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Home✈️Aircraft🚁HelicopterHelicopter Main Discussion › Reducing the internal resistance of LiPos
05-06-2017 01:48 AM  3 years ago
EEngineer

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A fan....Logo 600SXs, 800XX, TDR IIs
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05-06-2017 01:50 AM  3 years ago
heliraptor10

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kokomo, in-US

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Some people are just full of assumptions
Goblin! where have you been all my life?
RC helis, the original fidget spinners
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05-06-2017 01:51 AM  3 years ago
heliraptor10

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Did you change your mind?

You had said,
"You're too broke to buy a resistor, so you bought that instead"
Goblin! where have you been all my life?
RC helis, the original fidget spinners
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05-06-2017 07:16 AM  3 years ago
heliraptor10

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Two Zippy 5 cell 3 amp hour batteries
one labeled A and one B
For now A will be charged exclusively without Emf Boost
And B will be with EMF boost, exclusively.

For this, the first break in cycle I recorded 3 readings about ten minutes apart.

to save typing I've condensed them

Battery A No EMF
began at 6.64mo average per celll
ended at 6.34

Battery B EMF
began at 6.32
ended at 5.36

Charged at 1amp from storage voltage of 3.86

The battery Analyzer allows me to drain and monitor at a set amp rate

I drained each battery at 5amps,
until the monitor counted 1.5ah this took 18:00

The red battery is battery A
The green Battery B

Goblin! where have you been all my life?
RC helis, the original fidget spinners
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05-06-2017 03:28 PM  3 years ago
Heli_Splatter

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USA

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raptor10. What is the plan? How many cycles?

Still skeptical, but I am willing to watch and learn.

Good luck.
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05-06-2017 04:28 PM  3 years ago
DennisH

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So is there a "final" on this?

Just wondering
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05-06-2017 06:03 PM  3 years ago
heliraptor10

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I haven't figured out if there's a way to do resistance on the CBA

But the discharge curve should tell us some things.

More resistance = more sag in the curve.

With a consistent discharge rate there should be a growing difference between battery A and battery B.

These are just the break in cycles. Though I won't be able to do an amp draw higher than 5.9 amps on this.

But once they are broke in I will put them to work and we'll see what happens.

In case anyone is still wondering about that resistor,

I explained clearly that I want a weak EM field, I also explained that I believe that the EM field strength should be directly proportionate to current to the battery.

While there is a magnetic field through the coil before I start the charge (the "standby" power draw of the cell pro) it is almost non existent.

The way I am doing it,
The field ramps up and down with the current flow to the battery.
Goblin! where have you been all my life?
RC helis, the original fidget spinners
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05-06-2017 10:06 PM  3 years ago
AirWolfRC

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Let's clear out some of the smoke here.
You're talking about a Internal Resistance difference of maybe .005 ohms.
It appears you're talking about a 3AH pack (that only became clear with a recent picture of your newly acquired test specimens).
Using 5A discharge current, an IR of .005 ohms gives a voltage drop of 0.15V

So that affects the cut-off voltage by only 0.025 volts (3.775V / cell instead of 3.8V)

Using the photo you posted showing the discharge curve, 200mv/AH/cell, that equates to 0.125AH out of a battery capacity of 3AH
- - a mere 4% difference in capacity for the same cut-off voltage (which by the way your chart shows that you are only using 1/2 of the rated capacity to a 3.8V cut-off)

That's what a 5 mili ohm difference will get you - - 4%
- - that kind of number is down in the noise.
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05-06-2017 10:12 PM  3 years ago
heliraptor10

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I'm not sure why it wasn't clear what I am doing. I described the batteries,
And the screenshot also describes the batteries as 5 cell 3ah batteries.

They've only been cycled twice.

