Lithium Ion battery bank

rboggia85 · December 2013

http://www.lithionicsbattery.com/solar.html

curious as to how large of a battery bank I will need on my offgrid home. Everything is propane for the most part. I have about 40 10 watt recessed LEDS, a well pump that pumps 10gal per minute it runs off 240v. GE refrigerator, GE dishwasher, Washer + dryer, led smart tv, Rinnai propane hot water. thats really about it not much more for juice..

I was looking at a 48V400A-8D-CTRL400 51.2 volts and 400 lithium amp hours. Would this be sufficient for my setup? I have not bought solar panels, inverters or charge controllers but have been looking into the outback systems radian 8 series i think is what i need given my pump is 240v

I am thinking Sanyo Hit panels a full pallet to start. my goal is to have extra power incase i want to plug more in later. http://www.solarhome.org/sanyo225wmodulehit-n225a01hitpower225aPalletof20.aspx?gclid=CPyY_4r72LsCFfJxOgodNiQA4g 20 hit panels N series these are the ones i want to get will start with 1 pallet of 20 then if i need more ill get more

We live on the Coast of Maine 10 minutes from the border so not much sun, plenty of wind! although i really dont want to listen to a windmill. We have 65 acres so I could potentially put one off in the distance.

pretty sure i covered all bases... Thoughts? Advise? hit me with all you got I want the pros to chime in. this needs to be a grade A setup and i want all of the forums help doing so! I have a highly skilled electrician who will put everything together just need to know the best components to buy. I am going to post pics of house here shortly but pretty much its 65 acres off grid in a small town called Whiting, Maine nearest neighbor is 1 mile as the crow flies and 3 miles by road. nearest pole is 3 miles. off grid living at its finest. Ok im done rambling lets here what you guys got for advise ill post up some pics.

rboggia85 · December 2013

Re: Lithium Ion battery bank

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So here is the house from the outside. A few things need to be finished still. Inside needs appliances installed but i already have them all picked out.

Pretty much we are ready to setup the power supply. goal is to have extra power to run LED grow lights so we can have continuous vegetable garden indoors. each grow light is 60w and we will start with 4 of them they will be on for 12-16 hours a day.

mike95490 · December 2013

Re: Lithium Ion battery bank

Wow. Wait a minute. Do you have grid power in the neighborhood at all ? Do you know the Hp of the well pump? What size pressure tank does the well & pump have ? Lot's of ?'s for ya

Any electric bills from the "city" that you can use as a baseline ?

2 energy star fridges, energy star washer & dryer, TV, 2 laptops and a few lights and we burn 5-10 KWh a day

Are you doing your own solar design ?

rboggia85 · December 2013

Re: Lithium Ion battery bank

No grid. Nearest pole is 3miles. Well pump is 240v she pumps 10gal a minute into a 110gal pressure tank.
Plan is to come up with a solar design myself with the help of the forums.

solarix · December 2013

Re: Lithium Ion battery bank

Lithium batteries are great, but expensive of course. Their main advantage over Lead-Acid is they are so much lighter which in a non-portable application like off-grid solar is hard to justify.

BB. · December 2013

Re: Lithium Ion battery bank

Neglecting the LiIon batteries for a moment--Just a simple full off grid system design for Portland Maine using PV Watts (you might also try SolarElectricHandbook for more cities in your area--Portland may not have the same weather as you). A fixed array tilted to latitude would give:

Month    Solar Radiation (kWh/m 2/day)
1      3.73     
2      4.85     
3      5.25     
4      5.17     
5      5.32     
6      5.37     
7      5.73     
8      5.56     
9      5.18     
10      4.34     
11      3.14     
12      2.96     
Year      4.71

I think 10 kWH per day is about the minimum power you would "expect" for your home (you could easily go 33 kWH per day with not too much power effort--Central heat, a few computers, toaster oven, coffee maker, a freezer, etc...

A lead acid battery bank sized for 1-3 days of backup power and 50% maximum discharge--A 2 day + 50% usually is a good "balanced" bank size. And for larger systems, 48 volt battery bus:

10,000 WH * 1/0.85 inverter eff * 1/48 volt bank * 2 days of storage * 1/0.50 maximum discharge = 980 AH @ 48 volt battery bank

You can "adjust" the days of storage and maximum discharge range to something else--If desired.

