In order to answer this question we must first explore the type if discharge trays that are currently in use. Currently there are two major types. The first we will call a diode tray.
This type of tray will use a diode to cut off the discharge current when the voltage does not meet the level required to keep the diode forward biased ( turned on ). On most diode trays this will be anywhere from 0.5v to 0.9v per cell. The material that the diode is made from will determine how much voltage is required to keep it turned on. In general Silicon diodes are about 0.7v and Germanium diodes are about 0.3v. The way to identify which
type is to look at them. Most Silicon diodes are black and have a silver stripe at one end versus a Germanium type looking like clear glass with a wire inside. The other type of discharge tray in use is the pure resistor type. These type of trays will discharge your battery continuously until they are completely dead if left unattended. Now that you know what the two major type if tray are lets explore their uses. First and foremost almost every discharge tray is considered an equalizing device. That means
that if you tray your batteries they should all arrive at the same point in the discharge curve when they are complete. This means that when you charge your batteries all of the cells should arrive at the peak almost at the same time. This is good. This means that you should not get a weak cell that will become reversed by the others discharging through it while you are running. If you tray your batteries to 0.9v per cell regularly you will see that
the runtime should start to stabilize and the voltage start to go up some. This is the method I would use for runtime critical disciplines. ( modified and 12th scale) If you are not
looking so much for runtime as performance than you could use a resistor type tray to deep discharge your batteries. Here is where you need to be careful. Deep discharging of your cells will cause a trade off to occur. In general terms deep discharging will get the
voltage to come up significantly but it will cost you runtime. This trade off is anywhere from 15-60 seconds. We have seen batteries that have gone up almost .015 per cell.
Our race team uses the deep discharge method for stock racing and the .9v method for everything else.
When to tray your batteries is also important. NiMh batteries like to have all of their maintenance done just before they are needed. This means that just before you are ready to run your batteries is the best time to discharge them on your tray until that process is complete. Once that is done start to charge your batteries as normal.
7. Thoughts on dead shorting your batteries.
We do not dead short any of our batteries. This can be a dangerous process if you don't know what you are doing. It can lead to venting and or exploding cells.
A snippet from Fusion Batteries.
Interesting reading I thought.