batteries

Off Grid electricity is NOT free.

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Out with the old… The T-105’s are being retired.

I believe I am guilty of promoting free energy on the off grid homestead, and during the summer months it appears that way.  However, during the winter months cloudy skies make solar energy creation improbable, and it’s the battery bank that keeps the home’s electricity going from day to day.  When the fog and inversion continues throughout the week, a 5 gallon jug of fuel is added to the generator. The generator is fired up to produce the home’s power and to fill the battery bank for a few more days.

Winter is the time of the year when an off grid home realizes they are not living “free”.  Perhaps a nice sunny equatorial home would provide the energy the home needs and less reliance on a large battery bank.  But even then, a home close to the equator has a constant 12 hours day and night. In which the daylight begins at 6 and ends at 6 in the evening.  If only we lived on the equator… but I really like the 4 seasons, so that’s out for now.

If you are thinking about going off grid, depending on where you live and what your winter is like as far as darkness and climate, you will want to size your battery bank accordingly.  Our new bank, if we conserve, can get us about 4 days, without direct sunlight.  We have added so many new systems that require more power and we added to our family another person, so power usage has naturally increased.  More lights are on, our fridge runs more often, and the phantom load of the Internet and the propane tankless water heater begin to add up over a few hours.  If I remember, like I just did, I shut them off.

As seen in the video,  I crunched the numbers and our new battery bank (basic electric bill) is estimated at $25.00 a month over a 10 year period.  That’s not bad, but that doesn’t include the generator maintenance or the fuel for it.  A 5 gallon jug is required to charge the battery bank from 50% back up to 100% and to equalize them.  Without equalizing, it’s about 4 gallons of fuel needed.  I am keeping tabs on our generator usage this year with the new bank and tractor generator; it will be nice to be able to prepare a constant monthly budget by spreading the winter expenditures year round.

Off grid electricity is NOT free!

If my wife and I lived on the grid in this area and had solar panels that covered our electrical usage, the power company would still charge us a $25.00 minimum monthly hook up fee.  That doesn’t seem fair, but with many people trying to save money with increasing electrical bills the power companies do not want people wiggling out from their profit margins, plus someone has to pay for all those linemen who repair the down wires after a devastating storm.  Either way off grid or on, you will have to pay someone for your electricity.  As electricity bills increase, so does the price of batteries. The T-105’s I first bought were $155 each in 2011; this year they are $180 a piece.

If you are thinking about supplementing your on grid home or building an off grid power system, now is the time to start because prices are always going up.

When the Battery Bank Dies…

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At the end of this past summer, our battery bank of seven years decided to die.  It was an interesting cascade failure event.  One batter cell went dead and could not be revived, then another battery flagged a similar problem.  Pretty soon I was isolating batteries that would no longer hold a 6 Volt change.  The isolation meant I had to drop from a 3 string battery bank to a 2 string system.  I ordered the batteries at the perfect time.  The sun was shining well into September which carried the system long enough until the replacements arrived.  I was happy to receive them, another few weeks and we would have been in real trouble, running a generator to make due for the lack of electrical storage.

The video published was in a file waiting to be edited and published.  I admit blogging and YouTube videos which have grown intertwined has dwindled, and I discussed that briefly on another post.  Currently, I am enjoying Christmas break and I am gearing up for the return to teaching after the New Year’s holiday. I hope this post and the New Year 2019 greets you well.

My wife and I plan to make a list of this year’s highlights this evening and save them to be read next year.  It will be a bonding time between us as we recognize our successes despite the obstacles around us, including replacing a dying battery bank. I plan to include my son in the event as well, and I am curious to hear his own version of events.

May you enjoy this New Year’s Eve, celebrating with family, friends, and have a chance to reflect on the highlights this year.

God Bless,

Here comes the sun…

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Getting a charge... Our cat hangs out with the solar panels on our first official sunny day after weeks of gray skies.

Getting a charge… Olivia, our matriarch cat, hangs out with the solar panels on our first official sunny day after weeks of gray skies.

After a dreary month of January, the sun is making its appearance again.  We are all relieved and choose our own way to bask in sun’s warm rays. The solar panels have produced very little and we have relied on the storage capacity of our battery banks and the back up generator on a weekly basis for the past month of January.  Our power consumption ranges anywhere to a 10 %-15% drop in our battery bank’s power reserves each day.  What that translates to is an average drop of 90-100 amps a day or 2160 – 2400 watts  day of our 675 amp or 16 kilowatts of stored power in our battery bank.