Then there is the size of the solar array--Two calculations. First is the size of the array to properly recharge the battery bank. For Lead Acid, that would be 5% to 13% rate of charge with 10% to 13% being a pretty nice choice (fast battery recharging, good mixing of electrolyte, etc.):

980 AH * 59 volts charging * 1/0.77 panel+charge controller derating * 0.05 rate of charge = 3,755 Watt Array minimum
980 AH * 59 volts charging * 1/0.77 panel+charge controller derating * 0.10 rate of charge = 7,509 Watt Array nominal
980 AH * 59 volts charging * 1/0.77 panel+charge controller derating * 0.13 rate of charge = 9,762 Watt Array "cost effective maximum"

Next, is to support the desired loads per day... Of course, many folks have different loads in summer vs winter, pumping, A/C, Heat Pump usage, etc... Tossing the bottom three months (assume using generator when needed), that gives us October at ~4.34 hours of sun (long term average):

10,000 WH per day * 1/0.52 system eff * 1/4.34 hours of sun per day = 4,431 Watt array minimum (based on October Sun)

You should never plan on using 100% of your predicted power every day--Probably count on a base load of ~66-75% or so of predicted output. This allows for loads to grow, guests, bad weather, etc... If you have loads that can be rescheduled (washing clothes, water pumping for irrigation, turn off the A/C) or start the genset when needed.

A 980 AH @ 48 volt Lead Acid battery bank would work well for a maximum of 9.8 kW AC inverter and around a 12.7kW maximum solar array (based on our typical rules of thumbs).

Any numbers (batteries/PV Array/etc.) within ~+/-10% is pretty much within the margin of error.

Your thoughts?

-Bill

Blackcherry04 · December 2013

Re: Lithium Ion battery bank

Design by Forum, wow thats a huge task even for collective minds. You cannot build a Solar system a piece at a time . Your going to spend in the $80,000 range easy to support a house like you have. It's $30-$40,000 to do a 1,000 sq ft house and then your cutting corners to be off-grid. The generator support alone is in the $20,000 range depending on what you want, batteries $10-$12,000.

What direction does the house face ?? You have some major shading issues to deal with if you intended to put panels on it. A large ground mount within a close distance to the house in more in order.

I am thinking Sanyo Hit panels a full pallet to start. my goal is to have extra power incase i want to plug more in later. http://www.solarhome.org/sanyo225wmo...FfJxOgodNiQA4g 20 hit panels N series these are the ones i want to get will start with 1 pallet of 20 then if i need more ill get more

Your looking at 50 + panels would be a better guess based on BB's calculations. At 12kw you can figure 18k kwh on average year, that means a low year of 14k to a high of 22k, kwh. There is nothing consistent about weather, except it's never the same.

Best Forum advise is to hire someone that has been Designing and Installing systems your size for at least 5 years and has verifiable customers with installs to back up their claims of successful operation. Buy their advise and DIY or let them have the headaches, get it done turnkey.

rboggia85 · December 2013

Re: Lithium Ion battery bank

BB. wrote: »
Neglecting the LiIon batteries for a moment--Just a simple full off grid system design for Portland Maine using PV Watts (you might also try SolarElectricHandbook for more cities in your area--Portland may not have the same weather as you). A fixed array tilted to latitude would give:
Month    Solar Radiation (kWh/m 2/day)
1      3.73     
2      4.85     
3      5.25     
4      5.17     
5      5.32     
6      5.37     
7      5.73     
8      5.56     
9      5.18     
10      4.34     
11      3.14     
12      2.96     
Year      4.71
I think 10 kWH per day is about the minimum power you would "expect" for your home (you could easily go 33 kWH per day with not too much power effort--Central heat, a few computers, toaster oven, coffee maker, a freezer, etc...

A lead acid battery bank sized for 1-3 days of backup power and 50% maximum discharge--A 2 day + 50% usually is a good "balanced" bank size. And for larger systems, 48 volt battery bus:
10,000 WH * 1/0.85 inverter eff * 1/48 volt bank * 2 days of storage * 1/0.50 maximum discharge = 980 AH @ 48 volt battery bank

You can "adjust" the days of storage and maximum discharge range to something else--If desired.

