Updated: New Battery Technology for Solar Panels in Sub-Zero Temperatures

New battery technology for solar panels is always exciting news. Get ready for this battery technology perfect for sub-zero temperature installation sites: Silicon Salt is here.

Proper system design is paramount in off grid living. Choosing a battery technology that makes sense for the location, environmental concerns, access to the site and experience of the end user all play a role. One of the biggest challenges many of our customers face is temperature. How to mitigate capacity loss in colder climates is a question we hear quite often. So, we decided to use our Canadian branch to market test a new battery technology being referred to as Silicon Salt.

These batteries feature an electrolyte of an ultra-micro composite silicon salt forming solution giving them a smaller resistance ratio of 2 mili-ohm, twelve to thirteen times smaller than that of the lead-acid battery (lead-acid batteries are 25 mili-ohm and greater). Because this resistance is so low they are able to be heavily charged and discharged in an astounding temperature range of -40 degrees F up to 158 degrees F.

We have been testing them in various configurations. Currently, we have over 90 of these batteries in 11 systems with regular monitoring and communication from the owners. Our testing is covering small two battery 12V banks for telecom towers to large 48V grid-connected back-up systems and everything in between. They are located outside at fully exposed projects and inside various non-insulated power sheds as well as in insulated garages.

This new maintenance free Silicon Salt storage technology is being widely used by the Military, Telecommunications (UPS), GPS, Computer backup, Electric Vehicles (EV), Hospitals backup power, Airports, and many other applications in many countries. They are being readily used in these industries due to their low maintenance cost and excellent safety.

At this point we have found the claims regarding temperature to be valid. We are not seeing freezing or issues with capacity loss as expected with lead acid batteries. We have also found that after being fully charged and stored for 2 years they have retained 80% of their charge. The only claim we haven’t been able to substantiate quite yet is the longevity claim of 17-20 years. Our Canadian and U.S. testing time period has covered only a two years now.

In evaluating these batteries for living off the grid, we spoke with other testing facilities that have been running them a bit longer at five years. “After running them pretty hard we popped the top off and they looked brand new. There was no sulfation on the plates.” This is likely due to the ultra-micron composite silicon salt forming solution being neutral and thus unable to erode the plates inside.

We are excited to be carrying these batteries for all of these reasons. Obviously, the amazing claims need to be substantiated but so far, so good in our opinion. Additionally, due to the non-toxicity of the materials, they do not require an MSDS for shipment and are considered non-hazardous. They ship typical freight with no additional charges or exceptions. Also, they work well with other components currently on the market. There is no need for a sophisticated battery management system and most charge controllers, set at a sealed battery charging perimeter, work seamlessly with these batteries.

If you are working in sub-zero temperatures these may be a good fit for you. Give us a call for a free custom design of a system with this new and exciting Silicon Salt storage technology. We have them in stock and ready to go for your needs this winter.

UPDATE FROM OUR FRIENDS IN CANADA – MARCH 2016   We have been selling the Silicon Salt battery here in BC Canada for about 3 years. There are over 150 of these batteries installed here to date. There have been no failures in any installation with the exception of one 2V cell which was bad out of the box. It was replaced immediately.

I was skeptical about the claims of the manufacturer about the battery but so far they have met all of stated expectations and more.   The big issue for solar users here in Canada is freezing. The low sun months come with temperatures well below 0 degrees F (sometimes way below 0 degrees F). Low sun hours during those months can cause serious issues with off grid systems. Lead acid batteries will freeze at 32 degrees at 50% charge. This requires attention to the battery and often long hours of generator charging to maintain a state of charge adequate to offset freezing. The -40F freeze point for the Silicon Salt battery is a tremendous relief for solar users in cold weather.

A customer here ordered 12 of the 2volt 500 AH Silicon Salt cells. They were delivered to the site and the owner was called away for medical reasons and the battery sat outside exposed all winter with temperatures below 10 degrees F. When the battery was installed and tested 2 weeks ago (still freezing out) the voltage, under load, tested perfectly at 26.4 volts. We have heard similar comments from other customers.   The local Internet provider has been using the Silicon Salt (SI) batteries for the past 2 years. They have remote (unheated) microwave repeater sites using a variety of voltage SI batteries (the 6 V 220 AH, 12 V 100 AH, and 2 V 500AH). We are happy to report that they have ordered more!

