Outdoor Adventure USA

SOLAR POWER IN THE OUTDOORS


NOTICE: WE LOST OUR INTERNET CONNECTION AT OUR REPEATER. UNFORTUNATELY, THIS MEANS THAT BOTH IRLP AND ECHOLINK WILL BE DOWN FOR THE DURATION OF THE NET. HOPEFULLY, WE WILL BE BACK NEXT WEEK


SOLAR POWER IN THE OUTDOORS - PART II

There was just way too much material to cover in just one net, so we will wrap things up this week in Part II.


Original Posts

The "official" camping season starts soon, (although we know that the real camping season is year round.) None the less, we are beginning our new year with some camping nets that will help all the campers out there to make the most of their outdoor time. Like it, or not, electronics have crept into almost every corner of our lives, and that means that we need power to make these gadgets work.

For just about everyone who listens to these nets, we are already hooked on the various Ham radio gadgets that we use at home and on the trail. But, that's just the start. Wilderness travel requires that we also need to find a way to power what seems like an ever increasing number of devices that also require power, like:

• computers

• GPS units

• handheld transceivers (HTs)

• inverters

• air compressors

• air pumps (air mattresses)

• battery rechargers (flashlights, radios, headlamps, lanterns, etc

• APRS

• refrigerators

• and of course, Ham Radios

Everything is great, as long as the vehicle is running, but when parked at camp, with no motor running, the combination of all of these toys can drain a battery in a big hurry. One of the solutions is solar. It's cheap to buy, free to use, easy to carry, and best of all, it works anywhere you go (with some exceptions.)

Our guest this week is Paul Yuenger, KK6DYO. Join us for a discussion on alternate power and post your suggestions and pictures.

Questions answered
What is a solar power system?
What can it realistically do?
How can I build one?

What is a solar power system? My reason for going solar My imagination Electrical Basics

Volts, Amps, Watts Power over time is Energy Formulas and Notations

• Electrial pressure measured in Volts (V)
• Electrical flow rate (current) measured in AmperesAmps (A)
• Power measured in Watts (W) = Voltage * Current = V * A
• Energy = power over time, measured in Watt-hours (Wh) = W * time period
• Current over time measured in Amp-hours (Ah)

How much power do you need?

Rechargeable battery Ni-MH AA

• 1.2V x 2.4 Ah = 2.9 Wh
• x how many?

Phone + Camera iPhone 8

• 7 Wh

Rechargeable battery, HT Kenwood TH-K20 (5 Watts)

• 7.4V x 1.8 Ah = 13.3 Wh

Rechargeable battery, flashlight 18650

• 3.7V x 3.1 Ah = 11.5 Wh

Electric Vest

• 7.4V x 2.6 Ah = 19 Wh

Tablet iPad Pro

• 41 Wh

Refrigerator ARB 50 qt "maintain sub-freezing temperatures in 90°F heat"

• 12V * 1.35A = 16.2W
• x 24 hours = 389 Wh

Base station Kenwood TS-480SAT (100 Watts)

• 13.8V x 20.5A = 283 W
• x transmit how long?

Inverter - convert 12VDC to 120VAC

• Watts x how long (e.g., 1000 Watts x 0.5 hr = 500 Wh

Heating / Air Conditioning ClimateRight CR5000ACH

• Air Conditioner 5,000 BTUs/hr for 700 Watts (BTU = British Thermal Unit)
• Heater 4,300 BTUs/hr for 1300 Watts (3 BTUs/hr = 1 Watt)

Heating Mr. Heater Portable Buddy (Propane)

• 3,000 or 9,000 BTUs/hr propane -> 1,000 or 3,000 Watts eletrical

Cooking: Range

• 7,000 BTUs/hr per burner -> 2,500 Watts

Calculate Your Energy Needs

• Heating, cooling, cooking not practical
• Ask yourself: Do you really need that 1000-Watt inverter?
• Monitor your electrical use (how far do you let your devices' batteries run down?)
• Total your energy consumption in Watt-hours per day (natural solar cycle)
• Allow for growth
• Multiply by two!

How much power can you get? The Panel
Panel Types Monocrystalline

• Blackish
• More efficient (15-20%)
• More expensive
• Higher temperature resistance
• Entire panel affected by any partial shading (newer panels built with bypass diodes)

Polycrystalline

• Bluish, speckled
• Less efficient (13-16%)
• More expensive
• Higher temperature resistance
• Less affected by partial shading

Comparison - Renogy 50-Watt

• Monocrystalline: 24.8" x 21.3" (528 sq in), 9.9 lbs
• Polycrystalline: 26.7" x 21.6'" (567 sq in, 9% larger), 11 lbs (11% heavier)

Framed vs. Flexible 100-Watt
(I have no experience with flexible)

• Frame: 16.5 lbs $130
• Flexible: 4.4 lbs $300

Framed 12V Capacities (Renogy Monocrystalline)

• 50 Watt: $80 24.8" x 21.3" x 1.2" 9.9 lbs
• 100 Watt: $130 46.9" x 19.7" x 1.4" 16.5 lbs

Hold it!
Only ~100 Watts from one panel?
The panel just keeps the battery charged.
The battery collects power over time and stores it for later use.

