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Old 11-11-2005, 06:17 PM   #1
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Default Another dead shorting question...

Hey guys, I've got a question about dead shorting. I race about once a month and my batteries are coming up on their 2nd year and I'm considering dead shorting to increase voltage and lower the AIR. Would it be ok to dead short them for about 3-4 weeks at a time. I have all the equipment to do it. Pro match equalizing tray and integy 0-30. I race stock and am not worried about run time. Also,Does it really work??? Thanks in advance--Al
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Old 11-11-2005, 08:08 PM   #2
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You will not see any difference in your batteries, you need to start dead shorting from the begining. Dead shorting dosn't do any good for old batteries
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Old 11-11-2005, 08:12 PM   #3
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oh but it does
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Old 11-11-2005, 09:19 PM   #4
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Soooo...should I give it a go??
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Old 11-11-2005, 09:23 PM   #5
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BEFORE YOU DO ANYTHING!
This was written by the owner of Axxis Racing, he is a power engineer. (In other words, he knows more than humanly possible).

"DEAD SHORTING A BATTERY PACK.

It is claimed that Dead shorting serves to increase the power output of
a battery pack by slightly increasing the on-load operating voltage as
well as decreasing the internal resistance of the cells. However, short
circuiting a battery pack is definitely not recommended as the
destructive energy unleashed by the cellls is seriously under estimated.

Here is an example:

An IB3800 Battery stores approximately 5,950 Joules of energy (5,950
watt seconds). A 6 cell 3800mah battery pack stores 213,750 Joules !!!!

Now, what does that mean. Well, it only taks 10 Joules to punch a hole
through aluminum foil creating lots of sparks. 30 Joules is enough to
weld a wire to a small surface. This is because the discharge period is
very short, almost instantaneous, resulting in a power transfer of
hundreds of watts. A 3800mah - 6 cell battery pack has 7,125 times the
power necesary to weld a small wire...

Short circuiting these cells can cause extremely high currents and
temperatures within the cells resulting in the breakdown of the chemical
compounds from which they are made. This in turn can cause the rapid
build up of pressure within the cell resulting in its catastrophic failure,
with unpredictable consequences including the uncontrolled rupture of
the cell or even fire (The cells can actually explode if you dead short
with too much energy left inside them). Severe damage, burns or other
serious events can occur.

Dead shorting a charged battery pack is OUT OF THE QUESTION unless you
know exactly what you are doing. It is not only bad for the batteries,
it is very dangerous to yourself and the people around you.

I have read on other battery matching websites recomendations to
discharge a pack to 5.4 volts (0.9 volts/cell) and then dead shorting it.
This is extremely dangerous and the only thing you will achieve is the
speedy destruction of your pack and possible severe injuries or a fire.
The battery pack can still store over 25,000 Joules or 833 times the
energy necessary to weld a small wire. Do you see the potential danger
involved with this.

If you plan to dead short a battery pack in order to gain more power,
you must make sure that the pack is completely discharged down to 0
volts over a long period of time. Discharging with a battery discharger
like the one on your charger is out of the question. In order to do this,
you must discharge your pack in battery equalization board (like the
Axxis EQ series) that will discharge the batteries down to 0 volts over a
18-24 hour period. Once a battery is completely discharged then you
could attempt to dead short your pack. First, you must double check with
a voltmeter that each cell is at 0 volts before attempting it. Once
EACH cell in your battery pack has been discharged to 0 volts, apply a
jumper wire from the positive to the negative terminals of the pack. You
SHOULD NOT see a spark when attaching the jumper. If you do, STOP,
because the cells still contain energy and it will be DANGEROUS and VERY
DAMAGING to continue. The jumper should be made out of 12 or 10AWG wire,
smaller jumpers are dangerous and should not be used.

After attaching the jumper wire, leave your battery shorted until you
plan to use it again (not less than 5 days). The small amount of energy
(Joules) that is left in each cell will slowly break down any
crystalline formations that impedes the flow of energy into the electrodes. This
will lower runtime since a portion of the electrolyte is consumed
during this process. You can typically expect your cells to loose 15-35
seconds of runtime, as well as the pack longevity. Once your cells have
been deadshorted, the damage to runtime and cell life has been done and
there is no way to reverse it. Generaly, only professional racers who
run in either stock or 19t classes use this process - Racers who run
modified rarely dead short their packs as they do not want to loose
runtime in favor of a few millivolts.
Should you decide to dead short your packs, continue the process for
the life of the pack. If you choose not to, the overall performance of
your pack will rapidly decrease.

Most battery matchers will not guarantee a cell if it has been dead
shorted. As professionals, we can usualy tell when a pack has been
deadshorted.


AXXIS RACING WROTE THIS TO EXPLAIN WHAT HAPPENS WHEN YOU DEAD SHORT A
BATTERY. THIS ARE NOT INSTRUCTIONS. WE ARE NOT ENCOURANGING YOU TO DO
THIS. SHOULD YOU DECIDE TO DEAD SHORT YOUR PACKS, YOU ARE DOING WITH THE
KNOWLEDGE THAT IT IS A DANGEROUS AND POSSIBLY DEADLY PROCEDURE. WE DO
NOT RECOMMEND THE USE OF THIS PROCEDURE. USE AT YOUR OWN RISK, AND IF
YOU DO, PLEASE BE CAREFULL AND FOLLOW ALL THE SAFETY PROCEDURES.

Copyright 2005 - Axxis Racing, LLC & Isaac Krajmalnik, PE"
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Old 11-11-2005, 09:38 PM   #6
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I just this past week dead shorted some of my 8 month old GP3300's for the first time. I saw a very substantial gain in average voltage and RIR in my three older packs. The 3 newer packs I have (only about 3 cycles on them) did not show very much increase at all. Run time on the older packs only sufferd by 20 secs. The newer packs hardly lost any at all.
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Old 11-12-2005, 06:16 AM   #7
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I always thought by Deadshorting a pack you must discharge it down to 0.0v and leave it there for a substantial amount of time (on a tray)

Can somebody clear this up please?
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Old 11-12-2005, 08:00 AM   #8
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Quote:
Originally Posted by Team Duratrax
I always thought by Deadshorting a pack you must discharge it down to 0.0v and leave it there for a substantial amount of time (on a tray)

Can somebody clear this up please?
you start out by doing that, taking it down to 0v, and then unless you leave it in the tray, you hoook a jumper wire connecting the positive and negative terminals. this allows you do do multiple packs, as 1 tray only holds 1 set of cells.
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Old 11-12-2005, 08:53 PM   #9
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Any other opinions??...
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Old 11-12-2005, 09:28 PM   #10
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I use the integy to discharge to 0 volt.
Don't just watch the light bulbs go out, put a volt meter on the pack until it reads zero.
Then attach some wire (while still on the tray) to the + and - and then take out the pack.
Works very good.
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Old 11-13-2005, 07:56 PM   #11
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TTT
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