Aim of this project is to build a battery charger and discharger with the minimum cost, but without compromises on the quality of the charge and discharge process.

Charger characteristics:
- Current setting and control fixed, in two independent profiles for NiMh and NiCd
- Delta peak voltage for end of charge detection (NiMh and NiCd)
- Two technology (NiMh and NiCd) peak threshold setting
- Timeout period (1h) embedded in the PIC firmware
- Number of cells selectable modifying a single resistor

Discharger characteristics:
- Current setting and control fixed in two independent profiles for NiMh and NiCd
- Cut-off cell voltage embedded in the PIC firmware (NiMh and NiCd)

The general instrument features are the following:
- Very compact construction for direct power dissipator mounting
- Single key for settings, double LED for operation status
- Automatic charge, discharge and discharge then charge operations
- Very low cost

The cost reduction is achieved sensing the charge or discharge current through a cheap ceramic 6W resistor. This resistor is not very critical because the current sensing can be trimmed in a second time. All the circuits are reduced to their minimums in order to have a very high parts reduction and consequent cost breaking. The only active parts, except the two mosfets is the PIC micro that manages all the activities and controls the charge and discharge process. The total cost is under 10€ and for this reason can be replicated for charge series of battery packs or for single cell charge/discharge. The current settings are calculated in order to complete a cycle (discharge the pack and recharge completely) within an hour for the common used battery packs (2400mAh for NiCd and 3300mAh for NiMh). In the file download section of this project you can find a collection of firmware programming files for most commonly used battery parameters.