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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 06-28-2017, 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 06-28-2017, 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 06-28-2017, 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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Old 06-28-2017, 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 06-28-2017, 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 06-28-2017, 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 06-29-2017, 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
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Old 06-29-2017, 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 06-29-2017, 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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Old 06-29-2017, 10:34 PM   #14
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Originally Posted by kyleservicetech View Post
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.
That is exactly what I said. They weigh a lot more and take up a lot more space. That is why A123 18650 are not used in Electric Vehicles.

It appears some here do not know there are at least 6 types of Lithium Ion Batteries and what their uses are for.

Sure you can use A123 18650's in an RC. It means your plane will be a lot heavier, less distance, and less power.

A123 18650 are LiFeP04
LiPo's used in RC are LiCoO2

Both are lithium Ion, but have completely different operational parameters. A 2000 Mah LiFePo4 (LFP, A123 ) is not equal to a 2000 AH LiCoO2 (LiPo). A 2000 AH A123 has 6.4 Watt Hours of energy vs 7.4 Watt Hours for a Lipo. The A123 will be 30% larger/heavier, and less energy.
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Old 06-30-2017, 12:08 AM   #15
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Originally Posted by dereckbc View Post
That is exactly what I said. They weigh a lot more and take up a lot more space. That is why A123 18650 are not used in Electric Vehicles.

It appears some here do not know there are at least 6 types of Lithium Ion Batteries and what their uses are for.

Sure you can use A123 18650's in an RC. It means your plane will be a lot heavier, less distance, and less power.

A123 18650 are LiFeP04
LiPo's used in RC are LiCoO2

Both are lithium Ion, but have completely different operational parameters. A 2000 Mah LiFePo4 (LFP, A123 ) is not equal to a 2000 AH LiCoO2 (LiPo). A 2000 AH A123 has 6.4 Watt Hours of energy vs 7.4 Watt Hours for a Lipo. The A123 will be 30% larger/heavier, and less energy.
Yup
A 4S 2500 mah A123 will put out a bit more power than a 3S LiPo on the same motor and prop.

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Old 06-30-2017, 01:04 AM   #16
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Originally Posted by kyleservicetech View Post
Yup
A 4S 2500 mah A123 will put out a bit more power than a 3S LiPo on the same motor and prop.
That is what I was trying to point out. To get the same amount of power and energy wil requires a larger heavier battery. Not a good trade off on a plane or an EV.

You understand, someone else does not get it.
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Old 06-30-2017, 06:03 AM   #17
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Originally Posted by dereckbc View Post
That is what I was trying to point out. To get the same amount of power and energy wil requires a larger heavier battery. Not a good trade off on a plane or an EV.

You understand, someone else does not get it.
Who talked about a123 18650 ? We talk about the 26650... 2.5Ah.
And yes, we agree... for the same capacity a123 is heavier than LiPo and LiPo is heavier than Li-Ion...
Let's come back to real life... I have to give power to a 12s 80A EDF...
Option 1 : twin graphene 6s 6.0Ah (less 20%)... 1086g each
Option 2 : twin 7s2p a123... (full use of 5.0Ah)...1120g each
Option 3 : twin 7s4p VTC6 Li-Ion... 12.0Ah... 1280g each

I do not evaluate cheap LiPo...

Best choice is Li-Ion, but more than one hour charge, need for two sets
Next is a123 that charge in less than 15min, one set enough
Best is graphene : 34g lighter (bad case, no need for lest)


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Old 06-30-2017, 06:15 AM   #18
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Default Old 150% scratch built Electrostreak

Remember the original Electrostreak? That was the original electric model that actually flew pretty well, using 2400 Mah RC2400 Nicads, and a brush type motor. I built up three of them.

Some 15 years ago, I built a 150% version of that Electrostreak, and put a 21 cell Nih pack, a geared Astro 40 motor swinging a 13X10 prop. Did a lot of flying with that model. It flew well, except for the short gear box life. About 10 years ago, that model was upgraded to a 6S2P A123 battery pack, and a Hacker A50-12S motor with a 15X10 prop. The new power system cut a full pound of weight out of the model, doubled the power from 600 to 1200 Watts, and doubled the flying time from 3 minutes to 6 minutes.

