What makes matched cells so special?
When the cells are delivered to the
matching company, like Pro-Match Racing or Team Orion they are
"matched" (a process by which they are charged and discharged
"cycled") Cycling measures the performance parameters of each cell.
For information on performance parameters see our page on battery labels. The
cells are then grouped into categories like world spec, sport, team, xtreme ,
factory team. The cells with the lowest numbers go into the spec, sport, or
stick packs. The higher numbers go into the team, xtreme, or factory team
packs.
Run Time - Amount of time it takes to
discharge the cell to the discharge cutoff voltage. Run time is important, as
it tells you how long the cell will last when discharged at the discharge
current to the discharge cutoff voltage. Run time is most important to people
who drive modified on oval tracks. Divide this number by 60 to figure out about
how many minutes the pack will last under race condition. NOTE: Make sure when
comparing cells that they have the same discharge rate. The Run Time on a pack
discharged at 30 amps will be lower that the Run Time on a pack discharged at
20 amps. See the Pro-Match Racing conversion chart for more details.
Charge Rate - Amperage rate the cell is
charged at. The charge rate is a determining factor in the internal resistance
reading . The higher the amperage the cell is charged at the higher the
relative internal resistance number will be on the label.
Discharge Rate - Amperage load used to
discharge the cell. The discharge cutoff voltage standards are .85-.90 volts
for 30 amp and .90 for 20 and 25 amp cells. This is the voltage at which the
discharge process ends. Lowering this cutoff point will extend run time results
and lower the average voltage reading. Raising this point will shorten run time
but raise the average voltage reading.
Discharge Cutoff Voltage - Voltage level
used to stop the voltage averaging.
Average voltage - The average voltage
level throughout the discharge process. The average voltage is calculated by
sampling the voltage 10 times per second, starting at the peak voltage and
terminating the sampling when either the discharge cutoff voltage is reached,
or when the discharge time has expired. It is possible to 'fudge' the average
voltage by setting the **discharge cutoff time to be lower than the time it
takes the cell to discharge to the cutoff voltage. For example... if a cell
takes 250 seconds to discharge to .90 volts (the cutoff voltage) then it is
safe to assume that as long as the discharge cutoff time is set to be at least
250 seconds, the average voltage calculation will be correct. But what happens
if the discharge cutoff time is set to 200 seconds? Well, the answer is
simple... the average voltage will be calculated only for the first 200 seconds
of the discharge, resulting in an average voltage much higher than it would be
if calculated for the full discharge. Pro-Match always sets the discharge time
to 5000 seconds, so that the average voltage calculation will always be
correct! Beware of matchers that change this value or do not print this number
on their labels at all! The higher the average voltage, the faster top speed
your motor will have. Average voltage is most important to people who race in
stock oval classes.
Internal Resistance - The resistance of
the cell's internal structure. A cell's internal resistance is a key factor in
the amount of 'punch' it can provide. The lower the internal resistance, the
quicker the energy can be released from a cell, giving you more "bottom
end" power. This number is most important in off-road, touring car, and
small tight oval tracks where fastest acceleration is needed.
Discharge Cutoff Time - Number of
seconds before terminating the average voltage calculation. Make sure this
number is on the cell and set to 5000 (default setting) Team Orion also has a
great battery question page that can be found here.
What temperature in Farenheit should a
battery reach when being charged by a peak charger?
GP3300 - 125 Degrees
Panasonic 3000 - 108 to 115 Degrees
Sanyo 3000HV and 3300 - 120 Degrees
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