Then there is the size of the solar array--Two calculations. First is the size of the array to properly recharge the battery bank. For Lead Acid, that would be 5% to 13% rate of charge with 10% to 13% being a pretty nice choice (fast battery recharging, good mixing of electrolyte, etc.):
980 AH * 59 volts charging * 1/0.77 panel+charge controller derating * 0.05 rate of charge = 3,755 Watt Array minimum

980 AH * 59 volts charging * 1/0.77 panel+charge controller derating * 0.10 rate of charge = 7,509 Watt Array nominal

980 AH * 59 volts charging * 1/0.77 panel+charge controller derating * 0.13 rate of charge = 9,762 Watt Array "cost effective maximum"

Next, is to support the desired loads per day... Of course, many folks have different loads in summer vs winter, pumping, A/C, Heat Pump usage, etc... Tossing the bottom three months (assume using generator when needed), that gives us October at ~4.34 hours of sun (long term average):
10,000 WH per day * 1/0.85 inverter eff * 1/4.34 hours of sun per day = 2,711 Watt array minimum (based on October Sun)

You should never plan on using 100% of your predicted power every day--Probably count on a base load of ~66-75% or so of predicted output. This allows for loads to grow, guests, bad weather, etc... If you have loads that can be rescheduled (washing clothes, water pumping for irrigation, turn off the A/C) or start the genset when needed.

A 980 AH @ 48 volt Lead Acid battery bank would work well for a maximum of 9.8 kW AC inverter and around a 12.7kW maximum solar array (based on our typical rules of thumbs).

Any numbers (batteries/PV Array/etc.) within ~+/-10% is pretty much within the margin of error.

Your thoughts?

-Bill

so based on your calculations exactly how many of those solar panels should i buy? and you stated 980AH the lithium bank i was looking at is only 48v 400ah so would that mean I need to ordered two of these units? Also how many panels would put me in the nominal range? they are 225w panels module efficiency 17.1 %. Thanks for all the help!

BB. · December 2013

Re: Lithium Ion battery bank

I am sorry, I had made a mistake in typing up one of the formulas:
10,000 WH per day * 1/0.52 system eff * 1/4.34 hours of sun per day = 4,431 Watt array minimum (based on October Sun)

I used 0.85 inverter efficiency instead of 0.52 system efficiency (solar panels + charge controller + battery bank + AC inverter efficiency).

If you pick a 7,509 Watt array (10% nominal charge), in December the array would (on average) generate around:

7,509 Watt array * 0.52 system efficiency * 2.96 Hours of Dec sun = 11,558 WH = 11.6 kWH per day

To recharge with a very efficient AC charger a 980 AH @ 48 volt battery bank at 20% rate of charge (10-20% rule of thumb), you would be looking at generator in the range of:

980 AH * 59 volts charging * 1/0.90 charger eff * 1/0.95 power factor * 1/0.80 genset derating * 0.20 rate of charge = 16,906 WH (VA) rated genset

That is not a small generator and you have to pick a charger or Inverter/Charger to mate with the genset.

If you have 225 Watt solar panels and want to use a ~7,509 Watt array:

7,509 Watt array / 225 Watt panels = 33.4 panels = 34 panels minimum

Then you have to pick a MPPT type Solar Charge Controller based on your setup and local temperature (sub freezing temperature increases solar panel output voltage; high temperatures reduce array voltage). Using Midnite Solar's sizing tool:

http://www.solar-electric.com/misoclcoto.html

Model HIT Power 225A or HIT-N225A01
Rated Power (Pmax)1 225 W
Maximum Power Voltage (Vpm) 43.4 V
Maximum Power Current (Ipm) 5.21 A
Open Circuit Voltage (Voc) 53 V
Short Circuit Current (Isc) 5.66 A
Pmax temp coeff -0.336%/ °C
Voc temp coeff -0.147 V/ °C (this should be -0.277%/°C as used by website sizing tool)
Isc temp coeff 1.98 mA/ °C
NOCT 114.8°F (46°C)
CEC PTC Rating 209.1 W
Cell eff 20.2%
Module eff 17.8%
Watts per Ft.2 16.22 W
Maximum system voltage 600 V
Series Fuse Rating 15 A
Warranted Tolerance (-/+) -0% / +10%

Plug into calculator (as always, check my work--This is your system)...

Using a Midnite Classic 200 with 3 panels in series and 12 parallel strings (actually two charge controllers with 3s*6p strings each) appears to work well.

