Wednesday, June 10, 2020

My New (And Improved) Solar Battery Project (for CPAP)

My OLD Solar Battery Project


Although the primary focus of this blog is infectious diseases, running a close second is emergency preparedness.  And since I live in hurricane country, one of the biggest - and most common - emergencies I'm likely to face is a prolonged power outage. 
Having lived aboard a sailboat for over a dozen years, spending a good bit of that time away from the dock (and shore power), I've had to learn how to live with low power consumption.  
Now that I've swallowed the anchor ( sailorese for `moved ashore'), and have grown considerably older, I'm less willing to swelter in the dark. What was a grand adventure when I was in my 30s is much less so in my mid-60s.

Although I installed my first solar panel on my boat more than 35 years ago, technology continues to change, and so every few years I've upgraded my low-power devices (lights, radios, fans, etc.) and my power generating and storage options. 

Today, most of my needs can be met by a small USB Solar panel (21 watt), and several USB battery banks, which I detailed last month in My New Solar Power System (Updated For 2020)as depicted in the photo below.

The `core' ingredients are 2 or more USB battery banks (1 to use while the other charges), preferably 20,000 milliamps each ($25-$40 each), and at least one solar panel. I went with a single 21 watt 5 volt panel ($50) since two of my battery banks have (very) small integral solar panels.
This initial investment will run you between $110 and $140, depending on brand.  I'm not recommending any specific brands, so do your homework. 
The accessories:  . . . in my case, they include mini-fans, rechargeable lanterns, cell phones, my iPAD, and a USB powered battery charger. This allows me to recharge my supply of Ni-CD or Ni-MH batteries that power my walkie-talkies, battery operated lanterns, radios, and other devices.
This system is great except it doesn't provide 110v or 12v power. 
And anyone who depends upon a CPAP, or wants to power a small cooler, or some other 12 or 110 volt device, is out of luck.  Last summer, in Preparedness: Some Emergency Power Solutions, I described my first attempt to create a 12v/110v battery station that could be used with a small (10 to 15 watt) solar panel.

While quite limited in the power it could provide, and slow to recharge without damaging the battery, it was a partial solution.  But it really wasn't suitable for powering a CPAP for more than one night.  Unless the power came back on quickly, you'd be dead in the water after 24 hours. 
What I needed was a battery setup that could take a larger solar panel (I have two 40 watt panels left over from my boat), and that could be recharged enough in one day to power a CPAP for another night. 
Over the past couple of weeks I've ordered in a  Deep Cycle AGM 12 volt battery ($67), 2 - 7 amp solar charge controllers, and have upgraded my old battery to accept up to a 100-watt solar panel, and have created a second battery (see below).

Each battery has its own dedicated solar charge controller with a snap connector for a solar panel, duel 12 volt outlets, and a 150 watt 110 volt inverter. The new battery is a genuine deep cycle battery, which can be discharged longer, and more often, than the my initial setup. 
While a CPAP can be run off the inverter, it is far more power efficient to run it off a 12 volt outlet (using the correct 12 volt adapter plug).  I should get 2 maybe 3  (7-hour) nights off a fully charged battery, and - with two batteries - my solar panels are likely able to keep up with keeping them charged. 
Granted, I could have bought one of the new Solar Generators (a misnomer, since they don't generate, they only store and convert power), for $250+, and for roughly the same price (minus solar panels) have accomplished the same thing.  They are lighter, and far easier to set up.

But, in an emergency situation, I want the ability to fix something that I depend on, and these units aren't really user serviceable.  If the inverter fails, or the battery dies, you have to either send it to the factory for repair, or buy a new one.
And in the midst of an emergency, neither option is likely to be available. 
With my system, I have spare parts, and if I had to, I  could cannibalize one system to fix the other.  In the preparedness community, the old saying is `One is none, and two is one'. 
Meaning you don't risk you life on having only plan A.  On my sailboat, we named out dinghy/life boat  `Plan B'. 
Between our ageing infrastructure (see ASCE report card on America’s infrastructure), natural disasters like earthquakes and hurricanes, disruptions caused by solar flares (see NASA: The Solar Super Storm Of 2012), and even cyber attacks (see DHS: NIAC Cyber Threat Report - August 2017), and power shutdowns due to red flag warnings, the odds are that some kind of prolonged power outage is in your future.
Whether you go with a USB system, buy a `solar generator' - or build an `old school' system like mine - having the ability to generate and store electricity can reduce a prolonged power outage from being a genuine emergency to more of an inconvenience. 
But if you want to be prepared for the next emergency, you need to invest the time and money now, before the next threat appears on the horizon.  Once it become apparent, it is usually too late.

NOTE:  If you aren't familiar - and comfortable - with working with 12 volt batteries and electrical wiring - then get professional advice before attempting to construct any of these devices.  Batteries can off-gas flammable gases, a shorted 12 volt battery is both a burn and explosion hazard, and there are also shock hazards with 12v and 110 volt equipment.  Proceed at your own risk.