Emergency solar powered battery generator

Last winter we had a power failure which is something that happens often here in rural Maine due to snow and wind storms, but what was unusual was that my automatic backup generator didn't start.  I went out and tried to manually start it and it wouldn't go.  Turns out the valves were badly out of adjustment.

 

While I do have a substantial solar power system, it is grid inter-tied which means that it must power down in the event of a power outage so it cannot feed power back into the grid and harm the line workers.  I can't affort a huge whole house battery system like the Tesla Powerwall which would cost over $20,000.

 

So I was without power for four days, and that was quite tedious to say the least.  I had to keep wood stoves going in both my home and workshop to keep them warm and I was melting snow to flush toilets - and also peeing outside as often as practical.  I did have an old car battery and a 300 W inverter that I could use to power my phone and a few lights, but without Internet I also didn't have any entertainment other than what I could do on my phone.  However, my biggest concern was losing food in my fridge and freezer.

So I purchased a factory reconditioned Ecoflow Delta 2 solar generator for under $600.  This amazing device can put out over 1800W to power AC devices like lights, and my refrigerator.  It also has multiple USB charging jacks.  But more importantly, it can charge from solar, vehicle 12 V power, or AC power from an outlet. 

Since this unit can be charged from solar panels I did a lot of research and found a couple of Eco-Worthy 195W solar panels for about $300 so that I could charge the Ecoflow when the power has failed.  These are bifacial panels meaning that they can gain solar energy from both the front and the back.  In the winter with light reflecting off the snow this can add 15% more power.  Since power outages frequently happen when there is snow on the ground, I figured this was a smart move.

In order to get the solar power into the house, I drilled a hole through the wall and installed a short length of PVC pipe that I can cap on each end. 

I connected the two solar panels together with large hinges so I could fold them together face-to-face.  I then purchased a bunch of aluminum angle and riveted it together to create a tilt stand.

With the panels folded up I can easily move them on a dolly - they weigh over 40 lbs.  So I can store them in my workshop and deploy them easily.

 

 To connect the solar panels to the generator I purchased a special 12AWG 25FT Solar to XT60i Cable for that purpose.  The orange plug goes into the generator and the black MC4 plugs connect to the solar panels.  I wired the two solar panels in series so one just connects to the other then this cable connects to the other remaining ends.

 This photo shows the generator powering my refrigerator at 269W.  The generator is completely silent and uses lithium iron phosphate batteries that can be deep cycled thousands of times.

I drilled a hole in the floor and ran an extension cord down into the basement, along the basement ceiling, and back up behind the refrigerator which is about 20 feet from the generator.  You can see the cable going down to the floor in the picture on the left.

So now I leave the extension cord plugged into the outlet for normal usage, but when the power fails I simply move it over to the generator, turn on the generator, and then deploy the solar panels.

This system gives me a sense of security because my automatic standby generator is old (1200 hours of run-time) and could fail again in the future.  While this system does not provide enough power for my well pump, it does give me plenty of power to run my fridge, lights, TV system etc.  

In my initial tests at this time of year when there is plenty of sun the solar panels can charge generator in several hours.  Then the generator can run the fridge for over 16 hours each day and I could let it coast for the other few hours since I would not be opening the door at night.  

If there was not sufficient sun, I could always take the generator over to my car and plug it into the accessory outlet to charge it.  My Chevy Bolt EV has over 45 kW of battery-power that I could use sparingly.  My automatic backup generator does not provide power to my charging station, but I could go to a public charging station top off the battery in my car if needed.

If I need more battery capacity, I can purchase an ECOFLOW DELTA 2 1024Wh LiFePO4 Expansion Battery for about $500.  It's about the same size and shape as the generator and sits on top and would double the capacity of the system.

While this system is not cheap, it does provide real peace of mind.  And I could also use the generator to run power tools in locations where there is no power such as up to camp or my backwoods where I might need to run an electric chainsaw.

Removing my old solar augmented heating system

In 2001 my ex-wife and I purchased this property in rural Maine that included an open two-story barn that I converted into a heated and insulated workshop. Moving from California to Maine I was well aware I would need a heating system, but wanted to keep the carbon footprint as low as practical. With that in mind I super insulated the building with a combination of spray in foam and fiberglass resulting in R30 walls and R40 roof insulation.

