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Hey LIPO fans!!!!!!

Old 04-03-2017, 02:52 PM
  #1  
WizardMaster
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Default Hey LIPO fans!!!!!!

I will just leave this right here.... ....Guess what time it is!!

https://www.youtube.com/watch?v=adfydRg8PYU
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Old 04-03-2017, 06:17 PM
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solentlife
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If I could fly my models on 8A ..... well ...

His load test was unloaded !! Useless .. sorry ...

Yet another wonder battery .....

He keeps on about Watt Hrs .... for us - its not Watt Hrs we are interested in ... we need AMP's ... C rate ... we need POWER delivery.

Nigel
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Old 04-03-2017, 06:30 PM
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I agree. Unless I can get something that will deliver 100A safely, then these will not be of use to me.
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Old 04-03-2017, 09:44 PM
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Rockin Robbins
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2C maximum load. Just about useless for our purposes. What drugs is he taking?

Let's see, 100A eh? No problemo! Well, that would only take a 50k mAh battery. Should be doable, no?
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Old 04-03-2017, 11:10 PM
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dereckbc
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Originally Posted by solentlife View Post
He keeps on about Watt Hrs .... for us - its not Watt Hrs we are interested in ... we need AMP's ... C rate ... we need POWER delivery.
Nigel you are missing some important points. First he did a Full Load Test exactly like you would any battery including LiPo's There is no other way to determine the capacity. Was it accurate? Not exactly but as accurate as a DIY type can be. All lithium batteries are tested at 1C to measure capacity. He was a little higher than 1C which would make the measurement come out a little lower. You woul dtest capacity exactly like a LiPo or any Lithium battery at 1C.

Watt Hours is everything in a battery, and what he is referring to is Specific Power expressed as Watt Hours / Kg, and Energy Density expressed as Watt Hours /Liter. The Panasonic 18650B is most definitely the highest Specific Power and Energy Density battery on the market. It is the exact same cells Tesla uses in all of its Electric Vehicle. There is no equal.

C-Rate as you call it has no industry definition, in the industry it is called Power Density expressed as Watts/Liter and further defined as Maximum Continuous Discharge Current, and Maximum Pulse Discharge Current. In other words your C-Rate. No it is not near as high as LiPo batteries. LiPos are hybrid batteries and very unstable because they are formulated to have extremely Low Resistance which enables them to do what all f you call high C-Rates. To do so you have to give up some things like stability and cycle life. We would all love to have a LiPo that could match the Panasonic 18650. Imagine a battery with 1/3 less weight and size with 1000 cycles or 5 year service life without loss of capacity.

EV's do not need 20, 30 or 40C discharge rates. During acceleration for 30 seconds only need 3 to 6C and cruise at C/6 and lower. Who the hell would want an EV with a 5 minute battery. So while the Panasonic 18650B would not be a good Flight Motor battery, would make for an excellent RX or TX battery. When it comes to size and weight the Panasonic 18650 is 50% better, it has more capacity for a given volume and weight. Only place you would see a LiPo we use in an EV is a Dragster that only needs a few minutes to save on gross weight.

Now where he went off track is saying they would be good for flight batteries. No they would not work because they do not have the Power Density of a LiPo. Essentially for comparison sake are similar to say a A123 System LFP 18650 cells you would use as a receiver or transmitter battery, except twice as good for size and weight. The Panasonic is exactly what you want for an EV, Laptop, Power Tools, Medical Devices, Flashlights, Cameras and other like devices. I have a few in things like my military grade flashlights and handie talkie 2-meter radios. If you see a E-Cigarette, they have 18650 cells.

Wish there was a miracle battery, but no such thing exist. You cannot it have it all. If you could build say a battery with specs like:

Specific Energy = 400 Wh/Kg
Energy Density = 1000 Wh/L
Specific Power = 3000 W/Kg
Cycle Life @ 80% DOD = 10,000

You could literally buy the USA and be the King and in full control of the worlds energy. You would have solved all energy challenges with such a beast. Only thing you would have to use fossil fuel for is heavy transportation, shipping, and aerospace.