Still have that 150% Electrostreak, still flying it. A LiPo pack would likely cut another 1/2 pound out of the model. But that would require pulling the wing every time to change the battery pack. Along with the other LiPo issues.

Yes, LiPo's do have a significant savings in weight over an A123 pack. And, those A123's only come in one useable cell size. But for me, it's a matter of choosing a model to fit the A123 battery packs, rather than finding a LiPo pack to fit the model.

Properly setup, both battery types can work out quite well. I've purchased over 200 A123 cells over the past two years, both for my electric models, and for receiver battery packs for my club members. Every one of those cells were very close to the same exact IR value and the same mah capacity. For LiPos, it can be an issue to find a reliable mfg'r for them. Most LiPos are very good, some are not.

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Old 06-30-2017, 10:02 PM   #19
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Originally Posted by ramboman View Post
Who talked about a123 18650 ? We talk about the 26650... 2.5Ah.
Does not make any difference if it is 18650 or 26650. Just like there is no difference between between a 1100 mah lipo or 2500 mah LiPo. Only difference is the size or Form Factor. A 18650 is 18 mm Diameter x 650 mm Length. The 26650 is 26 mm Diameter x 650 mm Length.


Originally Posted by ramboman View Post
And yes, we agree... for the same capacity a123 is heavier than LiPo and LiPo is heavier than Li-Ion...
That is nonsense. Both A123 (LFP) and LiPo's (LCO) are both Lithium Ion batteries. In terms of Weight you are talking about Specific Energy Watt Hours / Kilogram (Wh/Kg). A123 batteries are LiFeP04 (LFP) which is the second lowest there is of the Lithium Ion Battery Family. From highest Specific Energy to lowest is:

1. LiNiCoAlO2 aka NCO, 200 to 280 Wh/Kg. Used in Cell Phones, and Laptops
2. LiCoO2 aka LCO and LiPo. 150-230 Wh/Kg. This is what the Tesla Motors and RC planes use.
3. LiNiMnCoO2 aka NMC, 150 to 200 Wh/Kg. This is what Nissan Leaf uses.
4. LiMn2O4 aka LMO, 100 to 150 Wh/Kg.
5. LiFePO4 aka LFP or what you call A123 cells. 80 to 110 Wh/Kg
6. Li4Ti5O12 aka LTO, 70-80 Wh/Kg

All 6 above are Lithium Ion batteries. A123 aka LFP are about the heaviest battery you can use. Only Lithium Ion that is heavier is LTO. Now if you want real heavy batteries go with Lead Acid aka Pb at 30 to 50 Wh/Kg

Originally Posted by ramboman View Post
Best choice is Li-Ion, but more than one hour charge, need for two sets
Next is a123 that charge in less than 15min, one set enough
Again more nonsense. LiPo's can be charged at the C/4 rate. However I would never recommend as a professional engineer to ever charge any battery faster than 1C.

I am not saying you SHOULD NOT use A123 cells as a TRACTION Battery. I am just saying you had better have a dang good reason for such low performance because there are a lot better options. Kyle so far is the only one to give a good reason toi make it fit, but knows he is giving up a lot doing so.
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Old 07-01-2017, 01:12 AM   #20
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Originally Posted by dereckbc View Post
That is nonsense. Both A123 (LFP) and LiPo's (LCO) are both Lithium Ion batteries. In terms of Weight you are talking about Specific Energy Watt Hours / Kilogram (Wh/Kg). A123 batteries are LiFeP04 (LFP) which is the second lowest there is of the Lithium Ion Battery Family. From highest Specific Energy to lowest is:

2. LiCoO2 aka LCO and LiPo. 150-230 Wh/Kg. This is what the Tesla Motors and RC planes use.

5. LiFePO4 aka LFP or what you call A123 cells. 80 to 110 Wh/Kg

Again more nonsense. LiPo's can be charged at the C/4 rate. However I would never recommend as a professional engineer to ever charge any battery faster than 1C.

Kyle so far is the only one to give a good reason toi make it fit, but knows he is giving up a lot doing so.
Lets put some real number in here.

An 2500 Mah A123 cell weighs exactly 0.074 Kg. At 3.3 Volts per cell times 2.5 Amp Hours per cell, that is 8.25 Watt Hours per cell. Divide by the weight, you get 115 Watt hours per Kg.

