Using the charger to run a deep discharge
|I have now had enough experience with the deep discharging, and have seen enough data showing the improvements it can bring, that I will explain the procedure, so that people that have found marginal recovery of their pack, can explore this process.|
Of course this process will allow some cells to fully discharge, and even reverse charge, which seems to be ok for low currents and short periods of time.
The procedure used is a bit cumbersome, as it was not anticipated when we wrote the code that deep discharging would be as useful as it is starting to be.The recently released V 3.01 of the code will have the deep discharger automated and will be a one press automatic procedure.
Of course the charger needs to be running at least V 2.4 code and have the discharger accessory.
The following procedure, for simplicity sake requires that you precharge the pack with a regular mode 1 or mode 2 charge before starting.
Connect the discharger and the charger to the battery pack, either in the car or on the bench.
set the charger run mode to mode 6(run mode key, then edit/display to change the mode, and edit/display to save the new runmode)
Now we need to setup the following charger variables, by scrolling to them and using edit/display to change them to the indicated values.
SampleTime* = 60 (will do a thorough recharge to plateau)
C-DcyclesMax* = 1 (will do single discharge cycles)
This variable will be adjusted after each of the discharge recharge cycles completes.
These values are simple suggestions based on a 144V nominal pack and you may want to start at a higher value if the pack you are conditioning is a 158V HCHII or 200V Prius pack
MinDischrgV * cycle 1 set to 100V
cycle 2 set to 75V
cycle 3 set to 50V
Press the setup key 2 times, and wait for the option display to show the 8 options selection.
press the left arrow (or the right arrow 7 times) to move the curser all the way to the right "Charge B4 dischg" position.
Press down arrow to change option 7 to "NoPrecharge."
Press the left arrow 3 times to move to the "Tech Edit Off" option, and press the down arrow.
This will take you right to the password entry display, where you will enter the password (contact me via e-mail for the password)
When finished entering the password, hit edit/display again, and you will be taken out of the setup, and will be ready to start the procedure.
The bottom line of the display will show "HCDisPWth* 2000", indicating that you have entered the Tech Edit mode.
The results of each discharge/charge cycle will be placed into bank 0, and when you press start, the previous data will be cleared, so be sure to write down the data from bank 0 cycle 1 before adjusting the MinDischrgV * and starting the next deeper discharge cycle.
At this point, you should see the Battery volts on the top line of the display, and have the discharger plugged in.
Press the start key
Depending on the battery voltage,and the code version you are running, you will see different prompts.
If the voltage is low (should not be the case as you were supposed to precharge the pack prior to starting the procedure), you could see the message "MDischgV too low
then after a short delay you will see
"[STOP] to Cancel
[Start to Disch "
While this message is showing, press start again.
On code V2.8 and up, a message
"Initial V match
? press DOWN now"
will show, do nothing, and the discharger should come on, and the discharge part of the cycle should start.
The display will show
Batt Volts XXX.X
Now that the discharge is running, press the test key, and the bottom line of the display will show
DischTEST to indicate that you are in the deep discharge mode.
The pack will discharge down to the set MinDischegV* value and then recharge and stop, with the results in bank0 cycle 1.
As the discharge passes the point where it would have stopped in the normal discharge mode, the display will show Dischrg****, and the charger will beep continously to warn that you are in this mode.
Recode the data from bank0 cycle 1, lower the MinDischV* and start the discharge again.
The tech edit no precharge, and deep discharge test modes will be remembered from cycle 1, so once the second and third cycles are running, you do not have to set any of those again.
All will be reset to default normal operation when the charger is powered off.