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Old 06-24-2002, 06:50 PM   #16
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i use pitbull~~ has all the feature that i really need since i am not a serious racers~~

and of course i turned most of the sounds off

Last edited by Fire; 06-24-2002 at 06:53 PM.
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Old 06-24-2002, 09:31 PM   #17
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Default Reverse Pulse Chargers

do any of you guys use the reverse pulse mode of your chargers (i.e. Milleniums and Tekin BC112s)?

I understand you shouldnt use it on NiMHs. However other people say they don't use it even on nicads?

BTW, I use BC112C. I like it for the following reasons.

1. internal power supply. Makes for a compact albeit heavy unit. Then again, my friends always have to lug heavier power supplies.

2. I can charge individual cells. Most charger let you charge a minimum of 4-cell packs.

3. Reverse Pulse. There is still much debate about the benefits of this. GE says it has no observeable benefit, NASA says it does control crystal formation. I'm sticking with NASA for now


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Old 06-24-2002, 10:37 PM   #18
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Default Re: Reverse Pulse Chargers

Quote:
Originally posted by rough512
3. Reverse Pulse. There is still much debate about the benefits of this. GE says it has no observeable benefit, NASA says it does control crystal formation. I'm sticking with NASA for now
There has been much debate about whether reverse pulse (or "burp") charging has any benefit. I know that GE did a bunch of research and said that there's no observable benefit, but it's entirely possible that they weren't observing the right things.

Back in the '92-94 time frame I tried flex charging on half my race packs and used straight linear on half of them. I never flex charged at the track, only when I did between race cycles. I found that the packs that got the flex charge during the between race cycles held up longer than those that didn't. I also came up with some aggressive discharging techniques that I used between race days. Everyone who I raced with at the time was convinced that I was getting some super special packs from my sponsor (at the time I ran for Powerline) but the truth was that I was getting the same packs anyone could buy, in fact the very best packs went to the stores and I got the next level down.

Interesting thing was, my packs numbers on the Turbomatcher never looked like anything special, even after the "treatments", but I did loan them to other racers from time to time and everyone said they ran better than any packs they owned. Basically my packs would feel strong all the way to the end of a race, they never got that "soft" feeling in the last minute or two.

I never could measure a difference on a matcher or during a cycle, but the difference was clear on the track.

As far as NIMH cells go, I haven't been experimenting yet, I only just got hold of a Victor IQ of the correct software revision to let me conduct the treatment and testing regimen I want to do. Maybe in a year or so I'll be able to say I know what NIMH cells really like, but for now I'm pretty much going by what others have to say. I have tried flex charging one NIMH pack that felt like it was going weak, but I can't say it helped in any way.

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Old 06-24-2002, 10:50 PM   #19
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if this helps any:

http://www.rcbatteryclinic.com/burp.html
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Old 06-24-2002, 11:02 PM   #20
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From what I've heard, talking to CE, Tekin, and Novak, (of course Tekin is/was convinced it works) "burp" charging will prolong the life of a pack, but the voltage will not be quite as high, the pack will not feel as punchy. Everyone seems to think it is bad for nimh packs, and having payed 80 each, I don't want to risk it

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Old 06-24-2002, 11:47 PM   #21
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I use a CS Electronics Spacecharger and an Orion Digital Discharger to abuse my batteries.
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Old 06-25-2002, 12:13 AM   #22
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Quote:
Originally posted by TSR6
if this helps any:

http://www.rcbatteryclinic.com/burp.html

I've read that page before, and all I can say about it is that the only laboratory that concerns me is the racetrack. Like I said in my post, I could never demonstrate any superiority to reflex charging or my special discharging regimen on a matching machine, the numbers didn't show any benefit at all. On the track, however, the difference was real and easily observable.

My opinion on this is that we're just not currently measuring the right things to see the difference. That does not prove that the difference isn't there.

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Old 06-25-2002, 12:37 AM   #23
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I'm getting curious on that discharging regimen of yours? care to share it?

Anyway, I dnt do any discharging as of now since I always go home with drained batteries. However I was thinking of converting my homebuilt variable rate pulse charger to a pulse discharger

Do you any of you guys know of any benefit of a pulse discharge? The discharge pulse shorts the battery very rapidly in a series of pulses. The discharge rate is controlled by varying the duty cycle of the discharge pulse much like of the pulse chargers.

Might try modifying it one of these days...
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Old 06-25-2002, 02:14 AM   #24
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Sure. This was for NiCads, so I don't know if it would benefit NIMH cells yet. I have just gotten another Victor so I am going to start testing it on half my race packs and see if I can tell a difference.

I used the Victor SuperIQ2 or later (with flex discharge) and set up a discharge at 28 amps, with flex discharge ON and set to 45 amps. Those settings were for my tenth scale pan race packs, for 1/12 scale packs I'd discharge at 18 amps with flex ON and set for 35 amps. I'd run a cycle on my race packs four days before a race day, charging at 4 amps linear for half the packs, and 4 amps with 20 amp burps for the other half of the packs all the packs got the flex discharge described above.

I started noticing that when I cycled the packs in this manner midweek, on race day they felt punchier throughout the race, if I didn't do this to them, they felt fine until a minute or two before the end of the race when they still had power but there was a definite lack of punch.

