shorting batteries

[daddy_200313]

i was told the other day that shorting my pack could revive some performance. I dont have any dead cells i just have low voltage over the whole pack. i have heard of this tecnique before but dont really know much about it. would you short the whole pack or cells individually? is there a safe way of doing it? such as having so many mah or voltage in the pack or cell?any info would be appreciated. im curious and dont want to blow myself up.

[rcguy2477]

Some people short out their cells for race purposes. It makes the pack perform better, but it also shortens the life of the cells. The way to do it is to, first drain the battery down all the way, not to 5.4 volts, but to as low as you can get it. Then get a wire and solder it from the positive wire to the negative wire.

[rcguy2477]

and also, this really is only for the 3300 cells.

[guver]

I don't think you should short out nimh cells.

[mattyk6]

From what I have read, you don't gain enough to make it worthwhile for the common RC'er. IMHO, it is only advantageous to the racer who can make it around the track without getting hung up. Which means that I am not in this category.

M

[rcguy2477]

Its not really shorting out your cells, its just to make sure that the voltage does not raise at all. Although many people may say to discharge your 3300 to 5.4 volts, you can actually fully discharge with no or minimal harm to the cell.

[highroller]

Before you do this consider several things.
The only cells that can be dead shorted are Nicads 1700 scr,2000, 2400 and GP3300NiMh even some of the Sanyo and Panasonics have been dead shorted(that's right these can be dead shorted). We started dead shorting 1200sc batteries but doing it at a full charge - after charging connected the ends and dropping in cold water. It increased the voltage but did shorten the life of the cells, plus cells weren't matched then.

Steps after running back discharge pack with load unitl pack reaches between 5.40 to 5.00 volts remove load and place in equalizing tray (Trinity Real Time2 or similar one) this will work only with side by side packs, while pack is still in tray attach a jumper wire either solder or use clips or attach the pos and neg connectors. Don't attach the wire when pack it not under a load or voltage is above 1.50 volts.

The down side of dead shorting (only recommended for matched cells) is that while it increases the punch or voltage output it can affect the runtime by 10-50 seconds so most modified racers don't use it. It won't effect the live of the cells-you could have a cell die at any time under normal use. It's only recommended for racing and with matched cells.

For bashing or those that can replace cells frequently just discharge the cell at load - do not run in car until it stops. Use a string of lightbulbs, a resister bank or charge with either a 10, 20 or 30 amp load setting (Integy makes 3 models) then use a equalizing tray (side by side packs) or pack equalizer (stick packs) so that cells are close to the same voltage. This will also help cells charge close to the same levels of voltage and increase some of the punch-as cells will now be near or closer to the same voltages. You may not notice this until after a couple of cycles depending on the age of the cells and type of battery.