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Batteries & Chargers Discuss Li-P, Li-Ion, NiMh, Nicad battery technology and the chargers that juice 'em up!

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Old 06-18-2017, 07:47 PM   #1
misterbill303
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Default A123's?

I've been following with great interest the various posts on A123's - I am in the throes of building a 1/4 scale Reeves Camel and really don't want to have to deal with all the Lipo hassles and access problems, so want to switch over to the 123's. Whereabouts does one source them? All I can seem to find listed are packs for Tx's etc., or does one need to build up your own flight packs?
Many thanks,
Mike
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Old 06-18-2017, 08:14 PM   #2
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As I recall, kyleservicetech seemed to be one of our more knowledgeable A123 guys. Haven't see him around in a while but I haven't spent a lot of my time here lately either. Searching his posts would most likely answer your questions.

https://www.google.com/#q=site:+watt....wattflyer.com

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Old 06-18-2017, 08:45 PM   #3
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Thanks for the info - did follow the link to Voltman batteries, but couldn't see any A123's - will keep hunting!
Mike
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Old 06-27-2017, 09:41 AM   #4
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Originally Posted by misterbill303 View Post
I've been following with great interest the various posts on A123's - I am in the throes of building a 1/4 scale Reeves Camel and really don't want to have to deal with all the Lipo hassles and access problems, so want to switch over to the 123's. Whereabouts does one source them? All I can seem to find listed are packs for Tx's etc., or does one need to build up your own flight packs?
Many thanks,
Mike
I fly with a123 only since the beginning in 2006...
Present best source follows :
https://eu.nkon.nl/a123-systems-anr2...v-a-grade.html
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Old Yesterday, 04:36 AM   #5
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Are you talking A123 for the radio Transmitter or Receiver/Servos?

Or are you taking as the Traction Motor battery.

If you are talking about an Electric Plane which I can only assume your because this place is called Watt Flyer, you would not want to use A123 cells.

Reason is real simple, their energy density is half that of an RC LiPo battery which means takes twice the weight for a given capacity. Secondly they do not even come close to the Specific Energy of RC LiPo's which means they cannot deliver the high C-Rates like 20 to 50C.

Lastly both LiPo's and A123 are lithium batteries and require the exact same care and chargers. Ot what you are calling Hassles and Access problems. You would be just shooting yourself in the foot.
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Old Yesterday, 04:59 AM   #6
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Originally Posted by dereckbc View Post
Are you talking A123 for the radio Transmitter or Receiver/Servos?

Or are you taking as the Traction Motor battery.

If you are talking about an Electric Plane which I can only assume your because this place is called Watt Flyer, you would not want to use A123 cells.

Reason is real simple, their energy density is half that of an RC LiPo battery which means takes twice the weight for a given capacity. Secondly they do not even come close to the Specific Energy of RC LiPo's which means they cannot deliver the high C-Rates like 20 to 50C.

Lastly both LiPo's and A123 are lithium batteries and require the exact same care and chargers. Ot what you are calling Hassles and Access problems. You would be just shooting yourself in the foot.
That's not true !
From my own experience :
1. weight radio is not twice, only 20% more
2. c-rate is bull I get regularly 50A from a cell... peak is 120A
3. no need to balance each time
4. charge in plane in 15min
5. no fire risk...
If you never tried, better not to talk about... its not politics !
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Old Yesterday, 07:19 AM   #7
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Cool @misterbill303

Using a123 is a good solution to balance a plane like the Camel.
Build your pack around your brushless... no add'l weight necessary.
7s2p a123 would be the right choice for the Camel... a Hacker A60 6xs v2 with a 20*13 prop.
Sample on my B25 :


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File Type: jpg B-25_a123 (2).jpg (60.9 KB, 26 views)
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Old Yesterday, 04:17 PM   #8
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Originally Posted by ramboman View Post
That's not true !

If you never tried, better not to talk about... its not politics !
Nice Joke, been working with every kind of battery professionally for over 40 years.
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Old Yesterday, 05:34 PM   #9
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Originally Posted by dereckbc View Post
Nice Joke, been working with every kind of battery professionally for over 40 years.
I fly with a123 batteries since the beginning in 2006... I am not sure you have the same experience... and I am note alone...