Each week is busier than the last helping the Kootenays region to become energy independent.   Thank you Bob and Cheryl! If you are in British Columbia and would like to visit our showroom in Canada please contact Cheryl and Bob at 250-366-4459 or backwoodscanada@gmail.com



Getting Your Off-Grid System Ready for Winter

Written by Backwoods Technician Alan Smith

Preparing for winter is best practice for extending the life of your off-grid power system, especially for those of you in cold and snowy climates.

Now is a good time to review the maintenance and condition of your power system (even for those of you in warm and dry climates).

It’s better to check on your system at your convenience rather than when something goes wrong in the middle of the night in three feet of snow or a flash flood. Here are the things you should check on and look into if something seems out of place.

Seasonal Angle: For Greater Energy Harvest & Shedding of Snow

If you have an adjustable rack mount for your panels, it is worth tilting them to the ideal angle to properly capture the winter sun.

An appropriate angle can make a big difference in the amount of power collected, especially during the shorter, cloudier days of the winter when sunshine is at a premium.

The ideal angle for your panels is easy to determine. Use the latitude of your location and add 15 degrees. The result is the angle of tilt of the panels, measured up from horizontal that will yield the best harvest during the winter months.

Example:  Sandpoint, Idaho is at 48 degrees north. Ideal winter angle is 48 + 15 = 63 degrees. 

For the folks that have vacation cabins that may only be visited once a month or so during the winter, consider a steeper angle to accommodate easier shedding of snow.

Clear Off the Snow

Remembering to clear off the snow seems obvious, right? Keep a broom or brush on a telescoping handle if needed and clear any freshly fallen snow off the panels on a routine basis.

If you let the snow sit and freeze on the panels, it will take that much longer until your panels are able to collect solar rays again.

It’s a horrible feeling to be sitting at work, when the grey skies open up to sunshine, and you know your array is sitting at home with six inches of snow on it. Make it a regular habit to brush them off whenever it snows.

Generator Tune-up

Now is the time to do your annual generator maintenance.  Besides the basics-oil, belts, coolant level, air filter, and spark plugs-be sure to check your owner’s manual for items specific to your machine. Check on the starter battery. If the generator has not been run since the previous winter, it is very likely that the starter battery may be dead or heavily discharged. Replace or recharge it before you need it.

Off-Grid Batteries

Batteries can be kept in a relatively cold area, with a couple of considerations. First, the energy storage capacity of batteries in a cold climate is temporarily reduced. Instrumentation such as battery monitors can be fine-tuned to reflect a more accurate state of charge.

Temperature sensors for both your charge controller and inverter/charger should also be used for optimum charging points of your batteries. Fully charged batteries, being used on a daily basis, will not freeze until the temperature drops to -70 degrees F. A battery at 50% state of charge, though, can freeze in temperatures as “warm” as -10 degrees F.

Don’t let the batteries get too low. The sulfuric acid in batteries that are being stored or lightly used will tend to stratify. This means that the water begins to separate out from the solution, resulting in layers more like water near the top of the battery and denser layers of sulfuric acid towards the bottom. If this occurs, it is very possible for the water layer to freeze at temperatures near 32 degrees F and crack the battery casing.

Extended Leave

When the power system will be unattended for extended periods of time, we have to make the best of a non-ideal situation.

Flooded lead acid batteries respond best to daily use, so depending on your installation and equipment there is a couple of options available.

Opinions on the best approach will vary. If you have an automatic generator start (AGS) function tied to your inverter/charger and you consider your generator to be highly reliable, the inverter can be left on so that a charging source is available if the panels become covered in snow.

If you do not have AGS, turn the inverter off. Turn all DC loads off. Leave the charge controller on, with the goal of supplying at least a bit of float charge to the batteries each week.

If available, ask a neighbor to check your array after any major snow storm to brush the snow off. One school of thought suggests reducing voltage settings, to reduce water consumption, and setting the equalization to automatically occur once per month.

