Author Topic: EEVblog #508 - Can You Test Battery Charge By Dropping It?  (Read 21800 times)

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Offline ciccio

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #50 on: August 20, 2013, 05:26:49 am »
Well, I'm really astonished: tested more than 40 dead or very discharged batteries (all VARTA INDUSTRIAL) against 10 new, charges batteries: it works. Dead cells bumps and fall down, charged cell stand up.
It's time to find the free time to investigate.
Best regards

Ciccio

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Offline Dread

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #51 on: August 20, 2013, 12:51:34 pm »
Reply 31 and 42 have the right answers.

While I find the bounce test to be impractical I do know of one practical application for a similar kind of testing.

For a long time myself and several other engineers at work noticed that 9V batteries could easily be tested to see how good they are by squeezing the flat side of the battery between our fingers.  A fresh fully charged battery feels solid but a dead battery feels squishy, we could actually see the sides squeeze inward between our fingers.  One day we decided to cut one open and what we found was that the material inside had contracted away from the sides as it dried out leaving about .5mm of space going around the battery.  It would stand to reason that the same thing happens with the AA battery and the contracted material allows the end cap to flex inward and create a greater bounce.   It's funny how stuff that a few engineers played around with 20 years ago comes back up again.
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Offline rsjsouza

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #52 on: August 22, 2013, 04:17:18 am »
Why would anyone think this is about weight? Weight changes would not change the bounce.
+1. Although there is a small change in mass given the decrease in energy (nice explanation here).

A fresh fully charged battery feels solid but a dead battery feels squishy, we could actually see the sides squeeze inward between our fingers.
I wonder if this is still valid if the 9V battery is comprised of six LR61 cells (or AAAA)... (wikipedia reference)
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Offline PA4TIM

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #53 on: August 26, 2013, 11:33:31 pm »
Funny, I'm gonna try this.
But about a tear ago I did some testing on batteries. Nicad, nimh, lead batteries and normal akaline. I found out full batteries have an impedance that is  Real Ohms with a small inductive imaginair part. Empty but still good rechargable batteries have a higher (AC, 1 kHz ) Rs as full ones but still an imaginairy part close to pure Ohms. A bad battery however has a much bigger negative imaginair impedance part. It is capacitive. I tested this with a lot cells and the measurement is done with a GR1650 and a HP decade to zero the bridge. And checked measurement (not from all tested cells because it takes a lot of time) with a VNA

I made a page about it on my site.  The reason I did this test was because I was experimenting with a desulfator. That test is not done yet. The dead battery is still connected to a loader and desulfator (so over a year) and I plan to do some tests again on it if I find the time.
 
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Online dexters_lab

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #54 on: August 27, 2013, 06:40:59 am »
yes but would the gas not be within pockets? i'm not sure if the gas would be distributed around the inside of the battery case ready to be released by drilling a hole.

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Offline EvilGeniusSkis

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #55 on: June 04, 2015, 12:42:54 pm »
Found this article on the bouncing batteries
http://www.princeton.edu/main/news/archive/S42/72/95S25/index.xml?section=topstories
turns out none of us got it right; @robrenz was the only one on the right track.



 

Offline HighVoltage

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #56 on: June 05, 2015, 04:54:38 am »
Found this article on the bouncing batteries
http://www.princeton.edu/main/news/archive/S42/72/95S25/index.xml?section=topstories
turns out none of us got it right; @robrenz was the only one on the right track.
Very interesting article.
Thank you very much !
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Offline EvilGeniusSkis

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #57 on: June 05, 2015, 07:55:21 am »
Found this article on the bouncing batteries
http://www.princeton.edu/main/news/archive/S42/72/95S25/index.xml?section=topstories
turns out none of us got it right; @robrenz was the only one on the right track.
Very interesting article.
Thank you very much !
Your Welcome, I read the article and the immediately thought of putting it on here for everyone else to read.
Maybe Dave should add a link in the video.
 

Offline ornea

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #58 on: August 21, 2015, 10:05:00 pm »
OMG it is not  rocket science...
 |O

Charged batteries have more electrons=> more weight,
Empty battery=>less electrons=>less weight.
 