Recommendations

• Consider storage space and mounting needs (more later)
• Easy to connect additional panels into system
• Once you've made room in your vehicle to store a panel, only another 1.5" for one more; consider two panels for double generation capability

News: Trump slaps big tariffs on imported solar panels
https://www.dailybreeze.com/2018/01/22/ ... -industry/

Update: After Trump tariffs, Chinese solar company says it will build U.S. factory
http://money.cnn.com/2018/01/30/news/ec ... index.html

Heart of the system: The Battery

Battery Terms

• Cold cranking amperage (CCA) = maximum current at 32°F for 30 seconds
• Reserve capacity (RC) - minutes providing 25 Amps at 80°F while keeping voltage above 10.5V
• State of charge (SOC) - percent of battery capacity remaining
• Depth of discharge (DOD) - percent of battery capacity used = 100% - SOC
• Deep cycle - ability to discharge deeply (50%+) before charging without harming battery
• Capacity - energy stored in battery at rated voltage in Amp-hours (Ah)
• C-Rating - fraction of charge/discharge rate relative to maximum capacity in one hour

Battery Chemistry More on lithium later

Type of Batteries by Purpose

Starter

• Short, high-current bursts for cranking engine
• Greater number of thinner lead plates
• Higher CCA
• Lower RC
• DOD around 3%
• Quickly recharge (topped off) by alternator
• Will fail after a relatively lower number of deep cycles

Deep Cycle Battery

• Continuous current for prolonged time
• Smaller number of thicker lead plates
• Lower CCA
• 2 to 3x the RC
• Recharge at lower amps for longer
• DOD up to 50-80% hundreds of times

Marine Battery

• In-between, but not a deep cycle battery
• DOD around 20%

For a solar power system, we need a deep cycle battery

Type of Deep Cycle Batteries

Wet cell or flooded

• Half the cost of Gel and AGM
• Requires maintenance (water replacement, specific gravity testing)
• Generally must be vented (hydrogen, possibly hydrogen sulfide)
• Can spill sulfuric acid; must be kept from moving; may not be suitable for rough travel
• Self discharge 13% of charge per month
• Appropriate for household solar system, not mobile

Sealed Lead Acid: Absorbed Glass Mat (AGM)

• Will not leak, even if punctured
• Can be used in any orientation
• Greater life span than wet cell
• Self discharge 1 - 2% of charge per month

Sealed Lead Acid: Gel vs. AGM

• Lose power faster in cold
• Higher price
• Shorter life span
• Slower charging
• Lower discharge rate
• Self discharge 3% of charge per month
• Better suited to deeper cycles

AGM it is!

Battery capacity falls off at low temperatures
Percent capacity vs degrees C (F) Battery Care

• Keep battery charged, on a maintainer when not in use
• Avoid discharging below 50% SOC

  

  ExpectedBatteryLifevDOD.gif (21.33 KiB) Viewed 4344 times

• Charge battery at correct voltage/amperage profile for type
• Protect from extreme cold

  

  BatteryChargingVoltage.jpg (14.91 KiB) Viewed 4344 times

AGM Charge Cycle Phase, Voltage, Amp
Battery Cost and Weight vs Capacity State of Charge vs Voltage for AGM Battery Recommendations

• SLA AGM (or Lithium, next section)
• Size based on your calculated daily energy needs
• Multiplied by some number of days of bad weather based on destination
• Multipled by factor based on expected temperature (see charts)
• Get the largest battery you can physically manage to limit DOD and have surplus capacity

The Future: Lithium Batteries
Disadvantages

• Cost 3x AGM
• Requires special controller

Advantages

• Half the weight of similar SLA
• Can be nearly fully discharged without harm, not just 50%
• Minimal self discharge
• Possibly 10x the number of recharge cycles
• Very high charging rate if power available
• No minimum charge current
• Runs well at high temperature

Lithium vs. SLA Performance in Cold
Battery Comparison

Renogy LiFePO4 100 Ah Vmaxtanks AGM 100 Ah Renogy 100 Ah LiFePO4 vs. Vmaxtanks 100Ah SLA AGM

• $900 vs. $273
• 28 lbs vs. 68 lbs
• 90% DOD (1152 Wh) vs. 50% DOD (640 Wh)
• 2000 cycles vs. 500 cycles (?)