Center of the universe... Our cat Copernicus unlike his name sake believes the sun revolves around him.

Center of the universe… Our cat Copernicus, unlike his name sake, believes the sun revolves around him.

To slow power consumption, I have begun shutting the well pump off and have relied on the stored water in the cistern to get us through to the next time we fire up the generator.  With the well pump’s float valve switch turning the well on, we consume more power and end up needing the generator more often, about every 4th – 5th day instead of every 6th or 7th day.  The two more days may get us to a partly sunny window in which we can go a few more days and so on.

Nothing but blue skies... When denied the basics in life, like the sun, something we take for granted becomes very dear and special when denied.

Nothing but blue skies… When denied the basics in life, like the sun, it becomes very dear and special.

Living sustainably is not an after thought when it comes to power consumption.  It has to been constantly in my conscience mind, especially when living off the grid and relying on the sun for electricity.  If my wife and I didn’t plan our power usage; such as when to fill the cistern, vacuum, wash clothes, and make candles for the business, we would be running our fossil fueled generator every couple of days in the winter.  Where is the sustainability in that?  It’s not and even though we are off the grid, we are still not completely self-sufficient because of our need to supplement our power in the winter with a gasoline generator.  I have a desire to remedy this.  I have looked into HHO generators, gasifiers, methane generators, wind turbines, thermo-electric generators, and a even bicycle generators.  However, each new generator takes time and money to construct, something I lack in both at the moment.

Hot & Cold... Our dog lies on the cool cement floor while basking in the warm sunlight.

Hot & Cold… Our dog lies on the cool cement floor while basking in the warm sunlight.

For the time being, I am constantly looking at ways to conserve electricity during the dark winter months.  We use LED lights throughout the house and even have an LED TV. We eliminate our phantom loads by using 6 strips on appliances that want to draw power constantly.  When we go to sleep, I power down the house by shutting the inverter off and everyone has a flashlight in case of a late night emergency.

Everything is better with the sun... Krista is cleaning up in the kitchen and enjoying the sun's beautiful warm rays on this cold winter day. During the summer the tilt of the Earth doesn't allow the sun's rays to enter the home.

Everything is better with the sun… Krista is cleaning up in the kitchen and enjoying the sun’s beautiful warm rays on this cold winter day. During the summer the tilt of the Earth doesn’t allow the sun’s rays to enter the home.

Now the sun is making its treasured appearances more frequently.  February is our transition month.  When the sun makes its appearances, the solar panels take over and keep the battery bank charged.  The generator will most likely not be called to action until late October or early November of this distant fall.  Truly a time for celebration.

So far, we haven’t had to bring out the generator for the month of February.  The sun has been gracious enough to show itself at key alignment times with our solar panels.  Currently, as of writing this post, our battery bank is at 70% charged and the cistern is 100% full.

A realistic look at the Tesla Powerwall

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The Specs of the Tesla PowerWall found at http://www.geek.com/news/tesla-launches-3000-powerwall-battery-for-your-home-1621832/

The Specs of the Tesla PowerWall

So what is all the hype about the Tesla Powerwall?

Is it really anything new or just a redesign of what is already out there? Is it new technology or just new packaging?

Let’s take a fresh look at the Tesla Powerwall specs…

  • Telsa 10 kw Powerwall
  • Lithium-ion
  • Quantity 1
  • 10 kilowatts of stored power = $3,500.00, not including shipping
  • 350 – 450 volts
  • 8 – 8.6 amps
  • 10 year warranty

Here are the specs of my personal battery bank I currently live with in my off grid home.

  • T-105 6 volt battery
  • Lead acid
  • Quantity (12)
  • 16.2 kilowatts of stored power = $1,860.00*, not including shipping
  • 24 volt system
  • 675 amps
  • 1 year warranty

If you are deciding to create an off grid home, money is usually an issue. Actually, usually money is an issue in all occasions to some degree, but most customers want the most they can for their dollar. At this point, the old lead acid battery technology still provides more for the dollar than the Tesla Powerwall. Personally, I think it is great what Eon Musk is trying to do, but is his technology ready for the mass market?

