: http://www.seia.org/about/solar-energy/solar-faq

Good luck!


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## MrsRaspberry (Sep 21, 2004)

--deleted--


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## MrsRaspberry (Sep 21, 2004)

SteveRobertson said:


> The setup you're talking about is nearly identical to mine. I run a 240VAC pump at 280' deep well, and it works fine. My batteries are similar to L16 but are the FullRiver AGM type. My inverter is the Magnum Magnasine 4400 watt pure sine wave inverter. It's a good setup. I also have 4.8kw solar panels and a 48vdc Thermodyne wind turbine. The pump usually kicks on a couple times each night when we take showers/baths.


We have started getting quotes for our off-grid system on our new-home build and the first one gave us sticker-shock (55K)! Just wondering how much (ball-park figure) you had to spend for this type of system. It looks similar to what we are considering. Thanks for any help!


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## Alaska (Jun 16, 2012)

Research is your key. And there are some smart folks here. If possibly you can find a local solar guru to set you up the money you spend up front can have many paybacks in the next few years if you make that when you have issues. On that same note be careful it is someone who has been around and intends to stay around.
On the internet one of the most helpful I have run into is backwoodssolar.com. At one time everyone that worked for them lived off the grid so they know what they are selling.


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## TnAndy (Sep 15, 2005)

MrsRaspberry said:


> We have started getting quotes for our off-grid system on our new-home build and the first one gave us sticker-shock (55K)! Just wondering how much (ball-park figure) you had to spend* for this type of system.* It looks similar to what we are considering. Thanks for any help!



That may, or may not, be high. 

You'd need to post the specifications of the proposed system for anyone to give you an informed opinion, otherwise it is impossible to say.


IF you're attempting to live off grid with an on grid use style, that figure may well be accurate.....and possibly low !


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## MrsRaspberry (Sep 21, 2004)

TnAndy said:


> That may, or may not, be high.
> 
> You'd need to post the specifications of the proposed system for anyone to give you an informed opinion, otherwise it is impossible to say.
> 
> ...


Thanks Andy,
We had incorrectly over-estimated our usage and now estimate from cost of materials up to what load it can support (7600 watts/day). We priced the batteries, controller/inverter, panels, poles (20 panels, controller, 24 2vdc 1050 Ah batteries, poles is about $23K)

Please can someone verify our well pump load calculation?
240vac well pump: 3.3amps rating with service factor of 3.9amps up to 300' depth.
Pump 3.9x240=surge, 3.3x240=running, figure 20min/day for 5gal/min for 100g/day so 3000g/month

We came up with 576 watts per day required to run the well pump.
Is that correct?


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## Steve_S (Feb 25, 2015)

There is some good discussion here but something is missed in this, like most other similar topics. CONSERVATION is worth far more $ when your looking at going off-grid. It's much like the old saying "An Ounce of Prevention is worth a Pound of Cure".

We all like our gadgets and conveniences but being smarter about them, using less of them or ones who are not energy hogs will save you a lot of initial outlay (building a big Solar System) and lifespan operating costs + eventual replacement items like Batteries.

I have a 280' deep Well with a Grundfos 5SQ, 120V Soft Start water pump. Solar Friendly, produced 45PSI without a blink and being "soft start" means no big massive pull on power when it starts up ! My 3Kw Inverter/Charger doesn't blink and even my small 3Kw Inverter Generator barely nudges out of Eco Mode during startup.

240V items can crush your power usage quickly, as can electric motors, any form of electric heat (resistance) and even inefficient lighting. Consider that my Well Pump cost me $750 (same price for a 240V model) but uses 1/3rd the power to start & run... Then consider how much extra power I would need to generate & store for a 240V which is more panel, battery & bigger inverter, or inverter/charger. For Example; Electric Hot Water tanks on solar systems is, simply put, insane ! 3kw+ running 15 mins per hour to keep water warm and doing nothing, all day & night long, there or not.... 

Granted I do not have a large family with kids and all the trappings that go with it (even just the necessary ones) but before I decided to go this route I looked at all the energy hogs and sought out the lower power alternatives & solutions which suited my needs today and down the road. I didn't cheap out on critical's or essentials either, like the water pump for example, as these items must be dependable & reliable.

Being frugal and reducing power consumption is the smartest thing to do and does not have to cause any hardships or difficulties... Audit what you use, challenge your preconceptions and look around at a globe filled with alternative methods, technologies... It is interesting to see how people are "rediscovering" methods & technologies that were used 500, 1000 even 2000 years ago and applying them today... did you know that in ancient Babylon they had evaporative cooling, then think about the Romans and their Heated Floors and running water (including hot in some cases) 

My own Solar System is 2.1kw panels, 3kw Inverter/Charger combo, 8 Rolls S-550's in 24V config and all in cost me under 9K (including my 3Kw Inverter Generator) which can be auto-started by the Inverter/Charger to back charge the batteries if/when needed.


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## wy_white_wolf (Oct 14, 2004)

MrsRaspberry said:


> Thanks Andy,
> We had incorrectly over-estimated our usage and now estimate from cost of materials up to what load it can support (7600 watts/day). We priced the batteries, controller/inverter, panels, poles (20 panels, controller, 24 2vdc 1050 Ah batteries, poles is about $23K)...


 How did you come up with that size of a battery bank? By my calculations it's undersized for your load.

