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Discussion Starter · #1 · (Edited)
Does applying Negative Pulse's during the Charging cycle result in a faster charge and deeper capacity from the Lead Acid Battery?

GM says NO after a study in 1971.

Negative Pulse Charging: Myths and Facts
Nasser Kutkut, Ph.D. - PowerDesigners, LLC - Madison, WI


Fast charging of industrial batteries is poised to become a main stream charging technology due to the operational savings and the increased productivity and safety that this technology offers. Users are realizing the benefits of fast charging as fast charge systems are already buzzing at manufacturing plants and distributions centers all around the US.

Some of the fast charging systems presently available incorporate negative pulse fast charging algorithms that claim to have great benefits to batteries including reduced recharge time, lower temperature rise, full recharge capabilities, as well as shorter equalization times. These claims are not new and this paper will shed some light on the history and realities of negative pulse fast charging techniques and attempt to separate fad from reality.



II. Brief History of Negative Pulse Charging

The concept of applying a short discharge pulse during the charge cycle sometimes referred to as "reflex charging" or "burp charging" started with patents 3,597,673 "Rapid charging of batteries" W. Burkett & J. Bigbee in 1971 and 3,614,583 "Rapid charging of batteries" in 1971 by W. Burkett & R. Jackson [1].

After the first patent was awarded, the patent holders took it to General Electric, then the leading Ni-Cd manufacturer in the US, where it was analyzed in detail. After extensive testing, GE could not find any conclusive evidence that the negative pulse offered any advantage [1].


Link - http://www.batterypoweronline.com/im...rdesigners.pdf
But other's say yes -​

Australian Dept Of Defense -​

Application of pulse charging techniques to submarine lead-acid batteries

Abstract

The development of pulse charging equipment for the unique application to submarine lead-acid batteries is described. A prototype pulse charger has been developed and applied to individual twin-cell submarine batteries, plus a 20 twin-cell pulse charger has been commissioned at the battery manufacturing facility. The paper provides a description of the pulse charging equipment and preliminary test results and analyses using the prototype twin-cell pulse charger, based on application of a range of positive and negative pulse parameters. The tests so far indicate potential benefits may arise from this form of charging, including enhancement of battery charge levels, reduced gas charging (Stage 3) times and reduced gas evolution rates.


A paper published by the Institute Of Electronic And Electrical Engineers say yes -​

Research on Fast Charge Method for Lead-Acid Electric Vehicle Batteries


Abstract

Electric vehicle (EV) is environment friendly and high efficient. But the shortages of traction battery limited the rapid development of EV. Battery as a key part of EV has aroused lots of engineers to explore the management method and fast charge method is a key technology of battery management for electric vehicle. Constant current-constant voltage (CC-CV) and multistage constant current-constant voltage (MCC-CV) are two traditional charging ways. According to the dynamic circuit model of Lead-acid battery and fast charge theory, on the basic of CC-CV and MCC-CV method, explored the fast charge method for Lead-acid battery of electric vehicle. Compare experiment result of the fast charge method and traditional method. The two major parameters like temperature rise and the capacity-time ratio are considered in order to compare the result. Lots of experiment result support that the negative pulse could eliminate the polarization effective. The MCC-CV with negative pulse method proves working efficient and practical.

2009 International Workshop on Intelligent Systems and Applications (2009)
Publisher: IEEE, Pages: 1-5​

ISBN: 9781424438938
DOI: 10.1109/IWISA.2009.5073068



Anyone have any thoughts, idea's or information about this?

Personally, I believe it works.
 

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Maybe it's better you don't mix 'negative pulse charge' and 'pulse charging', it makes more sense.
 

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Discussion Starter · #3 · (Edited)
However the paper stated that it used negative or tiny discharge between charge pulses. What about just pulsing without using a tiny discharge pulse between pulses. What I gather is that the pulsing dumps in a large high amperage pulse and then is allowed to sit for just a moment before the next pulse is applied. No discharging involved. This is supposed to allow you to push high amperage into the battery while keeping things cool and since lithiums are good at taking in high amperage charging it might just be a benefit for fast charging lithiums LiFePo4 cells.

Pete :)
Cheers Pete.

So could that strategy help to recuperate more energy during regen breaking?

I'm not sure what comes out of the motors when switched to regen, is it steady state current? If that was converted to high voltage pulses then maybe regen can be made more efficient?


Edit: A point about GM testing and their honesty - I saw an interview with the head of GM research and a BBC reporter. The reporter asked, why GM was not building engines with greater efficiency than 25mpg back in the 90's. Citing that at the time GM said they couldn't do it. The head of research responded that at the time they could do it, but decided they didn't want to change their economic model, so they didn't do it. Effectively, they lied at the time when they said that they couldn't do it.

So should we believe everything that GM says?
 

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Discussion Starter · #4 ·
Maybe it's better you don't mix 'negative pulse charge' and 'pulse charging', it makes more sense.
Well, the controversy appears to be exactly that - you do mix the charges.

A burst of positive charging energy, followed by a very short burst of negative voltage to dislodge the Hydrogen bubbles forming at the positive plate and help cool the battery before the next positive cycle.

Its been controversial since the GM study back in 1971.

