See you at the Extreme Flight Championships
[[email protected]]
Radio Control Helicopters Mark Fadely
Also included in this column:
• Clint Akins’ expert Li-Poly
advice
2007 XFC winner Alan Szabo’s T-Rex makes a high-speed,
sideways pass. The helicopter went briefly out of sight in a dip at
the end of the flightline.
Canada’s Colin Bell thrilled the crowd at the 2008 XFC with his
Raptor 90’s clockwork precision in a choreographed flight.
Clint Akins, manager of FlightPower batteries, keeps pilots
informed of the latest technology in Li-Poly cells.
Dominik Haegel’s Hirobo Turbulence won the 2008 XFC. His
flights included pirouetting reversal moves in 3-D flight.
THIS IS my favorite time of year. I love spring and early summer,
because you have the whole year of good flying weather to look
forward to.
Some lucky pilots live in temperate climates that allow for
year-round outdoor flying. I am stuck smack dab in the most
middle part of the Midwest: Indianapolis, Indiana. There are no
mountains or oceans here, but we do have one fabulous attraction.
The RC highlight of the nation is the AMA Headquarters and
International Aeromodeling Center. It is only 45 minutes from
where I live.
In a few days, the 2009 Extreme Flight Championships (XFC)
will be held at the AMA flying site. It takes place June 12-14. It is
the only competition that includes the world’s best airplane and
helicopter pilots in one spectacular show. Plan to attend this event
if you can. It is a jaw-dropping experience.
Let’s shift our attention to a concern that many pilots share. Batteries
are used in several facets of RC. When you have spent time in the
hobby, you start learning about the various types of batteries, along
with their chemical makeups.
Batteries are the lifeblood of successful RC flying, so you must
know how to handle each kind properly. If you do not follow the
rules, you might find yourself in a dangerous situation.
June 2009 127
06sig4.QXD 4/23/09 1:46 PM Page 127
I’m going to highlight the most misunderstood of all batteries: the
Li-Poly. They are used in many gadgets, including every cell phone
on the planet. If a battery is safely used by so many people, what is the
big problem?
I asked my good friend, Clint Akins, to write a brief explanation of
Li-Poly handling requirements. He is the manager of FlightPower
batteries, which makes a full line of Li-Poly cells. He takes these
batteries’ safety seriously. To help pilots better understand the
potential pitfalls of Li-Poly handling, Clint wrote something special
for us.
“Chargers 101: Taking the Black Magic Out of Li-Poly Batteries:
Let me start by saying that Li-Poly (Lithium-Polymer) batteries and
Li-Poly chargers have improved greatly over the last few years.
“In the beginning the chargers were very crude and often they
charged in stages. For example, the early chargers were simply set to
the desired voltage and charge rate, and they often charged very
aggressively in the first stage. This usually was fine until we (the end
users) made the mistake of putting a battery on a charger that was
already charged. The result was almost always the same: yep a
damaged pack, or worse, a fire.
“Let’s stop for a moment and understand why. Li-Poly batteries
are typically fully charged at 4.2 volts per cell. The early chargers
were programmed to blast a heavy charge to the pack for the first
cycle and they never sensed any info from the pack initially as to the
charge level. The chargers would push the voltage above 4.3 volts per
cell which can damage not only the cycle
life of the pack, but it becomes dangerous
and can cause a fire.
“We do not hear of nearly the problems
with charging batteries that we used to. Is it
because there are fewer people using Li-
Poly batteries? It is because the technology
of the chargers is much better, and the
education of the end user has improved?
“How do you keep up with it all? While
we are fortunate to have technology moving
fast, it can also be difficult to keep up with.
Like I stated previously, this document is
intended to help simplify some things, and
take the black magic out of Li-Poly charging
by explaining a little about the chargers and
the batteries.
“The basic Li-Poly chargers today are
pretty simple, and the user sets the voltage
or cell count (3.7 volts per cell) and the
charge rate, which is normally 1C. This
brings up the first question: what does 1C
mean?
