HOW TIME fritters away. I can’t believe
I’m starting my fourth year of this column
and there are still unanswered battery
questions. Since this is only my 78th orbit of
the sun, hopefully I will be around to
answer a few more.
Do you need more capacity or higher
voltage? Consider individual packs
harnessed together, in series or parallel.
Compared to a single “unit” pack,
harnessed packs have the following
advantages.
1) They are easy
to check, easy to
balance, and easy
and safe to charge.
Two packs
harnessed in
parallel, such as
2200 3S to achieve
a 3S2P, 11.1-volt,
4400 mAh pack,
can be disconnected
at any time, so you
retain the ability to
check each cell
through the balance
connectors and
charge safely by
separating the
packs.
If you have a
“hardwired”
parallel pack in a
single unit, you
can’t clearly
diagnose a single
weak cell. Charging
a pack with a weak
July 2008 101
The Battery Clinic Red Scholefield | [email protected]
Also included in this column:
• The new e-Station BC6-10
charger
• Making sense of loaded voltmeter
readings
• The Cellpro 10s offers more
power and dual ports
• How long can battery-to-ESC or
ESC-to-motor leads be?
FMA Direct’s new Cellpro 10s
The e-Station BC6-10 charger upgrades to higher power. dual-port charger.
The Cellpro 10s software presents battery data.
cell or cells can easily cause a fire during
charging—and the danger is compounded
by having so many cells in the pack for
“fuel” on that fire.
2) There is versatility in using packs. If
you decide to retire that big model, you can
instantly break your 3S2P pack to a pair of
3S packs for use in a smaller model.
3) They are easy to rewire. Do you need
to convert that 3S2P pack into 6S? It’s a
snap with a harness. A hardwired pack
would likely be damaged in the arduous job
of resoldering the individual cells, as is
required in such a conversion.
One big pack or individual packs harnessed together?
4) They are easy to arrange. Different
pack shapes are required to fit and balance
different models. Harnessed packs allow
you to choose the optimal arrangement—
front to back (in-line), side by side, or
whatever you need.
Harnessing two packs is easy. Choose
appropriate connectors for the expected
amperage, and wire them for series or
parallel operation. When running in series,
the packs must be the same capacity, from
the same manufacturer, and, if possible, the
same age.
They do not have to be the same
number of cells. For parallel operation,
they must be the same number of cells, but
they can be a different capacity.
Bantam Upgrades Its BC6: The latest
addition to the Bantam e-Station BC series
of chargers is the BC6-10, which ups the
charge rate to 10 amps. As is its brother,
the e-Station BC6, the BC6-10 is a 6S unit
with a built-in 6S balancer.
The BC6-10 supports Li-Ion, Li-Poly,
and Li-Fe (A123). It’s available for
$179.95 through RC Accessory Inc.; see
the end of the column for contact info.
The BC6-10’s specifications are: input
voltage, 10-18; power, 200 watts for
charging and 25 watts for discharge; charge
current, 100 mAh-10 amps; discharge
current, 100 mAh-5 amps; balancer drain,
200 mAh per cell; Li-xx cell count, 1S-6S;
Ni-xx cell count, 1-18; Pb cell count, 1-12
volts (2-24 volts); weight, 680 grams; and
dimensions, 140 x 120 x 36mm.
Loaded Voltmeter Readings: This still
seems to confuse a lot of people, so it
deserves another shot. Mike Oberst wrote:
“I would like your opinion if you don’t
mind. I have been using the Sanyo 2400
sub-C 4.8V Ni-Cd packs in several different
scale models for quite a while. These
models typically have 8-10 servos, mostly
digitals.
“I charge at 240 for 12-14 hours with an
Ace DMVC (the old analog one). I also have
an Ace ESV. It’s the analog unit with either
200 or 500 mAh load. For years, I have been
using the 200 mA load to test all my planes
during the flying day. Using that load, I have
always gotten four flights before I go into
the red.
“Recently, I have come to believe that
the 200 mA load is not a realistic
representation of the load the battery is
seeing in flight in most of my models. I base
this assumption on the number of servos (8-
10) that I am using in most of my models.
“Therefore, I have started using the 500
mAh load on the Ace ESV. In using this
load, I can only get two flights in before my
ESV shows in the red. I have checked the
Ace ESV with a digital meter to be sure it is
not over loading, and it is very accurate.
