I GET MANY questions from people who
want to build or rebuild their own battery
packs. The fact that they are asking basic
questions that anyone delving into doing
this should already know the answers to is
kind of scary.
When you are working with a battery,
be it Ni-Cd, NiMH, or Li-Poly, there is a
finite amount of energy that you have to
deal with. Although you might only get a
small burn, shorting any Lithium battery,
even for a few seconds, can cause the tabs
to heat enough to ruin a pack or start a fire!
So if you are going to do battery-pack surgery, connect only
one battery lead at a time to prevent a short. Strip one lead, solder
it to the connector and battery, and insulate. Repeat with the
remaining battery leads. It will save you considerable heartburn,
not to mention more serious kinds of burns.
From time to time I run into people who overprop their electricpowered
aircraft, thinking that if they never use full throttle they
Strip, solder, insulate; strip, solder, insulate
Septemeber 2006 123
Also included in this column:
• Your wattmeter lies!
• FMA Direct Cellpro 4s Charger
• LipoSack fire-retardant fabric
charging pouch
The Battery Clinic Red Scholefield | [email protected]
Adapter plugs for two- and three-cell packs using 0.1-inch pin
Cellpro connections for two-, three-, and four-cell Li-Poly packs. spacing.
will not exceed the system’s limits. If you understand just how an
ESC works, I think you will quickly see the fallacy in this.
An ESC switches the power on and off at a high rate, varying
the width of the pulses to achieve speed control. The on time can
vary from 100% on to full off. Intermediate throttle setting will be
some percentage of this pulse width with the same peak current
drawn from the battery and supplied through the ESC to the
motor.
If your wattmeter reads 20 amps at full throttle, it will indicate
something less than this at some intermediate setting, lulling you
into thinking you are not overstressing the battery.
The FMA Direct Cellpro 4s
balancing charger features
one-button programming.
not used
not used
not used
2 cell
pack
3 cell
pack
4 cell
pack
5 pin Cellpro balancing connector
09sig4.QXD 7/25/06 2:18 PM Page 123The wattmeter is averaging the current
while the peaks remain at 20 amps.
Regardless of the duration of these pulses
of power, they are always at the
maximum full-throttle current, essentially
hitting your battery, ESC, and motor with
what could be destructive over-spec
current pulses, regardless of the throttle
setting. If you persist with this setup you
can seriously reduce the life span of the
pack, ESC, and motor.
One solution is to propeller down so
that the maximum current does not exceed
the rating of the battery or ESC. This will
make your whole system much happier,
with the motor running at higher
efficiency and cooler, more rpm because
you are not loading the pack as heavily,
and longer ESC life from not overstressing
the components.
Fortunately the days when you have to
wring every last bit out of the system to get
acceptable performance are coming to an end with off-the-shelf
electric-flight components that are operated within their spec
limits while giving you all the adrenalin rush you need.
Balance, balance, balance is all we hear. A real Lithium pain
reliever is ready. FMA Direct has one heck of a product in the
Cellpro 4s Charger. (I was lucky enough to get a preproduction
unit to evaluate.) With it there is no more remembering blinking
and beeping or just taking a black box’s word for it.
I added banana plugs to the power lead as soon as I got the
unit since I will probably use it more in the shop where there are
a number of 12-volt outlets (banana jacks). You can rig a
cigarette-lighter plug to match the banana plugs by using a 7/8-
inch section of 3/16-inch-outside-diameter thin-wall brass tubing
and insulating with heat shrink (red + and black - please).
It’s a good idea to take a banana plug along to the hobby shop
to make sure you get the right size. The cigarette-lighter plug is
available in most auto-supply shops and RadioShack. Try to find
one with a fuse included. Fuses are our friends.
To quote a popular TV commercial, the operation is so simple
that even a caveman could do it. There is no way one could mess
up this charger or the battery pack. There is polarity protection
coming and going. There are no knobs to turn or buttons to
push—only one button to manually set the charge rate if you
don’t use the Auto mode.
This same button lets you scroll through the displays, giving
you percentage charged, charge rate, capacity input, sourcestring is the red lead.
All the nodes are connected for a fourcell
pack. For a three-cell pack the node
next to the most positive is omitted, and a
two-cell pack eliminates that node and
the one next to it. See the photo.
However, many other brands use only
three- or four-pin connectors—no pins
eliminated—so if you are trying to
connect to the Cellpro, you have to pick
up the right nodes.
