Negative Pulse Charging: Myths and Facts

[scottsAI]

Covers mostly Lead acid, a few references to other battery chem.

http://www.powerdesigners.com/pdf/Negative%20Pulse%20Charging%20Techniques%20Myths%20and%20Facts.pdf

Very good stuff!

Have fun,

Scott.

[bob g]

Thanks for the link

i could not agree more with the author if i tried

there is so much crap being claimed in not only battery charging but probably

and likely every other aspect of the offgrid game.

the market is small, so there is no big money to be made by investigating some of these wild assertions.

and i think it goes across the board, from the obvious issues with power claims by windgenerator manufactures (rating at tornado speeds), inverters( claims of 98% efficient at some load and never talking about the horrible efficiency at part or low loads), batteries (with fancy colored cases,and supposedly "new" technology), chargers( pulse, and other recovery types), panels (well these are a bit better), mppt/pwm controllers( where there are at least 3 different hardware topologies and at least 3 different approaches to algoritms, and god knows how well it is implimented)  etc.

slick ads sell stuff, and sadly people believe what they want to believe and make decisions on what they feel, and what they are told by manufactures instead of doing some critical thinking and investigation of their own.

won't be long before someone markets a new

pulsewidth modulated, multipoint power tracker, negative pulse battery rejuventator

that extends your t105 to twice its lifespan, double its capacity, and halve it's charge time,, for $99.95

and folks will buy it,, swear by it, and get mad if you even think of questioning its ability to do anypart of its claims.

and if you ask them for hard numbers,, they will respond with anecdotal evidence, no hard numbers and state flatly

"it works because the company say's it does"

i like the article,, i think there needs to be many more like it on all the various

parts that comprise all that is offgrid.

bob g

[LeissKG]

The only claim I have ever read about negative pulse chargers was the following:

They can prevent the forming of whiskers on the electrodes that can short your

battery electrodes.

This is never mentioned in the report. I have no knowledge if this is true, but I

did have batteries shorted by what seemed to be whiskers. One short high current pulse

did get rid of the short.

Klaus Leiss

 

[Flux]

I think this is true particularly for NiCd, but the discharge current pulses need to be large.

In certain electroplating applications a rough current gives more effective results and a more even coating than a true smooth dc. I suspect this may have some effect on battery technology as well.

Attempts to recharge the conventional dry batteries ( Leclanche based) have never been very satisfactory but in this case smooth dc is very ineffective, partial current reversal by superimposing ac or by reverse pulsing gives far better results.

I think most of the effect attributed to pulse desulphators comes from the pulse nature rather than any desulphating process.

Lead acid batteries are less inclined to crystal growth between plates but it does sometimes occur particularly on cells that are floated and lightly used. It seems not to occur on starter batteries so large current pulses may be of benefit.

After a century of using lead acid batteries we still don't seem to understand them and many claimed things are very questionable. For renewable energy duty where batteries are worked reasonably hard I doubt whether Burp charging has anything to offer, but under certain conditions it may show some benefit for some battery technologies.

I always say " have faith and believe in it and it will work", none of this stuff ever works for me.

Flux

[Bruce S]

Very nice read. I like the fact that they took the scientific approach and did the whole myth / fact layout.

I agree with Flux on the battery chemistry.

The whiskers causing a short is probably 99% NiCd. Sulfation is the bane of Lead acid of ALL types. I'm currently trying to revive 2 12V18Ahr batts that used to be in a UPS that is notorious for constantly charging batts thus killing them over time , which is about when the warranty gives out.

I have an order of magnitude of NiCds from everything from AAAs to Sub-C with packs P & S together in various voltages and current levels and the one thing that get these is non-use.

Those whiskers are what caused the whole memory in NiCd problem.

Scott: Thanks for the link!! very nice read, will keep this one in mind when those battery sales men show up around here.

Knowledge is power!!

Bruce S