As far as I'm aware, the idea that you can't fast charge a lead acid battery goes back to the 50's when they tried fast charging lead acids and got bent plates so concluded it couldn't be done.

is it feasible that with advances in manufacturing of batteries that the plates are not so susceptible to damage by fast charging?
 

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Well, the controversy appears to be exactly that - you do mix the charges.
No, you mix the methodes. You post articles as if 'negative pulse charging' is the same as 'pulse charging'. They are different methodes and the articles are about one or the other. And you mix them up.
 

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Discussion Starter · #6 ·
But maybe ditch the negative discharge part and apply it to lithiums. Mmmmmmm! Yes? No? Maybe? If I had a charger like that I'd do the testing.

Pete :)
Yes absolutely.

If pulse charging Lithiums 'positively' improves the charging time, then possibly not only do you get quicker recharge times but also capture more regen energy back if you chop the regen voltage to pulses before sending back to the battery.

Am I right in thinking a limitation to regen is the batteries ability to take in the power during braking?
 

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Am I right in thinking a limitation to regen is the batteries ability to take in the power during braking?
No, you would be wrong. I experience no limitations beyond the rubber to road.

And WTF is this crap about negative charging????? Come on.....get real. Current flows from positive to negative, or from negative to positive. You charge, or you discharge. End of story.
 

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Discussion Starter · #8 ·
No, you mix the methodes. You post articles as if 'negative pulse charging' is the same as 'pulse charging'. They are different methodes and the articles are about one or the other. And you mix them up.
No I don't think I am, I'm a bit confused by your response.

I've posted articles with opposing views on the same method.

The method is to use a short duration negative pulse or discharge period during a recharge cycle.

In other words, either -

Apply a short duration Negative Pulse periodically during a standard trickle charge cycle.

Or

Use Positive Pulse charging and occasionally apply a short duration 'Negative Pulse' in between the 'Positive Pulse'

I am simply asking if anyones knows anything about the method of utilising Negative Pulse or short discharge period to improve efficiency of charging.

I have posted articles 'For' and 'Against' as examples of the practice.
 

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Discussion Starter · #9 ·
No, you would be wrong. I experience no limitations beyond the rubber to road.
Ok, so the batteries are capable of taking all the energy produced during regen braking. I didn't know that.

And WTF is this crap about negative charging????? Come on.....get real. Current flows from positive to negative, or from negative to positive. You charge, or you discharge. End of story.

Ok, I merely used the same terminology as the papers I cited, but lets put it another way.

Short discharge period during the charge cycle.

Apparently it dislodges the Hydrogen bubbles that build up and helps to cool the battery.
 

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I saw something about micro cycling of batteries do to the pulses of charging . this was said to shorten the battery life do to cycles count .
 

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Ok, so the batteries are capable of taking all the energy produced during regen braking. I didn't know that.




Ok, I merely used the same terminology as the papers I cited, but lets put it another way.

Short discharge period during the charge cycle.

Apparently it dislodges the Hydrogen bubbles that build up and helps to cool the battery.
O.K. So I don't get you. What do you have? A bunch of babble. Nothing of any value. Please just go away.

Cheers,

major
 

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Discussion Starter · #12 · (Edited)
O.K. So I don't get you. What do you have? A bunch of babble. Nothing of any value. Please just go away.

Cheers,

major
WTF?

I don't see what your problem is - I am bringing research to your attention - you don't like the research fine, insult the researchers not me.

If you don't know anything about the topic then just stay out of it.

Do you understand what a Negative Pulse is?

Do you understand they exist?
 

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WTF?

I don't see what your problem is - I am bringing research to your attention - you don't like the research fine, insult the researchers not me.
What does it do for the Joe-6-pack diy EV builder? Besides sell him your line of BS?

We have the NewsBot, thank you very much.

What is your game?
 

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If you don't know anything about the topic then just stay out of it.

Do you understand what a Negative Pulse is?

Do you understand they exist?
O.K. Maybe I don't know as much about EVs and battery charging as you do. But I am familiar with Ohm's and Kirchoff's laws. I think that may outweigh you:)
 

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Discussion Starter · #15 ·
What is your game?

My line of BS?

Whatever.

It simply is not worth my time to discuss this with you.

You insult me for supplying information from other sources as if that research is my own, and is unsubstantiated 'babble'.

The title of the papers clearly show that improving the recharge process and life of batteries is beneficial for Electric vehicles - if you can't work out why that is useful knowledge to people that own or build EV's then that is your problem.
 

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Discussion Starter · #17 · (Edited)
But I am familiar with Ohm's and Kirchoff's laws. I think that may outweigh you:)
Well if we're going take our dicks out and see which one is bigger -

I studied the Bachelor of Engineering Power Systems module at Liverpool John Moores University while doing my Bsc and I studied Electronics from National Diploma Level under the man who wrote the book on Electronics for BTEC ND & HND syllabus here in the UK.

So do you outweigh me?

If you do, why don't you have anything constructive to add to this discussion?
 

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I studied the Bachelor of Engineering Power Systems module at Liverpool John Moores University while doing my Bsc and I studied Electronics from National Diploma Level under the man who wrote the book on Electronics for BTEC ND & HND syllabus here in the UK.
So if you're so smart and this is such a great idea, why not draw a simple diagram for us yanks so we can go further in our EVs?

And hey, no hard feelings. Give me a hard time please :)

Cheers,

major
 
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