HarshGuy

iTrader: (6)

I couldn't get the graphs to download with my 35BL ...so I picked up a GFX ...pretty darn kewl ...good information! ...I wrote a "parser" where I upload the graphs into a directory and it creates a table with the info I care about which I can download to an excel s/s to sort as I wish ...check it out at: http://dev.gearchart.com/?fuseaction=batchart.create ...you can click on the column "pack" to see the source file for that line.

mk2

iTrader: (6)

hey danny i got some of your new 3600 what should i expect the life span to be on these cells and do you recamend traying cells to 0 volts before a charge n0t dead shorting just to 0

Evilpete

iTrader: (1)

Isn't the 30 amps more if you're training your batteries for Mod? I heard 20 is perfect for Stock class and 19t motors, but then again, ask 10 people how to do something in this hpobby and...

HarshGuy

iTrader: (6)

Good question ...I only run stock and 19 ...should I still be using 35Amps to rate the packs with? i.e. is 20 or 30 a more "real" number of the amps drawn in stock and 19?

BigDogRacing

iTrader: (12)

Well, if you do the math, you will find we are averaging close to 30 amps in 19 turn. Not only that, but I've been in the battery business for only a short time, but I have learned that irregardless of what amp draw we are averaging, we want to train/test our cells at the highest discharge we can while keeping the cell from degrading due to high currents/temperatures. The main reason for this is because we want the cells to "learn" to release their energy as fast as possible. This is why we do things like dead short packs and keep the packs discharged even if not dead shorting- because we want the cell to "want" to be discharged.

If you don't believe this theory, or you honestly think NiMH cells don't develop a memory, then try keeping your packs fully charged all the time excpet when you race- your packs will be crap.

One note to those reading this thread for educational purposes- the act of dead shorting packs should begin with the first discharge of the pack and continue for the life of the pack. I didn't believe this was true until last year (because I automatically assume most of these rules are theory or not fully tested). If you quit dead shorting, you will lose a good pack. They will basically keep the runtime loss but the AV and AIR will revert back to numbers fairly common with virgin unzapped cells or even worse. If you begin dead shorting again after this happens, you might get some of the AIR back, but it will never be as good as it was.

HarshGuy

iTrader: (6)

kewl ...35 it is

ttso

iTrader: (1)

I just check over IB3600 SMC thread and learned IB3600 is tend to work better on warmer temp (pre-warm to 40'c, charge, hit track at 70~75'c after charge finished, said JDM_DOHC_SiR).

And I know GP330 tend to work better on a cooler temperture compare with IB3600. But which temperature it's? When I doing cycling and rating, what temperature should I use (if I got a warmer/cooler to make the battery stay in perfect temperature condition)?

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edit: typo

centax error!

bigdogracing- I really want to give dead shorting a try but not really sure if I understood what you meant by dead shorting the pack for the rest of it' life. Say I got 5 packs that I will be dead shorting. Do I also need 5 dischargers with 0 Volts cut-off? and do I have to discharge it, then deadshort until next weeks run? or I only need to discharge it .90 V /cell after run and keep it till next week and dead short it only prior to the race 30 mins before charging. How long does it take to fully charge a dead shorted pack? have you tried different charging rate that works best for a dead shortred pack? thanks.

CE-X

BigDogRacing

iTrader: (12)

Centax, here's the way I dead short-

rules- never start dead shorting packs that have been raced/cycled and not dead shorted. If you purchase new packs and decide to dead short them, continue to do so while they are used for racing.

1- New packs- discharge them to 5.4V and then tray them on a 0V discharge tray for at least 20 minutes after the lights go out.

2- Race day- unsolder the short wires before the race begins to let the cells regenerate some voltage (helps prevent against false peaks)

3- Charge like normal shooting for peak about 5-10 mins before the run. Repeak if neccessary. Use .050 delta peak or 40deg Celsius temp peak.

4- After the run, discharge pack to 5.4V on discharger.

5- Before charging the pack again, tray it to equalize the cells back to zero. Do not be concerned if they get a little warm. Don't bother using a fan in between charges because a warm pack will actually take a better charge than a cool pack. The only thing to be concerned about is charging a hot pack. You don't want it to be extremely hot.

6- After the last run, discharge the pack and tray it to 0V. Let it stay in the tray for about 10-20minutes and then use solder and connect the terminals. The reason I prefer solder is that if you mistakenly short the wrong pack or something happens the solder will simply melt away and disconnect before any fire/damage happens to the pack.

Note- From my own findings, I've concluded the first run on a shorted pack will usually feel flatter than the rest of the day. Also, don't be fooled by the thinking that you can only run a pack twice a day. Running it 10 times won't hurt it as long as you follow the rules of traying and not charging a hot pack (warm is OK).

Mr. McGoo

iTrader: (23)

bump to the top...

i just found this thread, and it really helped me understand some things about my batts.

any other comments?

Ben.C

Basically,I don't like the idea of dead shorting my cells.

Maybe,I'm not too sure...

But from what I know is that dead shorting of cells increases voltage but decrease the run time.As for a mod race like me,I need the run time while running single digit motors.

cr250

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