“I want to be safe, but I flew these same
models for 3-4 years, testing with the 200
mA load, and always got 4 flights with no
problems. Should I continue loading at 500
mA and only get two flights before fast field
charging, or is that being a bit too
conservative? Should I go back to using the
200 mA load? I am a bit confused as to how
I should proceed.
“If it helps any, my Graupner Ultra Duo
field charger shows that I typically use 350-
400 mAh per flight. Thanks in advance for
your help.”
Mike, it sounds like your 200 mAh test
load is doing okay.
Remember that your system is drawing
maximum current only when the servos are
moving. Your average drain, as you have
demonstrated, is not 500 mA. Drawing 400
mAh per flight indicates that you should be
comfortable with five flights and have a
decent capacity reserve.
I like to use a voltwatch so I can see the
actual state of the battery. With these, while
the battery is well into the green, rapid
movement of the sticks will get the orange
or red to flicker. The best method is to know
what your system takes in the way of mAh/
minutes of flight.
This is discussed in detail on The Battery
Clinic’s Web site. You seem to have a
handle on this, so you are in good shape.
Cellpro 10s Raises the Bar: After nearly
three months of beta testing by experienced
modelers, FMA Direct’s Cellpro 10s has
been released for production at $189.95.
Following the success of the Cellpro 4s
with both Li-Poly and A123 capability, the
10s employs the same simple-to-operate
philosophy of one-button programming.
Testing here at The Battery Clinic went
through a half-dozen firmware updates as
improvements and suggestions came in to
FMA Direct from the beta-test team. One
of the 10s’s features is that the user will be
notified of any firmware updates as soon as
he or she connects to a computer with the
USB cable (item FUIM2), which can be
ordered as an option for the 10s. These
updates will be loaded into that user’s 10s.
FMA Direct’s downloadable software
allows the user to plot the charge curves,
check individual cell internal resistance (a
good indication of battery health), and
save that data to compare at a future date.
It also allows the charger’s visual and
audio features and input current limit for
the 12-volt supply being used to be
changed.
However, use in the shop or at the field
does not require a computer connection.
The user can scroll through all the displays
to monitor real-time charge status, mAh
input, balance condition, balance current,
overall current, input voltage and current,
fuel level, etc. Connecting to your
computer does give you a bit more
information and a visual of what is
happening.
Although the 10s’s operation closely
resembles the 4s’s, with one-button
operation, there is a comprehensive
operator’s manual and another three pages
of pin lead connection diagrams covering
two- through 10-cell packs that the 10s
accommodates. Adapters come with the 10s
to match your current Cellpro two- to fourcell
packs or any FMA Direct-brand
adapters you have for other Li-Poly brands.
It is impossible to design a charger that
will meet everyone’s perceived needs, but
FMA Direct has raised the bar with the 10s
to meet electric-power modelers’ needs for
a long time. Details, specifications, and the
operating manual are available on the FMA
Direct Web site.
Long Battery-to-ESC Wires or Long
Motor Wires From the ESC? There has
been a fair amount of controversy about
this subject as e-flighters move into
multiengine models.
Logic would tell us that lengthening the
battery leads so the ESCs could be located
in the engine nacelles for cooling would be
the way to go. But according to those who
design the ESCs, that isn’t the way it goes.
“On the HV controllers especially, the
battery-ESC length is the critical length,”
said Patrick del Castillo of Castle
Creations. “You should not extend the
wires more than a total length of greater
than 12 inches without additional
capacitors. On the motor side, length is less
critical—18 inches is fine.”
Bob Boucher (Astrobob) of AstroFlight
went into a bit more detail. He wrote:
“I will repeat the message previously
given. I hope you heed some sound advice
based on theory and practice.
“1. Wire resistance may rob you of a bit
of power but will not destroy your speed
control or motor.
“2. Wire inductance will not damage
your motor nor will you be able to detect
any effect even with 100 feet of wire.
“3. Wire inductance will kill the mosfets
in your controller and may even blow the
caps.
“You must keep battery wires as short
as practical. Short means 1-foot or less.
Brushed or brushless, it makes no
difference.