You should only use 20% of the battery capacity in a day. so with a 7600 WH daily load you'll need a about a 1600AH @ 24VDC battery bank. That would also give you 2.5 days autonomy before discharging to 50%.

WWW


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## red-beard (Jan 10, 2016)

Steve_S said:


> There is some good discussion here but something is missed in this, like most other similar topics. CONSERVATION is worth far more $ when your looking at going off-grid. It's much like the old saying "An Ounce of Prevention is worth a Pound of Cure".
> 
> We all like our gadgets and conveniences but being smarter about them, using less of them or ones who are not energy hogs will save you a lot of initial outlay (building a big Solar System) and lifespan operating costs + eventual replacement items like Batteries.
> 
> ...


Steve, you have it absolutely correct. Before going solar, look to convert everything you can over to another fuel source. Wood for heating, etc.

Minimize what you need, look to VFDs for water pumps or have a water tower. Every house in Mexico has a 250 gallon (1000 liter) tank on the roof. If using standard pumps or motors (Air Conditioners) get soft starters which minimize in-rush current.

Look at your electric needs. Don't just add up all the appliances, you'll oversize the system. Make choices on what you will run at the same time. Don't use the dryer when the toaster oven or microwave is running. You can setup switches (double throw) to power one outlet or another to prevent yourself from running high draw appliances at the same time.

OP and everyone else, we build systems. They aren't kits, except for the solar panels, since we pre-assemble everything and generally install in NEMA4 (water proof) enclosures. We include everything you need, breakers/disconnects, batteries, and even an automatically controlled generator. Cost is generally LOWER than than many kits when comparing apples to apples. And they are far easier to install.

And we only use UL equipment. Many of the kits use inverters that are not electrically rated for use in the USA or Canada. Not saying they aren't going to work or aren't safe. But they are not tested. LOTS of the inverters on the market are this way.

If you want to see our systems, goto www.mi-grid.com


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## Bellyman (Jul 6, 2013)

Not sure if it's a bit of an off-shoot of the topic, but it's relevant...

I noticed in one of the posts, the idea of using eight L16 batteries. When getting to that size of a battery bank, would it make sense to start checking out forklift batteries? I've heard a few people talk about going in that direction for larger solar setups.

Kinda wondered what some of you guys think of that. I'm more of a spectator at this point and no dog in the fight like some of you guys. But I enjoy the discussions... and hopefully learn a little along the way.


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## red-beard (Jan 10, 2016)

Bellyman said:


> Not sure if it's a bit of an off-shoot of the topic, but it's relevant...
> 
> I noticed in one of the posts, the idea of using eight L16 batteries. When getting to that size of a battery bank, would it make sense to start checking out forklift batteries? I've heard a few people talk about going in that direction for larger solar setups.
> 
> Kinda wondered what some of you guys think of that. I'm more of a spectator at this point and no dog in the fight like some of you guys. But I enjoy the discussions... and hopefully learn a little along the way.


A lot of the battery price depends on what features come in the batteries. I prefer sealed AGM batteries with a recombinant catalyst. I also reprogram the chargers to limit/prevent off-gassing. 

And for me, it depends on the use. If I know I'll be going to 80% DOD everyday, I'll stick with a standard lead acid deep cycle since the premium doesn't pay at that level. Also for standby power that is rarely used.

For multiple cycles per day, I install carbon/graphite fluid batteries which increase cycle life. The premium is 20-30% but they last twice the cycles at 30-50% DOD. 

The only other choice is LiFePo4, which is a great battery, but is about 10X initial cost. You can discharge them nearly 100% and get 8000-10000 cycles. I use these in Military and Offshore where long life is most important.


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## wy_white_wolf (Oct 14, 2004)

Bellyman said:


> Not sure if it's a bit of an off-shoot of the topic, but it's relevant...
> 
> I noticed in one of the posts, the idea of using eight L16 batteries. When getting to that size of a battery bank, would it make sense to start checking out forklift batteries? I've heard a few people talk about going in that direction for larger solar setups.
> 
> Kinda wondered what some of you guys think of that. I'm more of a spectator at this point and no dog in the fight like some of you guys. But I enjoy the discussions... and hopefully learn a little along the way.


Apples Vs Potatoes

L16 simply refers to the size of the battery case. I've seen lots of them in forklifts and street sweepers.

A forklift battery would be a mobile industrial battery where a solar battery would be closer to a stationary industrial battery. Each have there strong and weak points.

Mobile industrial batteries will be built more robust on the inside usually containing plate separators. That way they can handle the abuse of being shaken around in a moving vehicle. Stationary batteries don't need that. The plate separators also impair the mixing of the acid which could speed up stratification when used as a stationary battery. That doesn't affect them when used mobile as the movement keep the acid mixed up.

So ,yes you can use forklift batteries in a solar system and many do as they are easy to find used/cheap. But they are not the best choice.

WWW


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## Steve_S (Feb 25, 2015)

Please Read this article which explains battery tech quite nicely...
Battery Chemistry
By: Justine Sanchez
*Published In: HomePower Magazine*
Issue #179, May / June 2017
https://www.homepower.com/articles/solar-electricity/equipment-products/battery-chemistry


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## ericliu126 (Jun 6, 2017)

seems lifepo4 don't mean lifemnpo4, they are quite different.


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