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Advanced Charger HV

General description

This charger has the same hardware of the Advanced Charger but can charge/discharge up to 19 cells.

The advanced charger HV is based on a hardware pratically identical to the non HV version: for this all the material (from the schematics to the PCB) can be dowloaded from the Advanced Charger version. The only differences between the two models are below listed with a detailed description.

Minimal changes

The minimal change for a complete high voltage charger are the following:
  1. Power supply with a 24V source (Current equal to maximum charge current).
  2. Change the R6 with 12 KOhm, 1% value.
  3. Heat sink the 7805 regulator.
  4. Change the fan cooler with a 24V model.
  5. Reprogram the PIC with the newch_HV.HEX file (see "files" section).
  6. Start the charge/discharge of your 14-cells pack!!!.

Change the value of R6 resistor to 12 KOhm

The resistor R6 and R5 are the input partitor for the battery voltage. This resistor in the Advanced Charger has a 33KOhm value for an input range of 12V, in the HV version this resistor has a value of 12KOhm for 24V input range. If the user uses others values or want to take into account the resistor tolerances can use the "CUSTOMIZATION" section in the assembler file and enter the exact value for these resistors. In this case the file must be recompiled.

Heat sink on 7805 regulator

If the power supply voltage is above 15V it is better to have an heat sink on the 7805 regulator in order to prevent excessive temperature on this component.

Change of the power supply

The power supply must be changed following the number of the cells to be charged. A simple rule for this is to multiply the number of cells for 1.6V and add 1.5V: with this rule the power supply of 24V is sufficient for 14 cells. This depends obviously from the cell voltage (high quality cells have a higher voltage): for this is necessary to try the charge process and check if the charge current is always at the set value.

Change of the fan cooler

The fan cooler must be changed because the PC fan has 12V power supply and does not work at 24V. The user can buy directly a 24V fan or lower the voltage on the fan with a resistor or regulator.

Firmware improvements

The improvements introduced in the HV firmware are the following:
  1. In this version the R5 and R6 resistor values are moved in an assembler code separated section named "USER CUSTOMIZATION" for easier editing.The assembler file must be recompiled and the PIC reprogrammed in order to make effective the change of this parameter.
  2. Another improvement possible is the setting of the maximum current when in "power supply" mode. This parameter is present in the "USER CUSTOMIZATION" section and is an integer representing the max amperes delivered to the load. The assembler file must be recompiled and the PIC reprogrammed in order to make effective the change of this parameter.
  3. The buzzer tone frequency is another customizable constant. This parameter is present in the "USER CUSTOMIZATION" section and is useful when the charger must drive a buzzer with a "resonant" frequency different from 2KHz. The assembler file must be recompiled and the PIC reprogrammed in order to make effective the change of this parameter.
  4. The buzzer tone at the end of the charge or discharge process has a fixed duration of about 20 seconds.
  5. The run-time firmware has a unique change in the setting of the cell number: this number can be from 1 to 19.

Charger profiles manager

This applicative allow the management via personal computer of the battery profiles stored into the Advanced Charger.

This applicative program allow the user to manage the battery pack profiles stored into the Advanced Charger. The program works when connected via a standard 3-wires serial cable to the charger, and when the charger itself is in "PC Management" -> "EEprom update". When the program is started check immediately for the charger connection: in case of no communication display a generic "LINK ERROR" message on the last line: to solve this problem check carefully the cabling and select the right communication port on the selection box located just below the "SAVE" button. If the communication has been established the first profile stored is presented on the user area.

The profiles selection area (the 7 large buttons) allows the user to display and check individually all the profiles stored on the charger. When the user display a particular profile can edit directly the values (check carefully for the data format), update the charger internal profiles (via "ADV Update" button), save on the hard disk the profile ("SAVE" button), recall an previously stored profile ("LOAD" button).

The user can also select the HV (1-19 cells) or the standard (named LV on the program) (1-9 cells) Advanced Charger configuration via dedicated selection box, just below the "LOAD" button.

Advanced Charger monitor

Program for charge/discharge waveform monitoring

This applicative program allow to view, monitor and store the main waveforms for the battery pack charge and discharge. The user can change the configuration parameters used in the Advanced Charger changing the HV_monitor.ini file released with the applicative. The value of R5,R6 and ISENS (as named in the Advanced Charger firmware) can be customized. The default values are for the Advanced Charger HV:

Current scale=25000

The program, when started, waits for the serial communications from the Advanced Charger: when the serial stream comes out from the charger the display is updated. The user can change the COM port number from the computer available list. The upper row contains the values of voltage, capacity and current as graphically displayed in the diagrams.
The user can record the values in a separate file pressing the button "RECORD on FILE". The file is created with the standard name "monitor[hour][min].txt" and is formatted for quick spreadsheet import.
The user can zoom the waveforms selecting a monitor region with the left mouse key pressed from the up left corner to the bottom right corner. The "zoom all" function is performed selecting a window from the bottom right to the up left, always with the mouse left key pressed. The "pan" is performed with the mouse right key pressed.

Nov 5, 2013, 1:01 PM
Nov 5, 2013, 1:02 PM