If this is not complicated enough, there
are at least two different pin spacings. On
some packs they are on 0.1-inch centers
and others are 2mm. On the ones with 0.1-
inch spacing you can make a matching
plug for two-cell packs using the inner part
of a Futaba male connector. This is
without the outer shell. This will give you
the three pins you need and fits perfectly
in the battery connector.
A pair of JST connectors cemented
together edgewise gets you a compatible
four-pin connector. Slip a piece of heat
shrink over it just to make it look neat. I
made this using one Cellpro connector Yd
into the three- and four-pin connectors.
(For the cavemen, don’t hook up two
packs at once.)
FMA Direct tries to simplify this by
offering the Cellpro to Thunder Power or
Poly-Quest Adapter (item CP-TP/PQ, for
$14.95), which has six sockets to accept
other brands of two-, three-, and four-cell
packs. The company also sells the female
balancing connector that is used on its
packs so you can retrofit your existing
packs with it.
You can find Jim Young’s in-depth
review of the Cellpro at www.rcgroups.com/
links/index.php?id=4994. My prediction is
that the Cellpro will blow away the
Lithium-charger market. Make sure you
order the adapter box if you are using
packs with balance connectors other than
the Cellpro.
For those who already have a healthy
investment in Lithium charging devices, a
number of balancing gizmos are being
offered. I have had the opportunity to look
at the AstroFlight (www.astroflight.com/)
Blinky and found that it performed as
advertised.
Aptly named, but not that hard to
interpret, this device works individually to
take all the cells to the same level or in
conjunction with any nonbalancing
charger. An adapter for 2mm pin spacing
is available.
Plug the Blinky into the balance plug
and connect the charger through the
power plug. I use it with the AstroFlight
109, which Astro Bob has updated to
eliminate the rare cell-miscount problem.
(Starting with a fully charged pack it
could jump the count.)
An easy-to-install chip to take your 109
to version 1.7 is available from AstroFlight
for $10. Bob also has upgrade chips for the
110 and 112 digital chargers.
So you’re not allowed to use the family
Crock-Pot as a Lithium charging chamber?
I noticed another take on Li-Poly charging
containers at the Southeast Electric Flight
Festival.
The LipoSack is a fire-retardant, 9 x
12-inch fabric pouch with a Velcro flap to
seal it. This product retails for $29.95. Just
pop in your Li-Poly pack, and while it’s
charging you can learn more and watch a
demonstration video at www.liposack.com/
index.html.
I was going to give you a tour of The
Battery Clinic lab, but I’m out of space
already. So maybe I’ll give it to you in the
November issue, when you will have time
on a cold, blustery evening to digest it.
I answer E-mail fast. The mail to
Newberry, Florida, is slower, but you can
write me at 12219 NW 9th Ln., Newberry
FL 32669, if the urge hits you. Please send
an SASE if you want a personalized,
autographed reply. MA
Edition: Model Aviation - 2006/09
Page Numbers: 123,124,126
Edition: Model Aviation - 2006/09
Page Numbers: 123,124,126
I GET MANY questions from people who
want to build or rebuild their own battery
packs. The fact that they are asking basic
questions that anyone delving into doing
this should already know the answers to is
kind of scary.
When you are working with a battery,
be it Ni-Cd, NiMH, or Li-Poly, there is a
finite amount of energy that you have to
deal with. Although you might only get a
small burn, shorting any Lithium battery,
even for a few seconds, can cause the tabs
to heat enough to ruin a pack or start a fire!
So if you are going to do battery-pack surgery, connect only
one battery lead at a time to prevent a short. Strip one lead, solder
it to the connector and battery, and insulate. Repeat with the
remaining battery leads. It will save you considerable heartburn,
not to mention more serious kinds of burns.
From time to time I run into people who overprop their electricpowered
aircraft, thinking that if they never use full throttle they
Strip, solder, insulate; strip, solder, insulate
Septemeber 2006 123
Also included in this column:
• Your wattmeter lies!
• FMA Direct Cellpro 4s Charger
• LipoSack fire-retardant fabric
charging pouch
The Battery Clinic Red Scholefield | [email protected]
Adapter plugs for two- and three-cell packs using 0.1-inch pin
Cellpro connections for two-, three-, and four-cell Li-Poly packs. spacing.
will not exceed the system’s limits. If you understand just how an
ESC works, I think you will quickly see the fallacy in this.