You can also spin batteries to check if they are charged:
If it is full with electrons, then the battery will not wobble, since the mass is distributed equally through he whole? battery.
In case it is discharged, then it will wobble, because the electrons will shift the mass center...
I dont think electrons are lost.  The same net electrons flowing out the neg (pos) equal the net electrons flowing into the pos(neg).  The battery does work to push them around.
 

Offline eilize

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #59 on: August 23, 2015, 05:37:45 pm »
Quote
Charged batteries have more electrons=> more weight,
Empty battery=>less electrons=>less weight.
 
You can also spin batteries to check if they are charged:
If it is full with electrons, then the battery will not wobble, since the mass is distributed equally through he whole? battery.
In case it is discharged, then it will wobble, because the electrons will shift the mass center...

nice try  ^^


a corpse   in free fall gain a speed
that speed....don't depend of the weight
it depend of gravity (ok it change from heigh...you need a lot of difference to see something :p)
a cannonball and a  feather fall at the same speed in vacuum
so, it depend of  air resistance (no luck a empty and a full battery have the same form or there is not enough difference)


IF you see difference when you let fall 2 battery ,it's because you don't blet fall at the same moment or the don't let fall from the same angle
 

Offline tree

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #60 on: August 29, 2015, 09:48:34 am »
Question is...If I slip on the batteriser, will the battery bounce higher or lower?
 

Offline amyk

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #61 on: August 30, 2015, 01:00:23 am »
Question is...If I slip on the batteriser, will the battery bounce higher or lower?
Probably not at all, thus it can increase the charge in the battery and make it last longer. :-DD
 

Offline Godzil

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #62 on: September 02, 2015, 08:29:15 am »
Question is...If I slip on the batteriser, will the battery bounce higher or lower?

Don't do that! With the 800x more energy in your battery you may create a blackhole! That's what batteriser is, accumulating more energy in a small area, like a blackhole does!
When you make hardware without taking into account the needs of the eventual software developers, you end up with bloated hardware full of pointless excess. From the outset one must consider design from both a hardware and software perspective.
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Offline Barny

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #63 on: September 02, 2015, 05:48:58 pm »
Funfact:
If you try the bounce-test with a button cell, the bouncing effect is extreme.
If you use a small button cell out of an hearing aid, it bounce nearly to the same high if it hit a hard surface when its emty.
 

Offline ez24

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #64 on: September 11, 2015, 06:20:14 am »
Found this article on the bouncing batteries
http://www.princeton.edu/main/news/archive/S42/72/95S25/index.xml?section=topstories
turns out none of us got it right; @robrenz was the only one on the right track.

Who would have guessed that bouncing batteries gets to this level:

Support for the project was provided in part by the National Science Foundation, the U.S. Department of Energy and Brookhaven National Laboratory.
YouTube and Website Electronic Resources ------>  http://www.eevblog.com/forum/other-blog-specific/a/msg1341166/#msg1341166
 

Offline apis

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #65 on: September 11, 2015, 08:29:14 am »
Nice picture:
« Last Edit: December 03, 2018, 04:15:09 am by apis »
 

Offline vinicius.jlantunes

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #66 on: September 11, 2015, 11:20:55 pm »
Thanks ez24 for that link, very interesting!

Offline ez24

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #67 on: September 12, 2015, 05:52:17 am »
Thanks ez24 for that link, very interesting!

Thanks but it was not my link -- it came from EvilGeniusSkis

So I also say thanks to EvilGeniusSkis  :-+
YouTube and Website Electronic Resources ------>  http://www.eevblog.com/forum/other-blog-specific/a/msg1341166/#msg1341166
 

Offline vinicius.jlantunes

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #68 on: September 12, 2015, 06:08:06 am »
ooops, right, thank you both!  :-+

Offline EvilGeniusSkis

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #69 on: September 28, 2015, 01:24:10 pm »
Thanks ez24 for that link, very interesting!

Thanks but it was not my link -- it came from EvilGeniusSkis

So I also say thanks to EvilGeniusSkis  :-+
Your welcome
 

Offline BrianHG

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Re: EEVblog #508 - Can You Test Battery Charge By Dropping It?
« Reply #70 on: December 02, 2018, 12:20:13 pm »
Here is a really good side-by-side comparison of full and empty batteries, and why they bounce higher when they are empty:

__________
BrianHG.
 


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