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Old Jan 21, 2005, 09:57 AM
Southern Pride
everydayflyer's Avatar
Haralson County GA. USA
Joined Oct 2004
34,554 Posts
Astro Flight 109 Facts or Fiction.

First let me state that I have this charger and think it is great.
Now a few areas of confusion.
Front(?) box flap states that Discharge is automatically terminated at 3 volts per cell.
WRONG
Discharge is a percentage of voltage when pack is connected. If not fully charged pack will be over discharged. Instructions in manual are correct but how many read manual or keep track of it?

Box Front :
Charges 1 to 9 cells
Rate 50 ma to 8 Amps
Chart in manual show approximately 7.5 A for up to 12 cells and 4 amps at 24 cells.
Perhaps the chart should be labeled volts instead of cell.

Mode 1
Dumb mode and charges at whatever rate set.
I have checked mine with both Analog and Digital Amp. meters as well as an Astro Flight Watt meter and mine only charges at 1/2 of the rate set during stage 1.
Charger set at 1 A all meters read 0.5A and Watt meter shows 25 mA in 3 minutes which just happens to be correct for 0.5A not 1.0A.
Link to astrobob's post on same:
http://www.rcgroups.com/forums/showp...3&postcount=38

Charles
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Last edited by everydayflyer; Jan 21, 2005 at 10:17 AM.
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Old Jan 21, 2005, 10:28 AM
Registered User
Los Angeles
Joined Oct 2002
573 Posts
in answer to your questions.
1. discharge is to 69% of initial voltage
discharge is designed to measure the capacity of fully charged pack.
the voltage will drop to between 2.8 and 3v per cell and discharge will stop.
if pack is removed and reconnected to measure resting voltage on will
usually see between 3.5 and 3.7 volts. Even if the pack were at 3.7 when
starting dischage the voltage would drop to 2.5v for few seconds then
jump back up to over 3v. if i am going to solder on new connectors
i allways discharge to 3.7 volts first.

2. after over a year of selling these chargers you are the first guy to
actually study the instructions. Congratulations.
yes that chart was copied from the 110 and those were nicads cells
got to fix that on next printing.

3. during model 1 the charger is actually pulsing the battery at a high rate
and a 50% duty cycle. so for the first three minutes the average current
is 1/2 of the set current. we do this to condition the pack before charging
at full current. congratulations you just figured out another of our
secrets but don't tell anyone.
astrobob
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Old Jan 21, 2005, 10:29 AM
Stress Be Gone
GBR2's Avatar
Snohomish, WA
Joined May 2000
3,376 Posts
You are right about the discharge. I never use it anyway. As to the Mode 1, yes the current is 1/2 the set charge rate and then it ramps up from there to the full rate by Stage 2. Think of it this way, say you were charging a 2000ma pack at 2 amps. You forget to turn the dial down, plug in a 1000ma pack, the charger will say 2 amps at first but due to the way it works, it has just prevented you from over charging the pack at first. Of course, this is all relative as you might have the knob all the way up but at least it is something.

Personally, I wish the firmware was changed so that if the knob was not turned down before starting, the charger would not start till you do so. I don't see why this couldn't be done and would certainly prevent the problem of having the knob not at zero to begin with. I've used my 109 a lot but still forget to dial down the knob numerous times.
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Old Jan 21, 2005, 10:37 AM
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unbalanced prop's Avatar
Washington, PA, USA
Joined Aug 2003
1,486 Posts
Quote:
Originally Posted by astrobob
3. during model 1 the charger is actually pulsing the battery at a high rate
and a 50% duty cycle. so for the first three minutes the average current
is 1/2 of the set current. we do this to condition the pack before charging
at full current. congratulations you just figured out another of our
secrets but don't tell anyone.
astrobob
I am a little confused here. If the knob is set to zero as you suggest, how is the charger "pulsing the battery at a high rate and a 50% duty cycle"? Isn't 50% of nothing still nothing? So Bob..........should the knob be turned to zero when starting a charge or not?

Doug
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Old Jan 21, 2005, 10:42 AM
Southern Pride
everydayflyer's Avatar
Haralson County GA. USA
Joined Oct 2004
34,554 Posts
Quote:
Originally Posted by astrobob
in answer to your questions.
1. discharge is to 69% of initial voltage
discharge is designed to measure the capacity of fully charged pack.
the voltage will drop to between 2.8 and 3v per cell and discharge will stop.
if pack is removed and reconnected to measure resting voltage on will
usually see between 3.5 and 3.7 volts. Even if the pack were at 3.7 when
starting discharge the voltage would drop to 2.5v for few seconds then
jump back up to over 3v. if i am going to solder on new connectors
i always discharge to 3.7 volts first.