“Here are some examples of problems
customers have had: A modeler had a blimp
with 30 feet of wire to ESC near the
steering motor in the tail. ESC rating 60
volts 50 amps, motor load at 12v was 20
amps. Result: instant smoke first run of the
motor.
“I replaced controller at no cost and the
same result occurred, instant smoke. Then I
was told about long wires and ran a test
with 3-feet of cord. Result: 30 volt
switching spikes on 100 uf input capacitor.
I had the customer put the ESC near battery
in the gondola. Result: 30 feet wire to
motor, end of problems.
“We have customers running very long
wires from the ESC to motors for industrial
applications with no problems, hundreds of
feet or more. With ESC to the battery, keep
battery wires short, period!”
If you must run long battery leads,
Shultze shows us how to add capacitors
(with instructions in English and German).
That’s it for this month. Support your US
Postal Service and send an SASE if you
want a personalized answer. E-mail is
faster. MA
Sources:
AstroFlight
(310) 821-6242
www.astroflight.com
FMA Direct
(800) 343-2934
www.fmadirect.com
RC Accessory, Inc.
(813) 765-0124
www.rcaccessory.com
Shultze
www.schulze-elektronikgmbh.
de/guide/gfutc-de.pdf
The Battery Clinic
12219 NW 9th Ln.
Newberry, FL 32669
www.rcbatteryclinic.com
Edition: Model Aviation - 2008/07
Page Numbers: 101,102,104
Edition: Model Aviation - 2008/07
Page Numbers: 101,102,104
HOW TIME fritters away. I can’t believe
I’m starting my fourth year of this column
and there are still unanswered battery
questions. Since this is only my 78th orbit of
the sun, hopefully I will be around to
answer a few more.
Do you need more capacity or higher
voltage? Consider individual packs
harnessed together, in series or parallel.
Compared to a single “unit” pack,
harnessed packs have the following
advantages.
1) They are easy
to check, easy to
balance, and easy
and safe to charge.
Two packs
harnessed in
parallel, such as
2200 3S to achieve
a 3S2P, 11.1-volt,
4400 mAh pack,
can be disconnected
at any time, so you
retain the ability to
check each cell
through the balance
connectors and
charge safely by
separating the
packs.
If you have a
“hardwired”
parallel pack in a
single unit, you
can’t clearly
diagnose a single
weak cell. Charging
a pack with a weak
July 2008 101
The Battery Clinic Red Scholefield | [email protected]
Also included in this column:
• The new e-Station BC6-10
charger
• Making sense of loaded voltmeter
readings
• The Cellpro 10s offers more
power and dual ports
• How long can battery-to-ESC or
ESC-to-motor leads be?
FMA Direct’s new Cellpro 10s
The e-Station BC6-10 charger upgrades to higher power. dual-port charger.
The Cellpro 10s software presents battery data.
cell or cells can easily cause a fire during
charging—and the danger is compounded
by having so many cells in the pack for
“fuel” on that fire.
2) There is versatility in using packs. If
you decide to retire that big model, you can
instantly break your 3S2P pack to a pair of
3S packs for use in a smaller model.
3) They are easy to rewire. Do you need
to convert that 3S2P pack into 6S? It’s a
snap with a harness. A hardwired pack
would likely be damaged in the arduous job
of resoldering the individual cells, as is
required in such a conversion.
One big pack or individual packs harnessed together?
4) They are easy to arrange. Different
pack shapes are required to fit and balance
different models. Harnessed packs allow
you to choose the optimal arrangement—
front to back (in-line), side by side, or
whatever you need.
Harnessing two packs is easy. Choose
appropriate connectors for the expected
amperage, and wire them for series or
parallel operation. When running in series,
the packs must be the same capacity, from
the same manufacturer, and, if possible, the
same age.
They do not have to be the same
number of cells. For parallel operation,
they must be the same number of cells, but
they can be a different capacity.
Bantam Upgrades Its BC6: The latest
addition to the Bantam e-Station BC series
of chargers is the BC6-10, which ups the
charge rate to 10 amps. As is its brother,
the e-Station BC6, the BC6-10 is a 6S unit
with a built-in 6S balancer.
The BC6-10 supports Li-Ion, Li-Poly,
and Li-Fe (A123). It’s available for
$179.95 through RC Accessory Inc.; see
the end of the column for contact info.
