Solar, Field Day, or Emergency Response:
Emergency Power Options
George Ure
AC7X
Agenda
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Outage Scenarios: When could the power fail?
Power demands are band and mode dependent
On-the-fly power
Introduction to Generators
Battery Basics – Charge and Discharge Parameters
Battery-powered Options
– Inverters
– Inverter/Chargers
– Grid-Interactive Systems
• Wind Machines
Where’d I Learn About Batteries?
Power-Outage Scenarios
• Drunk driver hits a power pole
– (1-12 hours)
• Earthquake (New Madrid?)
– 1 Day – 1 month
• Terrible weather event (Sandy-class)
– 1-day to 2-months
• EMP/Regional Nuclear Event/Bio war
– ???
• Field Day: Till the beer runs out?
Emergency? What to Plan Power For…
• “Crisis Lite” 1-4 Days
– Almost ALL hams with a handheld are set!
• “Regular Crisis” 5 Days to 5 weeks
– 30% of hams are ready? 1-5 recharge periods
• Major Crisis 5+ Weeks
– 5% or less are ready: Ongoing recharge
requirement is harder to meet
KEY PLANNING POINTS
• Emergency Power requirements depend on:
– Expected duration of emergency
– Bands which will be used in response
– Role of ham using equipment
• Net control talks more, needs more energy
• Traffic handlers need more, too!
– Antennas, transmitter power, various losses
Example Emergencies
• Semi/Local: (Ike passing through, Joplin)
– Mostly VHF/UHF – scattered HF
– Quick recovery period – external aid coming quick
• Regional: (’64 Alaska quake, supply lines disrupted,
regional coms down)
– V/UHF for impact areas
– HF Health, Welfare, and News from ‘outside’ Phone
patch?
• EMP/Nuke War/Massive Solar Flares: (still ahead?)
– Mainly HF – most repeaters/grid would be down long-term
due to the grid impacts, most repeaters gone in a week.
Reacting to the Disaster
On the Fly Power
• Alligator Clips are your friend:
– Some open 1” wide
• http://www.caltestelectronics.com/ctitem/143-fully-insulated/CT3251
Don’t forget the
cable to connect to
the radio!
Language of Power
A “Cell” is a single chemical reaction device.
– C cells, D cells
– AA cells, etc.
A “Battery” is a collection of cells
“Cells” are measured in volts/per cell
“Batteries” are measured by terminal voltage
A Cell vs. Battery
• A single cell is just like a polarized capacitor:
EXCEPT instead of a dielectric there is a chemical
reaction which delivers or absorbs energy!
Batteries (Collections of Cells)
Key Terminology to be aware of:
• Energy Density: The “work to weight” ratio.
• Cycle Life: How many discharge/charge cycles will a
given battery deliver?
• Discharge Rate: How many hours will a battery deliver
how many amp? Typically 20 min., 1-hour, and 20hour rates are cited.
• Depth of Discharge: What is the recommended level of
discharge beyond which cycle life rapidly declines?
• Peukert Exponent: Effective shrink rate of a battery at
high rates of discharge.
Dry Cell Basics
Dry Cells:
1. Metal cap
2. Plastic Seal
3. Expansion Space
4. Porous Cardboard
5. Zinc Can
6. Carbon Rod (center)
7. Chemical “Goo”
Major difference between cells is
the chemistry of the “goo” and
whether the chemical reaction is
reversible!
Where Lead-Acid Battery Electricity
comes from during Discharge…
What a Completely Discharged
Battery Looks Like
Batteries Don’t “Die” –
They Are Murdered!
EQUALIZING Restores Capacity
How to EQUALIZE
Never attempt to equalized SLA – sealed lead/acid
batteries!!!!!! They tend to blow up.
• Use plenty of ventilation (outside!) because
Brown’s Gas is HIGHLY EXPLOSIVE
• Usually Charging Voltage is increased to drive 25% of the battery’s 20-hour rate (in amps) into
the battery. So a 100 AMP-Hour battery would
equalize at the 2-5 AMP rate for 1 hour.
• Monitor closely to prevent thermal runaway!
• Safety timer! Safety Glasses! Do NOT overfill
batteries (with distilled water only) if Equalizing!
Deep Cycle VS Starting Batteries
Plate depth versus toal plate area determines it:
Battery Spec Sheet Example
Typical good quality deep cycle battery is a
Trojan T-105 which is a 6-volt standard.