An ESC switches the power on and off at a high rate, varying
the width of the pulses to achieve speed control. The on time can
vary from 100% on to full off. Intermediate throttle setting will be
some percentage of this pulse width with the same peak current
drawn from the battery and supplied through the ESC to the
motor.
If your wattmeter reads 20 amps at full throttle, it will indicate
something less than this at some intermediate setting, lulling you
into thinking you are not overstressing the battery.
The FMA Direct Cellpro 4s
balancing charger features
one-button programming.
not used
not used
not used
2 cell
pack
3 cell
pack
4 cell
pack
5 pin Cellpro balancing connector
09sig4.QXD 7/25/06 2:18 PM Page 123The wattmeter is averaging the current
while the peaks remain at 20 amps.
Regardless of the duration of these pulses
of power, they are always at the
maximum full-throttle current, essentially
hitting your battery, ESC, and motor with
what could be destructive over-spec
current pulses, regardless of the throttle
setting. If you persist with this setup you
can seriously reduce the life span of the
pack, ESC, and motor.
One solution is to propeller down so
that the maximum current does not exceed
the rating of the battery or ESC. This will
make your whole system much happier,
with the motor running at higher
efficiency and cooler, more rpm because
you are not loading the pack as heavily,
and longer ESC life from not overstressing
the components.
Fortunately the days when you have to
wring every last bit out of the system to get
acceptable performance are coming to an end with off-the-shelf
electric-flight components that are operated within their spec
limits while giving you all the adrenalin rush you need.
Balance, balance, balance is all we hear. A real Lithium pain
reliever is ready. FMA Direct has one heck of a product in the
Cellpro 4s Charger. (I was lucky enough to get a preproduction
unit to evaluate.) With it there is no more remembering blinking
and beeping or just taking a black box’s word for it.
I added banana plugs to the power lead as soon as I got the
unit since I will probably use it more in the shop where there are
a number of 12-volt outlets (banana jacks). You can rig a
cigarette-lighter plug to match the banana plugs by using a 7/8-
inch section of 3/16-inch-outside-diameter thin-wall brass tubing
and insulating with heat shrink (red + and black - please).
It’s a good idea to take a banana plug along to the hobby shop
to make sure you get the right size. The cigarette-lighter plug is
available in most auto-supply shops and RadioShack. Try to find
one with a fuse included. Fuses are our friends.
To quote a popular TV commercial, the operation is so simple
that even a caveman could do it. There is no way one could mess
up this charger or the battery pack. There is polarity protection
coming and going. There are no knobs to turn or buttons to
push—only one button to manually set the charge rate if you
don’t use the Auto mode.
This same button lets you scroll through the displays, giving
you percentage charged, charge rate, capacity input, sourcestring is the red lead.
All the nodes are connected for a fourcell
pack. For a three-cell pack the node
next to the most positive is omitted, and a
two-cell pack eliminates that node and
the one next to it. See the photo.
However, many other brands use only
three- or four-pin connectors—no pins
eliminated—so if you are trying to
connect to the Cellpro, you have to pick
up the right nodes.
If this is not complicated enough, there
are at least two different pin spacings. On
some packs they are on 0.1-inch centers
and others are 2mm. On the ones with 0.1-
inch spacing you can make a matching
plug for two-cell packs using the inner part
of a Futaba male connector. This is
without the outer shell. This will give you
the three pins you need and fits perfectly
in the battery connector.
A pair of JST connectors cemented
together edgewise gets you a compatible
four-pin connector. Slip a piece of heat
shrink over it just to make it look neat. I
made this using one Cellpro connector Yd
into the three- and four-pin connectors.
(For the cavemen, don’t hook up two
packs at once.)
FMA Direct tries to simplify this by
offering the Cellpro to Thunder Power or
Poly-Quest Adapter (item CP-TP/PQ, for
$14.95), which has six sockets to accept
other brands of two-, three-, and four-cell
packs. The company also sells the female
balancing connector that is used on its
packs so you can retrofit your existing
packs with it.
You can find Jim Young’s in-depth
review of the Cellpro at www.rcgroups.com/
links/index.php?id=4994. My prediction is
that the Cellpro will blow away the
Lithium-charger market. Make sure you
order the adapter box if you are using
packs with balance connectors other than
the Cellpro.
For those who already have a healthy
investment in Lithium charging devices, a
number of balancing gizmos are being
offered. I have had the opportunity to look
at the AstroFlight (www.astroflight.com/)
Blinky and found that it performed as
advertised.