“Just to simplify things, 1C means one
times the capacity. Packs are usually rated in
mAh (milliamp hours), and chargers are set
in values of amps. Let’s just simplify this
and make it easy. There are 1000 mAh in an
amp.
“As an example, we will use a 3S, 2100
mAh pack. 3S means we have three cells,
three times the nominal voltage of a cell (3.7
x 3 = 11.1 volts). We know that the pack is
11.1 volts at nominal voltage and fully
charged it will be 4.2 volts per cell, or 4.2 x
3 = 12.6 volts. This pack could be called a
2.1 amp pack: by dividing 2100 mAh by
1000 will give us the value of the pack in
amps which is 2.1. If we want to charge this
2.1 amp pack at 1C we would set our charge
rate at 2.1 amps.
“Now that we understand terms like 1C,
and we know how to figure charge rate and
the voltage we want to charge at, we will
move on. A good tool to use with a basic
charger is a balancer. I prefer to take it one
step further by using a feed-through
balancer. What is the difference, and why
should I use a balancer?
“A basic balancer equalizes the cell
voltage on a pack to within set parameters.
This will keep the cells in the pack at or
close to the same voltage with each other,
which will allow them to perform at their
best. It will also lengthen the cell life.
“The difference between the feedthrough
balancer and the typical balancer is
that the feed-through checks each cell as it is
charging, and maintains the proper levels. It
also includes a safety shutoff in case
problems are found in one or more cells.
This is an added safety feature that is very
affordable and can be used on most chargers.
“For example the FlightPower VBalancer
goes between the charger and the
battery and it reads information from the
battery while it balances the pack. Where is
this safety feature? The internal circuitry of
the V-Balancer is monitoring the cells and if
there is a problem during the charge there
are parameters set to cause the balancer to
unlink, which breaks the circuit between the
charger and the battery.
“To simplify, if you set the charger to the
wrong cell count, the balancer will unlink
before damaging the pack. This gives you a
chance to reset the charger to the correct
settings and then relink the balancer and
continue the charge. Chargers with these
features sell for around $50.
“The next type of balance charger is a
‘loop system’ or ‘closed circuit.’ In these
systems the charger has an add-on balancer
and data cable. The balancer not only
balances, but it also reads info from the
balance taps of the battery, which can be
displayed on the LCD screen of the charger.
This information that is being fed back to the
charger is also used to slow the charger
down when needed and also terminate the
charger when needed, but the balancing is
being done outside of the charger.
“The next type of charger I would like to
mention is a ‘balance charger.’ Typically the
balance chargers have internal balancers and
work very much like the loop systems but
they only have an external board to hook the
balance taps to and an output for the main
power wires. Most of these chargers charge
through the main power wires and read the
info through the balance taps as well as
balance through the same taps with their
internal balancers.
“There are a few chargers that charge
through the balance taps usually at 1C. The
balance chargers typically ramp the charge
rate up and down as needed and usually
have the ability to terminate the charge if
there is a problem.
“This has been a basic overview of
different types of Li-Poly chargers and an
attempt to help others understand a little bit
about basic charging and the knowledge
needed to do so. Always read the
recommendations made by both the battery
manufacturers and the charger
manufacturers. Never charge any battery
unattended, no matter how much you trust
your charger.
“The use of Li-Poly sacks and/or Li-Poly
bunkers is also recommended, and I
personally recommend that you never
charge a pack while it is in a model. Never
run a pack below 80% of its capacity. As an
example, a 2100 mAh pack should never
have more than 1680 mAh discharged
without recharging. This is not only a good
safety practice, but it is also recommended
to prolong the life of your investment. I
hope this has been helpful.”
Thank you, Clint! That is some great
information about safe charging practices
for the most popular type of battery. I hope
pilots can reduce their risk of accidents by
adhering to the guidelines you have laid out.