Tuning Gear, More Panels, & Winter Behavior

The sun tends to be shy in the winter. Let’s take advantage of the days it does show up. An experienced system owner will know how their system responds to normal charging and equalizing. Consider increasing the absorb time and the equalize settings on your charge controller for the winter months.

Keep a notebook handy in your power room and write-down the summer and winter settings that you find work best, so you know what to change them back to when the seasons change. Search mode on an inverter should be enabled year-round, but especially so during the winter. A couple hundred watt-hours per day can make a big difference.

How Many Solar Panels Should I Get?

You honestly can never have too many solar panels, we can all agree on that. How much is too much though?

It depends on your geographical seasonal factors and budgets. The idea being that, if you can manage to get one good sunny day a week during the winter, you’ll really harvest some good power and minimize your generator run-time and fuel use. Long time off-gridders will tell you they simply change their behavior during the winter months.

For example, leaving the coffee pot on for an hour is fine in the bountiful sunny days of summer, but the coffee maker gets turned off after 15 minutes in the winter, and the coffee goes into a thermos. Or better yet, wait until you get into work and make the coffee there! Less TV time and more book reading cuts down on the power used too.

Simple conservation in several small steps (replace light bulbs with LED’s) can add up to a big difference in the amount of power needed during the winter. It’s better to take care of your system now, than to experience failures at the most miserable time imaginable.

Routine maintenance and a thorough knowledge of how your system responds to your daily usage will serve you well, not only for the winter, but for the lifespan of your system as well.

Stay warm and don’t forget to keep your snow chains, a shovel, and a bag of sand in the trunk of your car! If you’re interested in fine-tuning your off-grid power system or setting one up for winter, Contact Us at Backwoods Solar at 208-263-4290 for help designing a customized renewable energy system that works best for you.

Getting Started with Micro-Hydro

Written by Sequoya Cross
Getting started with micro-hydro off-grid power? If you are blessed to have flowing water on your property, you may benefit from a micro‐hydro system that can provide power 24 hours a day. Water turbines steadily charge 12-, 24-, or 48-volt batteries, working around the clock. Compare this with solar modules that are in sunshine for at best six full‐power hours a day, and that’s just on sunny days.

A micro-hydro generator producing 10 amperes around the clock matches the usable power generated by over 40 amps of solar modules. Micro‐hydro is one of the most cost-effective and reliable forms of renewable energy, but planning and site considerations can make the difference between success and failure.

Look ahead to late winter into early spring for the best time to start the planning process. As snow begins to melt and water begins to flow into the foothills you will be able to gather the data necessary for a quality design.

Power from a Micro-Hydro System

The amount of power that your system will generate is dependent on the head, the amount of water flow, and the efficiency of the turbine generator. The head is the vertical drop over the distance of pipe to be utilized. Head correlates with water pressure available since every 2.31 feet of vertical drop equals 1 psi. Flow is measured in gallons per minute (gpm).

These variables will change throughout the stream, so it’s a good idea to take several measurements from areas that you are comfortable tapping or are allowed to tap for energy production purposes. A calculation to figure the available power in watts follows: Multiply head in feet, times flow in gallons per minute (gpm), divided by 13. Example: (H ft x F gpm)/13 = Power in Watts

Components to a Micro-Hydro System

This is the area of the stream where you are beginning the pipeline or penstock for the system. The intake should utilize either natural elements of the stream, or a dam to direct the streams flow into the pipeline. Utilizing the narrowing of a stream and building up rocks will allow a more natural look to your system without disturbing the existing ecological elements.

A place where the stream drops naturally, is stable, and would not alter its course over time is ideal. A screening product should be utilized to prevent debris from entering the pipe.

Pipe or Penstock418
This is the “fuel line” of the system. It is critical that the pipe is sized to minimize friction and “pipe loss.” Too small and you lose potential energy, too large and you are spending excess money for no significant gain in energy produced.

There are many choices of pipe types: PVC, steel, HDPE, etc. The wall’s thickness determines the amount of pressure the pipe can handle before failure. What you choose will depend on your site, the amount of pressure required, the length of the pipeline, what is available locally, friction losses, and, most important, budget.