Lithium is most cost effective battery, if you can justify the initial cost

Links to other LiFePO4 batteries
https://www.altestore.com/store/deep-cy ... es-p40844/
https://www.bioennopower.com/collection ... lf-12100as
https://www.ebay.com/sch/i.html?_nkw=li ... +12v+100ah

The Brains of the System: The Controller

Also called Solar Charge Controller

• Takes higher panel voltage
• Drives 12V load
• Draws from battery when panel insufficient
• Charges battery when panel surplus
• Note: can also connect load directly to battery

Type of Controllers

Pulse Width Modulation (PWM)

• Inexpensive
• Functional

Controller Displays: Is it working? Happy sight! Maximum Power Point Tracking (MPPT)

• Adjusts charging voltage to get maximum current into battery ("maximum power point")
• Provide 10 to 30% more power to battery
• Better yield when cloudy
• Biggest advantage is with panels wired in series for higher voltage

Data Screen of BlueSolar iPhone App (Bluetooth) Recommendations

• Make sure load output provides sufficient current, if used
• Must have setting for your type of battery's recharging profile (older don't support lithium)
• Should display State of Charge

The Wiring, Connectors, and Fuses

Use recommended cable sizes or larger to avoid resistance / power loss Use color coded cable to avoid polarity problems Good copper cable isn't cheap https://powerwerx.com/red-black-bonded-zip-cord

Most panels come with waterproof MC4 connectors MC4 Connector MC4 Tool Use convenient connectors, like Powerpoles A crimping tool is necessary for Powerpoles MC4 Adapter to Powerpole Inverter Cables

• 1000 Watt 120VAC inverter
• Divide by 12VDC for current / amperes -> 83 A
• Check against length / current table
• Get next larger gauge (smaller number) for safety

Inverter Cable 6 ft Inverter Cable, 2/0 Gauge, with Lugs Fuses

Be safe ... fuse everything Use proper fuses and ground your inverter Recommendations

• Powerpoles are quick and easy
• Must protect from water and dust
• Buy a good crimper if you're making your own cables

Protected Powerpole

How much energy can you really get? The Sun Designating Sun's Location: Azimuth and Elevation Differences Between Summer and Winter Solstice Different Methods of Tracking Automatic Sun Tracking Panel can be misaligned with sun by 20 degrees and still provide 95% Modeling/Analysis Spreadsheet

• Latitude
• Day of year
• Position of sun relative to panel direction throughout day (elevation: angle above horizon, azimuth: east to west position)
• Atmospheric effect due to sun elevation (angle of sun in sky)
• Various scenarios
  • panel straight up
  • panel fixed pointing toward sun only at noon
  • panel position periodically changes with sun
  • panel fully tracks sun

Modeling Spreadsheet Panel Straight Up for Travel Keep the Pane in the Sunlight! Panel Flat on Roof Panel Tracking Sun, Winter Panel Tracking Sun, Summer Value multiplied by panel’s Watt rating gives maximum Watt-hours produced per day under perfect conditions Recommendations

• Must understand seasonal path of sun, except during Summer
• Panel mount should be able to easily tilt for sun's elevation and be moved for sun's azimuth
• Periodically point panel where sun will on average be during next period
• Figure out where shadows will be during each period and avoid them
• Watch out for thin shadows (e.g., stalk of weed)
• Two smaller (e.g., 50-watt) panels in series: easier to manage, can provide more power (higher voltage/less loss, MPPT controller)
  • But possible to lose produce in any shade on either panel

100W Panel Stand with Three Tilt Angles 50W Panel Stand with Three Tilt Angles Sun Az El Chart Panel Settings 100W Renogy Folding Suitcase Panel

In Conclusion

My Setup: Charger

• 12V 125 Ah (1500 Wh) AGM battery in car
• Board on left steps up car power socket voltage to 14.5V to charge AGM battery
• PWRgate on right limits current to 4A (58 Watts) ... reserve 6A+ to run device chargers from car voltage
• Keeps battery fully charged in car with typical commuting

Alternative for Shorter Trips

• Refrigerator requires an average of 16 Watts or 384 Watt-hours per day
• Battery could provide 4 days of refrigerator power
• 384 Watts-hours / 48 Watts = 7 hours of driving per day to keep refrigerator running and battery fully charged
• Depending on trip length, could "borrow" from battery to shorten driving, then charge battery when I return home

My Setup: Fridge, Battery, and Solar Controller Battery in back of rear seat; solar controller under seat

• Plug battery into controller instead of charger when stationary
• Position panels on ground or car and plug into controller

Your Solar Power System

Sufficient Solar System ~$380

• Solar Panel (50-Watt) $65
• AGM Battery (100Ah) $275
• PWM Charge Controller (20A) $20
• Wiring $20

Great Solar System ~$1350 when my batteries wear out

• "Suitcase" Solar Panel (100-Watt) $200
• Lithium Iron Phosphate (LiFePO4) Battery (100Ah) $900
• MPPT Charge Controller (40A) $200
• Wiring $20

Links

Solar Panels, Controllers, Batteries
https://www.renogy.com/

"Solar" (Deep Cycle) Batteries
https://www.vmaxtanks.com/

Wiring, Connectors, Crimpers
https://powerwerx.com/

MPPT Solar Controllers
https://www.victronenergy.com/solar-charge-controllers

”Canned” Solar Systems
http://www.goalzero.com/solar-kits
http://www.goalzero.com/p/463/goal-zero ... -panel-kit

Just About Anything
https://www.ebay.com/
https://www.amazon.com/

What I'm Using
https://www.amazon.com/Renogy-Watts-Vol ... 009Z6CW7O/
https://www.amazon.com/dp/B07235YXT2/]
https://www.vmaxtanks.com/SLR125-12Volt ... _p_38.html