View Full Version : Pic Battery Charger

- 9th August 2004, 07:35
I have a PIC circuit that flattens it's power source (9 volt battery) after a few days.

I would like to modify the circuit so that if an external dc voltage source is connected (say 12 volts) the PIC will sence it and then start charging the nicad battery.

Is it possible to have the pic charge it's own power source? What considerations should be made when charging a nicad?


- 24th October 2004, 02:52
This thread has been stuck in a posting queue until it got flagged today!

If you have a 9v NiCad, and you plug in a 12v supply, then the PIC need not have anything to do with it. A simple Diode to block the 12v from directly connecting to the Battery with a Resistor across it to determine the charging current.

Ni-cads are a little wimpish and don't like being mistreated (chose NiMH's for a more robust device). If the 12v Supply is likely to be left connected for any length of time (ie sevaral days), simply select a Resistor that will give you a trickle charge rate between say 5mA and 8mA.

- 4th October 2006, 10:04

i want to produce a battery charger (using PIC16HV785) like that "rich DelRossi" worked on it: (its application note from Microchip)


and i need its BASIC source file. its source file is in assembly language.

can anyone help me?

with best regards, Mostafa

- 20th October 2006, 02:02
Would it be possible to take this one step further and produce a UPS?

I have a bank of 4x 100A Deep Cycle Lead Acid batteries and 2x 3000W 12V DC to 120V AC invertors.

I was hoping to put 2 batteries on each invertor and make some sort of charging system to go between the batteries and the invertors.

I would like to put a PIC with either RS232, RS485, USB or even LAN in the charger to interface with a computer and an LCD to display the current power source (either AC or the Batteries) as well as how much power (either battery capacity or time) is remaining to allow for safe shutdown of the computers.

I figured by using the AC invertors and a good 30A AC Power Supply might help make the project a bit easier. I would just have to make the interface between the power supply, batteries and invertor.

Any help pointing me in the right direction would be greatly apreciated.


- 5th November 2006, 19:23
I want to build a Lead Acid Battery Charger with PIC16F785. I find that a "PS 200 Powrer Tools" from Microchip site conrol a schematic of charger of the Application Note.

- 7th September 2011, 23:53
hi Squibcakes,could you solve this problem.because I have same problem with same project.

- 8th September 2011, 03:01
Just so you know, Squib posted on 9th August 2004. :)

- 22nd January 2012, 05:56
Moved from Schematic.