Original solar collectors in 2003

6 new solar PV panels 2024

I then designed a hydronic heating system that included in-floor heating and radiators upstairs.  The heat source came from a Bosch Aquastar propane heater and 4 large 4 x 8' solar water collectors. I was not particularly impressed with the contribution from the solar collectors and my propane bills were relatively substantial over the years. So a few years later I installed a wood stove as a backup heating system which worked out really well. I now use it whenever the temperatures outside drop below 20°F.  I now purchase about one cord of fire wood per year and augment that with wood that I harvest from my own property and other places.

new solar electric panels installed bottom right

In November 2021 I self installed a MrCool heat pump system designed to heat the entire building using only electricity which is mostly renewable thanks to my substantial solar array and renewably sourced utility electric supply. I then removed the solar collectors and replaced them with six solar panels, you can see a video about this process here. 

 As part of the removal process, I had a great deal of left over copper pipe that I was able to sell to a recycling company for over $130.  I also sold the four large solar collectors to someone who could make good use of them.

I kept the interior plumbing and heating system thinking that I could use it as a backup.  But in the last few years I have not used it so I decided to decommission it.  The large insulated tank seen in the picture is an 80 gallon water heater used as the solar thermal heat storage tank.  And of course there is a great deal of copper plumbing parts, pressure tank, and the propane boiler.

I took everything apart very carefully so that the copper could be recycled and other parts could be reused.  I literally saved every nut bolt and screw along with wire nuts and every other small component and put them back into my storage system.

 

There is a local guy who recycles metal as his side hustle, so he came by with his large trailer and hauled off all the parts that could be recycled.  I'm sure he made some good money on all that.

Here is a view of my utility room all cleaned out.  I'm now waiting for the propane utility company to disconnect the line so I can remove the boiler.  I'm hoping to find a buyer for this well used, and well loved Bosch Aquastar unit that is still working great.  The interesting feature about it is that it does not require any electricity to operate so it's optimal for off grid situations.

 

Here are before and after views of the manifold and PEX plumbing that feeds into the floor.  I left the PEX in place just in case a future owner chooses to install a radiant heating system in the floor.  Here is how I installed the PEX.

As someone who is committed to living sustainably, I am invoking the 4 R's - Reduce, recycle, reuse, repair.  So in addition to scrapping out the metal I also donated some of the useful plumbing parts to the Habitat for Humanity Re-store near me so that someone else can use them.  And I'm also selling some of the more valuable parts such as the pumps on eBay as they are in good usable condition.  All in all, very little went into the trash. 

It was sad to say goodbye to all of this equipment because it took me many, many weeks to design and install back in 2001.  Back then, heat pump systems were not common and very expensive.  What has happened over the intervening years is that solar power system installers are also now installing mini-split heat pump systems because it is a natural pairing.  Heat pumps are very efficient and have the benefit of both heating and cooling.  

While heat pumps are relatively expensive, and installation costs can range from $5000-$10,000, I installed my own heat pump system in the workshop at a cost of less than $2000 and another larger system in my home for less than $2800.

My nearly new Chevy Bolt

Chevrolet Bolt

I have owned two Chevy Volts starting back in 2012 when I first heard about the vehicle and was a huge fan.  It was GM's experiment to see how people would handle a plug-in electric vehicle with a "range extender" gasoline powered generator on board.  They studied aggregated data from their OnStar system and found that the average commute was about 45 miles so they designed the vehicle to run that far in electric mode and then it would switch on a four-cylinder gas engine that powered a 50 kW generator to provide electric power to the vehicle while operating at approximately 40MPG.  It was a have your cake and eat it too solution that worked for me for over 12 years.

They introduced the Chevy Bolt in 2017 - this is a fully electric vehicle with a range of over 200 miles.  My 2021 model has an EPA rated range of over 238 miles in theory (more on that later).   I purchased it used from a nearby dealer for very reasonable price of $18,500 with only 12,000 miles on the clock.  The reason it was so affordable is due to the battery issue that this vehicle had which had caused some fires - a couple of which burned down houses.  GM identified the problem as a manufacturing defect in the batteries and offered three options for owners of these vehicles:

1. They would replace the battery if it was a known defective one.
2. They would install updated software in the vehicle that would limit the charging range to a maximum of 80% charge so as not to stress the battery.  And the update would also monitor the battery very closely.  If any of the battery cells showed heating or degradation issues they would then replace the battery.  If nothing shows up after 6200 miles they would consider the battery safe to drive and would then increase the battery back to the full range.
3. They would simply buy the vehicle back from the owner.