Aptly named, but not that hard to
interpret, this device works individually to
take all the cells to the same level or in
conjunction with any nonbalancing
charger. An adapter for 2mm pin spacing
is available.
Plug the Blinky into the balance plug
and connect the charger through the
power plug. I use it with the AstroFlight
109, which Astro Bob has updated to
eliminate the rare cell-miscount problem.
(Starting with a fully charged pack it
could jump the count.)
An easy-to-install chip to take your 109
to version 1.7 is available from AstroFlight
for $10. Bob also has upgrade chips for the
110 and 112 digital chargers.
So you’re not allowed to use the family
Crock-Pot as a Lithium charging chamber?
I noticed another take on Li-Poly charging
containers at the Southeast Electric Flight
Festival.
The LipoSack is a fire-retardant, 9 x
12-inch fabric pouch with a Velcro flap to
seal it. This product retails for $29.95. Just
pop in your Li-Poly pack, and while it’s
charging you can learn more and watch a
demonstration video at www.liposack.com/
index.html.
I was going to give you a tour of The
Battery Clinic lab, but I’m out of space
already. So maybe I’ll give it to you in the
November issue, when you will have time
on a cold, blustery evening to digest it.
I answer E-mail fast. The mail to
Newberry, Florida, is slower, but you can
write me at 12219 NW 9th Ln., Newberry
FL 32669, if the urge hits you. Please send
an SASE if you want a personalized,
autographed reply. MA
Edition: Model Aviation - 2006/09
Page Numbers: 123,124,126
I GET MANY questions from people who
want to build or rebuild their own battery
packs. The fact that they are asking basic
questions that anyone delving into doing
this should already know the answers to is
kind of scary.
When you are working with a battery,
be it Ni-Cd, NiMH, or Li-Poly, there is a
finite amount of energy that you have to
deal with. Although you might only get a
small burn, shorting any Lithium battery,
even for a few seconds, can cause the tabs
to heat enough to ruin a pack or start a fire!
So if you are going to do battery-pack surgery, connect only
one battery lead at a time to prevent a short. Strip one lead, solder
it to the connector and battery, and insulate. Repeat with the
remaining battery leads. It will save you considerable heartburn,
not to mention more serious kinds of burns.
From time to time I run into people who overprop their electricpowered
aircraft, thinking that if they never use full throttle they
Strip, solder, insulate; strip, solder, insulate
Septemeber 2006 123
Also included in this column:
• Your wattmeter lies!
• FMA Direct Cellpro 4s Charger
• LipoSack fire-retardant fabric
charging pouch
The Battery Clinic Red Scholefield | [email protected]
Adapter plugs for two- and three-cell packs using 0.1-inch pin
Cellpro connections for two-, three-, and four-cell Li-Poly packs. spacing.
will not exceed the system’s limits. If you understand just how an
ESC works, I think you will quickly see the fallacy in this.
An ESC switches the power on and off at a high rate, varying
the width of the pulses to achieve speed control. The on time can
vary from 100% on to full off. Intermediate throttle setting will be
some percentage of this pulse width with the same peak current
drawn from the battery and supplied through the ESC to the
motor.
If your wattmeter reads 20 amps at full throttle, it will indicate
something less than this at some intermediate setting, lulling you
into thinking you are not overstressing the battery.
The FMA Direct Cellpro 4s
balancing charger features
one-button programming.
not used
not used
not used
2 cell
pack
3 cell
pack
4 cell
pack
5 pin Cellpro balancing connector
09sig4.QXD 7/25/06 2:18 PM Page 123The wattmeter is averaging the current
while the peaks remain at 20 amps.
Regardless of the duration of these pulses
of power, they are always at the
maximum full-throttle current, essentially
hitting your battery, ESC, and motor with
what could be destructive over-spec
current pulses, regardless of the throttle
setting. If you persist with this setup you
can seriously reduce the life span of the
pack, ESC, and motor.
One solution is to propeller down so
that the maximum current does not exceed
the rating of the battery or ESC. This will
make your whole system much happier,
with the motor running at higher
efficiency and cooler, more rpm because
you are not loading the pack as heavily,
and longer ESC life from not overstressing
the components.
Fortunately the days when you have to
wring every last bit out of the system to get
acceptable performance are coming to an end with off-the-shelf
electric-flight components that are operated within their spec
limits while giving you all the adrenalin rush you need.