The BC6-10’s specifications are: input
voltage, 10-18; power, 200 watts for
charging and 25 watts for discharge; charge
current, 100 mAh-10 amps; discharge
current, 100 mAh-5 amps; balancer drain,
200 mAh per cell; Li-xx cell count, 1S-6S;
Ni-xx cell count, 1-18; Pb cell count, 1-12
volts (2-24 volts); weight, 680 grams; and
dimensions, 140 x 120 x 36mm.
Loaded Voltmeter Readings: This still
seems to confuse a lot of people, so it
deserves another shot. Mike Oberst wrote:
“I would like your opinion if you don’t
mind. I have been using the Sanyo 2400
sub-C 4.8V Ni-Cd packs in several different
scale models for quite a while. These
models typically have 8-10 servos, mostly
digitals.
“I charge at 240 for 12-14 hours with an
Ace DMVC (the old analog one). I also have
an Ace ESV. It’s the analog unit with either
200 or 500 mAh load. For years, I have been
using the 200 mA load to test all my planes
during the flying day. Using that load, I have
always gotten four flights before I go into
the red.
“Recently, I have come to believe that
the 200 mA load is not a realistic
representation of the load the battery is
seeing in flight in most of my models. I base
this assumption on the number of servos (8-
10) that I am using in most of my models.
“Therefore, I have started using the 500
mAh load on the Ace ESV. In using this
load, I can only get two flights in before my
ESV shows in the red. I have checked the
Ace ESV with a digital meter to be sure it is
not over loading, and it is very accurate.
“I want to be safe, but I flew these same
models for 3-4 years, testing with the 200
mA load, and always got 4 flights with no
problems. Should I continue loading at 500
mA and only get two flights before fast field
charging, or is that being a bit too
conservative? Should I go back to using the
200 mA load? I am a bit confused as to how
I should proceed.
“If it helps any, my Graupner Ultra Duo
field charger shows that I typically use 350-
400 mAh per flight. Thanks in advance for
your help.”
Mike, it sounds like your 200 mAh test
load is doing okay.
Remember that your system is drawing
maximum current only when the servos are
moving. Your average drain, as you have
demonstrated, is not 500 mA. Drawing 400
mAh per flight indicates that you should be
comfortable with five flights and have a
decent capacity reserve.
I like to use a voltwatch so I can see the
actual state of the battery. With these, while
the battery is well into the green, rapid
movement of the sticks will get the orange
or red to flicker. The best method is to know
what your system takes in the way of mAh/
minutes of flight.
This is discussed in detail on The Battery
Clinic’s Web site. You seem to have a
handle on this, so you are in good shape.
Cellpro 10s Raises the Bar: After nearly
three months of beta testing by experienced
modelers, FMA Direct’s Cellpro 10s has
been released for production at $189.95.
Following the success of the Cellpro 4s
with both Li-Poly and A123 capability, the
10s employs the same simple-to-operate
philosophy of one-button programming.
Testing here at The Battery Clinic went
through a half-dozen firmware updates as
improvements and suggestions came in to
FMA Direct from the beta-test team. One
of the 10s’s features is that the user will be
notified of any firmware updates as soon as
he or she connects to a computer with the
USB cable (item FUIM2), which can be
ordered as an option for the 10s. These
updates will be loaded into that user’s 10s.
FMA Direct’s downloadable software
allows the user to plot the charge curves,
check individual cell internal resistance (a
good indication of battery health), and
save that data to compare at a future date.
It also allows the charger’s visual and
audio features and input current limit for
the 12-volt supply being used to be
changed.
However, use in the shop or at the field
does not require a computer connection.
The user can scroll through all the displays
to monitor real-time charge status, mAh
input, balance condition, balance current,
overall current, input voltage and current,
fuel level, etc. Connecting to your
computer does give you a bit more
information and a visual of what is
happening.
Although the 10s’s operation closely
resembles the 4s’s, with one-button
operation, there is a comprehensive
operator’s manual and another three pages
of pin lead connection diagrams covering
two- through 10-cell packs that the 10s
accommodates. Adapters come with the 10s
to match your current Cellpro two- to fourcell
packs or any FMA Direct-brand
adapters you have for other Li-Poly brands.