Turbine HydroPeltongeo92pg3p8
This is the “engine” of the system. There are many different turbines available, each designed for different site considerations. Backwoods Solar has many techs that are very experienced and can guide you through choosing the right turbine for your site.

Turbines are available with different nozzle choices which can regulate the flow during periods of time when the stream’s flow changes due to the season. Turbines include a “runner” or wheel that utilizes the water’s kinetic energy to drive the alternator, which generates the power.

PERFORMANCE DEPENDS ON THE SITE more than on the cost. Greater water pressure at the nozzle, produced by more head (elevation change from the top end of pipe to the bottom), brings more power. Greater water volume (gallons per minute) onto the wheel can also bring more power. Sites with higher head are most desirable because they need less water, smaller pipe, fewer nozzles, costs less to install, and fare better in low water years.

System Types

Stand‐Alone System with Batteries
This system is very similar to an off‐grid solar or wind system where the renewable energy source is charging batteries or a generator system that charges a battery bank. In addition, you will need a controller to protect the batteries from overcharging and a diversion load to accept excess energy when the batteries approach full charge.

Battery-Based Grid‐Tie System
This is very similar to the above example, you will still need the additional components listed, but they will only be used in times of a power outage. When the grid is on, grid‐power will take the lead in charging and regulating the batteries and any excess power generated by your hydro system will be back fed into the grid, reducing your electric bill.

Battery-Less Grid‐Tied System
Like solar or wind grid-tie systems, a grid-tie micro-hydro system produces electricity that feeds back into utility lines. They can use either AC or DC generators. AC systems will use AC generators to feed directly into the grid with the need for an inverter.

An approved shut off device is needed to prevent the system from back-feeding into the grid when the grid is down and under repair. DC systems will use a specific inverter to convert the output of a DC power to AC. The biggest drawback of any battery-less system is that when the utility is down, your electricity will be out too. These systems are designed to automatically shut off at the inverter if the grid fails.

Let Us Help You

Pipe size, number and size of nozzles and choice of alternator depend on measurements of your site. Since there are so many combinations of water volume and head, it is best to Contact Us at Backwoods Solar and describe your creek site so that we can help you custom design the micro-hydro system that works best for you.

Tell us specifically:

  • What elevation change (from intake to the turbine) over the length of the pipe?
  • How many gallons per minute flow, minimum and maximum?
  • What size, type, and length of pipe (if it is already installed)?
  • Wire distance from hydro plant (lower end of creek) to the home or power shed?

Contact Us online or call us today at 208-263-4290 to get started on your project.

Have Solar, Will Travel

All Women's Horse Packing Adventure in Argentina - Off-Grid Power - Backwoods Solar
All Women’s Horse Packing Adventure in Argentina

-By Krista Miller

I have an iPhone. I’m not sure how that happened but I digress. This story is about being prepared whilst traveling with one.

On a whim I decided to join up on an all-woman’s-horse-packing-adventure in a very remote part of western Argentina. I’ve never traveled alone before and this seemed like the perfect chance for me to prove to myself that I could do it. But first I had to make sure I packed smart and light.

I wasn’t allowed in the Boy Scouts when I was growing up but I really identified and still do with their motto “Be Prepared”. I was raised off-grid and know what it means to be self-sustaining. So, my co-workers at Backwoods Solar suggested that I take the Sunjack mobile solar charger and test it out on my trip, I jumped at the chance.

Let me get back to that iPhone again and say that in a previous life I would have left it behind on a trip like this. I mean, I was going to “un-plug”, not to worry about devices and international payment plans. There were two things which happened in succession that lead to my enthusiasm in packing the Sunjack with my iPhone.

One, people insisted I take photos (great camera on that thing). Two, my parents and my husband were worried sick about me traveling alone. So, into my luggage it went and, because I’m a “boy scout”, I winced at the extra weight (1 lb 15.6 oz).

Tack Barn at Estancia Ranquilco - Off-Grid Power - Backwoods Solar
Tack Barn at Estancia Ranquilco

After a five hour drive south to San Francisco, a flight to Dallas, an overnight flight to Buenos Aires, an overnight bus to Zapala, a three hour 4 x 4 drive to the meet-up place, and a three hour horse-back ride, I made it to my destination, Estancia Ranquilco. And wouldn’t you know it, my phone was dead.

