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Old 10-30-2004, 10:01 AM   #1
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Default dead shorting tips. (needed)

just want to know what is the best way to dead short cells.
-do i short it after the very first charge?
-do i cycle it first?
-how should it be charged?

dead shorting is greek (no offense to greeks out there!!) to me and i would appreciate it!! thanks!!


i know if you ask 6 guys on how to do something you would probably get 9 diff. answers. i appreciate your comments on this.
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Old 10-30-2004, 10:09 AM   #2
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I would NOT short Ni-Mh cells.
Nicads I may try (but never have) if they were old and knackered...nothing to lose
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Old 10-30-2004, 10:28 AM   #3
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As long as the Nimh cells are Gen 2 or Gen3(Shortie Cells) they actually love to be dead shorted.

My questions are this.
What type of Racing do you do?
Deadshorting while keeping Voltage up and Resistance Down will cost you 12-25 seconds of runtime.

What Charger do you have?
The reason for asking this is not all chargers will charge DeadShorted Cells.

What Discharger and Tray do you have?
This will help so I can answer your intial Question.

Les
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Old 10-30-2004, 10:32 AM   #4
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Quote:
Originally posted by TexRacer
As long as the Nimh cells are Gen 2 or Gen3(Shortie Cells) they actually love to be dead shorted.

My questions are this.
What type of Racing do you do?
Deadshorting while keeping Voltage up and Resistance Down will cost you 12-25 seconds of runtime.

What Charger do you have?
The reason for asking this is not all chargers will charge DeadShorted Cells.

What Discharger and Tray do you have?
This will help so I can answer your intial Question.

Les
What type of Racing do you do?

i run stock and 19T racing.



What Charger do you have?

i have 2 chargers a pro-trak and a futaba CDR-5000


What Discharger and Tray do you have?

i use a rayspeed discharger. BUT i have access to a novak smart tray for the DS function.
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Old 10-30-2004, 10:54 AM   #5
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Im not a huge fan of using the Novak Tray for DeadShorting.

Trinity Realtime 2 or 2.5(Best tray's for DeadShorting)
Trinity Zero(Takes a LONG TIME)
Integy Octane 2

Best to get a volt meter or multimeter.
That way when the lights go out you can at least test the cells to make sure they are at 0.Just a built in safety feature.

Seems like you have some really nice stuff but also seems like your new to the industry.

Unless you have 430+ cells at 30 amps Im not sure I would be deadshorting my 19 turn packs.Depending on your driving skills this could actually make 420 and Lower packs dump in 19 turn if DeadShorting.
430+ packs are kinda rare right now.

NEVER deadshort Sanyo 3600's.Not enough Info on them yet..

In stock I would DeadShort away.So it really depends on how many packs you have if you wanna deadshort or not.

Gen 1 Rainbow packs with the raised Positive pole didnt like being deadshorted or stored low.They would discharge themselves.
The newwer cells hold a charge longer.

Hope this helps.
Les
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Old 10-30-2004, 10:57 AM   #6
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If you wanna do a small test on your 19 turn packs.
Do this.

Charge the pack at 6.0amps with whatever cutoff you like.
I go as high as 5mv/c or .05 and as low as 3mv/c or .03 depending on outside temp.I want the pack to finish at 120-130 degree's when done charging.

If the pack sits for more than 15 minute's hit it with a peak at 2mv/c or .02

Run the pack in 19 turn and make sure you finish the race.
When you come off the track discharge the pack at 30 amps and see how much time is left in the packs.
35 seconds or less.I wouldnt deadshort my 19 turn packs
40 seconds or more then yea go ahead.

Hope this helps as well.

Les
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Old 10-30-2004, 06:36 PM   #7
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les - well i have been racing for about one year now and to be honest i'm not bad (driving skills wise). i just started out with mod racing for about 3 months now and had quite good results.


well my runtume with my 19T motor is about nine minutes on a freshly repeaked batt. and around 8 minutes on a monster stock motor. i believe that i could make runtime (5 1/2 mins).

do i dead short it after the very first charge?

thanks on all the info
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Old 10-31-2004, 07:50 AM   #8
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i just started dead shorting. I race stock, and i noticed a difference. so did onlookers...

I have a trinity zero tray, after I run, discharge on gfx, then put in tray, take gfx, and hook up just voltage leeds to it so i can see voltage, when the pack drops down to 0.5v i solder the wire across. then remove it from the tray...

my batts are arond 8-10 months old, and even just after being deadshorted and cycled 24 hours, I noticed better voltages.
Ive been told the longer shorted, the better the results...
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Old 10-31-2004, 07:55 AM   #9
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Has anyone figures out the life expectancy on packs that are being dead shorted???

How long are you guys leaving them dead shorted for?
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Old 10-31-2004, 08:01 AM   #10
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DeadShorting doesnt hurt the packs longevity at all as far as Im concerned.It may actually help them due to not storing power.
You can leave packs deadshorted for however long you like.
I have had them as short as 2 days and as long as 3 weeks.

Striker-If your getting that kind of runtime under race conditions then yea go ahead and deadshort.

** IMPORTANT NOTE **

Personally I dont dead short my packs till after the 5th charge.My reasoning behind this is even though the cells are matched they are not matched as a pack but actually assembled as one.
I like to make the cells get use to each other before I start Deadshorting the pack.
I would say after 4th or 5th charge is fine.Thats just an opinion.
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Old 10-31-2004, 08:14 AM   #11
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I'm actually contemplating doing it because my cells are over a year old now and losing their punch.... It's time I invest in new cells, but if I can get some more life out of these I'll be even happier....
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Old 11-01-2004, 12:00 PM   #12
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I've got an older Integy tray with the small automotive lights. I tested out an old Nicad pack on it last night and it dropped the voltage down to around 0.1v per cell. Is this low enough to dead short the GP3300 shorty cells or do I need to get a new tray that will take the cells all the way down to zero volts?
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