After watching the documentary Revenge of the Electric Car, I suspect Tesla may be jumping the gun slightly since it has not yet proven its battery technology on the open market. 10 kilowatts is not that much power for the price. Sure, it’s lithium-ion versus lead-acid, but the numbers don’t add up. Currently, my battery bank has turned 4 years of age and with proper maintenance these past few years, they still are functioning in their prime. I am predicting I will have 10 years on them easily, which gives Tesla at least 6 years to prove their batteries on the open market. The only item on Telsa’s list is the warranty, 10 years, which is great. A person could buy the Tesla Powerwall for “peace of mind”, but if they need to use the warranty, they are without power until Tesla approves the replacement.

How much stored power could I have if I bought $3,500.00 of lead acid 6 volt batteries?

I have a 24 volt system, meaning I currently have four, 6 volt batteries in one string to make 24 volts. I have 3 strings of batteries, 4 batteries in each string which equals 12 batteries total. If I spent $3,100.00 on the Trojan T-105 batteries, I would have 5 strings or 20 batteries. My storage capacity would be an amazing 27 kilowatts of power almost 3 times the Tesla Powerwall, now that puts stored battery power into proper perspective.

*price at Backwoods Solar at $155.00 per battery, not including shipping

Electricity: The 411 on the battery bank

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(12) T-105 6 volt batteries capable of 675 amps of stored electrical power

(12) T-105 6 volt batteries capable of 675 amps of stored electrical power

The Battery Bank, not a pretty picture, but most battery banks for an off grid home usually are not beautiful, just functional. This is our stored electrical power and how we power the home at night and during cloudy or low solar producing days. What you are seeing is (12) T-105, 6 volt batteries hooked in parallel and series. Each battery has 225 amps of stored power. Each row creates 24 volts x 225 amps = 5400 watts. To understand how much power that is, I could run one 60 watt incandescent light bulb for 90 hours, or I could bake a potato in a conventional electric oven for 1 hour.

The reason we bought the T-105 batteries is because we wanted a battery that would work well for us also we didn’t want to break our other bank of the piggy kind.  We also figured since we never had an off grid house before that to experiment and learn on an expensive battery bank could be costly, especially if we made mistakes in maintenance or neglect.  However, we have had these batteries for 4 years now and they still function as if in mint condition. I would consider replacing these batteries with the T-105 batteries again when the time comes.  If I decide I want more power to last longer in the winter months, I could easily modify the battery box for a 4th string, increasing my overall battery storage to 900 amps or 21,600 watts.

Calculating a fair estimate on how long a battery bank will last due to the home's use.

Calculating a fair estimate on how long a battery bank will last due to the home’s use.

Since 3 rows are here, we have 675 amps of stored power times 24 volts or    (675 x 24) = 16,200 watts of stored power. Amps x Volts = Watts. Now there is an important rule to follow. Never discharge your batteries to 0% of power. It creates a dead battery for one and also limits the life of the battery. Since these are deep cycle cell batteries, the manufacturer recommends not using them below 20% of charge. When discharging or using the energy down to 20%, the batteries life on average is capable of 700 recharges to full before the batteries begin to degrade significantly. So technically, we only have 80% x 16,200 watts = 12,960 watts of usable power.

This is where the game begins, having a home that functions like a conventional home, but uses the least amount of power in all its appliances to stretch the need to recharge through the cloudy days to the next sunny day or partial sunny day for a recharge. Because we designed our home to function efficiently, we do not worry about how much power we are using from February to late October each year, the solar panels keep the batteries powered up during these months. Unfortunately, from November to January, we have to rely on a backup generator for about 5 – 7 charges during these 3 months (Electricity: When the backup generator is called upon…).

Another way to maintain battery life is to create a comfy environment for them. I built the battery box in our utility room. The utility room is part of the main house and the temperature fluctuations aren’t as extreme as if stored outside. Extreme cold can greatly reduce battery efficiency, so to store them outside in an unheated environment isn’t the best option to maintain battery efficiency. I also placed a 2 inch foam board on the bottom of the box to prevent the cold concrete floor from cooling the batteries below room temperature. I placed a fan direct to outside in the box as well that when turned on opens the outside vent and blows out any off gassing hydrogen from the batteries without letting cold air in. Also, the battery box is directly below the inverter and charge controller, so the electricity doesn’t have to travel far. I also equalize them every month. In the winter I use the generator, but in the spring, summer, and fall months the solar panels are scheduled to equalize the batteries through the charge controller. After I equalize the batteries, I always make sure to add more distilled water to them.  I usually end up adding about a quart of distilled water to the battery bank of 12 batteries once a month.