That next morning, as I waited for fresh milk from the cow, I hung the Sunjack by its handy carabineer to a metal chair leg that I perched on the main lodge’s veranda ledge overlooking the river facing the eastern sunrise. Just doing that made me feel, well you know, resourceful like Macgyver. I sat back enjoying some Mate as the morning sunshine illuminated the day and charged the Sunjack’s  8,000mAh lithium-polymer battery. After that it would be ready to charge my phone via the 5V/2A USB port.

With my sleeping bag and extra clothes packed on the mules, I was left to pack my saddle bags with just the essentials.  My horse Sultan carried me, the Sunjack, my phone/camera, a wool poncho, snacks, and water. The seven of us headed off into the foothills of the Andes, snapping pictures, and getting to know our horses.

Sultan doesn't mind the Sunjack on his back - Off Grid Power Systems - Backwoods Solar
Sultan doesn’t mind the Sunjack on his back.
Attached and charging - Off-Grid Power - Backwoods Solar
Attached and charging.

When I noticed my phone getting low on juice then I would secure the Sunjack behind my saddle to charge it up again. One of the other women on the trip needed her phone charged at some point and I was more than happy to do that for her (the battery holds enough charge to power up to four smartphones!). It was so cool to be able to continue our tools to function out in the middle of nowhere.

Traveling on my own gave me the confidence to continue seeking adventures like this. I think I was able to be prepared and not feel weighed down by too many devices. I had just what I needed to make myself feel safe. If I needed to I could communicate to my parents, my husband, my friends, and take lots of pictures-all thanks to the power of the sun. Have solar, will travel!


Krista is happily planning her next solo adventure while she fulfills her duties as Executive Assistant at Backwoods Solar. She obviously recommends the Sunjack for all Boy Scouts.

Heating Your Off Grid Home

Heating Your Off-Grid Home - Off-Grid Power - Backwoods SolarHeating Your Off Grid Home

Many options exist for heating your off grid home. Determining how much heat you will need is a great place to start. Optimal temperature range varies so widely depending on your location, comfort level, and efficiency goals you may have. Some folks need only 60 degrees to stay warm while others want their seasonal use cabin to be a toasty 72 degrees. Ninety percent or more of the total energy budget for a home is used for heating, hot water and cooking. There are also options to consider if you are looking at heating for a home in the design/build phase versus an existing home or a remodel. For example, passive solar design and solar thermal radiant is great but to be most effective must be incorporated during construction.

We recommend that you use propane, natural gas, oil, or wood heaters and furnaces, never electric heat. Propane is a good answer, as one large tank can be used for heating, stove, water, and clothes dryer; with one or two fill-ups per year if you are in range for delivery. If age is a factor sometimes doing firewood is a pain so pellets and a pellet stove can be a solution requiring minimal power.

Electric heat pumps use substantial amounts of energy, less than resistance heat, but way too much for independent power. They are reversible air conditioners. Also beware of ducted forced air and blowers. Common in manufactured homes, the blower takes much more power than can be justified.

Cozy brand propane direct-vent (through the wall) heaters save fuel because each room can have its own heater and wall thermostat. No circulation blowers are needed so they work with no electric power. This is the easiest and lowest cost heating installation. Many folks use these to heat rooms that may not receive good air circulation from the wood stove as a zone/supplemental heating.

Wood or gas furnaces located on bottom floor or basement in a multistory home allow heated air to rise by convection from lower to higher floors without powered fans or ducted blowers. Larger ducts for natural convection circulation can work with no power blower needed, or a very low power quiet DC fan to boost output. The Caframo Ecofan or low power fans can also increase efficiency of gas heaters or wood stoves by moving air over the surface of the unit. Some home designs add a space alongside a masonry chimney as a hot air duct to the upper floors, and perhaps also run water pipes through it. Each stairway should have a door to control rise of heated air.