Balance, balance, balance is all we hear. A real Lithium pain
reliever is ready. FMA Direct has one heck of a product in the
Cellpro 4s Charger. (I was lucky enough to get a preproduction
unit to evaluate.) With it there is no more remembering blinking
and beeping or just taking a black box’s word for it.
I added banana plugs to the power lead as soon as I got the
unit since I will probably use it more in the shop where there are
a number of 12-volt outlets (banana jacks). You can rig a
cigarette-lighter plug to match the banana plugs by using a 7/8-
inch section of 3/16-inch-outside-diameter thin-wall brass tubing
and insulating with heat shrink (red + and black - please).
It’s a good idea to take a banana plug along to the hobby shop
to make sure you get the right size. The cigarette-lighter plug is
available in most auto-supply shops and RadioShack. Try to find
one with a fuse included. Fuses are our friends.
To quote a popular TV commercial, the operation is so simple
that even a caveman could do it. There is no way one could mess
up this charger or the battery pack. There is polarity protection
coming and going. There are no knobs to turn or buttons to
push—only one button to manually set the charge rate if you
don’t use the Auto mode.
This same button lets you scroll through the displays, giving
you percentage charged, charge rate, capacity input, sourcestring is the red lead.
All the nodes are connected for a fourcell
pack. For a three-cell pack the node
next to the most positive is omitted, and a
two-cell pack eliminates that node and
the one next to it. See the photo.
However, many other brands use only
three- or four-pin connectors—no pins
eliminated—so if you are trying to
connect to the Cellpro, you have to pick
up the right nodes.
If this is not complicated enough, there
are at least two different pin spacings. On
some packs they are on 0.1-inch centers
and others are 2mm. On the ones with 0.1-
inch spacing you can make a matching
plug for two-cell packs using the inner part
of a Futaba male connector. This is
without the outer shell. This will give you
the three pins you need and fits perfectly
in the battery connector.
A pair of JST connectors cemented
together edgewise gets you a compatible
four-pin connector. Slip a piece of heat
shrink over it just to make it look neat. I
made this using one Cellpro connector Yd
into the three- and four-pin connectors.
(For the cavemen, don’t hook up two
packs at once.)
FMA Direct tries to simplify this by
offering the Cellpro to Thunder Power or
Poly-Quest Adapter (item CP-TP/PQ, for
$14.95), which has six sockets to accept
other brands of two-, three-, and four-cell
packs. The company also sells the female
balancing connector that is used on its
packs so you can retrofit your existing
packs with it.
You can find Jim Young’s in-depth
review of the Cellpro at www.rcgroups.com/
links/index.php?id=4994. My prediction is
that the Cellpro will blow away the
Lithium-charger market. Make sure you
order the adapter box if you are using
packs with balance connectors other than
the Cellpro.
For those who already have a healthy
investment in Lithium charging devices, a
number of balancing gizmos are being
offered. I have had the opportunity to look
at the AstroFlight (www.astroflight.com/)
Blinky and found that it performed as
advertised.
Aptly named, but not that hard to
interpret, this device works individually to
take all the cells to the same level or in
conjunction with any nonbalancing
charger. An adapter for 2mm pin spacing
is available.
Plug the Blinky into the balance plug
and connect the charger through the
power plug. I use it with the AstroFlight
109, which Astro Bob has updated to
eliminate the rare cell-miscount problem.
(Starting with a fully charged pack it
could jump the count.)
An easy-to-install chip to take your 109
to version 1.7 is available from AstroFlight
for $10. Bob also has upgrade chips for the
110 and 112 digital chargers.
So you’re not allowed to use the family
Crock-Pot as a Lithium charging chamber?
I noticed another take on Li-Poly charging
containers at the Southeast Electric Flight
Festival.
The LipoSack is a fire-retardant, 9 x
12-inch fabric pouch with a Velcro flap to
seal it. This product retails for $29.95. Just
pop in your Li-Poly pack, and while it’s
charging you can learn more and watch a
demonstration video at www.liposack.com/
index.html.
I was going to give you a tour of The
Battery Clinic lab, but I’m out of space
already. So maybe I’ll give it to you in the
November issue, when you will have time
on a cold, blustery evening to digest it.
I answer E-mail fast. The mail to
Newberry, Florida, is slower, but you can
write me at 12219 NW 9th Ln., Newberry
FL 32669, if the urge hits you. Please send
an SASE if you want a personalized,
autographed reply. MA