2. after over a year of selling these chargers you are the first guy to
actually study the instructions. Congratulations.
yes that chart was copied from the 110 and those were nicads cells
got to fix that on next printing.

3. during model 1 the charger is actually pulsing the battery at a high rate
and a 50% duty cycle. so for the first three minutes the average current
is 1/2 of the set current. we do this to condition the pack before charging
at full current. congratulations you just figured out another of our
secrets but don't tell anyone.
astrobob
Thanks Bob for confirming my findings. I have tried to get these points across to others in the past but some refuse to believe anything unless it comes from the manufacture and then others refuse to believe anything the manufactures say.

Charles
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Old Jan 21, 2005, 10:55 AM
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Mark Wood's Avatar
United States, CA, Bear Valley Springs
Joined Feb 2000
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Quote:
Originally Posted by everydayflyer
Thanks Bob for confirming my findings. I have tried to get these points across to others in the past but some refuse to believe anything unless it comes from the manufacture and then others refuse to believe anything the manufactures say.

Charles
That's when Darwin steps in.

mw
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Old Jan 21, 2005, 10:56 AM
Registered User
Ottawa
Joined Feb 2004
112 Posts
I know at least one lipo balancer that states not to use with a pulsed charger such as the 109. does anyone know if this true with all balancers?
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Old Jan 21, 2005, 11:12 AM
Registered User
Los Angeles
Joined Oct 2002
573 Posts
Doug
I recommed always to set the current to zero when first connecting
pack so that you can observe the pack voltage at rest. that way
you can make an informed decision on how to charge pack.
the turn up voltage slowly and observe voltage. if pack is allready fully
charged no need to charge again. if half full charge at 1.2 C or 2/3 C,
if pack is aroung 3.7 to 3.9 volts it is practically empty so charge at
1C . If pack is at 3.2 volts or less charge a c/10 until pack voltage
reaches 3.7 volts and stays there for 20 seconds after turning current
down. Charging a deeply discharged pack at 1C can cause pack to
puff up and be ruined.
astrobob
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Old Jan 21, 2005, 11:19 AM
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unbalanced prop's Avatar
Washington, PA, USA
Joined Aug 2003
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Thanks for setting me straight Bob.

I like getting info straight from the horses mouth.

BTW.............great charger!!

Doug
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Old Jan 21, 2005, 01:28 PM
Southern Pride
everydayflyer's Avatar
Haralson County GA. USA
Joined Oct 2004
34,554 Posts
Quote:
Originally Posted by astrobob
Doug
I recommed always to set the current to zero when first connecting
pack so that you can observe the pack voltage at rest. that way
you can make an informed decision on how to charge pack.
the turn up voltage slowly and observe voltage. if pack is allready fully
charged no need to charge again. if half full charge at 1.2 C or 2/3 C,
if pack is aroung 3.7 to 3.9 volts it is practically empty so charge at
1C . If pack is at 3.2 volts or less charge a c/10 until pack voltage
reaches 3.7 volts and stays there for 20 seconds after turning current
down. Charging a deeply discharged pack at 1C can cause pack to
puff up and be ruined.
astrobob

1.2 C


We all suffer from typos and I am very sure astrobob meant to type 1/2C not
1.2C

Charles
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Old Jan 21, 2005, 07:42 PM
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Dan Baldwin's Avatar
United States, CA, Norwalk
Joined Apr 2004
2,710 Posts
Bob saved me from taking my scope to the field Sunday to confirm that the 109 charges at 50% duty cycle in stage one.

Dan
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Old Jan 21, 2005, 10:18 PM
Registered User
Walled Lake, MI, USA
Joined Feb 2000
11,182 Posts
Quote:
Originally Posted by everydayflyer
some refuse to believe anything unless it comes from the manufacture and then others refuse to believe anything the manufactures say.
Yep, that's a good summary of RC Groups' Batteries and Chargers forum.
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Old Jan 22, 2005, 11:27 AM
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unbalanced prop's Avatar
Washington, PA, USA
Joined Aug 2003
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Quote:
Originally Posted by Dave Hederich
Yep, that's a good summary of RC Groups' Batteries and Chargers forum.
Funny but true Dave.

Doug
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