Amp-Hours VS Kilowatt-Hours
• Amperes of current for X number of hours
• BUT Battery voltage declines over time
• SO Ending energy is different than starting
energy:
– 13 V times 10 AMPS = 130 WATTS
– 11 V times 10 AMPS = 110 WATTS
• A Watt-Hour integrating meter is what
measured actual ENERGY (work done)
• 1,000 Watt-Hours = 1 Kilowatt-Hour
Battery Rules for Hams
• Terms like “cold cranking AMPs” is only
marginally useful as comparison information.
• Most ham gear will operate to 10.5 Volts
• Operating to 10.5 V was required for marine
SSB type acceptance
• 10.5 V is when a 12V battery is “dead”
Peukert: Shrinking Battery Effect
• Batteries deliver less total energy on their way to 10.5V
“dead” if discharged FAST
Where Cp is Peukert Capacity and both i and t are time and
currents of two different discharges such as 10 amps for 20
hours (20-hour rate) vs. 20 amps for 1 hour (1-hour rate). The
n is the exponent value.
Typical Exponent Values for 100 AHr
Ideal Charge Curve (Proctor et al)
Battery Temp Compensation
Sample Cycle Life – T-105
Percent of Capacity Drops When Cold!
One More Rule
Here’s what a T-105 weighs:
If you are down to two batteries in your
shopping, pick the heavier battery if you’re after
long cycle life – heavier means more plate
material is being used!
Feed Battery Banks Correctly!
How to Charge Batteries
Multiple Choices:
• From a gen-set: Simplest is a chain saw motor
on a piece of plywood connected via a drive
belt to an alternator. Add voltmeter and
whatever if more control is needed.
• From Solar
• From Wind
Why Wind is a POOR Choice In Texas!
• Works good on a
sailboat – such as
the one we lived on.
• BUT no significant
power below 10
Knots/ 12 MPH
• Generates some
noise, besides PWR
• Depends on swept
area – bigger is
better on wind gens.
Main Problem with Wind is?
Solar is GREAT HERE!
4.5-6.5 kWHr’s / M2 Per Day
Solar is not initially cheap, but over the long
term is does have good payback – breakeven at
between 10-18 years depending on how much
you do yourself.
Solar Has Many Pieces
• The Panels
• Charge Controller
• Battery bank
• Grid-Interactive inverter
Kinds of Mounts
• Simple (fixed)
• Single-Axis (panels are mounted on hinges so
from March 21 to Sept 21 they are at 20° tilt
otherwise (wintertime) they are at 45°
• Highest priced:
Full tracking systems
Which track E/W
I chose T-Post and
Rebar for ours…
Small Scale Solar Example
• Components are: Panel,
Battery, Charge Controller.
This plus an old ATV winch
raises and lowers my
tower.
• Low NO maintenance!
Projects You Can “Bury” Solar In…
HOW TO SELL SOLAR TO A SKEPTICAL XYL:
• Solar-power driveway and outdoor lighting!
• Battery “topper-upper” for RV or other
battery use which gets infrequent use:
– Tractor, ATV, Go Karts, Motorcycles, Lawn tractor…
• “Helping the environment!” “Global
Warming!”
Generators
• Basic choices:
– Gas (get avgas?) or Diesel (works in tractor)
• Ham favorite is the Honda 2 kW with inverter
mode which varies engine speed to load
• Conventional generators are much cheaper.
• In gas generators, consider a good oil additive
like AvBlend which is FAA Approved:
AvBlend.com or AircraftSpruce.com
Operating Highlights
• Pop for electric start if over 2 kW!
• If using for your home, have electrician put in a
transfer switch
• Best quality choices:
–
–
–
–
2 kW & Under: Honda
2-6 kW – Onan or other RV type are good
6 kW up: Tractor PTO Type -
6 kW+ Isuzu diesel
Basic Rules & Axioms for Gens
• RUN-TIME EQUALS FUEL AVAILABLE
• Natural gas gens require lots of fuel but are a
very long-life option.
• Bad choice though if concerned about
earthquakes or infrastructure damaged.
Some Notes on the Honda EU2000i
Very good unit reports
WA7BRI – he uses the Econo
Mode with Icom 7000 and
now voltage sag problems
from key down to listening.
