By Scott McFadden, EAA 611467, Vintage 726528; Thunder Bay, Ontario, and KCFC, Grand Marais, Minneapolis
In early 2020 I had an opportunity to buy a 48’x 42’ hangar. It is the oldest hangar on the field and was in dire need of repairs. It was so bad, in fact, that I ultimately paid an amount roughly based on my estimated value of the footings, which appeared to be well constructed in concrete. COVID-19 made progress on the renovations and repairs challenging, slow, and more expensive than anticipated, but the structure was salvaged, and the Airport Commission was very supportive and actually waived ground lease payments for over two years. I’ve ended up with a clean, dry space to keep my aircraft and hang out, at a very reasonable ongoing cost. At this point I’ll state that I’m not affiliated in any way with any of the organizations mentioned in this piece.
The largest single capital cost was the concrete floor (I spoiled myself) followed by a new bi-fold door (I will take this opportunity to thank Diamond Doors for their support and patience during COVID-19). The door has a relatively large 220-volt motor, so it created the need for an electrical system. Although the hangar is located within a couple of meters of the ‘grid,’ the local power utility was not very cooperative. I never actually received a quote for the electrical connection but did find out that there was a $50 per month flat fee. Customers are required to pay this fee whether power is used or not. I reasoned that $50 a month could pay for a relatively substantial solar system ($50/mo pays interest @ 5% on $12,000). So I decided to research the options available. The starting current of the door is reportedly around 8 amps at 220VAC. Solar and battery systems produce direct current (DC) voltage, so an inverter to convert DC to AC is required. These inverters generally do not handle inductive loads (like the door motor) very well. The cost of inverters increases dramatically above 3000 Watts and a larger battery bank becomes necessary.
I decided to ensure that I’d be able to reliably open and close the door, regardless of the amount of sun available. So I purchased a low-priced 5.3 Kilowatt 240V generator. The remaining loads, lights, 110VAC outlets, 1.5hp 15-gallon compressor, battery chargers, shop vac, etc. would be relatively easy to accommodate. I ended up with two 320W solar panels, a 2000w full sine wave inverter/charger, four 6-volt 225 Amp-hour batteries (for a total of 450ah at 12V nominal), and a 60amp solar controller. It’s a bit of a “wild frontier” when it comes to retail solar power components, and I think there are more claims than realities when it comes to actual performance.
Research is necessary to determine if the product will do what it’s supposed to, has understandable installation and operating information, and some level of after sales support. I’ve put together four solar systems, so not an expert by any means, but here’s my shopping list of items that meet the above criteria.
Renolgy 320 Watt Solar panel x2 $669.80
EP Ever 60 Amp Solar Controller* $239.99
KISAE Abso SW 2000W Inverter/Charger $520.19
Trojan T105 6V 225 Amp-hour Batteries x 4 (Cdn) $992.72
DC Voltage Controller 12V- 6.5V (for lockbox) $13.95
DC Voltage Switch (for dehumidifier) $8.31
Solar wiring Shirbly 10 AWG 50’ $31.99
Installgear DC Fusible link 150Amp x 2 $12.99
Square D 20 Amp Double pole breaker $16.50
HQST Solar Panel Tilt Mounts x2 $44.99
Miscellaneous Wire, battery lugs etc. $100.00
Solar Total (U.S. Dollars) $2373.47
“Westinghouse” 5.3Kw Generator $460.59
Generator Wiring, plugs, Breaker, etc. $170.00
Grand Total (U.S. Dollars) $3,004.59
I recently installed a BougeRV 60amp controller in another project. It has a Bluetooth interface so can be setup and monitored on your phone, which is a good option. So far it has met expectations also. When I’m in the hangar on a sunny day I can turn on all the lights (LEDs) without using battery capacity. If I need to use my compressor (1.5hp 15 gal) I need to turn the lights off so the inverter can start the motor. Once running I can turn one bank of lights on again. Eventually I’ll either upgrade the inverter or get a lower start draw compressor. For now it’s fine. I fill the compressor tank and that’s all I need for compression tests and small jobs. The important thing is I have lots of light and outlets for battery chargers, power tools, etc. When I’m not there, the batteries receive a float charge around 13.7 V from the controller. On a sunny day, this means there’s lots of power available that is not used, so I installed a switch to power a dehumidifier. The switch senses battery voltage and is set to turn on at 14.4V (when the batteries are nearing full charge) and turn off when the battery voltage drops below 13V. Once running the dehumidifier draws less power than the solar panels can provide so there’s no battery drain.
A vapour barrier was installed before pouring the floor, so the small dehumidifier is able to provide a drier environment for my airplanes, and also a source of fresh water for hand and aircraft washing, even making coffee! I also installed a lock box so FedEx and UPS could make deliveries. It has 4 AAA batteries, but unfortunately when the temperature drops much below freezing, the keyless lock stops working. I added the small voltage controller to provide constant 6.5V from the main battery bank to solve this problem.
This brings up the topic of lithium batteries. I looked at the option of using lithium-based batteries. They offer advantages such as light weight and slightly higher operating voltage. They are not good performers in cold conditions, however. Some have built-in heaters to improve cold tolerance, but this obviously comes at the expense of capacity. The lithium battery landscape is also in its relative infancy so it’s hard to know what you’re getting, and I remain nervous about the potential for spontaneous combustion! Finally, they are very expensive. I settled on flooded lead acid. Distilled water is 99 cents from Walmart, and I top up the electrolyte every three months or so. You’ll have noticed that I came in well under my $12,000 upside. Interest on $3,005 even at today’s inflated rates is under $18/month. In the past year the generator has used under 2 gallons of gas and of course there’s the $.99 for distilled water. Assuming the system lasts 10 years (average, batteries 5-7 years), amortization is another $25 (noncash cost) per month. Still under the flat rate charge of the power company and I’ve not included the usage charge or $18k-25k for the electrical hookup (or the inevitable price increases).
Perhaps most importantly the “stick it to the man” feeling is priceless, and it’s satisfying to know that my not-so-environmentally-friendly aircraft are offset to some small degree by my off-the-grid hangar.