I'd been told that Nicads tend to discharge in the same manner as their last discharge. THe purpose of the cycle was to "train" the packs to give up big current from the start of the discharge to the end. I felt that racing them and dumping at 20 amps after the run was training them to deliver hard until a certain point, and then not to worry about giving up more than 20 amps after.

Like I said before, I never could see any benefit looking at the numbers on the matcher, but on the track those packs definitely worked better for me and anyone whose packs I cycled midweek. At the end of the '95 season I was cycling packs for five or six racers midweek, and everyone agreed that it helped on the track.

The packs that I charged with the burps enabled during the midweek cycle seemed to last longer as good race packs than the ones that got a regular charge. I didn't really notice much difference until the packs were over a year old though.
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Old 06-25-2002, 02:15 AM   #25
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By the way, your idea of pulse discharging with high rate spikes sounds very interesting... If you ever modify your discharger to do this, I'd really like to hear your impressions.

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Old 06-25-2002, 02:34 AM   #26
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Trips,

I'll let you know when I finish the discharger.

4 amps charge, 20 amps flex discharge... that's double the revelse pulse rate of the Tekins (2.5 * charge rate) !!!... You're giving me the upgrade bug right now

On the Flex Discharge, does it go as follows? Linear discharge @ 18amps for say 900mS then a spike charge of 35 amps for 5 msecs? never mind the actual number of secs. What I want to point out is that, it appears that your cells are getting zapped at the same time they are discharged... wow!!!

BTW, how does your discharger know when to stop discharging? Minimum Terminal Voltag cut-off?

Thanks a lot
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Old 06-25-2002, 03:46 AM   #27
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Just want to say thanks to everyone (especially Jayhaya & Speedo, who answered very directly) who responded to this. Am I correct in my interpretation that a Turbo35 will not actually make a better job of charging my cells than something like a pitbull, millenium or maybe the new LRP Pulsar?

If so my current discharging equipment is a realtime 2 tray & the 10 Amp discharge function on my Apex Sigma+. So would I see any benefit in performance using the higher discharge rate of the Turbo 35.
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Old 06-25-2002, 07:40 AM   #28
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Quote:
Originally posted by rough512
4 amps charge, 20 amps flex discharge... that's double the revelse pulse rate of the Tekins (2.5 * charge rate) !!!... You're giving me the upgrade bug right now

On the Flex Discharge, does it go as follows? Linear discharge @ 18amps for say 900mS then a spike charge of 35 amps for 5 msecs? never mind the actual number of secs. What I want to point out is that, it appears that your cells are getting zapped at the same time they are discharged... wow!!!

BTW, how does your discharger know when to stop discharging? Minimum Terminal Voltag cut-off?

Thanks a lot
rough,

I'd have to look to be certain, but I'm pretty sure that the Victor defaults to 5x the charge rate for the burps... I never experimented with different burp rates (gotta have time for SOME other things)

On the discharge, there's an option screen to turn the "flex" discharge feature on. When you enable the feature you also enter the rate. Then when you do a discharge, the VIctor discharges at the "nominal" rate you selected on the discharge screen, the every 15 or 20 seconds or so it jumps up to the high rate for a second or two, then immediatelty drops to half the nominal rate for a second or two, then back to nominal for another fifteen or so seconds.

The discharge terminates at a predetermined voltage, you set the cutoff voltage on the discharge screen. I'm pretty sure the Victor only looks for the cutoff voltage during the nominal rate portions of the discharge, because when it jumps to the hig rate late in the discharge the voltage clearly drops below the preset cutoff momentarily without tripping the cutoff.

Hope that helps,

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Old 06-25-2002, 07:45 AM   #29
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Quote:
Originally posted by JohnA
Just want to say thanks to everyone (especially Jayhaya & Speedo, who answered very directly) who responded to this. Am I correct in my interpretation that a Turbo35 will not actually make a better job of charging my cells than something like a pitbull, millenium or maybe the new LRP Pulsar?

If so my current discharging equipment is a realtime 2 tray & the 10 Amp discharge function on my Apex Sigma+. So would I see any benefit in performance using the higher discharge rate of the Turbo 35.
John,

For charging at the racetrack, the Turbo35 does a great job, but so do the other chargers you mention.

As far as discharging goes, I believe NiCads will benefit from higher discharging rates than ten amps. For NIMH, I can't tell with any certainty yet, but some of the serious matchers (SMC for one) recommend 30 amp discharging. I always discharge at 30 after a race, whether NiCad or NIMH.

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Old 06-25-2002, 09:18 AM   #30
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I just want to help back up Trips observations about reverse pulse charging. I also used the 'burping' method of charging and while no numbers on the batteries seemed to change drastically, the pack didn't seem to go flat in the middle of a race and the battery life seemed to extend longer (ie. number of charge/discharge cycles before one had to toss the pack increased). Now normally one doesn't care too much about this, but with my dad, my brother and I racing all at the same time (all on my dad's wallet at that time in history) it was very important to squeeze as much as we could out of everything. But several things have changed since then (ie. battery construction and charger designs) so the benefits may no longer exist.
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