Energy Efficiency Kit possibly at your local library.

Energy Efficiency Kit possibly at your local library.

If you are interested in finding out more about how much power you use on average in your home.  There is a unique program starting at our local library in which a patron can check out an “Energy Efficiency Kit”.  I have a feeling this program is offered in several states, if not nationwide, since I found the same kit on a library website in California.  It includes a meter and pamphlet that explains how to measure your electricity usage.  It’s not necessary to have, but it’s an easy way to see how much power certain appliances use.

Sorry about all the mathematics, but when I asked my high school math teacher when I would ever use math again, I had no clue what I was in for.

 

Electricity: When the backup generator is called upon…

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Rigid 6,800 watt generator. Out in the cold and doing its job like a champ.

Rigid 6,800 watt generator. Out in the cold and doing its job like a champ.

What to do when that sun stays hidden behind the clouds for weeks on end? Well, the answer is a backup generator powered by non-ethanol, high octane fuel. To take the batteries from 35% of discharge to 100% full is about four hours of generator time on our 6,800 watt Rigid generator from Home Depot. To equalize the batteries or overcharge the batteries enough to clean off the lead plates, it takes about 6 hours, which we do once a month. This picture was taken on our fifth time we had to use the generator this year. We used the generator twice in January 2014 and again from November through January 2015. So from February through October, it is all solar. During November through January, it is a mix of fuel and solar. We use about 3 gallons of gas for each charge up from 35% to 100% full on the battery bank. We used the generator 7 days this past year, so our electric bill is about an average of $4 per gallon times 21 gallons used, which equals an $84 electric bill for 2014 and early 2015.

I admit I have not maintained my generator as I should have.  It was a financial compromise when I bought it.  It is a loud, loud, machine, making a lawnmower seem like a peaceful babbling brook. However, the generator has been a faithful companion, has run everything I have asked it to and without complaint.  I just add oil when necessary and purchase the highest octane gas for it.  If I was to use the cheaper gas, it could cause serious problems for the carburetor if I let it sit as long as I do between uses. During the last charge of the season, I run it one extra time with fuel stabilizer for 5 minutes to prepare it for the next winter.  The generator has run out in the rain, snow, sleet, and hail.  The generator has shaken loose its air filter, its electronic shutoff buttons, and casing for the 240v plug, but it still works fine as we rigged the air filter with bailing wire, shut off the generator using the gas shutoff valve, and carefully plug in the house to the 240v plugin.  It has been a great generator for the past 5 years.  Before we installed the solar panels and batteries, it ran every day for a few hours.  When I installed the batteries, it ran every 4th day.  Once the solar panels were installed, it runs only 7 times a year at the most, thus far.

The generator protected from the elements in the pump house.

The generator protected from the elements in the pump house.

Now most of the time, we leave the generator running in the pump house to quiet the noise and protect it from the elements. The generator charges the house, but also runs the house at the same time it is charging.  During this time, we turn the well pump on to fill our cistern, run load after load of laundry, sweep and vacuum the house, and we top off our batteries on our laptops and cell phones.  By doing this, we are preparing our battery bank to last till the next sunny or partially sunny day.  Our batteries are rated for around 700 discharge/charge cycles at 20%.  This means the batteries will be taxed to a point of no return around the 700th charge cycle if we drop to 20% charge each time. During the winter we never allow our battery bank to drop below 30%.  When our battery bank approaches 40%, we begin planning to use the generator to charge the system.  Since we use the generator only seven times a year, that doesn’t mean our batteries will be good for 70 years; however, if we properly maintain them, we should easily get 10 years out of them.

For this generator, we hope to retire it before it shakes itself apart for a hydrogen generator in the future, an exercise bike generator, and a generator which uses the difference in hot and cold to create electricity on the wood cook stove, a TEG / thermo electric generator.  However, I believe we still have plenty of time left until this die hard generator’s retirement.

Update: “Generating Repairs” posted January 21st, 2017