It is impossible to design a charger that
will meet everyone’s perceived needs, but
FMA Direct has raised the bar with the 10s
to meet electric-power modelers’ needs for
a long time. Details, specifications, and the
operating manual are available on the FMA
Direct Web site.
Long Battery-to-ESC Wires or Long
Motor Wires From the ESC? There has
been a fair amount of controversy about
this subject as e-flighters move into
multiengine models.
Logic would tell us that lengthening the
battery leads so the ESCs could be located
in the engine nacelles for cooling would be
the way to go. But according to those who
design the ESCs, that isn’t the way it goes.
“On the HV controllers especially, the
battery-ESC length is the critical length,”
said Patrick del Castillo of Castle
Creations. “You should not extend the
wires more than a total length of greater
than 12 inches without additional
capacitors. On the motor side, length is less
critical—18 inches is fine.”
Bob Boucher (Astrobob) of AstroFlight
went into a bit more detail. He wrote:
“I will repeat the message previously
given. I hope you heed some sound advice
based on theory and practice.
“1. Wire resistance may rob you of a bit
of power but will not destroy your speed
control or motor.
“2. Wire inductance will not damage
your motor nor will you be able to detect
any effect even with 100 feet of wire.
“3. Wire inductance will kill the mosfets
in your controller and may even blow the
caps.
“You must keep battery wires as short
as practical. Short means 1-foot or less.
Brushed or brushless, it makes no
difference.
“Here are some examples of problems
customers have had: A modeler had a blimp
with 30 feet of wire to ESC near the
steering motor in the tail. ESC rating 60
volts 50 amps, motor load at 12v was 20
amps. Result: instant smoke first run of the
motor.
“I replaced controller at no cost and the
same result occurred, instant smoke. Then I
was told about long wires and ran a test
with 3-feet of cord. Result: 30 volt
switching spikes on 100 uf input capacitor.
I had the customer put the ESC near battery
in the gondola. Result: 30 feet wire to
motor, end of problems.
“We have customers running very long
wires from the ESC to motors for industrial
applications with no problems, hundreds of
feet or more. With ESC to the battery, keep
battery wires short, period!”
If you must run long battery leads,
Shultze shows us how to add capacitors
(with instructions in English and German).
That’s it for this month. Support your US
Postal Service and send an SASE if you
want a personalized answer. E-mail is
faster. MA
Sources:
AstroFlight
(310) 821-6242
www.astroflight.com
FMA Direct
(800) 343-2934
www.fmadirect.com
RC Accessory, Inc.
(813) 765-0124
www.rcaccessory.com
Shultze
www.schulze-elektronikgmbh.
de/guide/gfutc-de.pdf
The Battery Clinic
12219 NW 9th Ln.
Newberry, FL 32669
www.rcbatteryclinic.com
Edition: Model Aviation - 2008/07
Page Numbers: 101,102,104
HOW TIME fritters away. I can’t believe
I’m starting my fourth year of this column
and there are still unanswered battery
questions. Since this is only my 78th orbit of
the sun, hopefully I will be around to
answer a few more.
Do you need more capacity or higher
voltage? Consider individual packs
harnessed together, in series or parallel.
Compared to a single “unit” pack,
harnessed packs have the following
advantages.
1) They are easy
to check, easy to
balance, and easy
and safe to charge.
Two packs
harnessed in
parallel, such as
2200 3S to achieve
a 3S2P, 11.1-volt,
4400 mAh pack,
can be disconnected
at any time, so you
retain the ability to
check each cell
through the balance
connectors and
charge safely by
separating the
packs.
If you have a
“hardwired”
parallel pack in a
single unit, you
can’t clearly
diagnose a single
weak cell. Charging
a pack with a weak
July 2008 101
The Battery Clinic Red Scholefield | [email protected]
Also included in this column:
• The new e-Station BC6-10
charger
• Making sense of loaded voltmeter
readings
• The Cellpro 10s offers more
power and dual ports
• How long can battery-to-ESC or
ESC-to-motor leads be?
FMA Direct’s new Cellpro 10s
The e-Station BC6-10 charger upgrades to higher power. dual-port charger.