That is all we have room for this month,
so I hope you’ll be back here again next
time. MA
Sources:
Extreme Flight Championships:
www.futaba-rc.com/xfc-rc/index.html
FlightPower batteries:
Tower Hobbies
(800) 637-6050
www.towerhobbies.com
Edition: Model Aviation - 2009/06
Page Numbers: 127,128,129
Edition: Model Aviation - 2009/06
Page Numbers: 127,128,129
See you at the Extreme Flight Championships
[[email protected]]
Radio Control Helicopters Mark Fadely
Also included in this column:
• Clint Akins’ expert Li-Poly
advice
2007 XFC winner Alan Szabo’s T-Rex makes a high-speed,
sideways pass. The helicopter went briefly out of sight in a dip at
the end of the flightline.
Canada’s Colin Bell thrilled the crowd at the 2008 XFC with his
Raptor 90’s clockwork precision in a choreographed flight.
Clint Akins, manager of FlightPower batteries, keeps pilots
informed of the latest technology in Li-Poly cells.
Dominik Haegel’s Hirobo Turbulence won the 2008 XFC. His
flights included pirouetting reversal moves in 3-D flight.
THIS IS my favorite time of year. I love spring and early summer,
because you have the whole year of good flying weather to look
forward to.
Some lucky pilots live in temperate climates that allow for
year-round outdoor flying. I am stuck smack dab in the most
middle part of the Midwest: Indianapolis, Indiana. There are no
mountains or oceans here, but we do have one fabulous attraction.
The RC highlight of the nation is the AMA Headquarters and
International Aeromodeling Center. It is only 45 minutes from
where I live.
In a few days, the 2009 Extreme Flight Championships (XFC)
will be held at the AMA flying site. It takes place June 12-14. It is
the only competition that includes the world’s best airplane and
helicopter pilots in one spectacular show. Plan to attend this event
if you can. It is a jaw-dropping experience.
Let’s shift our attention to a concern that many pilots share. Batteries
are used in several facets of RC. When you have spent time in the
hobby, you start learning about the various types of batteries, along
with their chemical makeups.
Batteries are the lifeblood of successful RC flying, so you must
know how to handle each kind properly. If you do not follow the
rules, you might find yourself in a dangerous situation.
June 2009 127
06sig4.QXD 4/23/09 1:46 PM Page 127
I’m going to highlight the most misunderstood of all batteries: the
Li-Poly. They are used in many gadgets, including every cell phone
on the planet. If a battery is safely used by so many people, what is the
big problem?
I asked my good friend, Clint Akins, to write a brief explanation of
Li-Poly handling requirements. He is the manager of FlightPower
batteries, which makes a full line of Li-Poly cells. He takes these
batteries’ safety seriously. To help pilots better understand the
potential pitfalls of Li-Poly handling, Clint wrote something special
for us.
“Chargers 101: Taking the Black Magic Out of Li-Poly Batteries:
Let me start by saying that Li-Poly (Lithium-Polymer) batteries and
Li-Poly chargers have improved greatly over the last few years.
“In the beginning the chargers were very crude and often they
charged in stages. For example, the early chargers were simply set to
the desired voltage and charge rate, and they often charged very
aggressively in the first stage. This usually was fine until we (the end
users) made the mistake of putting a battery on a charger that was
already charged. The result was almost always the same: yep a
damaged pack, or worse, a fire.
“Let’s stop for a moment and understand why. Li-Poly batteries
are typically fully charged at 4.2 volts per cell. The early chargers
were programmed to blast a heavy charge to the pack for the first
cycle and they never sensed any info from the pack initially as to the
charge level. The chargers would push the voltage above 4.3 volts per
cell which can damage not only the cycle
life of the pack, but it becomes dangerous
and can cause a fire.
“We do not hear of nearly the problems
with charging batteries that we used to. Is it
because there are fewer people using Li-
Poly batteries? It is because the technology
of the chargers is much better, and the
education of the end user has improved?
“How do you keep up with it all? While
we are fortunate to have technology moving
fast, it can also be difficult to keep up with.
Like I stated previously, this document is
intended to help simplify some things, and
take the black magic out of Li-Poly charging
by explaining a little about the chargers and
the batteries.
“The basic Li-Poly chargers today are
pretty simple, and the user sets the voltage
or cell count (3.7 volts per cell) and the
charge rate, which is normally 1C. This
brings up the first question: what does 1C
mean?
