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A BETTER BATTERY CHARGER

Part 2: Hardware and Software Implementation
by Thomas Richter

Start ý The Buck Converter ý Voltage Reference and Battery Temperature ý AT90S2333 Battery Charger ý ATtiny15 Battery Charger ý Charge Current ý Software Implementation ý User Settings ý Source Code ý INT Battery Function ý The Stable_ADC Function ý BC.H ý B_DEF.H ý Charge MethodýSLA.C ý Charge MethodýNiCd.C and NiMH.C ý Charge MethodýLilon.C ý Suggested Improvement ý Sources and PDF

CHARGE METHODýNiCd.C and NiMH.C

NiCd and NiMH battery types are charged with a constant current. In fast-charge mode, this current is set to 1 C, and in trickle-charge mode, it is C/40. The charging is terminated by the voltage drop (ýdV/dt) method for NiCd batteries and is terminated by the temperature rise (dT/dt) and voltage drop (ýdV/dt) methods for NiMH batteries. Maximum charge voltage (dT/dt) and maximum charge time are used as backup termination for both batteries. And, temperature rise is another backup termination for NiCd batteries.

In case the battery is fully charged, the charge status is automatically changed to trickle-charge, causing the program to jump to the trickle_charge() function (see the Charge Parameter Summary document).

The fast_charge() function for NiCd batteries can be seen in Figures 10, and in Figures 11 for NiMH batteries. And, the trickle_charge() function for NiCd batteries can be seen in Figures 12 and in Figure 13 for NiMH batteries.

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