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Old 01-08-2013, 11:55 AM   #1
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Questions?? Generate Discharge Curves?

Is there a discharger (or charger/discharger) out there that allows you to download high current discharge data (ie. curves) to a computer for analysis/comparison?

If so which dishcharger is it?

I have an LRP Pulsar Touch which dishcharges 2S packs at 20A (4S will only go to ~ 10A) and it does display some discharge curve data on it's screen, but I don't think you can get the data off the charger onto a laptop for further analysis...

Thanks!
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Old 01-08-2013, 02:01 PM   #2
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Comp. Electronics GFX
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Old 01-08-2013, 02:29 PM   #3
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My icharger 208b has these capabilities, but I've never used it.
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Old 01-08-2013, 03:26 PM   #4
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You can get a multimeter that has logging capabilities and just monitor the voltage of the pack while using something as a load to discharge it (light bulbs, for example). Then just download the data to the PC.
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Old 01-08-2013, 05:21 PM   #5
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The lipos we are using now are so good there is almost no point to doing this. The variance is a couple hundredths of a volt from the best to the worst packs, a couple hundred Mah and a 1-2 tenths in IR. None of this add up to much of anything on the track.

That is if you are buying good Lipos from Trinity, Reedy, EA, OHP, SMC, etc...
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Old 01-08-2013, 11:13 PM   #6
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iCharger 206B as mentioned above. Use the free logview software. I use this method to test my packs. Here's a sample of the results:

https://www.dropbox.com/s/bu7gzzywyv...e%20Charts.xls

After discharging at 20A constant to the 6 minute mark, the variance between best to worst packs i've tested is about .30V. Haven't had a chance to run IR benchmarks yet, although I really should.

As AdrianM says, there isn't TOO much difference in terms of simple voltage, but more than a few hundredths of a volt. Whether that matters to you will be different for each person and racing class.
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Old 01-09-2013, 09:14 AM   #7
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Default I discharge at 35 amps on my CE GFX

I cycle my lipos about every month to check them and see which packs are starting to fall off. Also, one of the biggest things I watch for is how long the packs will hold above a specific voltage more so than just the average.

I have new Revtech 100c packs that are holding above 8 volts at 35 amps for well over 50+ seconds. This is a huge gain over even my 6 month old packs that would only hold over 8 volts for 30+ seconds but now due to age and cycles they only hold for about 15 - 20 seconds.

For me when a pack will not hold above 7.8 volts for more than 80 - 100 seconds it is time to retire it for a freash pack.

Let me also state that these are my packs for spec racing where the voltage is really important. For mod racing or just casual racing/bashing this would not be nearly as important.
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Old 01-09-2013, 09:33 AM   #8
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Both bigger mah and higher c with lower ir will all help with better voltage at a given duration

I would always check and com pair my packs based off of 25a discharge looking at the 300sec voltage and ir of the pack .
Back when 25/5400 were big backs
With a 25a discharge on my gfx at the 300sec mark they were about 7.4-7.6v ...so that's a bit of difference in spec racing
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Old 01-09-2013, 02:38 PM   #9
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Quote:
Originally Posted by gazza View Post
Comp. Electronics GFX
The problem with the GFX is they read different from one GFX to another.

Best thing to do is this:

http://www.youtube.com/watch?v=usRE3...eature=related
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Old 01-09-2013, 02:41 PM   #10
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Quote:
Originally Posted by JFuel11 View Post
I cycle my lipos about every month to check them and see which packs are starting to fall off. Also, one of the biggest things I watch for is how long the packs will hold above a specific voltage more so than just the average.

I have new Revtech 100c packs that are holding above 8 volts at 35 amps for well over 50+ seconds. This is a huge gain over even my 6 month old packs that would only hold over 8 volts for 30+ seconds but now due to age and cycles they only hold for about 15 - 20 seconds.

.
The Revtech batteries are the best right now.
A guy at our track here bought 100 different lipos and tested them all.
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Old 01-09-2013, 03:30 PM   #11
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Nice video
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