“Just to simplify things, 1C means one
times the capacity. Packs are usually rated in
mAh (milliamp hours), and chargers are set
in values of amps. Let’s just simplify this
and make it easy. There are 1000 mAh in an
amp.
“As an example, we will use a 3S, 2100
mAh pack. 3S means we have three cells,
three times the nominal voltage of a cell (3.7
x 3 = 11.1 volts). We know that the pack is
11.1 volts at nominal voltage and fully
charged it will be 4.2 volts per cell, or 4.2 x
3 = 12.6 volts. This pack could be called a
2.1 amp pack: by dividing 2100 mAh by
1000 will give us the value of the pack in
amps which is 2.1. If we want to charge this
2.1 amp pack at 1C we would set our charge
rate at 2.1 amps.
“Now that we understand terms like 1C,
and we know how to figure charge rate and
the voltage we want to charge at, we will
move on. A good tool to use with a basic
charger is a balancer. I prefer to take it one
step further by using a feed-through
balancer. What is the difference, and why
should I use a balancer?
“A basic balancer equalizes the cell
voltage on a pack to within set parameters.
This will keep the cells in the pack at or
close to the same voltage with each other,
which will allow them to perform at their
best. It will also lengthen the cell life.
“The difference between the feedthrough
balancer and the typical balancer is
that the feed-through checks each cell as it is
charging, and maintains the proper levels. It
also includes a safety shutoff in case
problems are found in one or more cells.
This is an added safety feature that is very
affordable and can be used on most chargers.
“For example the FlightPower VBalancer
goes between the charger and the
battery and it reads information from the
battery while it balances the pack. Where is
this safety feature? The internal circuitry of
the V-Balancer is monitoring the cells and if
there is a problem during the charge there
are parameters set to cause the balancer to
unlink, which breaks the circuit between the
charger and the battery.
“To simplify, if you set the charger to the
wrong cell count, the balancer will unlink
before damaging the pack. This gives you a
chance to reset the charger to the correct
settings and then relink the balancer and
continue the charge. Chargers with these
features sell for around $50.
“The next type of balance charger is a
‘loop system’ or ‘closed circuit.’ In these
systems the charger has an add-on balancer
and data cable. The balancer not only
balances, but it also reads info from the
balance taps of the battery, which can be
displayed on the LCD screen of the charger.
This information that is being fed back to the
charger is also used to slow the charger
down when needed and also terminate the
charger when needed, but the balancing is
being done outside of the charger.
“The next type of charger I would like to
mention is a ‘balance charger.’ Typically the
balance chargers have internal balancers and
work very much like the loop systems but
they only have an external board to hook the
balance taps to and an output for the main
power wires. Most of these chargers charge
through the main power wires and read the
info through the balance taps as well as
balance through the same taps with their
internal balancers.
“There are a few chargers that charge
through the balance taps usually at 1C. The
balance chargers typically ramp the charge
rate up and down as needed and usually
have the ability to terminate the charge if
there is a problem.
“This has been a basic overview of
different types of Li-Poly chargers and an
attempt to help others understand a little bit
about basic charging and the knowledge
needed to do so. Always read the
recommendations made by both the battery
manufacturers and the charger
manufacturers. Never charge any battery
unattended, no matter how much you trust
your charger.
“The use of Li-Poly sacks and/or Li-Poly
bunkers is also recommended, and I
personally recommend that you never
charge a pack while it is in a model. Never
run a pack below 80% of its capacity. As an
example, a 2100 mAh pack should never
have more than 1680 mAh discharged
without recharging. This is not only a good
safety practice, but it is also recommended
to prolong the life of your investment. I
hope this has been helpful.”
Thank you, Clint! That is some great
information about safe charging practices
for the most popular type of battery. I hope
pilots can reduce their risk of accidents by
adhering to the guidelines you have laid out.
