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Old 07-07-2005, 11:46 PM   #1
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Default Battery cycling for race day

I've been trying to read up alot on this. I'm trying to figure out the right cycling process for my batteries. I'll be running 19turn, and I have come to the conclusion that traying them down to 0.0v will not harm the batteries if done right. From what I've read, you tray the batteries down to 0.0v the night before and leave them on the tray until you charge them. Then after using them, discharge them to 0.9v and store until the night before the next race.

Right now I have a 30amp discharger and a Novak Smart tray. My main question is do I have to buy seperate 0.0v trays for each of my batteries? Or can I tray them one at a time then store them?


On the otherhand, if I don't tray them to 0.0v, can I just tray them to 0.9v and leave them like that until I need to charge them?

On another topic, does anyone know were I can get some cheap Speedmind Hybrid 2(28mm) and Speedmind 35 shore rear(30mm) foams?
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Old 07-08-2005, 12:42 AM   #2
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If you pay for your packs, take my advice.

Don't discharge much below 0.9.
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Old 07-08-2005, 01:06 AM   #3
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I'm not an expert nor do I play one on RCTech but, here is what I do.

-I place my batteries on a Novak Smart tray to equalize
-Charge them
-Run them
-Discharge at 30A (I do not dead short to 0V)
-If I plan to practice next week, after the pack cools, I'll store them if I don't plan to run the next week, I charge about 500 mah on the pack then store till I use them again.
-Repeat.
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Old 07-08-2005, 03:57 AM   #4
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there is a difference between dead shorting and equalizing to 0.0v

i've not had much experience with dead shorting so i wont comment on that... but myself and many people i know that race in australia are all now traying their cells down to 0.0v on either the team much more zero v or the integy zero 6s

both trays take the cells down and hold them there at 0.0v but they will NOT dead short the cells or harm them but reversing the polarity

im not sure about equalizing to 0.0v for modified but for stock and 19t where run time is not so much of an issue, it definately lowers internal resistance giving better punch which is what you want for stock & 19t

i always store my batteries at 0.9v (5.4v per pack) between race days.
i havent raced for a few months now and all my batteries were stored @ 5.4v and cycled regularly... they havent lost any runtime or voltage

try both methods and see what you prefer... i personally wouldnt dead short... but i recommend equalizing to 0.0v, it ensures even cell voltage and the lowest IR

just my 0.02c

cheers

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Old 07-08-2005, 04:51 AM   #5
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I am traying my packs on a Smart Tray and here is what I've found. I followed the recommendation of traying to 0.9, and did that for a while. When going into the race (stock class), I felt I had lost alot of punch in my cells.

So what I do is after racing is done, I tray all my cells down to 0.9, then the night before racing I tray them again, but this time to 0.3. It definitely made a difference for me.

Anyone give your imput on this method. As I said it seems to work for me.
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Old 07-08-2005, 06:14 AM   #6
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Remember that no matter what voltage you trey your batterys to....right after you remove them from the trey, with in seconds they will re-bound to aprox 1.2 volts give or take......so don't beat yourself up with excessive specific voltage battery treying before their going to be stored till next race day..... no matter what you do (except deadshorting) they'll be around 1.2volts after they sit.....the important part is that the cells are equalized right before you charge them, without any "excessive" time for them to rebound (possibly unevenly)......In my fairly lengthy experience, bringing any of the gold peak cells to zero or even deadshorting them does nothing at all to decrease cell life nor does it kill much runtime, and Iv'e seen nothing but advantages doing it for years on dozens of packs...... even some of the most reputable battery matchers like SMC are recomending such regimines for GP3300's......my preference for stock and "even" 19turn is to deadshort which will hold the pack at true zero until your ready to charge, giving you the most full even charge possible.....and for mod where every bit of runtime is needed, anywhere between 0.9 and zero, and then put right on the charger......so it's no surprise that treying from 0.9 to 0.3 gave you more punch because I'd be willing to bet that treying down to zero volts and even deadshorting will give you that much more.....good luck
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Last edited by Joe B; 07-08-2005 at 06:49 AM.
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Old 07-08-2005, 02:21 PM   #7
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Ok so traying the cells to 0v is just putting them on the tray and them taking them off when done right? And dead shorting is leaving them on the tray until you charge the pack?

How long does it take to go from 0.9v down to 0v?
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Old 07-08-2005, 02:51 PM   #8
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Quote:
Originally Posted by Altrodesigns
Ok so traying the cells to 0v is just putting them on the tray and them taking them off when done right? And dead shorting is leaving them on the tray until you charge the pack?

How long does it take to go from 0.9v down to 0v?
Well, not really, but sorta.....

Traying to 0.0 and holding is in my opinion much safer for the cells (and you) than dead shorting, unless you have a fuse on your dead short.

Even if you trayed the cells down to 0 on the Smart Tray, there is still a good chance that there is residual charge left in the cell. as has been discussed, when the cells are brought down to a specific voltage, if they are not "held" there, once the discharge process has turned off (like what happens with the ST) the cell voltage rebounds. This means the cells can still produce voltage into a very small load. Because no two cells are exactly the same, this rebound can happen at different speeds, to different levels.