Floor heating by hot water circulation requires power to circulate water. Use of 1/2 inch or larger floor pipes allows a lower power pump. Use separate DC circulating pumps and control each by a thermostat for its zone, rather than zone valves. We have seen problems using special boiler systems and zone valves. We have seen success using tank gas hot water heaters or the wood fired boilers that heat water directly in the storage tank. You can also warm water beds and compost toilets by circulating hot water from the tank through coiled pipes under them and back again. Radiant with wood or propane is possible, but some very careful design should be done before hand. They can be power hogs in the worst time of year and would be easier done with new construction. Remember floor circulation heating puts added demands on your power supply in the season when you have the least power.

Do the research and find the heating solution that is tailored to your needs. Stay  warm off grid!

Off Grid Holiday Gift Guide

The Off Grid Holiday Gift Guide is back! This holiday season the gang at Backwoods got together to dream up some of the items in our catalog that we would like to see this gift giving season. We think most off-gridders would agree. Here is a selection of some easy to purchase, and affordable tools and gadgets that fit the off-grid lifestyle we all love. Go to our website for more information on these unique and thoughtful gifts for the off grid folks you know!

This is the Super Ventilation Fan you’ve been looking for!

Large DC Super Fan - Solar Panels - Backwoods Solar
The S is for Super because it’s packing  a powerful brushless motor.

Looking for a new DC ventilation fan? Backwoods is now manufacturing, here in the USA, a brushless 16 inch, 12/24 V ventilation fan. Our fan is designed to meet your needs every season, either in the greenhouse or as an attic install. Intended for use with 12 volt or 24 volt solar panels as low as 30 watts up to 280 watts and can be used in conjunction with 24 volt battery banks. It will also perform with 285-300 watt,  72 cell modules with open circuit voltages of 44 volts. The F16-Plus is protected from moderate over-voltage and thermal fluctuations.

The Super Fan has been tested through a variety of panel and voltage configurations. We recommend three configurations for “small”, “medium”, and “large” applications. “Small”: all 12 volt panels; a 30 watt solar module will provide an airflow of about 9 mph. “Medium”: a 60 watt will produce up to 17 mph. “Large”: a 135 watt or larger solar module will hit 18 mph and faster.

The best thing about our new DC Super Fan is the brushless motor. Motor brush replacements were common on previous fans especially if they were run at high RPM’s. With no brushes the F16-Plus will outperform other fans. Solve your circulation issue with this solar direct solution! Check it out here

Humanitiarian Outreach and International Projects


Fuel to run generators became scarce and expensive after the Haitian earthquake. Many of the schools and clinics did not have proper lighting. Sun Energy Power International (SEPI) and Solar Energy International (SEI) reached out to companies in the solar field for help. Answering that call were  Backwoods Solar Electric Systems and Alternative Energy Engineering with donations of solar modules. Morningstar donated charge controllers, and Ed Eaton of Our Sun Solar built and donated LED lights. Most of the systems went to 15 physicians who had taken a training course the year before. Some went into schools where people slept and others went to Doctors without Borders.


Backwoods Solar Electric Systems worked in conjunction with SEI to design and supply product at a discount to Border Green Energy Team who educate and install solar systems in Burma and Thailand. These systems serve thousands of people within the community who rely on clinics that need power for lighting nighttime surgery, vaccine refrigerators, medical devices, etc.


In Nigeria, Backwoods Solar worked with NIGCOMSAT & Project Engineering to design solar powered systems for the numerous Community Telecenters in the country. These systems have been installed both in urban and rural areas. The systems use Outback Flexware 500 power panels, and roof mounted Kyocera modules. The telecenters provide broadband service, have laptops, servers, and communications equipment that the communities can use. The solar energy system powers all of the equipment and lighting needed for the communities to be successful in their goals. We are currently providing quotes and system design ideas for an additional 1500 systems.


This project was installed in the Democratic Republic of Congo, and one that we were very excited about. Backwoods worked with a satellite telecom company to provide solar power to 220 remote towers. We reviewed the specifications with the client and designed each system to provide continual solar power using two Yingli modules, MPPT charge controllers, and Deka batteries. These telecom towers were installed in remote areas of the DRC in an effort to have people who have not had the chance to vote, vote for the first time in the upcoming presidential election. After the election the systems continued to provide telecommunications service from village to village. We have been asked to provide an additional 4,500 systems to help expand the communication infrastructure in the future.