That is all we have room for this month,
so I hope you’ll be back here again next
time. MA
Sources:
Extreme Flight Championships:
www.futaba-rc.com/xfc-rc/index.html
FlightPower batteries:
Tower Hobbies
(800) 637-6050
www.towerhobbies.com
Edition: Model Aviation - 2009/06
Page Numbers: 127,128,129
See you at the Extreme Flight Championships
[[email protected]]
Radio Control Helicopters Mark Fadely
Also included in this column:
• Clint Akins’ expert Li-Poly
advice
2007 XFC winner Alan Szabo’s T-Rex makes a high-speed,
sideways pass. The helicopter went briefly out of sight in a dip at
the end of the flightline.
Canada’s Colin Bell thrilled the crowd at the 2008 XFC with his
Raptor 90’s clockwork precision in a choreographed flight.
Clint Akins, manager of FlightPower batteries, keeps pilots
informed of the latest technology in Li-Poly cells.
Dominik Haegel’s Hirobo Turbulence won the 2008 XFC. His
flights included pirouetting reversal moves in 3-D flight.
THIS IS my favorite time of year. I love spring and early summer,
because you have the whole year of good flying weather to look
forward to.
Some lucky pilots live in temperate climates that allow for
year-round outdoor flying. I am stuck smack dab in the most
middle part of the Midwest: Indianapolis, Indiana. There are no
mountains or oceans here, but we do have one fabulous attraction.
The RC highlight of the nation is the AMA Headquarters and
International Aeromodeling Center. It is only 45 minutes from
where I live.
In a few days, the 2009 Extreme Flight Championships (XFC)
will be held at the AMA flying site. It takes place June 12-14. It is
the only competition that includes the world’s best airplane and
helicopter pilots in one spectacular show. Plan to attend this event
if you can. It is a jaw-dropping experience.
Let’s shift our attention to a concern that many pilots share. Batteries
are used in several facets of RC. When you have spent time in the
hobby, you start learning about the various types of batteries, along
with their chemical makeups.
Batteries are the lifeblood of successful RC flying, so you must
know how to handle each kind properly. If you do not follow the
rules, you might find yourself in a dangerous situation.
June 2009 127
06sig4.QXD 4/23/09 1:46 PM Page 127
I’m going to highlight the most misunderstood of all batteries: the
Li-Poly. They are used in many gadgets, including every cell phone
on the planet. If a battery is safely used by so many people, what is the
big problem?
I asked my good friend, Clint Akins, to write a brief explanation of
Li-Poly handling requirements. He is the manager of FlightPower
batteries, which makes a full line of Li-Poly cells. He takes these
batteries’ safety seriously. To help pilots better understand the
potential pitfalls of Li-Poly handling, Clint wrote something special
for us.
“Chargers 101: Taking the Black Magic Out of Li-Poly Batteries:
Let me start by saying that Li-Poly (Lithium-Polymer) batteries and
Li-Poly chargers have improved greatly over the last few years.
“In the beginning the chargers were very crude and often they
charged in stages. For example, the early chargers were simply set to
the desired voltage and charge rate, and they often charged very
aggressively in the first stage. This usually was fine until we (the end
users) made the mistake of putting a battery on a charger that was
already charged. The result was almost always the same: yep a
damaged pack, or worse, a fire.
“Let’s stop for a moment and understand why. Li-Poly batteries
are typically fully charged at 4.2 volts per cell. The early chargers
were programmed to blast a heavy charge to the pack for the first
cycle and they never sensed any info from the pack initially as to the
charge level. The chargers would push the voltage above 4.3 volts per
cell which can damage not only the cycle
life of the pack, but it becomes dangerous
and can cause a fire.
“We do not hear of nearly the problems
with charging batteries that we used to. Is it
because there are fewer people using Li-
Poly batteries? It is because the technology
of the chargers is much better, and the
education of the end user has improved?
“How do you keep up with it all? While
we are fortunate to have technology moving
fast, it can also be difficult to keep up with.
Like I stated previously, this document is
intended to help simplify some things, and
take the black magic out of Li-Poly charging
by explaining a little about the chargers and
the batteries.
“The basic Li-Poly chargers today are
pretty simple, and the user sets the voltage
or cell count (3.7 volts per cell) and the
charge rate, which is normally 1C. This
brings up the first question: what does 1C
mean?