Attachment not found.

Again I am not an expert in this--Just trying to put your data into Midnite's software. Double check everything and talk with NAWS (our host) or Midnite if you have any questions.

Also, this is based on a minimum of 10kWH per day of power usage (our guesses and your original back pick). Electrical usage is a set of highly personal choices. While 10 kWH per day may work OK for my home (it is close), it may not really work well for you.

One option you may wish to consider... Run a genset for a few weeks to power your entire home using appliances, computers, etc. as you would normally--And measure your power usage. See how much you are using with the genset and decide where to go next from there.

Solar power is a highly variable source of power--You have to decide what is the minimum power you will need per day (vs clear days when you can use more power). You will have to make that power up with a genset and/or larger solar array.

A 17kW diesel genset will easily use 2-3 gallons per hour of diesel at full load. If using gasoline or propane, even higher GPH usage. And if propane, you need a large propane tank to maintain pressure during cold weather (or use liquid propane and a vaporizer on genset--In -40F weather, an above ground propane tank may not even pressurize).

Do lots of research/paper designs before you start buying hardware. Mistakes on this size of system can be very costly.

-Bill

rboggia85 · January 2014

Re: Lithium Ion battery bank

alright so if I buy 40 panels and 2 of the 400AH battery banks then i should be good to go. I also have a 60kw diesel genset runs at 1800rpm puts out 55kw continuous. built for prime power. could use that to recharge if need be... but id like to build the system so the generator never has to turn on. that big of a gen is probably overkill for recharging that small of a bank anyways.

so the next step is to get the proper controllers. Check this out let me know what you think. http://www.ebay.com/itm/Outback-GS8048-8kW-48VDC-120-240VAC-COMPLETE-SYSTEM-grid-tie-off-grid-OFFER-/290737906785?_trksid=p2054897.l4275 its the OutBack COMPLETE SYSTEM with GS8048, 8000W 48VDC 120/240VAC Off-Grid/Grid-Tie Inverter. I am pretty sure this will fit my system.. correct?

BB. · January 2014

Re: Lithium Ion battery bank

You have to go through each major component (MPPT charge controllers, AC inverter and charger output, breaker sizes, etc.)...

My first concern is your solar panels and the Outback charge controllers. I suggested a 200 VDC rated Midnite and 3 panels in series. With the Outback, I believe you will need to limit your array to two panels in series (your panels have a higher Vmp than some others)--This will mean that you need to check the wiring for proper gauge and voltage drop (lower array voltage means larger diameter cable from array to charge controllers). Also, you will need a combiner box to manage ~10 solar arrays in parallel with fuses/breakers (it was 6 for the Midnite configuration).

The FM 60 controllers look like they would be OK for 20 panels per array (again, you have to check the planned configuration to ensure that everything works well together).

Do you need a 120/240 VAC system? You can get into a bit of pinch balancing the Line A and Line B hots of your 120/240 VAC split phase system. If you have some big 120 VAC loads, you may be limited to ~50% to 70% of the AC inverters full rating on one leg.

Still very concerned about your loads and if 10kWH per day is "good enough" for your needs. This is a big expense. But the Radian is expandable--So you can go larger.

Of course, if 10kWH is really too big for your needs (you are very efficient with your energy usage). You have higher costs and ongoing maintenance.

-Bill

mike95490 · January 2014

Re: Lithium Ion battery bank

wait - PLAN first, plan it all FIRST - then think about buying gear

rboggia85 · January 2014

Re: Lithium Ion battery bank

BB. wrote: »

You have to go through each major component (MPPT charge controllers, AC inverter and charger output, breaker sizes, etc.)...

My first concern is your solar panels and the Outback charge controllers. I suggested a 200 VDC rated Midnite and 3 panels in series. With the Outback, I believe you will need to limit your array to two panels in series (your panels have a higher Vmp than some others)--This will mean that you need to check the wiring for proper gauge and voltage drop (lower array voltage means larger diameter cable from array to charge controllers). Also, you will need a combiner box to manage ~10 solar arrays in parallel with fuses/breakers (it was 6 for the Midnite configuration).

The FM 60 controllers look like they would be OK for 20 panels per array (again, you have to check the planned configuration to ensure that everything works well together).