‘BRI meticulously runs every
month and uses STABIL in
his gas, however! Runs 8-12
hours on a single fill in
contest setting, 100 watt
xmt class, no RFI issues
How Big a Genset?
• From Onan manual good
list of watts.
• Applies whether your are
planning an inverter off
batteries (sep. charger),
solar (big or small) or
buying a genset.
• Add up peak loads and
that’s your sizing.
• More loads = More $$$
Other Goodies from the Onan Manual
2.8 kW Onan Generator Fuel
Consumption
Typical 24-hour contest time: 6.7 gallons at 50%
load.
Full Power 24-hours = 11 Gallons per day
Full load uses almost 3 times fuel of no load.
Generalized Fuel Consumption
• Ballpark: 50% load is 60% of max fuel use
Generator Time to Charge Batteries
85% of charge in Battery size divided by
generator/alternator output.
Example: 100 AHr battery will be 85% full in one
hour on 100+ Amp alternator or generator-run
source such as charger.
Last 15% of charge takes about 2 ½ Hrs.
regardless of size – “absorption charge rate” also
called “finishing” charge.
If on PURE Battery Source
• Operate initially from 100% full to 60% depth
of discharge.
• Recharge to 85% of charge level
• Resume ops to 60% depth of discharge
The 85% down to 40% of capacity is the “sweet
spot” where batteries give up – and accept
charge most readily.
Don’t Get Fooled by an Ammeter
• When charging begins, battery may not begin
charging right away.
• Reason: Takes time for the battery chemistry to
“change directions”
• Delay in discharge to charging reaction is called
‘Coup de Fouet’ by battery gurus. (“crack of the
whip”)
• Read current after 5-minutes of charging, or so
• Coup de Fouet is why active (charging braking) on
electric vehicles is so problematic – energy can’t
just “reverse and save” – takes time!
Real Example of Coup de Fouet
Operating Style
• Plan on 10% transmit and 90% receive unless you are
net control.
• Turns off dial lights is available.
• Use power output at minimum level to get the job
done. V/UHF 1 watt often sufficient. HF use 100 to
establish coms, then reduce to path requirements.
• Keep mental picture of fluid situations, make notes if
possible.
• Keep Radiogram pads on hand if regional emergency –
doing public service traffic – be sure to get delivery
phone number and confirm them.
Power and S-Units
One S-unit is a change of 6dB in signal strength,
which corresponds to double the VOLTAGE or
four times the POWER at the receiver input.
Example:
If a 100-watt
station is S-9 and
drops to 25 watts
the result is S-8.
From 25 watts
down to 6 Watts is
about S-6
2W about S-4 etc.
100 W increased to 2 kW ≈ 1½ S-Units
On HF Horizontal Antennas are Quieter
With S-6 Signals, Antenna Noise becomes a
major factor in good communications…
Max Signal
Is 6 DB over
Noise Floor
Max Signal
Is 18 DB over
Noise Floor
For HF Emergency Use
Easiest to Install Quickly
• Buddy-Pole ™
• Mobile Whip
• Vertical into a tree
Best Performance
• Random Long Wire
(Horizontal or “L”)
• Inverted VEE
• Flat-Top Dipole
• Delta Loop
• Horizontal Loop, 1λ
overall length and at
least 1/2λ high
My Dream Emergency Antenna
to Minimize Power Requirements
160 Meter 1 λ Loop at 25’ or higher Used on 20
Meters where it has some gain…
NVIS low bands, 160/80 some gain on 40-& 20 Meters. Quiet (it’s a loop!).
Only problem is size and height and needs a tuner and open wire!
For Antennas that are GroundDependent
Verticals, Mobile Whips, and Long-wires need grounds
Signals Depend on Grounds
IMPROVISE!
• Metal Roofs
• Metal gutters
• Chain link fences (noisy in certain wind conditions)
• Sprinkler Systems (copper), fire stand pipes, hydrants
• (My favorite!)….
RAILROAD TRACKS!
Lifesavers
• Keep all generators 50 -100 feet or more – and
preferably downwind - from humans. Carbon
monoxide is carried as easily as oxygen in the
bloodstream.
• Never work circuits hot even if they are 12V 12 V is enough to kill! It’s the current (less
than 5 ma.) that kills!
• When wiring wear rubber-soled shoes and
trust no one.
Thank You!
Questions?