A new hardware implementation for the Advanced Charger or Universal Charger (the two firmwares are completely compatibles) is proposed on this page. This new hardware has the same basic functionning of the old versions but overcomes some limitations and add some new features. The main blocks of this new hardware are the following (at the end of the hardware development I will publish a detailed illustrated "book" on how to build an "Universal Charger"):


The selected charger enclosure is the 1598ESGYPBK from Hammond. This case has a dimensions of approx. 160x160x80mm, sufficient to contain the charger (with included DC/DC converter), the display and keys, the heatsink and the fan. There is also the possibility to put inside the AC/DC converter in order to have a complete solution from the 220V. This case is composed by two parts (upper and lower) and two panels (front and rear). The two panels are not used for charger building because they will be substituted by a pre-milled PCB of the same tickness, realized together the PCB for electronics mounting.






These panels are the front and rear of the charger. They substitutes the ones shipped with the 1598E case. This panels are fabricated in FR4 with 1.6mm thickness (the same of 1598E panels) and finishd with a black solder resist in order to give the same estetic effect that the original pieces. An adhesive label will be developed for better front panel estetic result.
The front panel has the milling for:

• 16x2 display with led backlight
• 2+2 - 4mm socket for battery force and sense connection
• 4 keys, round shaped with a diameter of 12mm
• One D-sub 9 pin female (socket) connector

The rear panel has the milling for:

• 70mm,12Vdc fan cooler
• 2 - 4mm socket for 12VDC power supply
• Air inlet port for heatsink forced cooling

The front PCB is designed for display, keys and connectors mount. The front PCB will be fixed to the front panel with 4 screws M3 and the right spacers fro display and keys alignement are the types of 10mm height . The front panel PCB has these main components:

• Display generic, 16x2, 80x36mm, 16 pin connector upper-right
• Keys MCDTS-2 from Multicomp. (Farnell 9471650)
• Blue key cap, for UP/DN keys. (Farnell 9561528)
• Green key cap, for OK keys. (Farnell 9561501)
• Orange key cap, for RESET keys. (Farnell 9561498)

Other components are the D-sub 9 pin connector (socket) and a 5W 47Ohm resistor for display backlight (LED type).




The charger is directly derived from the Advanced Charger. The grounding diagram has been improved allowing the analog to digital conversion to be referenced directly on the battery negative pole. The current and voltage measurement are performed using a 4 separated wires.
The main parts are the following:

• PIC16F876A PIC microcontroller clocked at 20 MHz, 5 MIPS effective rate
• Discharge mosfet (TO247) and Charge mosfet (TO220) can be generic type
• Current pick-up: the PCB is compatible with both LTS25-NP and ACS750
• MAX232 or equivalent for serial communications
• Generic electromagnetic buzzer with a diameter of 12-14mm and pin spacing of 6 or 7.6mm.
• The main PCB for the charger is a single sided, 1.6mm tick printed circuit board.

The heatsink and fan cooler are a very important assembly for the performances of the charger. The selected heatsink is a standard extrusion from Aavid thermalloy, fixed with spring fasteners to the mosfet case (no screws and no holes). This heatsink as a thermal impedance of 0.44 celsius degrees/Watt (in forced air cooling) allowing the dissipation of about 300W. The fan cooler is 12Vdc type, generic brand, 25mm max tickness, 70mm overall dimensions capable to an air flow of 900l/min.




The most "difficult to find components" will be available directly from this website. In a few weeks we can provide the following items:

• Enclosure 1598ESGYPBK
• Front and rear pre-milled panels
• Front and Main single sided PCB
• Keys and key caps
• ACS750 current pick up