Car dealers took advantage of this situation and purchased them inexpensively from GM.  My dealer had sold 40 of these recalled vehicles last year.  In some cases these vehicles had batteries replaced, and in others the software update had been installed.  This was the case with my vehicle so the range is limited to  around 180 miles nominal.  This suits my needs perfectly since over 95% of my driving is local, and on longer trips I can simply stop at a super charging station for an hour or so to add over 200 miles range quickly. 

On a recent trip where I drove around 120 miles round-trip I returned home with 29 miles range left.  I was carefully monitoring the miles remaining and the range gauge which we EV owners refer to as the "guess-o-meter" changed from green to amber to warn me of this limited range when it dropped below 30 miles.  Temperatures on this trip were in the mid 30s and low 40s Fahrenheit so I was using some cabin heating which draws down the battery, and I also took advantage of the heated seats and steering wheel which use a lot less power to keep me warm.  

I plugged the vehicle into my level II (240V) charging station and it was fully topped up after about seven hours.  If I were to plug into a (level III) super charging station while on the road, I could fully charge the vehicle in about 1.5 hours. All electric vehicles are provided with a charging adapter for a regular 120 V outlet and this would take about 16 hours for the Bolt.  So clearly it makes sense to install a home charging station. The Bolt draws more power from my home charging station - about 6 kW compared to only 4 kW for the Chevy Volt so I can get more miles of range per hour of charging while charging at home.  

it is important to know that the Volt and Bolt both need to be kept plugged in to a charging station at all times. The reason for this is that the battery needs to be maintained at a comfortable temperature or it could be damaged.  I have an energy monitor that shows that during the winter months the charger delivers power to a heating system in the vehicle periodically in order to maintain a safe temperature for the battery.  I recently saw a news story about some people who got into their Chevy Bolt and it refused to let them drive it until it had warmed up the battery.  Clearly they had not left the vehicle plugged in so it was actually draining the battery down throughout the day in an effort to keep the battery warm.  If you drive with a very cold battery, it can be damaged. 

Overall I am extremely pleased with this vehicle - it is even faster than the Volt with a neck snapping acceleration of 0 to 60 in 6.5 seconds.  One feature that I enjoy is the so-called "one pedal driving" mode.  When you shift from D to L, the regenerative braking system allows you to lift your foot off the accelerator which slows the car to a complete stop without ever touching the brake pedal.  (note that the letters D and L no longer refer to gears because there aren't any in electric vehicles).  This extends the driving range by putting a lot more energy back into the battery.  I was going down a steep hill recently and the dashboard showed that 50 kW (FIFTY. THOUSAND. Watts!) were going back into the battery for several seconds.  Holding down the brake pedal gently while in D mode would have accomplished something similar, but I find the one pedal driving mode to be comfortable.  There is also a paddle on the left side of the steering wheel which can be used to engage regenerative braking as well.  

There are a few things I need to adjust in this vehicle.  One of the criteria for any vehicle I own is that it should be able to fit 8ft pieces of lumber inside.  A friend of mine has a Bolt and he recently had 6 2X4s inside the vehicle by folding down the front passenger seat and the rear seats.  

In my model year the rear cargo area drops down about a foot behind the rear seats. This would be fine for normal people who use that area for groceries or suitcases, but I prefer a large flat area.  I looked at 2020 models and they had a hinged cover for that rear cargo well that brings it up to the same height as the folded down rear seats.  

 

I did some research and found that I can put a hinged cover back in to replicate what was in those earlier models at a cost of around $140.  

 

 

 
Another thing I do with all my vehicles here in Maine is put WeatherTech brand rubber floor mats in the two front locations.  Maine is muddy for many months of the year and that can really wear down the front carpets.

Incidentally, the license plate that I've had for many years is SUN PWRD, since all my electric vehicles have been powered from my solar power system which currently has 39 panels rated to up to 7 kW.  This means that I am driving essentially for free from the power of the sun it feels like an Infinite Improbability Drive (a reference to the Hitchhikers Guide to the Galaxy).  I found a nice chrome emblem that I can add to the back of the car to reflect this:

And I always keep a towel in the back of the car, just in case! 😀