Last edited by dereckbc; 04-04-2017 at 12:56 AM.
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Old 04-03-2017, 11:14 PM
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Rockin Robbins
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Yup it's all about appropriate use for the appropriate battery chemistry. There's a price to pay for our high amperage draw batteries, however you choose to describe their C rate. And there is a price to pay for higher W/h batteries with lower draw capabilities.

It's sort of like aerodynamics: a zero sum game. But change the chemistry and maybe we can change the rules. These batteries are old li/ion technology--nothing new: evolution not revolution.

Like Dereck says, if we were making electric cars we'd be making fun of the LiPo batteries.
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Old 04-04-2017, 05:17 AM
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TopSpin
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That was a very interesting test and he pointed out some very useful information. The power density of those batteries is for weight/volume, is much higher than the Lipos we are used to. So in terms of usefulness allocation is everything. If you wanted to keep a very light plane aloft for a long time the low C 18650's would work exceptionally well. Obviously they would not work in performance applications.
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Old 04-04-2017, 07:01 AM
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solentlife
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Derek ... I know... and finally after at the end of the post you basically say what I said ... they have great power / density but no power output to fly most models. They cannot feed our amp crazy motors.

I think we all realize that in a Tx they would be best .... but who really needs it ? We already have incredible use out of typical Tx battery packs.

His test although may be a standard - is useless for us. That is my point. We test how many amps and what voltage sag ... against a load.
What he did was to run a motor with no prop or load at all, just to work out watt/hrs. Basically we could have a featherweight battery with 1000 W/hrs .... but it 'aint' gonna power any motor to fly any model unless its a featherweight indoor jobbie !!

Nigel

Last edited by solentlife; 04-04-2017 at 07:52 AM.
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Old 04-05-2017, 01:00 AM
  #9  
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Originally Posted by solentlife View Post
His test although may be a standard - is useless for us.
Far from useless. It tells you they are not good for most planes. If you look at the specs tells you what you want to know with honest ratings, and no exaggerated C-Rates. Wished our LiPo's published spec sheets like this one. If they did you could tell for sure what the real C-Rates are. If you know how to read the spec sheet you know the Internal Resistance is 75 milli-ohms and from that C-rate is 3/6, an honest 3/6 that can tested and measured.

I get your point that the battery is nor practical for most plane motors, but usable for something like a Glider maybe. But I know a lot of folks who use A123 System 18650 cells in TX and RX, and Panasonic 18650 cells run circles around A123 cells. That is why no EV manufacture uses A123 cells. A 2S1P Panasonic 18650 is more than twice the energy of a A123 2S2P at 1/2 the weight. That is a 400% improvement.

Bottom line th eguy really does not know WTF he is talking about. He knows just enough to be a fool which you spotted.

Last edited by dereckbc; 04-05-2017 at 02:10 AM.
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Old 04-05-2017, 08:19 AM
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Originally Posted by TopSpin View Post
The power density of those batteries is for weight/volume, is much higher than the Lipos we are used to.
No, the power density is much lower than LiPos.. Power density is how much power (watts) they can produce for unit of volume. Because these batteries have low C rate they cant produce much power, so their power density is low.

Where they score in energy density.. Energy is not the same thing as power
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Old 04-05-2017, 03:56 PM
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Whatever way you want to parse it, those batteries are useful for flying a very narrow range of non-typical RC planes.

Now I wonder if hooking up a plane with a low capacity LiPo for takeoffs and one of these "wonder batteries " for cruise wouldn't actually work out for a long duration glider. You'd have to be able to switch out the LiPo and switch in the "wonder battery " Quorneng, you've done this stuff before, didn't you hand launch?
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Old 04-05-2017, 05:51 PM
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Originally Posted by Rockin Robbins View Post
Whatever way you want to parse it, those batteries are useful for flying a very narrow range of non-typical RC planes.

Now I wonder if hooking up a plane with a low capacity LiPo for takeoffs and one of these "wonder batteries " for cruise wouldn't actually work out for a long duration glider. You'd have to be able to switch out the LiPo and switch in the "wonder battery " Quorneng, you've done this stuff before, didn't you hand launch?
]

Maybe one of the old fashioned car reversing speed controllers ... a switch wont do it because launch power is too much. But one of the old wiper style car speed controls ... one way is high power ... other is the low power battery ...