Do you need a 120/240 VAC system? You can get into a bit of pinch balancing the Line A and Line B hots of your 120/240 VAC split phase system. If you have some big 120 VAC loads, you may be limited to ~50% to 70% of the AC inverters full rating on one leg.

Still very concerned about your loads and if 10kWH per day is "good enough" for your needs. This is a big expense. But the Radian is expandable--So you can go larger.

Of course, if 10kWH is really too big for your needs (you are very efficient with your energy usage). You have higher costs and ongoing maintenance.

-Bill

I am really liking the midnite controller. Sounds like its a step up from the Outback fm60. All i want is the absolute best. The only reason why i chose a 120/240 system is for my well pump it runs on 240v i had a beefy one installed, we do a lot of gardening.

Can I use the midnite controller in conjunction with the Radian system? or should I stick with outback and upgrade to the fm80? I really like the looks of the flexmax extreme how does that compare to midnite as far as quality is concerned?

BB. · January 2014

Re: Lithium Ion battery bank

The founders of "Outback" sold Outback and went on to start "Midnite"--So you will see Midnite as an evolution from Outback.

Midnite (and Outback) both have active solar forums too.

Midnite is doing a lot of ongoing development (Internet connections, much easier to upgrade firmware, wind/micro hydro based MPPT capabilities). Lots of new firmware based functions. And they have an integrated battery shunt to control charging current/defined termination current/state of charge of the battery bank/etc.

Read about both and see what works well for you... Either has a long history of reliable operation (and idiosyncrasies).

I have a Grid Tied system--So I am not the best person to ask about off grid component details in day to day use (I, and the other moderates here, are not in the Solar Business).

-Bill

Sulfur · January 2014

Re: Lithium Ion battery bank

As others have said, don't buy any hardware until you have your system fully designed. I would not buy those panels from SolarHome if this is a DIY project. I have bought 2 Sunny Islands by SMA and 2 Outback Autoformers from SolarHome at a good price, they are a good company but consider buying your panels on Ebay for DIY project, I bought 1/2 of mine from MLSolar on Ebay and was happy with them, my panels are 240 watt Sharp's, less than 1/2 the cost/watt of the ones your considering. For the loads your proposing, I would want at least 50-60 panels. You should also get a small generator for backup, the one you have is not practical or economical for a solar house, it might be practical for Bill Gates house.

jcheil · January 2014

Re: Lithium Ion battery bank

rboggia85 wrote: »

The only reason why i chose a 120/240 system is for my well pump it runs on 240v i had a beefy one installed, we do a lot of gardening.

It may save you a TON of money and hassle to just stick with 120v and replace the 240v well pump with a newer 120v model.
There have been several people on here in the past few months with that same situation where the only 240 they needed was for a pump and they ended up being a lot happier replacing the pump with a 120v model and eliminating all of the 240v stuff.

You could also get a 120v->240v transformer to run the pump but again, when all said and done, you would likely have less money and hassle invested just changing the pump to 120v.

mike95490 · January 2014

Re: Lithium Ion battery bank

jcheil wrote: »

.... when all said and done, you would likely have less money and hassle invested just changing the pump to 120v.

If, you can live with a 3/4hp or less pump! The larger the pump, the more AC amps, the more copper wire needed to carry them, and on the DC side (regardless of the AC voltage) you still have to have enough copper and battery, to not have voltage sag shut the inverter off for Low DC.

1,000W AC =
83 amps @ 12V
21 amps @ 48V

And the 1 second starting surge is at LEAST 4x that.

jcheil · January 2014

Re: Lithium Ion battery bank

mike95490 wrote: »

If, you can live with a 3/4hp or less pump! The larger the pump, the more AC amps, the more copper wire needed to carry them, and on the DC side (regardless of the AC voltage) you still have to have enough copper and battery, to not have voltage sag shut the inverter off for Low DC.

1,000W AC =
83 amps @ 12V
21 amps @ 48V

And the 1 second starting surge is at LEAST 4x that.

I was talking about the newer VFD pumps that a bunch of people on here switched to.
Yes they are more expensive but from what I have seen have no surge and don't even draw as much as the old pump would when running.

It would be something to look into. Like I said, several people here in the recent past had the SAME issue and were happy with the results of switching to the 120v VFD pumps.

Lithium Ion battery bank

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