Looking at several different 3S LiPos such as Flight Power in Tower Hobbies, they run around 0.193 Kg for a 3S 25C 2500 Mah LiPo. With 28 Watt Hours divided by the weight, you get 143 Watt Hours per KiloGram.

Result is an A123 pack will be 25% more weight per Watt Hour than a same size LiPo. And, they are rated to be charged at 10 Amps, or 4C.

I have a 12S3P 7500 Mah A123 pack that when brand new on a Rimfire 50 cc motor that turned a 22X10 XOAR prop at 7200 RPM. After a recorded 160 flights pulling 130 Amps, that same pack turned the same exact prop at 7170 RPM. (After a 7 minute hard flight, the 12S3P pack turns the prop at 6820 RPM) Out of my 150 plus A123 cells in my collection of electric models, that's typical as the cells age, even after 6 or 8 years of use.

Yes, a 8000 Mah LiPo pack would do better. But on a 23 pound giant scale model that will fly straight up out of sight on that A123 pack, that's good enough for my 75 year old requirements.

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Old 07-01-2017, 01:57 AM   #21
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Originally Posted by kyleservicetech View Post
Lets put some real number in here.

An 2500 Mah A123 cell weighs exactly 0.074 Kg. At 3.3 Volts per cell times 2.5 Amp Hours per cell, that is 8.25 Watt Hours per cell. Divide by the weight, you get 115 Watt hours per Kg.

Looking at several different 3S LiPos such as Flight Power in Tower Hobbies, they run around 0.193 Kg for a 3S 25C 2500 Mah LiPo. With 28 Watt Hours divided by the weight, you get 143 Watt Hours per pound.
143 Wh/Lb = 314 Wh/Kg. Me thinks you made a Brain Fart.

Kely my debate is not with you as you clearly understand the sacrifice, and that Lithium Ion batteries come in 6 flavors and each with its own pros and cons.

But when someone tells me I do not have experience and that I do not know what I am talking abou take issue with when it is clearly they do not know what they are talking about. I am a PE with 40 years of experience working with batteries and sit on IEEE Battery Committee and write the practices and standards on batteries. My other expensive hobby besides play golf is build/design EV and Racing Golf Carts. Ever been 100 mph in an electric golf cart that does 0 to 60 in 4 seconds? It is dome with Lithium Ion Batteries.
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Old 07-01-2017, 02:08 AM   #22
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[QUOTE=dereckbc;1006975]143 Wh/Lb = 314 Wh/Kg. Me thinks you made a Brain Fart.

QUOTE]


Yup, big brain fart! So used to the obsolete Pounds versus KiloGrams on this side of the big pond.

That should have been 143 Watt Hours per KiloGram. So, an A123 pack is roughly 25% more weight per Watt Hour, Horsepower Hour, what ever, than a LiPo pack.

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Old 07-01-2017, 02:56 AM   #23
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Many years back I started buying up so called "defective" DeWalt A123 drill packs. Upon opening EVERY one of them the "fusible link" was burned through indicating the owner was a moron and repeatedly tried to run the tool in a low charge high amp draw state and cooked the link. After link failure it simply won't run or charge. Every pack I opened had all cells that tested good individually! I've flown several planes on those A123's but what has been a great testament to their strength is that in early 2011 I built a 4S2P pack for my Kawasaki Vulcan 500 motorcycle. I added balance taps when I built the pack and once a year or so I pull the pack and test it. It's always 100 charged (from the alternator on the bike!) and 100% balanced! In the Arizona heat you're damned lucky to get 3 years service from a motorcycle or car battery. I've gotten 6 from those "defective" A123 cells with no end in sight. They still test good and I have no clue when I may need to replace them.........

If you have a plane that can handle the minimal extra weight like a trainer or scale bird with a big wing then A123 cells are well worth looking into as a Li-Po alternative.

Joe

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Old 07-01-2017, 06:53 AM   #24
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This is a useless discussion between an expert in theory (who does not read the specs) and some people having practice...
The only argument against a123 is weight... if you need weight to balance your plane, there is no more argument.
I try to avoid LiPo for a lot of reasons : short life, risk of fire, complex maintenance, need to remove from the plane, modification of the plane for easy swapping...


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