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Old 02-06-2005, 01:02 PM   #31
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Ok fellas that was all a good read. I'm new into electric and have a couple questions. Running carpet oval, stock. What exactly is the internal resistance of the battery? And why would it compete over voltage as to making one think a batt was better because of this number or that number?

I've got some used matched 3300's and am using a lrp pulsar (first version) for my charging. And it has a matching feature. I'm sure it's not to great compared to the high end stuff, but I figured it would give me an idea of how my batts are. I ran my three batts the other day and was surprised.

The batt I thought was the worst had more average volts, less mah, and the least seconds. My other two that I like were almost the same in all the numbers with eachother. I was just surprised that the batt with the highest average volts was the one I think the worst of.

So of these batteries #3 would be my best by the numbers? And since they are all so far off 3300 mah are they nearing the end of their life? Thanks!

Batt 1: 4.9 average Volts
2602 mah
985 seconds

Batt 2: 4.81 average Volts
2760 mah
1044 seconds

Batt 3: 4.79 average Volts
2772 mah
1048 seconds
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Old 02-06-2005, 02:17 PM   #32
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I'm not entirely sure what cycling does to your batteries. I noticed that my Integy 16x5 charger has that function & I was wondering how, when & why I should use it. It would be great if someone could tell me how to set it up & when I should do it. Thanks in advance.
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Old 02-06-2005, 03:18 PM   #33
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I cycle my packs to "rate them" against themselves i.e. my own "inventory" of packs and to see when they strat fading off to much and time for replacement. People hae told me that I shorten the like of my packs by doing so, but I ain't to worried about it as I replace my packs every 8 months or so anyways.

....I will be cycling then at 30 amps from now on though
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Old 02-06-2005, 11:32 PM   #34
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jbrow: The LRP charger only dischargese at 10 amps plus it doesn't have the voltage sensing leads like the T-35 has so the numbers will tend to be inconsistant.


The packs IR will make it drop more or less voltage under high loads. So you can have 2 packs with the same voltage at 20 amps but the one with the lower IR will hold up better under higher loads.


nrctc: Cycling can be done to verify the condidtion of your packs. Lets say you have a slow run and think your motor was fine and your setup was good you can cycle your pack and see if all looks normal.
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Old 02-07-2005, 07:28 AM   #35
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Danny, I've got a combination of your packs ...3300, 3600's cycled at 25 amps, and anothe matcher's 3300's that cycles at 30 amps (good quality bat's though) ...should I cycle ALL my packs at 35 amps?
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Old 02-07-2005, 08:06 AM   #36
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I personally cycle my packs at 35 amps. To me the higher load will show you which pack has the better performance.

The numbers you see should be used as reference. If your an experienced racer you should be able to see by track performance which pack runs the best.
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Old 02-07-2005, 08:09 AM   #37
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Kewl that's what I will do then, also I've been doing some research ...I have a T35 and it looks like if I get a 9 pin null modem cable I can hook up the printer port to my pc, then running hyperterminal should be able to see the graph with the discharge curve ...is this the case? Or can I only do this with the GFX ...or do you know
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Old 02-07-2005, 08:22 AM   #38
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Yes you could get graphs but they aren't that important.

With average voltage and AIR that will tell you which one is your best pack.

Don't cycle yor packs just to cycle them. You should do this when you feel a pack mght have an issue. Compare it to the last time you cycled it if the voltage and IR has changed allot then your pack is most likley starting to decline.
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Old 02-07-2005, 08:26 AM   #39
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Quote:
Originally posted by Danny/SMC
Harshguy: First of all to properly train your packs and see which ones are better you should use 30 amps or even 35 amps. With todays motors 20 amps is outdated.
I'm not so sure about this, which class are you talking about? I'm racing stock class, and if I completely discharge a pack at 20 amps, the pack is much hotter, than if I race it untill it drop... After a discharge, the pack is in the 60-65 degrees celsius (140-149) area, after a race, it's close to 50 degrees celsius (122F)....
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Old 02-07-2005, 08:35 AM   #40
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humm ..ok ..I was looking at graphs to see which packs "stayed up there" for the fill 5 minutes of racing.

yea actually I sycle them usually once a month if I raced/practiced a lot during that month or every other month otherwise

Good info though thanks to all who have contributed to this topic
Quote:
Originally posted by Danny/SMC
Yes you could get graphs but they aren't that important.

With average voltage and AIR that will tell you which one is your best pack.

Don't cycle yor packs just to cycle them. You should do this when you feel a pack mght have an issue. Compare it to the last time you cycled it if the voltage and IR has changed allot then your pack is most likley starting to decline.
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Old 02-07-2005, 08:36 AM   #41
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When we cycle cells on TM-4 they will reach 175-185 degrees farenheit that is using a 35 amp rate.
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Old 02-07-2005, 08:40 AM   #42
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Quote:
Originally posted by crimson eagle
Mlane,

Read my CDAT website.

I find voltage secondary to run time, particularly as I run mod 12th. However, even if I ran stock I'd be more interested at the voltage at 5 minutes than the total average voltage. Recently I have been looking closely at the data from the last minute of discharge to look at eh slope of the curve and how much voltage cell has during the last 30 seconds of discharge.

Chris.
Totally agree with you eagle. Although I am new to the electric scene (1/8 off road guy) I find that the measurement @ the 5 minute mark is something that makes sense.

Oh and by the way... someone talked about temperatures. I have some LRP team packs and I was wondering why on a cycle of 5 - 30 on a GFX they reached 60 degrees celsius... What's with that....?? anyone?
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Old 02-07-2005, 08:46 AM   #43
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Danny,

Are these temperatures withing GP's specs for the cells?
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Old 02-07-2005, 08:46 AM   #44
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The temperature your seeing after a full cycle is normal.

The pack with the highest average voltage will have the better voltage at the 5 min(300sec) mark.
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Old 02-07-2005, 08:56 AM   #45
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Quote:
Originally posted by Danny/SMC
The temperature your seeing after a full cycle is normal.

The pack with the highest average voltage will have the better voltage at the 5 min(300sec) mark.


That's a relief to hear from an expert.
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