??

Nigel
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Old 04-06-2017, 12:53 AM
  #13  
dereckbc
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Originally Posted by Rockin Robbins View Post
Now I wonder if hooking up a plane with a low capacity LiPo for takeoffs and one of these "wonder batteries "
I would not call them "Wonder Batteries" as they have been around for quite some time. Every Tesla EV uses them. I am no fan of Tesla motors or I should say Elon Musk because he is a con artist and hell has a special place waiting for him. but the so called Mega Battery Factory Musk is building with your money in Nevada will be making the batteries under a license from Panasonic.

Anyway I do not think it would require any kind of switch to do what you suggest. Just use them in parallel. The LiPo would take care of the high demand, and when you back off the throttle the 18650 work in unison and would actually put more energy (some recharge) back into the LiPo's. The only thing you would have to guard against is over discharge of the LiPo. The 18650 are good to 2.5 volts and LiPo to 3.0 volts. Easy enough with any ESC to manage.

You just have to think outside the box. The real challenge is form factor. LiPo;s are Coffee Bag aka Pouch cells and can be made into any shape or form. 18650 are round cylinders 18 millimeters in diameter and 65.0 millimeters in length.
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Old 04-06-2017, 01:06 AM
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Originally Posted by TopSpin View Post
That was a very interesting test and he pointed out some very useful information. The power density of those batteries is for weight/volume, is much higher than the Lipos we are used to. .
FWIW the correct terms so we are on the same page. Power Density is not what you are talking about. It is Specific Energy and Energy Density.

Watt is the unit of power, and indicates the rate in which energy is being used. Watts = Voltage x Current
Watt-Hour is the unit of energy. Watt Hours = Watts x Hours. Example if you have a 100 watt light bulb on for 10 hours you use 100 watts x 10 Hours = 1000 watt hours aka 1 Kwh.
Watt Hours also = Battery Nominal Voltage x Amp Hours


Specific Energy (Wh/kg) – The nominal battery energy per unit mass, sometimes referred to as the gravimetric energy density. Specific energy is a characteristic of the battery chemistry and packaging. Along with the energy consumption of the vehicle, it determines the battery weight required to achieve a given electric range.

Energy Density (Wh/L) – The nominal battery energy per unit volume, sometimes referred to as the volumetric energy density. Specific energy is a characteristic of the battery chemistry and packaging. Along with the energy consumption of the vehicle, it determines the battery size required to achieve a given electric range.

Specific Power (W/kg) – The maximum available power per unit mass. Specific Power is a characteristic of the battery chemistry and packaging. It determines the battery weight required to achieve a given performance target. This is related to C-Rates.

Power Density (W/L) – The maximum available power per unit volume. Specific power is a characteristic of the battery chemistry and packaging. It determines the battery size required to achieve a given performance target. Again related to C-Rate

Maximum Continuous Discharge Current – The maximum current at which the battery can be discharged continuously. This limit is usually defined by the battery manufacturer in order to prevent excessive discharge rates that would damage the battery or reduce its capacity. Along with the maximum continuous power of the motor, this defines the top sustainable speed and acceleration of the vehicle. More C-rate stuff

Maximum 30-sec Discharge Pulse Current –The maximum current at which the battery can be discharged for pulses of up to 30 seconds. This limit is usually defined by the battery manufacturer in order to prevent excessive discharge rates that would damage the battery or reduce its capacity. Along with the peak power of the electric motor, this defines the acceleration performance (0-60 mph time) of the vehicle. More C-rate stuff

C- and E-Rates – In describing batteries, discharge current is often expressed as a C-rate in order to normalize against battery capacity, which is often very different between batteries. A C-rate is a measure of the rate at which a battery is discharged relative to its maximum capacity. A 1C rate means that the discharge current will discharge the entire battery in 1 hour. For a battery with a capacity of 100 Amp-hrs, this equates to a discharge current of 100 Amps. A 5C rate for this battery would be 500 Amps, and a C/2 rate would be 50 Amps. Similarly, an E-rate describes the discharge power. A 1E rate is the discharge power to discharge the entire battery in 1 hour.
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