The Cellpro 10s software presents battery data.
cell or cells can easily cause a fire during
charging—and the danger is compounded
by having so many cells in the pack for
“fuel” on that fire.
2) There is versatility in using packs. If
you decide to retire that big model, you can
instantly break your 3S2P pack to a pair of
3S packs for use in a smaller model.
3) They are easy to rewire. Do you need
to convert that 3S2P pack into 6S? It’s a
snap with a harness. A hardwired pack
would likely be damaged in the arduous job
of resoldering the individual cells, as is
required in such a conversion.
One big pack or individual packs harnessed together?
4) They are easy to arrange. Different
pack shapes are required to fit and balance
different models. Harnessed packs allow
you to choose the optimal arrangement—
front to back (in-line), side by side, or
whatever you need.
Harnessing two packs is easy. Choose
appropriate connectors for the expected
amperage, and wire them for series or
parallel operation. When running in series,
the packs must be the same capacity, from
the same manufacturer, and, if possible, the
same age.
They do not have to be the same
number of cells. For parallel operation,
they must be the same number of cells, but
they can be a different capacity.
Bantam Upgrades Its BC6: The latest
addition to the Bantam e-Station BC series
of chargers is the BC6-10, which ups the
charge rate to 10 amps. As is its brother,
the e-Station BC6, the BC6-10 is a 6S unit
with a built-in 6S balancer.
The BC6-10 supports Li-Ion, Li-Poly,
and Li-Fe (A123). It’s available for
$179.95 through RC Accessory Inc.; see
the end of the column for contact info.
The BC6-10’s specifications are: input
voltage, 10-18; power, 200 watts for
charging and 25 watts for discharge; charge
current, 100 mAh-10 amps; discharge
current, 100 mAh-5 amps; balancer drain,
200 mAh per cell; Li-xx cell count, 1S-6S;
Ni-xx cell count, 1-18; Pb cell count, 1-12
volts (2-24 volts); weight, 680 grams; and
dimensions, 140 x 120 x 36mm.
Loaded Voltmeter Readings: This still
seems to confuse a lot of people, so it
deserves another shot. Mike Oberst wrote:
“I would like your opinion if you don’t
mind. I have been using the Sanyo 2400
sub-C 4.8V Ni-Cd packs in several different
scale models for quite a while. These
models typically have 8-10 servos, mostly
digitals.
“I charge at 240 for 12-14 hours with an
Ace DMVC (the old analog one). I also have
an Ace ESV. It’s the analog unit with either
200 or 500 mAh load. For years, I have been
using the 200 mA load to test all my planes
during the flying day. Using that load, I have
always gotten four flights before I go into
the red.
“Recently, I have come to believe that
the 200 mA load is not a realistic
representation of the load the battery is
seeing in flight in most of my models. I base
this assumption on the number of servos (8-
10) that I am using in most of my models.
“Therefore, I have started using the 500
mAh load on the Ace ESV. In using this
load, I can only get two flights in before my
ESV shows in the red. I have checked the
Ace ESV with a digital meter to be sure it is
not over loading, and it is very accurate.
“I want to be safe, but I flew these same
models for 3-4 years, testing with the 200
mA load, and always got 4 flights with no
problems. Should I continue loading at 500
mA and only get two flights before fast field
charging, or is that being a bit too
conservative? Should I go back to using the
200 mA load? I am a bit confused as to how
I should proceed.
“If it helps any, my Graupner Ultra Duo
field charger shows that I typically use 350-
400 mAh per flight. Thanks in advance for
your help.”
Mike, it sounds like your 200 mAh test
load is doing okay.
Remember that your system is drawing
maximum current only when the servos are
moving. Your average drain, as you have
demonstrated, is not 500 mA. Drawing 400
mAh per flight indicates that you should be
comfortable with five flights and have a
decent capacity reserve.
I like to use a voltwatch so I can see the
actual state of the battery. With these, while
the battery is well into the green, rapid
movement of the sticks will get the orange
or red to flicker. The best method is to know
what your system takes in the way of mAh/
minutes of flight.
This is discussed in detail on The Battery
Clinic’s Web site. You seem to have a
handle on this, so you are in good shape.
Cellpro 10s Raises the Bar: After nearly
three months of beta testing by experienced
modelers, FMA Direct’s Cellpro 10s has
been released for production at $189.95.