As I continue to cycle them, a much larger difference in IR will become clear.
Goblin! where have you been all my life?
RC helis, the original fidget spinners
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05-06-2017 10:15 PM  3 years ago
heliraptor10

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I edited the post to hopefully make the battery details more clear.Goblin! where have you been all my life?
RC helis, the original fidget spinners
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05-06-2017 10:16 PM  3 years ago
AirWolfRC

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I didn't see confirmation of battery capacity until thread page 12 out of 13 pages.
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05-06-2017 10:24 PM  3 years ago
heliraptor10

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Yeah

I stopped posting stuff with the batteries I was already using. No one seemed interested in those numbers.

So I said I had new batteries on the way for tests with fewer variables between them.

And that's what I'm doing now...
Goblin! where have you been all my life?
RC helis, the original fidget spinners
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05-06-2017 10:33 PM  3 years ago
AirWolfRC

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If you want some meaningful numbers, you should be testing under flight conditions - - namely about 10C discharge rates - - regardless of charge rates (but make sure charging procedures are the same for all test runs except your coil).

For your 5 cell pack, you can simulate that with a 0.666 ohm resistor good for about 1000 watts (including margin) and time it to cut-off voltage.
That will require some length of NiCr wire setup like a heating element (like a toaster).

That's where the "rubber meets the road".
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05-06-2017 10:55 PM  3 years ago
EEngineer

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"a 0.666 ohm resistor "

Too costly....
Logo 600SXs, 800XX, TDR IIs
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05-06-2017 10:58 PM  3 years ago
heliraptor10

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Yeah the CBA caps At 5.9 amps.

But my claim is less about increased performance,
And more about lowering the IR.

This of course should equate to increased performance. My belief is that this may be a way to condition batteries, leading to a longer life.

After these batteries are broke in,
They'll be going in my son's power wheels.

They'll see some use there

After a couple weeks of use,
I'll switch A and B

And we'll see what happens.
Goblin! where have you been all my life?
RC helis, the original fidget spinners
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05-06-2017 11:08 PM  3 years ago
AirWolfRC

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"a 0.666 ohm resistor "
Too costly....
About 15 ft of 0.032 aircraft safety wire should do the trick.

- - same stuff I use for my hot wire foam cutter.
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05-06-2017 11:18 PM  3 years ago
EEngineer

rrProfessor

TX

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"
About 15 ft of 0.032 aircraft safety wire should do the trick.
- - same stuff I use for my hot wire foam cutter."

I agree....

But.....

"Are you actually reading anything I'm posting?
I've said the original patent described the various axis' for the field and they concluded that it should be perpendicular, right angle, longitudinal...
Long ways across the field.
I plan on using a small straight wall bucket.
Eventually, I'm broke at the moment. "

Still might be too costly.....
Logo 600SXs, 800XX, TDR IIs
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05-06-2017 11:50 PM  3 years ago
heliraptor10

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So AirWolfRC

You're talking about adding a resistor in series to get the discharge rate up to a reasonable test level?

And the CBA would in this manner
Still show the correct voltage yet the amp hours drawn would be just the CBA

So I would have to manually account for the resistor draw?
Goblin! where have you been all my life?
RC helis, the original fidget spinners
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05-07-2017 12:08 AM  3 years ago
AirWolfRC

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In the end you're trying to see if it improves battery performance, aren't you ?
To that end, forget the CBA for discharge and just use the resistor and a volt meter and time it until cut-off voltage is reached. At 10C, that is only about 6 minutes.
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05-07-2017 12:19 AM  3 years ago
heliraptor10

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1)Take 2 equal packs and cycle them to get them both to the same discharged point. Not in the coil and on a discharger so they are both cut off at the same voltage. Document pack temps and IR's. Now presumably you have 2 identical packs (as far as practical)
2)Cycle one pack in the coil and one without the coil documenting pack temps and IR's
3)Repeat to make sure things are consistent.
4)Present your numbers
This is the simplest for me to do at this time.

Any reason why this wouldn't answer questions?
Goblin! where have you been all my life?
RC helis, the original fidget spinners
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Home✈️Aircraft🚁HelicopterHelicopter Main Discussion › Reducing the internal resistance of LiPos
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