[NSRCA-discussion] Fwd: New fast charge battery

Fri Mar 20 05:02:47 AKDT 2009

Yup - heated with ovens and even other more desperate methods. :) Every week there was another "trick" that promised more power AND more longevity. As long as I've been doing this I can't ever remember the two going hand in hand. Don't get me wrong, I welcome new technology and new techniques as much as anyone. I just prefer to be "cautiously optimistic" and I try to look at all of the facts before jumping on the latest thing. I'm still flying 72MHz and I just recently gave up my analog cell phone. LOL

John Pavlick

BTW - My new cell phone takes nice pictures and the appointment calendar is a big help too. The telephone "feature" doesn't work all that well though.

--- On Fri, 3/20/09, James Oddino <joddino at socal.rr.com> wrote:

From: James Oddino <joddino at socal.rr.com>
Subject: Re: [NSRCA-discussion] Fwd: New fast charge battery
To: "General pattern discussion" <nsrca-discussion at lists.nsrca.org>
Date: Friday, March 20, 2009, 5:27 AM

John, you've got to be an optimist.  We want it all.  Who ever dreamed we'd have what we have now back in the NiCd days. 

The peaking you did was no doubt heating them and lowering the Internal resistance.  Did anyone ever try just heating them with an oven?  That's what I do now and I believe it not only gives you better power right off the ground but I believe it is easier on the batteries.  We'll see how my new packs hold up over time but so far they are looking great.

Jim

On Mar 19, 2009, at 10:09 PM, John Pavlick wrote:

Going back to my "How many of you guys ever raced R/C cars" question - the reason I asked is because if you did you'd already be thinking like Dave. Well, not exactly. I don't believe anyone can think like Dave! LOL

Back when I raced, we used NiCADs. Why? Because that's all we had. We had basically 2 kinds: high output / fast charge (SCR) and high capacity / slow charge (SCE) types. At the risk of oversimplifying - the difference had to do with internal resistance. For stock class we ran the high output type, for modifieds we used the high capacity type. To get Max performance from the high output batteries in stock class we charged them at 1 - 4C, then we re-peaked them before the race at 10 - 30C! Some guys used to charge until the cell vents opened. The result: a super hole-shot, lotsa power, 4 minutes worth of fun. Then we threw the battery pack out. They could only handle this kind of abuse once. You didn't do this every weekend, just for the really big events. OK, if you were spoonsored you did this all the time. :)
The high capacity batteries had to be treated differently. Normally you charged at 1-4C. In a 2WD modified car you could expect to get at least a few cycles before you used the pack for practice. If you were "cheap" you'd take a pack that had been used 4 or 5 times, put it on a trickle charger overnight to "re-balance" the cells (sound familiar?) and used it until it dumped on the last lap and cost you a race. If you were sponsored you always had brand new "computer matched" batteries so you didn't have to do this.

Bottom line: You can't have everything. You're going to trade off something. You need to understand exactly what you're getting with a new technology and if it's worth giving up something that the existing technology might do better. I doubt very much that you'll see a 30C discharge rate + 3C charge rate capable pack that weighs half as much as what we have now AND delivers more usable cycles as well. But I guess we can dream. VBG

John Pavlick
http://www.idseng.com

----- Original Message ----- 
From: Dave 
To: 'General pattern discussion' 
Sent: Thursday, March 19, 2009 9:54 PM
Subject: Re: [NSRCA-discussion] Fwd: New fast charge battery

The faster you charge, the fewer the cycles you get!!  Figure cycle life is reduced by about 50% at 3C charge rates.

Regards,

Dave

From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Stuart Chale
Sent: Thursday, March 19, 2009 6:48 PM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] Fwd: New fast charge battery

The key in my mind as we already have enough power in a makable weight for a new set of batteries, is the number of cycles you can get.  It the new technology gets us 200 cycles before degradation then I'll take 2 :)  Don't need three any more because they charge faster.
Stuart

Ed Alt wrote: 

This is very straightforward.  The ideal battery is one that has 0 ohms internal resistance and infinite current delivery capability.  This new technology gets you somewhat closer to that ideal.  All it means is that it minimizes power losses due to much lower internal resistance, and reduces limitations that are placed on the performance of the thing you are powering with it.  Even the ideal battery can only deliver as much current into the load as that device will draw based on its own resistance (actually impedance, but we'll keep it simple) Doesn't matter whether it is a motor, a light bulb or whatever.  It's all good...

Ed

----- Original Message ----- 

From: Keith Hoard 

To: General pattern discussion 

Sent: Thursday, March 19, 2009 5:15 PM

Subject: Re: [NSRCA-discussion] Fwd: New fast charge battery

How good would these batteries work in my glow starter?. . .

2009/3/19 Ed Alt <ed_alt at hotmail.com>

No way! That is simply evidence that your paint needs to be upgraded!

----- Original Message ----- 

From: Rex 

To: NSRCA-discussion 

Sent: Thursday, March 19, 2009 4:33 PM

Subject: Re: [NSRCA-discussion] Fwd: New fast charge battery

Now I'm just guessing here....  I'm thinking that if you throttle up and the paint
strips off the fuse, that's probably a bit too much!

Rex

From: joddino at socal.rr.com
To: nsrca-discussion at lists.nsrca.org
Date: Thu, 19 Mar 2009 14:10:06 -0700
Subject: Re: [NSRCA-discussion] Fwd: New fast charge battery

I used to say that an engine is a machine that doesn't make enough power.  Now I say a motor is also a machine that doesn't make enough power.   

Jim

On Mar 19, 2009, at 8:29 AM, J N Hiller wrote:

Hay Rex how much power do you need? You can do a vertical ROG now.

Jim

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-- 

Keith Hoard
Collierville , TN
khoard at gmail.com

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