Following the success of the Cellpro 4s
with both Li-Poly and A123 capability, the
10s employs the same simple-to-operate
philosophy of one-button programming.
Testing here at The Battery Clinic went
through a half-dozen firmware updates as
improvements and suggestions came in to
FMA Direct from the beta-test team. One
of the 10s’s features is that the user will be
notified of any firmware updates as soon as
he or she connects to a computer with the
USB cable (item FUIM2), which can be
ordered as an option for the 10s. These
updates will be loaded into that user’s 10s.
FMA Direct’s downloadable software
allows the user to plot the charge curves,
check individual cell internal resistance (a
good indication of battery health), and
save that data to compare at a future date.
It also allows the charger’s visual and
audio features and input current limit for
the 12-volt supply being used to be
changed.
However, use in the shop or at the field
does not require a computer connection.
The user can scroll through all the displays
to monitor real-time charge status, mAh
input, balance condition, balance current,
overall current, input voltage and current,
fuel level, etc. Connecting to your
computer does give you a bit more
information and a visual of what is
happening.
Although the 10s’s operation closely
resembles the 4s’s, with one-button
operation, there is a comprehensive
operator’s manual and another three pages
of pin lead connection diagrams covering
two- through 10-cell packs that the 10s
accommodates. Adapters come with the 10s
to match your current Cellpro two- to fourcell
packs or any FMA Direct-brand
adapters you have for other Li-Poly brands.
It is impossible to design a charger that
will meet everyone’s perceived needs, but
FMA Direct has raised the bar with the 10s
to meet electric-power modelers’ needs for
a long time. Details, specifications, and the
operating manual are available on the FMA
Direct Web site.
Long Battery-to-ESC Wires or Long
Motor Wires From the ESC? There has
been a fair amount of controversy about
this subject as e-flighters move into
multiengine models.
Logic would tell us that lengthening the
battery leads so the ESCs could be located
in the engine nacelles for cooling would be
the way to go. But according to those who
design the ESCs, that isn’t the way it goes.
“On the HV controllers especially, the
battery-ESC length is the critical length,”
said Patrick del Castillo of Castle
Creations. “You should not extend the
wires more than a total length of greater
than 12 inches without additional
capacitors. On the motor side, length is less
critical—18 inches is fine.”
Bob Boucher (Astrobob) of AstroFlight
went into a bit more detail. He wrote:
“I will repeat the message previously
given. I hope you heed some sound advice
based on theory and practice.
“1. Wire resistance may rob you of a bit
of power but will not destroy your speed
control or motor.
“2. Wire inductance will not damage
your motor nor will you be able to detect
any effect even with 100 feet of wire.
“3. Wire inductance will kill the mosfets
in your controller and may even blow the
caps.
“You must keep battery wires as short
as practical. Short means 1-foot or less.
Brushed or brushless, it makes no
difference.
“Here are some examples of problems
customers have had: A modeler had a blimp
with 30 feet of wire to ESC near the
steering motor in the tail. ESC rating 60
volts 50 amps, motor load at 12v was 20
amps. Result: instant smoke first run of the
motor.
“I replaced controller at no cost and the
same result occurred, instant smoke. Then I
was told about long wires and ran a test
with 3-feet of cord. Result: 30 volt
switching spikes on 100 uf input capacitor.
I had the customer put the ESC near battery
in the gondola. Result: 30 feet wire to
motor, end of problems.
“We have customers running very long
wires from the ESC to motors for industrial
applications with no problems, hundreds of
feet or more. With ESC to the battery, keep
battery wires short, period!”
If you must run long battery leads,
Shultze shows us how to add capacitors
(with instructions in English and German).
That’s it for this month. Support your US
Postal Service and send an SASE if you
want a personalized answer. E-mail is
faster. MA
Sources:
AstroFlight
(310) 821-6242
www.astroflight.com
FMA Direct
(800) 343-2934
www.fmadirect.com
RC Accessory, Inc.
(813) 765-0124
www.rcaccessory.com
Shultze
www.schulze-elektronikgmbh.
de/guide/gfutc-de.pdf
The Battery Clinic
12219 NW 9th Ln.
Newberry, FL 32669
www.rcbatteryclinic.com