If your cells haven't been held at 0 for enough time to adequatly reduce their ability to rebound, then the possibility exists that when the dead short is placed across the packs, some cells may have a higher voltage than others. This is bad. If you have one cell that is completly dead, and the others (under dead short) are producing .05 volts- then that current is being passed through the dead cell, in effect charging it in reverse. This is the cell reversal that is so widely discussed and despised. For the most part, if care is taken, deadshorting can work for you just fine. I personally don't do it because I just don't have to time to fiddle with my packs to the point I would feel comfortable dead shorting them. I, like many others, follow this regiment:

Discharge pack on tray RIGHT before charging, to around .5 volts per cell.
Charge at between 5-6.5 amps (depending upon application)
Race
Discharge on llights to cut-off 5.4 (acctually the mechanical cut off stops at around 4 volts)
Store
Repeat at next race day.

Run cells only once per day. ( I have 22 packs, so can get away with that )
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Old 07-08-2005, 02:56 PM   #9
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Well what I was thinking of doing, is picking up a couple INDI Zero 6S trays for my packs. So I can leave them on the trays overnight before a race.

How do people go about deadshorting a pack?
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Old 07-08-2005, 03:07 PM   #10
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The question I have is if I have a pack that won't go back up after taking off the dead short what's happening? I've got six packs and are treating them all the same but are getting mixed results.
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Old 07-08-2005, 03:35 PM   #11
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Those of you that are dead shorting be sure what batteries you have. The latest GP3300's (Purchased after February 05) and 3700's DO NOT like dead shorting. The older 3300's love shorting.

If you short your new stuff you will lose run time and increase the IR.

Unfortunately, there is no good way of telling what you have.

The top pros are all doing the same thing:

1. Tray until lights are out and the pack is cool to touch (~0.0v per cell)

2. Charge at 5-6A with a .03v cut

3. Wait 60 seconds.

4. Re-peak at 4-5A with a .02 cut. The re-peak is super important. It really increases punch and packs in a few more Mah in run time.

5. Race

6. Dump pack @30A to 5.4v ( 0.9V per cell)

7. Put them away until the next race day.

If you do this your cells will maintain capacity for quite a while and probably increase in voltage over time. Generally you will lose 20-30 sec over ~20-30 runs no matter what you do to a battery.
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Old 07-08-2005, 03:51 PM   #12
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Quote:
Originally Posted by AdrianM
Those of you that are dead shorting be sure what batteries you have. The latest GP3300's (Purchased after February 05) and 3700's DO NOT like dead shorting. The older 3300's love shorting.

If you short your new stuff you will lose run time and increase the IR.

Unfortunately, there is no good way of telling what you have.

The top pros are all doing the same thing:

1. Tray until lights are out and the pack is cool to touch (~0.0v per cell)

2. Charge at 5-6A with a .03v cut

3. Wait 60 seconds.

4. Re-peak at 4-5A with a .02 cut. The re-peak is super important. It really increases punch and packs in a few more Mah in run time.

5. Race

6. Dump pack @30A to 5.4v ( 0.9V per cell)

7. Put them away until the next race day.

If you do this your cells will maintain capacity for quite a while and probably increase in voltage over time. Generally you will lose 20-30 sec over ~20-30 runs no matter what you do to a battery.
do you mean charge your batts normally..when they finish charging, leave them for 1 minute and then repeak?
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Old 07-08-2005, 04:17 PM   #13
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"Traying to 0.0 and holding is in my opinion much safer for the cells (and you) than dead shorting, unless you have a fuse on your dead short."

Here's some advice from the olden days (Sanyo 2000):
Take some thin solder and run it between the terminals while the pack is still on the tray. If there is a problem, the solder snaps in half (won't take any kind of amp load). It works.
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Old 07-08-2005, 11:20 PM   #14
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Something worth mentioning for the guys that are new to deadshorting is....NEVER trust the lights on any of the discharge treys out there.....out of the 5 integy discharge treys I have, each trey has the cells at a different voltages when the lights go out so don't "assume" that when the lights go out on your trey, the pack is at zero, many brand treys are very far from zero when they go out.......some have a dial inside that can be adjusted so that the lights going out actually represents a certain voltage,but to be absolutely certain , always "everytime" confirm each cell with a voltmeter, and connect the short(a piece of thin solder like others mentioned for safety)while the cells are still on the trey being held at absoloute zero volts per cell.......I know im stressing having the packs at absolute zero before you short them but this is where 99% of the horror story's come from concerning deadshorting and it's effects........goodluck
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Old 07-09-2005, 07:13 AM   #15
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Alright so is the volt meter on my GFX good enough to use?,cause it gives me weird readings? if I have a pack connected to the gfx while it's being taken down to zero with my integy zero thirty how do I know if all the cells are at zero? If a pack has been dead shorted for say a week and I take off the dead short should the voltage come back up? if it doesn't, does this mean I have a reversed cell in the pack? this is for three month old GP3300's.One other question guys, can you dead short stick packs? I have some other questions also but I'll wait untill I get this dead short thing straight first
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