The only weak point is the increased weight... If you need weight to balance a plane like the Camel (or most warbirds) it becomes an advantage.

Good evening.
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Old Yesterday, 09:46 PM   #10
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Originally Posted by ramboman View Post
I fly with a123 batteries since the beginning in 2006... I am not sure you have the same experience... and I am note alone...

The only weak point is the increased weight... If you need weight to balance a plane like the Camel (or most warbirds) it becomes an advantage..
You are half right, you forgot they not only weigh more but take up more space. Two things you do not want in a plane. If you knew what battery terms meant, you would not have stuck your foot in your mouth.

So here is a little education for you.

Specific Energy (Wh/kg) – The nominal battery energy per unit mass, sometimes referred to as the gravimetric energy density. It determines the battery weight required to achieve a specific amount of energy in Watt Hours per Kilogram of weight. LiFeP04 (LFP) aka A123 ANR 18650 has 90 Wh/Kg. A Gens Ace or similar Lipo 140 Wh/Kg. Not even remotely close. a Lipo has roughly 50% greater Specific Energy. In other words it would take a 1.5 Kg A123 to equal a 1 Kg LiPo. No contest.

Energy Density (Wh/L) – The nominal battery energy per unit volume, aka volumetric energy density. It determines the battery size required to achieve a given electric range. Again A123 ANR 18650 is a looser with a Energy Density of 150 Wh/L and LiPo at 220 Wh/L. So as far volume goes it would take a 1.3 Liter sized A123 ANR 18650 to equal a 1 Lither LiPo.

This is exactly why commercial Electric Vehicles do not use LiFeP04 batteries. They would weigh to much and take up to much room.

The only real advantages of LiFeP04 is Cycle Life and Safety (fire). Both are Lithium Ion batteries and thus both require some type of Balance Charging techniques.

For Radio Transmitters and RX/Servos, LiFePo4 is a great choice, but for Traction Batteries in a plane just suk. That is why LiPo's are used instead of LiFeP04. Not hard to figure out if you understand the physics involved.
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Old Today, 02:45 AM   #11
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Originally Posted by misterbill303 View Post
I've been following with great interest the various posts on A123's - I am in the throes of building a 1/4 scale Reeves Camel and really don't want to have to deal with all the Lipo hassles and access problems, so want to switch over to the 123's. Whereabouts does one source them? All I can seem to find listed are packs for Tx's etc., or does one need to build up your own flight packs?
Many thanks,
Mike
Those A123's are about 35% more weight per horsepower hour than a LiPo. But, on the other hand, virtually zero fire hazard, no storage issues, very long life. They can be topped off after the day's flying, and will be ready to go next day, next week, next month, don't matter much. They can be charged at 10 Amps per cell per the A123 specs. With the larger size of the battery, they have more area for cooling, so temperature rise is less than a LiPo under similar loads. I've actually had mine heating up while sitting in the sun for awhile, and found their temperature dropped after a flight.

As an example, on my giant PeakRC models Corvus, I've got a 12S3P 7500 Mah A123 pack, divided up in to two 6S3P packs for charging. Current pulled is 130 Amps at full power.

When brand new, that pack turned the Rimfire 50 cc 22X10 XOAR prop at 7200 RPM. Now, 160 flights later on the same motor and same exact prop, the motor turns at 7170 RPM, a drop of 30 RPM. Typical for these cells.

Every one of my models of 400 Watts and larger are powered by A123's. Some of the battery packs are 8 years old and still perform quite well.

They don't work well for foamies, and smaller models because of their size, they simply don't fit.

On that giant Corvus model, going to LiPo's would have saved about two pounds of batteries, on a 23 pound model. But, the power system hauls that model straight up, out of sight, good enough for me.