“Just to simplify things, 1C means one
times the capacity. Packs are usually rated in
mAh (milliamp hours), and chargers are set
in values of amps. Let’s just simplify this
and make it easy. There are 1000 mAh in an
amp.
“As an example, we will use a 3S, 2100
mAh pack. 3S means we have three cells,
three times the nominal voltage of a cell (3.7
x 3 = 11.1 volts). We know that the pack is
11.1 volts at nominal voltage and fully
charged it will be 4.2 volts per cell, or 4.2 x
3 = 12.6 volts. This pack could be called a
2.1 amp pack: by dividing 2100 mAh by
1000 will give us the value of the pack in
amps which is 2.1. If we want to charge this
2.1 amp pack at 1C we would set our charge
rate at 2.1 amps.
“Now that we understand terms like 1C,
and we know how to figure charge rate and
the voltage we want to charge at, we will
move on. A good tool to use with a basic
charger is a balancer. I prefer to take it one
step further by using a feed-through
balancer. What is the difference, and why
should I use a balancer?
“A basic balancer equalizes the cell
voltage on a pack to within set parameters.
This will keep the cells in the pack at or
close to the same voltage with each other,
which will allow them to perform at their
best. It will also lengthen the cell life.
“The difference between the feedthrough
balancer and the typical balancer is
that the feed-through checks each cell as it is
charging, and maintains the proper levels. It
also includes a safety shutoff in case
problems are found in one or more cells.
This is an added safety feature that is very
affordable and can be used on most chargers.
“For example the FlightPower VBalancer
goes between the charger and the
battery and it reads information from the
battery while it balances the pack. Where is
this safety feature? The internal circuitry of
the V-Balancer is monitoring the cells and if
there is a problem during the charge there
are parameters set to cause the balancer to
unlink, which breaks the circuit between the
charger and the battery.
“To simplify, if you set the charger to the
wrong cell count, the balancer will unlink
before damaging the pack. This gives you a
chance to reset the charger to the correct
settings and then relink the balancer and
continue the charge. Chargers with these
features sell for around $50.
“The next type of balance charger is a
‘loop system’ or ‘closed circuit.’ In these
systems the charger has an add-on balancer
and data cable. The balancer not only
balances, but it also reads info from the
balance taps of the battery, which can be
displayed on the LCD screen of the charger.
This information that is being fed back to the
charger is also used to slow the charger
down when needed and also terminate the
charger when needed, but the balancing is
being done outside of the charger.
“The next type of charger I would like to
mention is a ‘balance charger.’ Typically the
balance chargers have internal balancers and
work very much like the loop systems but
they only have an external board to hook the
balance taps to and an output for the main
power wires. Most of these chargers charge
through the main power wires and read the
info through the balance taps as well as
balance through the same taps with their
internal balancers.
“There are a few chargers that charge
through the balance taps usually at 1C. The
balance chargers typically ramp the charge
rate up and down as needed and usually
have the ability to terminate the charge if
there is a problem.
“This has been a basic overview of
different types of Li-Poly chargers and an
attempt to help others understand a little bit
about basic charging and the knowledge
needed to do so. Always read the
recommendations made by both the battery
manufacturers and the charger
manufacturers. Never charge any battery
unattended, no matter how much you trust
your charger.
“The use of Li-Poly sacks and/or Li-Poly
bunkers is also recommended, and I
personally recommend that you never
charge a pack while it is in a model. Never
run a pack below 80% of its capacity. As an
example, a 2100 mAh pack should never
have more than 1680 mAh discharged
without recharging. This is not only a good
safety practice, but it is also recommended
to prolong the life of your investment. I
hope this has been helpful.”
Thank you, Clint! That is some great
information about safe charging practices
for the most popular type of battery. I hope
pilots can reduce their risk of accidents by
adhering to the guidelines you have laid out.
That is all we have room for this month,
so I hope you’ll be back here again next
time. MA
Sources:
Extreme Flight Championships:
www.futaba-rc.com/xfc-rc/index.html
FlightPower batteries:
Tower Hobbies
(800) 637-6050
www.towerhobbies.com