My supplier of A123 cells is below. If you buy 10 cells or more, their price drops to $9.30 per cell, plus a flat $20 shipping charge. I've ordered over 200 A123's from this place in the past year or two. Nice place to do business with.

http://www.a123batteries.com/product-p/anr26650m1-b.htm

You will need a quality soldering iron to solder up these cells. I use a temperature regulated Weller 100 Watt iron with an 800 degree 3/8 inch diameter iron plated tip.
WELLER SOLDERING IRON 100 W
http://www.wattflyer.com/forums/showthread.php?t=59884

And, you need heavy duty jumper straps between cells. If you use inadequate straps, that will affect the voltage output.
http://www.radicalrc.com/category/Tabs--Bars-338
SKU Number: RRCGBARS6PK


These cells will hold 2.90 Volts per cell at 40 Amps load. I limit my 6S2P A123 packs to a maximum of 80 Amps. Not really a problem, since the 40 Amp load per cell represents a bit over three minutes flying time.

Here are some of my models powered by these A123 packs. After five hundred flights, and 5 years, they still will turn the prop at nearly the same RPM as when brand new. FYI, every one of these models will fly straight up, out of sight at full power.

IMHO, some of those "C" ratings on LiPo cells are a bit misleading. For example, actually running a LiPo at 60C will result in a flight of less than 60 seconds. For me, not that useful. And, some of the LiPo suppliers are claiming 150C, pure BS if there ever was any. (One of them claims 150 C on an 8000 Mah pack. That's 1200 Amps, on the battery packs #12 wire. That wire will melt in a few seconds at 1200 Amps)

Giant Corvus Model
https://www.rcgroups.com/forums/show...-Models-Corvus

Giant Peak Model
http://www.rcgroups.com/forums/showthread.php?t=2563126

Giant Scale Big Stick Conversion
http://www.wattflyer.com/forums/showthread.php?t=65052

Great Planes Giant Escapade
http://www.rcgroups.com/forums/showt...5#post32798968

Carl Goldburg Extra 330 Electric Conversion
http://www.wattflyer.com/forums/showthread.php?t=59273

Thread on 70 size glow engine conversion to electric
http://www.wattflyer.com/forums/showthread.php?t=45222

Hacker 6S2P A123 powered Models
http://www.wattflyer.com/forums/showthread.php?t=44686

Hangar 9 Kantana Model
http://www.wattflyer.com/forums/showthread.php?t=68844

Hanger 9 Twist 40 Model
http://www.wattflyer.com/forums/showthread.php?t=70548

TwinStar
http://www.wattflyer.com/forums/showthread.php?t=74837

DennyV
Retired and the days are just too short, busier than ever!
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Old Today, 06:38 AM   #12
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Cool

Thank you Dennis
Practice vs theory
Don't forget the main switch :
http://shop.rc-electronic.com/SPS-Sy...catalog&p=2263
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Old Today, 06:58 AM   #13
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Originally Posted by dereckbc View Post
You are half right, you forgot they not only weigh more but take up more space. Two things you do not want in a plane. If you knew what battery terms meant, you would not have stuck your foot in your mouth.

So here is a little education for you.

Specific Energy (Wh/kg) The nominal battery energy per unit mass, sometimes referred to as the gravimetric energy density. It determines the battery weight required to achieve a specific amount of energy in Watt Hours per Kilogram of weight. LiFeP04 (LFP) aka A123 ANR 18650 has 90 Wh/Kg. A Gens Ace or similar Lipo 140 Wh/Kg. Not even remotely close. a Lipo has roughly 50% greater Specific Energy. In other words it would take a 1.5 Kg A123 to equal a 1 Kg LiPo. No contest.

Energy Density (Wh/L) The nominal battery energy per unit volume, aka volumetric energy density. It determines the battery size required to achieve a given electric range. Again A123 ANR 18650 is a looser with a Energy Density of 150 Wh/L and LiPo at 220 Wh/L. So as far volume goes it would take a 1.3 Liter sized A123 ANR 18650 to equal a 1 Lither LiPo.

This is exactly why commercial Electric Vehicles do not use LiFeP04 batteries. They would weigh to much and take up to much room.

The only real advantages of LiFeP04 is Cycle Life and Safety (fire). Both are Lithium Ion batteries and thus both require some type of Balance Charging techniques.

For Radio Transmitters and RX/Servos, LiFePo4 is a great choice, but for Traction Batteries in a plane just suk. That is why LiPo's are used instead of LiFeP04. Not hard to figure out if you understand the physics involved.
Thank you for the lesson...
If you are logic with yourself you should recommend li-ion !
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